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5. Dysphagia, Aspiration, and Nutritional Interventions for Patients with Acquired Brain Injury

Penny Welch-West M.Cl.Sc. SLP, Pavlina Faltynek MSc, Amber Harnett MSc Magdalena Mirkowski MSc MScOT OT Reg.(Ont.) Jo-Anne Aubut BA Robert Teasell MD

Abbreviations

ABI         Acquired Brain Injury
BCAA     Branched-Chain Amino Acids
BSE        Bedside Swallowing Evaluation
EN          Enteral Nutrition
FEES       Fiberoptic Endoscopic Examination of Swallowing
FIM        Functional Independence Measure
GCS        Glasgow Coma Scale
GH          Growth Hormone
ICP         Intracranial Pressure
ICU        Intensive Care Unit
IGF-I      Insulin-like Growth Factor-I
LOS        Length of Stay
MBS       Modified Barium Swallow
MEBD    Modified Evans Blue Dye
NPO       Nothing by Mouth
PMV      Passy-Muir Speaking Valve
PN          Parenteral Nutrition
REE        Resting Energy Expenditure
SLP         Speech-Language Pathologist
TBI          Traumatic Brain Injury
TPN       Total Parenteral Nutrition
VMBS    Videofluoroscopic Modified Barium Swallowing
WST       Water-Swallowing Test

Key Points


Oral hygiene results in a significant decrease in dental plaque.

Maintaining good oral hygiene during hospitalization has been shown to reduce the risk of nosocomial infections and pneumonia post ABI.

The evidence regarding which method of feeding (EN or PN) is optimal to deliver nitrogen, meet required energy expenditures, nutritional goals and prevent complications (e.g. diarrhea and pneumonia) is conflicting.

Enteral nutrition with high protein formulas may improve FIM motor and cognitive scores and result in less weight loss.

For those with ABI being provided with enteral nutrition, energy expenditure levels may be beyond those predicted by equations.

Early enteral nutrition may be more beneficial than standard or late enteral nutrition for several patient outcomes post ABI.

There may be an increased risk of developing pneumonia in ventilated stroke and head injury patients fed by a nasogastric tube.

Surgical feeding tube placement strategies can reduce the number of unnecessary surgical feeding tubes. 

There is conflicting evidence as to whether immune enhanced enteral feeding solutions reduce infection rates, ventilator dependency, GCS, and hospital length of stay in patients post ABI.

The use of metoclopramide to aid in gastric emptying may not be effective post TBI.

Parenteral nutrition with a continuous infusion of insulin may lower blood glucose levels in ABI populations.

Early parenteral nutrition support of patients with ABI may improve immunologic function.

Further research is needed to clarify the effect of combined (EN + PN or EN or PN alone) feeding routes on nitrogen balance and albumin levels post ABI.

Combined enteral-parenteral nutrition post ABI may lead to nutritional independence by 6 months post injury.

Zinc supplementation in the immediate post-injury period may improve neurological recovery and visceral protein concentrations, but not mortality rates, in patients with ABI.

Growth hormones may enhance nutritional repletion, however, the evidence is conflicting regarding improvements in nitrogen balance, in patients post ABI.

High-protein nitrogen feedings may restore nitrogen losses post ABI.

Branched-chain amino acid supplementation may improve disability scores in patients with ABI.

Introduction

After an acquired brain injury (ABI) a wide range of swallowing disorders may occur. Focal and diffuse cortical and brainstem damage may impair swallowing ability, leading to the development of dysphagia and aspiration (Morgan & Ward, 2001). Dysphagia is defined as difficulty or discomfort with swallowing. Aspiration is defined as the entry of material into the airway below the level of the true vocal cords. The two terms are not synonymous, as many patients with dysphagia do not aspirate, although, they are closely associated (Morgan & Ward, 2001). Reported rates of aspiration post ABI vary in the literature, however, trends illustrate a decrease in the incidence of aspiration over time, particularly beyond 3-month follow-up (Kim & Suh, 2018; Morgan & Ward, 2001). This module will discuss dysphagia, aspiration, as well as nutritional interventions for individuals post ABI. ABI specific literature related to dysphagia, aspiration, and nutrition is limited. For this reason, some stroke literature is included as supplementary information. Generalizations applied from the stroke literature to individuals with ABI should be approached with caution. In 2016, a set of clinical practice guidelines for the rehabilitation of adults with moderate to severe TBI were developed by the Ontario Neurotrauama Foundation and INESSS. A portion of these guidelines focus on dysphagia and nutrition, which can be accessed here. Many of the recommendations in this section were based off the evidence found throughout this module.

Swallowing is implicated in both dysphagia and aspiration. Swallowing has four sequential coordinated phases which are summarized in Table 5.1 and illustrated in Figure 1.

Table 5.1 The Four Phases of Normal Swallowing (Platt, 2001)

Figure 5.1: The phases of swallowing

5.1 Dysphagia Post ABI

Dysphagia post ABI has been attributed to pharyngeal muscular dysfunction and lack of coordination, secondary to central nervous system loss of control. The reported incidence of dysphagia among individuals with brain injury varies considerably, due to differences in the timing and method of assessment, as well as the initial level of severity. Although the incidence of dysphagia can be high following ABI, swallowing function frequently improves in this population over time.

Rates of dysphagia in ABI are variable, with the literature ranging between 26% and 70% (Cherney & Halper, 1996; Cherney, 1989; Field & Weiss, 1989; Halper et al., 1999; Mackay et al., 1999; Schurr et al., 1999; Winstein, 1983). Many of these rates are determined at hospital admission, however, Winstein (1983) reported that at the time of discharge, 84% of those patients admitted with swallowing problems were eating orally. At follow-up, in the outpatient clinic, this number increased to 94%. The most common swallowing problems among patients with ABI included prolonged oral transit (87.5%), delayed swallow reflex (87.5%), valleculae pooling (62.5%), and pyriform sinus pooling (62.5%) (Field & Weiss, 1989). In a study by Mackay et al. (1999), other swallowing abnormalities included: loss of bolus control (79%), reduced lingual control (79%), decreased tongue base retraction (61%), delayed trigger of swallowing reflex (48%), reduced laryngeal closure (45%), reduced laryngeal elevation (36%), unilateral pharyngeal paralysis (24%), absent swallow reflex (6%), and cricopharyngeal dysfunction (3%). For these studies, the most common factor impacting swallowing problems was cognitive functioning (Mackay et al., 1999; Winstein, 1983). Spontaenous jaw muscle activity has also been observed in those with an ABI at rates as high as triple as those compared to healthy controls (Kothari et al., 2018), which can result in further impairment as a result of an ABI.

5.1.1 Risk Factors for Dysphagia Post ABI

Typically the more severe the brain injury, the more severe the swallowing problem (Logemann, 2013), however, the relationship between injury severity/characteristics and the nature of the swallowing disorder needs to be further studied. Within the literature, many have attempted to identify the factors that may affect the presence and severity of dysphagia post ABI (Cherney & Halper, 1996; Halper et al., 1999; Mackay et al., 1999; Morgan & Mackay, 1999). For example, injuries that result from translaryngeal intubation or tracheostomy may contribute to prolonged swallowing dysfunction in patients with ABI (Morgan & Mackay, 1999), but their etiology is secondary compared to primary dysphagia.

5.2 Aspiration Post ABI

When assessing the patient for signs of aspiration, a videofluoroscopic swallow study or, as is sometimes called, a modified barium swallow (MBS) may be undertaken. Each of these tests require the patient to swallow liquids or solids of various consistencies (from thin to thick, or thick to thin) and examines the path taken by the bolus during the swallow is observed. This procedure allows for observation of any structural or functional anomalies as well as determining whether aspiration occurs.

Rates of aspiration within the literature range from 25% to 71% depending on the sample surveyed (Mackay et al., 1999; O’Neil-Pirozzi et al., 2003b; Schurr et al., 1999). Terre and Mearin (2009) followed 26 patients with traumatic brain injury (TBI) who aspirated (35% were silent aspirators – no cough/throat clear response to aspiration), for one year.  With silent aspiration there are no overt signs that an individual has aspirated, and the individual themselves may not be aware that either solids or liquids have entered their airway or lungs (Terre & Mearin, 2009). At 3, 6, and 12 months, the number of patients who aspirated continuously declined, such that aspiration was present in only 6 of the 26 patients by the end of the first year (Terre & Mearin, 2009). For the majority of patients, the most significant changes were seen at the 3-months post evaluation. Relating to assessment, O’Neil-Pirozzi et al. (2003b) studied 12 patients with tracheostomy who also had severely disordered consciousness and found that an MBS was successfully completed with all of them. Consequently, these more severely impaired patients with TBI remain potential MBS candidates. In terms of potential treatment for aspiration, a study by Steele et al. (2013) found that patients had improvements on measures of tongue pressure and reduced penetration aspiration after the completion of a 24-session tongue-pressure resistance training program. Increased tongue strength may therefore be seen as beneficial in improving swallowing and isometric tasks. Studies examining interventions for aspiration do exist in evidence-based literature, though no studies met our inclusion criteria. For those who do develop difficulty with swallowing post injury it is reassuring to note that the majority make good gains within the first year.

5.2.1 Risk Factors for Aspiration Post ABI

Aspiration should be suspected when the patient with an ABI has any of the following: a complaint of trouble swallowing, an abnormal chest x-ray, congested vocal quality, or a delay in voluntary initiation of the swallow reflex and coughing during or after swallowing (Horner & Massey, 1988). While all patients with ABI have the potential to aspirate, there are risk factors that place some patients at higher risk (Table 5.3). Initial severity of the brain injury appears to be the strongest predictor of dysphagia-related aspiration. Therefore, the risk of dysphagia-related aspiration is proportional to the initial severity of head injury. Further, patients with severe ABI, neurogenic dysphagia and a tracheostomy are at a particularly high-risk of aspiration (Morgan & Mackay, 1999). The negative effects can be minimized by ensuring the use of appropriately sized tracheostomy tubes and by avoiding over-inflation of any cuff (Tolep et al., 1996).

5.2.2 Silent Aspiration

Silent aspiration is defined as “penetration of food below the level of the true vocal cords, without cough or any outward sign of difficulty” (Linden & Siebens, 1983). The incidence of silent aspiration among individuals with ABI has not been well documented. One reason for this, is that aspiration cannot always be diagnosed by a bedside examination, as patients may aspirate without showing outward signs. Furthermore, detailed clinical swallowing assessments have been shown to underdiagnose or miss cases of aspiration (Horner & Massey, 1988; Splaingard et al., 1988). Silent aspiration may be missed in the absence of an instrumental assessment, such as a MBS or fiberoptic endoscopic examination of swallowing (FEES). Silent aspiration should be suspected in patients with ABI who have recurrent lower respiratory infections, chronic congestion, low-grade fever, or leukocytosis (Muller-Lissner et al., 1982). Clinical markers of silent aspiration may include a weak voice or cough, or a wet-hoarse vocal quality after swallowing. Patients who silently aspirate are considered to be at increased risk of developing more serious complications such as pneumonia, which is discussed in more detail in the next section.

Lazarus and Logemann (1987) identified aspiration in 38% of their ABI sample and found that many of these patients, despite aspirating, did not produce a reflexive cough and required prompting to clear aspirated material. In another study, approximately 33% of the subjects silently aspirated and issues with aspiration seemed to resolve within the 12 month duration of the study (Terre & Mearin, 2009).

5.2.3 Pneumonia and Aspiration Post ABI

Aspiration of small amounts of saliva occurs during sleep in almost half of healthy subjects (Finegold, 1991; Huxley et al., 1978). The presence of aspiration alone is not sufficient to cause pneumonia. Aspiration pneumonia is thought to occur when the lung’s natural defenses are overwhelmed. This may occur when excessive and/or toxic gastric contents are aspirated, leading to a localized infection or a chemical pneumonitis. Patients with reduced levels of consciousness, a tracheostomy, gastric reflux or emesis, nasogastric tubes (due to mechanical interference with the cardiac sphincter), or a compromised immune system are at increased risk for the development of aspiration pneumonia (Finegold, 1991). In individuals with severe TBI, Langmore et al. (1998) identified the following factors as predictors of pneumonia: dependence in self-feeding and oral-care, the amount of tooth decay, the need for tube feeding, greater than one medical diagnosis, smoking, and the total number of medications. In a study by Vejdan and Khosravi (2013), significantly fewer patients with head injury experienced nosocomial pneumonia when they received flexible bronchoscopy and bronchoalveolar lavage in combination with routine methods compared to routine clearance procedures alone (14% versus 34%, p=0.03), demonstrating that it is possible to treat aspiration.

The clinical criteria used to define aspiration pneumonia varies between studies, impacting the reported incidence. Due to the absence of ABI specific studies, the criteria used within the stroke literature is provided in Table 5.4.

Discussion

Within the TBI population, there are significant gaps in the literature in this area, thus we rely on data from stroke populations to infer an understanding of the relationship between dysphagia, aspiration and aspiration pneumonia. In stroke, an association between pneumonia and dysphagia/aspiration has been reasonably well-established, in that the presence of dysphagia and aspiration has been associated with an increased risk of pneumonia (Dziewas et al., 2004).

Hansen et al. (2008) explored the risk factors associated with pneumonia in patients with severe TBI. They found that pneumonia was more common among individuals with low levels of consciousness and for those with a feeding or tracheotomy tube, similar to patterns seen in stroke. Glasgow Coma Scale (GCS) scores and Rancho Los Amigos scale scores were also associated with increased risk of pneumonia in individuals who had lower GCS scores, as well as individuals with lower Rancho Los Amigo Scale scores. These two scales, along with the Functional Oral Intake Scale and Functional Independence Measure (FIM) scores were found to be predictive of return to an unrestricted diet (Hansen et al., 2008). Further, Hui et al. (2013) found that patients were more likely to develop pneumonia if they were older, on ventilation for a longer period of time, suffered blunt trauma, and/or had suffered a severe TBI.

5.3 Assessment of Dysphagia and Aspiration Post ABI Using Stroke Models of Care

Following a head injury, a thorough assessment of swallowing is often required. Assessments may include a bedside clinical evaluation and/or a radiological procedure such as the MBS/videofluoroscopic swallow study or a FEES most often completed by a SLP. Assessments should be completed at various times throughout rehabilitation admissions. Established deficits, hydration or nutritional needs, or any risk factors for swallowing difficulties must be taken into account when making dietary decisions. Once again, there are limited studies discussing assessment of dysphagia post ABI so stroke models of care will be highlighted.

To be clinically useful, screening tests need to be valid, reliable, easy to use, non-invasive, quick to administer (15-20 min), and pose little risk to the patient. Although many screening tools have been developed it is unclear how many of them are used in institutions beyond those where they were initially developed. Many institutions use informal processes, or simply restrict all food and drink intake until an assessment has been completed by a SLP.

Although ERABI focuses primarily on interventional studies, information pertaining to assessment tools used in dysphagia practice have been included within this section to increase its clinical relevance. Although many of these tools are used in practice with ABI populations, none have been studied extensively within this population.

5.3.1 The Bedside Clinical Examination

Several forms of clinical or bedside swallowing evaluations (BSE) have been described for the purposes of screening and/or assessment. Some of these methods target specific functions or tasks, while others evaluate swallowing ability using a more comprehensive approach (Table 5.5). The clinical BSE typically involves general observations, an oral motor examination, a review of expressive language, receptive ability to understand directions, and a review of current medications (Halper et al., 1999). The protocol may or may not include a water-swallowing test (WST), and in some cases various consistencies of food and liquids. While the BSE is non-invasive and easy to perform, this method has been shown to poorly predict the presence of silent aspiration. Moreover, aspiration cannot be distinguished from laryngeal penetration using a bedside evaluation, resulting in the over diagnosis of observed aspiration and, in some cases, needless dietary restrictions (Smith et al., 2000).

The BSE is typically completed by an SLP or a professional trained in dysphagia. This examination is generally completed once the patient’s history has been reviewed by the clinician (Logemann, 1989). Clinicians are expected to make several observations: status of lip closure, oral versus nasal breathing, level of secretions, patient’s awareness of secretions, patient’s awareness of clinician’s approach, and the nature of content of initial verbalization by the patient (Logemann, 1989).

5.3.2 Water Swallowing Test

The WST originally required a patient to swallow 3oz (90ml) of water, however, smaller amounts have also been used. Although the WST has not been studied in ABI individuals, it warrants inclusion given its persistent use by health providers (especially non-SLPs) at the bedside. This sensitivity and specificity of this test has been studied extensively within the stroke population.

Stroke populations are used to illustrate the benefit of these screening tools, as research and supporting evidence specific to the TBI population is lacking. The results of a systematic review by Martino et al. (2000) evaluating the accuracy of 49 individual clinical screening tests for oropharyngeal dysphagia suggested that there was only sufficient evidence to support the value of two tests: abnormal pharyngeal sensation and the 50 mL WST. Both of these tests assessed only for the presence or absence of aspiration. Their associated likelihood ratios were 5.7 (95% CI 2.5-12.9) and 2.5 (95% CI 1.7-3.7), respectively. Evidence suggests that the number of aspirations observed increases as the amount of liquid increases (Osawa et al., 2013). Daniels et al. (2012) reviewed the sensitivity, specificity, and positive likelihood ratio of items on 17 screening tools designed to detect aspiration. Items with high sensitivity (>80%) included weak palatal movement, cough on a 50 mL and repeated 5 mL WST, dysarthria, abnormal volitional cough, abnormal voice, and abnormal pharyngeal sensation. Only 1 item (impaired pharyngeal response) was associated with a likelihood ratio greater than 10, the clinically relevant threshold. According to Nishiwaki et al.  (2005), cough/voice change in the WST was the only variable that was significantly associated with aspiration on videofluoroscopic modified barium swallow (VMBS) examination, with a sensitivity of 72% and a specificity of 67%.

5.3.3 Videofluoroscopic Modified Barium Swallow Studies

When aspiration is suspected, the Videofluoroscopic Modified Barium Swallow (VMBS) study is considered by some to be the “gold standard” in confirming the diagnosis (Splaingard et al., 1988). A VMBS study examines the oral and pharyngeal phases of swallowing, however, the patient must have sufficient cognitive and physical skills to undergo testing (Bach et al., 1989). The subject is placed in a seated position, in a chair designed to simulate the ideal/optimal mealtime posture. Radio-opaque materials of various consistencies are tested: barium impregnated thin and thick liquids, pudding, bread, and cookies are routinely used. Various aspects of oral, laryngeal, and pharyngeal involvement are noted during the radiographic examination (Table 5.6). In some, but not all cases, it may be appropriate to follow the VMBS study with a chest x-ray to document any barium, which may have been aspirated into the tracheobronchial tree. If a VMBS study is indicated and the result is positive, a second VMBS study may be appropriate in 1 to 3 months, if swallowing concerns persist.

Those patients who aspirate over 10% of the test bolus or who have severe oral and/or pharyngeal motility problems on VMBS testing are considered at high risk for pneumonia (Logemann, 1983; Milazzo et al., 1989). In many cases, it is difficult to practically assess whether 10% or more of the test bolus has been aspirated, particularly since images are seen two dimensionally. Nevertheless, the degree of aspiration seen on VMBS study is a critical determinant of patient management. Predicting whether a patient will develop pneumonia post aspiration is, to some extent, dependent on other factors such as the immune state or general health of the patient with ABI.

The VMBS assessment not only establishes the presence and extent of aspiration but may also reveal the mechanism of the swallowing disorder. Aspiration most often results from a functional disturbance in the pharyngeal phase of swallowing related to reduced laryngeal closure or pharyngeal paresis. A VMBS study is recommended in those cases where the patient is experiencing obvious problems maintaining adequate hydration/nutrition, where concern is expressed regarding frequent choking while eating, or in the case of recurrent respiratory infections. Other factors such as cognition, cognitive-communication, depression, underlying lung disease, and being immunocompromised must also be considered.

5.3.4 Fiberoptic Endoscopic Evaluation of Swallowing

Although VMBS (or MBS) studies are considered by some to be the gold standard for detection of aspiration, other clinical assessment techniques are currently used as they are more cost effective, more easily accessed, or easier to administer.

FEES, is recognized as an objective tool for the assessment of swallowing function and aspiration. FEES is a procedure that allows direct viewing of swallowing function by passing a very thin flexible fiberoptic tube through the nose to obtain a view directly down the throat during swallowing. FEES allows for the full evaluation of the swallow function as food passes from the mouth into the throat. The evaluation identifies functional abnormalities and helps to determine the safest position and food texture for the patient in order to maximize nutritional status and eliminate the risk of aspiration and unsafe swallowing.

In addition to assessing the motor components of swallowing, FEES can also include a sensory testing assessment when an air pulse is delivered to the mucosa innervated by the superior laryngeal nerve. This form of assessment is known as flexible endoscopic examination of swallowing with sensory testing.

As a result of the multiple benefits of FEES (reliability, safety, ease of administration, low cost, and lack of exposure to radiation), this tool has gained much support for the detection of dysphagia, particularly in acute stroke (Bax et al., 2014). FEES in combination with a cough reflex test and clinical swallowing evaluation may focus the criteria for the induction of candidates for FEES to make this service more efficient and productive. The selection of patients for referral to instrumental assessment may be improved by the use of these assessments together as they provide stronger evidence for the presence of dysphagia and subsequent complications among those who fail the cough reflex test (Bax et al., 2014). Furthermore, conflicting evidence from other studies suggests that an increase in the length of hospital stay is associated with increased rates of pneumonia (Finlayson et al., 2011; Wilson & Howe, 2012). However, some results suggest the opposite is true in the study by Bax et al. (2014). The authors explain that this relationship may be due to the provision of FEES leading to a higher referral rate for swallowing rehabilitation and a subsequent increase in length of stay. In support of this conclusion, there was an increase in the proportion of patients leaving the hospital on normal diets. Overall, the use of FEES, especially in combination with cough reflex testing, appears to benefit patient health outcomes.

A good quality randomized controlled trial (RCT) assessed the use of Facial-Oral Tract Therapy versus FEES as a standard assessment indicating the opportunity for initiation of oral feeding (Kjaersgaard et al., 2014). After excluding patients who developed pneumonia outside of the primary study criteria, there was no difference in the incidence of this respiratory infection between the two groups (3/62 Facial-Oral Tract Therapy patients; 4 of 57 FEES patients). These results were supported in a study by Barquist et al. (2001), who found that the risk of pneumonia was not significantly different between 70 patients screened with either FEES or clinical assessment, within 48 hours of endotracheal intubation. It seems that FEES, when combined, may be beneficial to some clinical non-instrumental assessments such as Facial-Oral Tract Therapy in reducing the risk of aspiration pneumonia after initiating oral feeding.

Aviv (2000) compared the incidence of pneumonia over a one-year period between patients screened by MBS or FEES for dysphagia and aspiration with sensory testing and treated based on their respective outcomes. Within stroke patients, the incidence of pneumonia for those assessed with FEES with sensory testing was significantly lower compared to those assessed with MBS. The authors speculated that one of the reasons for the lower incidence might be due to the sensory testing component of the FEES examination, absent from the MBS evaluation, which was used to more effectively guide management.

Rather than attempt to compare the accuracy of swallowing abnormalities assessed between VMBS and FEES evaluations, Leder and Espinosa (2002) compared the ability of six clinical identifiers of aspiration (dysphonia, dysarthria, abnormal gag reflex, abnormal volitional cough, cough after swallow, and voice change after swallow) with FEES assessment to determine the accuracy of predicting aspiration risk following stroke. Their results suggest that the ability of the test to correctly identify patients not at risk of aspiration was poor using clinical criteria (low specificity). However, two studies conclude that FEES is the gold standard to assess the accuracy of either the WST and/or pulse oximetry to detect aspiration within the stroke population (Chong et al., 2003; Lim et al., 2001).

5.3.5 Pulse Oximetry

Pulse oximetry has also been suggested as an additional method of detecting aspiration, based on the principle that aspiration of food into the airway leads to bronchospasm or airway obstruction, which leads to a reduction in oxygen saturation. This technique is non-invasive, requires little patient cooperation and is easy to obtain, however, its accuracy in detecting aspiration is unproven and it remains uncertain whether oxygen desaturation can predict aspiration. Wang et al. (2005) reported no significant association between the reduction in oxygen saturation and aspiration, identified simultaneously by VMBS, among 60 patients with dysphagia due to stroke and nasopharyngeal cancer. While Collins and Bakheit (1997) reported that pulse oximetry could be used to detect a high proportion of stroke patients who aspirated on the VMBS study.

Although pulse oximetry is a quick and non-invasive method to detect aspiration following stroke, its association with oxygen desaturation has been inconclusive. Generally, its performance when measured against VMBS studies has been poor due to its low sensitivity and specificity (39%-87%) (Collins & Bakheit, 1997; Smith et al., 2000; Wang et al., 2005). Therefore, it is unclear whether it is a clinically viable tool for the detection of dysphagia and aspiration.

5.3.6 Blue Dye Assessment for Swallowing

The blue dye assessment for swallowing has been used since the early 1970’s with patients who have a tracheostomy, however, the accuracy of the test has been questioned since the 1980’s (O’Neil-Pirozzi et al., 2003a). For patients with a tracheostomy, this assessment involves placing blue dye on the tongue or, in the case of the modified blue dye test, mixing it with water or semisolid food. If blue dye appears in or around the tracheostomy tube, or at defined intervals during suctioning, then the patient has possibly aspirated. This test tends to be relatively easy to administer, inexpensive and can be performed at a patient’s bedside. Unfortunately, research has shown that the test may have a 50% false-negative error rate in the detection of aspirated material (Belafsky et al., 2003; Brady et al., 1999; Donzelli et al., 2001). There is conflicting evidence regarding both the sensitivity and specificity of the blue dye assessment in specific population groups as well. Belafsky et al. (2003), in a study of 30 patients with tracheostomies, concluded that the use of the modified Evans blue dye test (MEBD) is beneficial specifically in patient populations who have a tracheostomy tube (82% sensitivity) and in particular those who receive mechanical ventilation (100% sensitivity). O’Neil-Pirozzi et al. (2003b), found that the blue dye test was unable to correctly identify aspiration in 20% of the study’s patients with tracheostomy and 38% of patients with a tracheostomy who were not aspirating.

Brady et al. (1999), in a study looking at the effectiveness of the MEBD test and the VMBS, found that the MEBD test was not able to detect “trace amounts” of aspiration in patients who had a tracheostomy. On the other hand, if patients aspirated more than “trace amounts”, then the MEBD was able to detect it. Brady et al. (1999) recommended that the MEBD be followed by a VMBS to rule out the possibility of trace aspiration. Although this test is used in practice with individuals post ABI, no studies were found looking at its effectiveness within that specific population, therefore, individuals who are assessed for aspiration or dysphagia using the MEBD test should be followed up with a more established test with greater sensitivity and specificity.

5.3.7 Additional Methods

In addition to conventional assessment methods, tracheal pH monitoring has been used experimentally to detect drops in pH, which may indicate aspiration. Clayton et al. (2006) reported that in 9 of 32 patients examined, there was a drop in tracheal pH following ingestion of acidic foods. Tracheal pH was monitored by the use of a sensor, which was inserted into the trachea by the cricothyroid membrane. All patients were studied following the ingestion of foods which had been considered to be safe on the basis of a VMBS examination.

Another assessment tool is voice analysis. Ryu et al. (2004) evaluated voice analysis as a means to clinically predict laryngeal penetration among 93 patients (46% of whom had suffered a stroke) using VMBS to confirm aspiration.  Of five voice parameters tested (average fundamental frequency, relative average perturbation, shimmer percentage, noise-to-harmonic ratio, and voice turbulence index), changes in relative average perturbation most accurately predicted aspiration.

Cervical auscultation, another tool to assess aspiration, is conducted using a stethoscope or other listening device (Borr et al., 2007; Leslie et al., 2007; Youmans & Stierwalt, 2005). It is believed that this type of test can provide additional information on the pharyngeal swallow in all patients without any additional costs or intrusive methods (Borr et al., 2007; Youmans & Stierwalt, 2005). Cervical auscultation was compared to the VMBS in patients being treated for dysphagia (Zenner et al., 1995). Although agreement was found between the two tests on the oral phase, pharyngeal phase, and diet management components, the VMBS did appear to be slightly more sensitive in identifying patients who had aspirated. In another study, Stroud et al. (2002) found that raters were able to identify patients who were aspirating quite easily but challenges arose when evaluating patients who were not aspirating, resulting in a significant number of false positives. Due to the limited evidence for cervical auscultation, caution should be taken when using this technique and it should not be used in isolation (Leslie et al., 2007).

5.4 Management of Dysphagia Post ABI

The careful management of dysphagia is essential for successful rehabilitation in acute brain injury patients (Hoppers & Holm, 1999). For patients with dysphagia following head injury, based on the status of swallowing function at the time of admission, three distinct types of rehabilitation programs have been described: 1) non-feeding, 2) facilitation and feeding, and 3) progressive feeding (Winstein, 1983). One goal of dysphagia treatment is to have individuals become independent in their feeding skills. It’s known that individuals with dysphagia that are fed by someone else have a 20 times greater risk of pneumonia than those who are able to feed themselves (Langmore et al., 1998).

The non-feeding program was designed as a stimulation program for very low-level patients, in order to prepare them for later feeding. It includes desensitization techniques (e.g., stroking, applying pressure, or stretching) to facilitate normal swallowing, sucking, and intraoral responses (Winstein, 1983). The facilitation and feeding program use small amounts of puree consistency food to promote normal feeding patterns (Winstein, 1983). Finally, the progressive feeding program uses specialized techniques to help the patient develop swallowing endurance by systematically increasing the amount of oral intake. This progressive feeding program continues until the patient can consume a complete meal within thirty minutes without difficulty (Winstein, 1983).

For patients who are safe with some form of oral intake, therapeutic strategies utilized in dysphagia management can be divided into two categories: (a) compensatory treatment techniques and (b) therapy techniques (Logemann, 1999). Compensatory treatment techniques do not involve direct treatment of the swallowing disorder, rather they reduce or eliminate the symptoms of dysphagia and risk of aspiration by altering how swallowing occurs (Logemann, 1991, 1999). The types of compensatory strategies include: (a) postural adjustment of the head, neck, and body to modify the dimensions of the pharynx and improve the flow of the bolus, (b) sensory stimulation techniques used to improve sensory input either prior to or during the swallow, (c) food consistency and viscosity alterations, (d) modifying the volume and rate of food/fluid presentation, and (e) use of intraoral prosthetics (Logemann, 1999). Conversely, therapy techniques are designed to alter the swallow physiology (Logemann, 1999). They include range-of-motion and bolus handling tasks to improve neuromuscular control without actually swallowing. They also include swallowing maneuvers that target specific aspects of the pharyngeal stage of the swallow. Medical and surgical management techniques are included in this category (Logemann, 1999), with these interventions typically only introduced once trials with more traditional behavioural treatment techniques have proven to be unsuccessful.

Several interventions have been investigated for the treatment of dysphagia. Included among these are vocal fold adduction exercises, range of motion exercises for the lips, tongue, and jaw, and chewing exercises (Logemann, 1993). Many of these exercises, although tested within stroke or other populations, have not been tested specifically within the ABI population. As there is a need for more clinical data supporting dysphagia treatments within an ABI population, this section will focus on research based on both ABI populations that did not meeting inclusion criteria, as well as stroke patient data and will discuss the literature supporting dysphagia management in a stroke population.

5.4.1 Oral Motor Exercises

Exercises introduced with those who have developed a swallowing disorder include various oral motor exercises, such as range of motion exercises for the tongue and the pharyngeal structures (Logemann, 1998). These exercises are designed to improve strength, movement, awareness, and muscle coordination when swallowing (Kramer et al., 2007). To aid in the improvement of oral transit, exercises to assist in tongue elevation and lateralization may be implemented. Here the patient may be asked to perform very specific tongue exercises in an effort to improve speech and swallowing (Logemann, 1998). Individuals may also be asked to participate in tongue resistance exercises (pushing the tongue against a tongue blade or popsicle stick for 1 second) and bolus control exercises (to allow the patient to learn to control or manipulate items placed in the mouth) (Logemann, 1998).

5.4.1.1 Range of Motion Exercises

When participating in range of motion exercises, the individual is asked to bear down while holding his or her breath from a seated position. This exercise is not recommended for those with uncontrolled blood pressure (Logemann, 1998). It is recommended that this exercise be done 5 to 10 times each day for 5 minutes.

5.4.1.2 Vocal Fold Adduction Exercises

Vocal fold adduction exercises aim to improve vocal quality and reduce the risk of aspiration. Individuals are asked to bear down, with one hand against a chair while producing a clear voice. This is done five times. The individual is then asked to repeat an “ah” sound five times. Again, it is recommended that these exercises be repeated three times in sequence, 5 to 10 times each day for five minutes. If there is no significant improvement in swallowing at the end of one week, individuals may be asked to pull up on the seat of a chair, while sitting in it, and prolong phonation (Logemann, 1998). This exercise is recommended for those individuals whose vocal folds fail to close completely (Kramer et al., 2007).

5.4.2 Strengthening Exercises

Exercises which strengthen the muscles in the throat and neck may improve swallowing function. However, patients need to be able to physically complete the required motions without injury in order to use this treatment method (Kraaijenga et al., 2015).

5.4.2.1 The Shaker Exercise

For the Shaker exercise, patients are asked to lay flat on the floor or in bed and raise their heads high enough to see their toes. This position is held for one minute, and then the patient rests for one minute. The exercise is repeated three times. Following this sequence, the patient lifts their head, looks at their toes, and then lowers their head. This head up then down sequence is repeated 30 times. It is recommended that the Shaker exercise be completed three times per day for a period of six weeks. This exercise has been shown to have some success in improving hyolaryngeal movement (Logemann, 1998; Shaker et al., 2002; Shaker et al., 1997), however, it has not been studied specifically in the ABI population.

5.4.2.2 Chin Tuck Against Resistance

An alternative exercise to strengthen suprahyoid muscles is the chin tuck against resistance exercise. This involves two steps for participants: 1) squeezing a rubber ball by tucking the chin in for 10s (isometric) and 2) squeezing a rubber ball with the chin as hard as possible 10 consecutive times (isokinetic) (Yoon et al., 2014). A preliminary study using healthy subjects evaluating the potential use of the chin tuck against resistance exercise in populations with dysphagia concluded that this method resulted in greater maximum surface electromyography when compared to the Shaker exercise (Yoon et al., 2014). However, in order to determine the effectiveness of exercising suprahyoid muscles for dysphagia the authors stated that clinical trials are needed (Sze et al., 2016; Yoon et al., 2014).

5.4.3 Swallow Maneuvers

During the acute stage of recovery, patients may experience more swallowing difficulties than they do during later rehabilitation. Failing to address and treat swallowing difficulties in the early stages may lead to compliance issues with the recommended diets, and possible setbacks secondary to aspiration pneumonia. Overall, this can hinder the patient’s ability to participate in formal rehabilitation. Post-ABI swallowing difficulties are often the result of eating too quickly, taking large bites, cognitive impairments, and decreased swallowing sensitivity (Logemann, 1998). Swallowing difficulties can be addressed through four maneuvers but they require the patient to follow directions, be alert, and be able to exert the physical effort it takes to perform the maneuvers correctly (Kramer et al., 2007).

5.4.3.1 Supraglottic Swallow

This maneuver is meant to close the airway at the level of the true vocal folds before and during the swallow, as well as clear residue afterwards (Logemann, 1998; Logemann et al., 1997). Individuals are asked to hold their breath while swallowing and then to cough immediately after the swallow. This maneuver encourages closure of the true vocal cords in an effort to address reduced or delayed vocal fold closure or delayed pharyngeal swallow. The cough portion of this maneuver is meant to eject any objects or residue within the laryngeal vestibule.

5.4.3.2 Super-Supraglottic Swallow

This maneuver targets closure of the entrance to the airway both before and during the swallow, increases pressure generation, and aims to clear residue after the swallow is complete (Logemann, 1998). During this maneuver the patient completes the following sequence: 1) take a deep breath, 2) hold the breath while bearing down hard, 3) swallow hard while holding this breath, 4) cough immediately after the swallow and clear throat, and 5) swallow again (Logemann et al., 1997).

5.4.3.3 Effortful Swallow

Effortful swallow is meant to increase posterior movement of the tongue base (Kramer et al., 2007). This technique involves asking the individual, as they swallow, to squeeze hard with all the muscles they use for swallowing (throat and neck muscles).

5.4.3.4 Mendelsohn Maneuver

The objective of this maneuver is to address decreased laryngeal movement and discoordination of the swallow. Improvements in swallowing function are achieved through increasing the extent and duration of laryngeal elevation which increases the duration and width of the cricopharyngeal opening (Logemann, 1998). Typically, patients are asked to swallow, but as they do so, to hold their larynx (i.e. Adam’s apple) elevated for two to three seconds prior to completing the swallow.

5.4.4 Thermal-tactile Stimulation

Thermal stimulation or thermal-tactile stimulation was developed to stimulate the swallowing reflex in patients who have neurological impairment (Lazzara et al., 1986). The procedure for thermal-tactile stimulation involves having the patient open their mouth and applying a cold laryngeal mirror to the base of the faucial arches. The mirror, while being in contact with the arch, is rubbed up and down five times. For those patients who have sustained a trauma, contact will be made on the normal (non-injured) side of the mouth (Logemann, 1998). Pharyngeal swallow may not be triggered at the time of stimulation, but the purpose is to heighten the sensitivity for swallowing via the central nervous system. It is hoped that once a patient attempts to swallow, the pharyngeal swallow will be triggered more quickly (Logemann, 1998).

The use of a chilled laryngeal mirror applied to the anterior faucial pillars (three strokes per side) before swallowing was compared to 10 consecutive swallows of semi-solid boluses in 22 patients with dysphagia post stroke (Rosenbek et al., 1996). Following the stimulation, patients were asked to swallow a bolus. Results indicated that the duration of stage transition and total swallow duration was reduced following thermal stimulation (Rosenbek et al., 1996). This method requires further research before conclusions on its efficacy in post-ABI populations may be made.

5.4.5 Postural Techniques

Physically moving the patient in order to change the position of the head, neck, and/or body may assist in changing the direction of the bolus flow, thereby improving pharyngeal clearance and/or reducing the risk of aspiration. Five postures that have been shown to have some success in assisting individuals improve their swallowing function are presented in Table 5.7 below (Logemann, 2008).

For individuals with significant cognitive deficits post injury, having the patient engage in any one of these techniques may be challenging. It has been suggested that patients with oral and pharyngeal deficits consistently do the following: remain upright for 30 minutes post meal to reduce the risk of aspiration, take controlled bites/sips, alternate solids and liquids, take multiple swallows, and clear or remove food that has pocketed in the mouth (Kramer et al., 2007).

5.4.6 Diet Modification

Modification in consistency and viscosity of foods and liquids is common practice in the management and treatment of dysphagia. Unfortunately, standardization of these diets, as well as the language used to describe them has been challenged.  Although an attempt has been made to standardize dysphagic diets (McCallum, 2003), there continues to be significant variation in their use in clinical practice, and in how these diets are labelled. The following tables illustrate two examples of diets for dysphagia (Table 5.8; Table 5.9). These examples illustrate the wide variations in level of description and detail in dysphagia diets.

It should be noted that restrictions to diet and specific consistencies of food should be the last strategy examined (Logemann, 1997). Restrictions to diets and consistencies, especially thin fluids, can be very challenging for individuals (Logemann, 1997). Often patients may begin with a very restrictive diet (liquids of various consistencies – purees) and move to less restrictive diets (diced to regular foods) at a pace that has been deemed safe for that individual (Kramer et al., 2007). Asking the patient to limit the amount of food they attempt to swallow (taking smaller bites) will also help reduce difficulties with swallowing.

 

International Dysphagia Diet Standardization Initiative

In 2013 an International Dysphagia Diet Standardization Initiative committee was formed from a volunteer group of individuals in nutrition & dietetics, medicine, speech-language pathologists, occupational therapy, nursing, patient safety, engineering, food science & technology. The goal was to develop standardization in terminology used in describing dysphagia diets for individuals across age, care settings and cultures, internationally. The work by this committee resulted in the creation of what is now known as the International Dysphagia Diet Framework (Initiative, 2018).

Research efforts by Steele et al. 2018 to evaluate the International Dysphagia Diet Standardization Initiative Functional Diet Scale showed strong consensual validity, criterion validity, and interrater reliability (Steele et al., 2018). In their study, 176 respondents from 29 countries completed a web based survey related to 16 clinical cases.  They found poorest consensus with the cases “involving liquid-only diets, transition from non-oral feeding, or trial diet advances in therapy”. Perhaps more telling was the finding that “most (>70%) respondents indicated enthusiasm for implementing the International Dysphagia Diet Standardization Initiative Functional Diet Scale” in general (Steele et al., 2018).  This certainly speaks to great need for standardization of language and descriptors in providing best practices in therapeutic diet interventions.

5.4.7 Passy-Muir Speaking Valve (PMV)

Passy-Muir (Positive Closure) Speaking Valves (PMV) can improve voice quality and speech production while, at the same time, improving swallowing and reducing aspiration risks (Passy-Muir Incorporated, 2004). Aspiration is often problematic in patients who have a tracheostomy. These patients are essentially unable to achieve the apneic interval necessary for an efficient swallow. It is thought that, normalization of subglottic air pressure, achieved through placement of a PMV, reduces the potential for aspiration.

The valve may be attached to the 15mm connector found on most adult tracheostomy tubes (Dettelbach et al., 1995; Passy et al., 1993). With the PMV in place, a noticeable decrease in the amount aspirated has been observed. While wearing the valve, patients also have the opportunity to more easily express themselves verbally (Bell, 1996). Passy et al. (1993) found that patients began speaking almost immediately and their speech improved making it easier for them to communicate with hospital staff, doctors, and family. This ease of communication is very beneficial to the patient’s ability to direct their own care related to feeding, swallowing and diet preferences.

Within the literature, the benefits of the PMV have been supported. Manzano et al. (1993) found that patients experienced a decrease in secretions and showed improvement in ability to cough with the PMV in place. Further supporting its effectiveness, the volume of secretions appears to increase when the PMV is removed (Lichtman et al., 1995; Passy et al., 1993). The use of a PMV has also been shown to significantly reduce aspiration (Elpern et al., 2000; Stachler et al., 1996), provide the ability to safely ingest thin liquids (Suiter et al., 2003), improve oxygenation, decrease oral and nasal secretions, improve sense of smell, enhance airway clearance, and improve swallowing (Bell, 1996). To determine its effectiveness specifically within the ABI population more research is recommended.

5.5 Oral Care Interventions

Key Points

Oral hygiene results in a significant decrease in dental plaque.

Maintaining good oral hygiene during hospitalization has been shown to reduce the risk of nosocomial infections and pneumonia post ABI.

Oral hygiene and dental care have become an important component in treating patients post TBI (Clayton, 2012; Zasler et al., 1993). Management of proper oral hygiene decreases the medical risks associated with dysphagia and poor oral care. The actual provision of mouth care is more challenging in patients with TBI given the frequent presentation of significant cognitive-communication issues including: fatigue, reduced level of alertness, cooperation and comprehension, as well as a lack of physical recovery necessary to complete the task of brushing independently (Zasler et al., 1993). For the reasons listed, as well as improper or insufficient staff training, there may be less priority placed on providing mouth care as part of the overall care routine. It becomes important then, to provide regular education about the beneficial effects of thorough oral hygiene practices from a social integration, comfort, medical, and safety management standpoint.

Oral biofilm (or plaque) is a combination of proteins/glycoproteins and bacteria. Following oral care, oral biofilm/plaque begins forming again in as little as 15 minutes. Within two hours, bacteria have multiplied and this biofilm may even double in mass and begin forming complex networks of bacteria colonies that are able to communicate with each other. There is a four to six-fold increase in the incidence of aspiration pneumonia in patients with periodontal disease and/or poor oral care (Maddi & Scannapieco, 2013). In patients who are NPO (nothing by mouth) with enteral feeding for total nutrition there is no mechanical disruption of the biofilm through movement of food and liquid or by the tongue and oral muscles; therefore, biofilm accumulates more easily (including formation on the soft issues). For this reason, the role of thorough mouth care for patients who are NPO becomes even more critical (written communication from Dr. Greenhorn-November 23, 2012).

Unlike the general population, mouth care in patients with dysphagia is best performed before eating/drinking. The rationale is that the introduction of oral bacteria to the lungs via aspiration is more problematic than the food or liquid that is aspirated alone. Brushing before eating/drinking for patients with dysphagia means that bacteria have no opportunity to be introduced to the lungs even in “known aspirators”, thereby reducing the incidence of pneumonia (Seguin et al., 2014).

As noted earlier, many patients with TBI may be more difficult to approach with regards to mouth care. For this reason, the key elements of care must be known so care is as efficient as possible. Clayton (2012) states “education of staff regarding the importance of oral hygiene and obtaining quality oral care equipment is vital.” Currently, there is very little evidence in the literature to suggest that oral care is routinely performed, particularly when the patient with TBI is in hospital or long-term care (Kelly, 2010; Landesman et al., 2003; Talbot et al., 2005). Education in oral health and good oral care is needed to reduce the risk of dysphagia and other associated complications that can result from a brain injury. The following table presents literature surrounding oral hygiene post ABI (Table 5.10).

Discussion

In the Zasler study (1993), patients who were provided verbal oral hygiene instructions and taught to remove plaque had significantly less plaque on their teeth post intervention compared to the control group. Study authors suggest that this improvement can lead to greater integration back into society, as the potential negative consequences associated with poor oral hygiene have been addressed (Zasler et al., 1993). Verbal education appears to be sufficient to improve dental plaque control (Zasler et al., 1993). In a RCT conducted by Lam et al. (2013), multiple oral care protocols were examined including various combinations of instruction, mouth rinse and assisted tooth brushing. No significant differences were found between the three protocols when looking at the amount of oral opportunistic pathogens that developed.

Seguin and colleagues (2014), investigated the efficacy of povidone-iodine versus a placebo drug in reducing ventilator-associated pneumonia. The occurrence of ventilator-associated pneumonia, although reduced in the experimental group, was not significantly different from the control group (Seguin et al., 2014). Povidone-iodine was also shown to increase the risk of secondary infections including acute respiratory distress syndrome (Seguin et al., 2014). However, another study demonstrated reduced rates of non-ventilator hospital-acquired pneumonia among patients receiving enhanced oral care. Robertson and Carter (2013) found that patients receiving the enhanced oral care protocol had a significant decrease in acquired pneumonia when compared to the standard oral care group.

Two RCTs investigated the effectiveness of chlorhexidine gel on the development of nosocomial infections in patients assigned to the intensive care unit (Cabov et al., 2010; Fourrier et al., 2000). Both studies showed that chlorhexidine gel was effective in reducing the number of nosocomial infections and overall length of stay compared to placebo or standard oral care. Furthermore, research conducted in long-term care or acute care facilities reported a decline in mortality rates, risk for developing dysphagia, and risk of aspiration pneumonia with the introduction of an oral care program (Sarin et al., 2008; Watando et al., 2004). Patients in a nursing home who received oral care had fewer febrile days and cases of pneumonia, and fewer patients were dying from pneumonia (Yoneyama et al., 2002).

Conclusions

There is Level 2 evidence that providing oral hygiene education to patients post TBI results in a significant reduction of dental plaque, measured by the Plaque Index Score.

There is level 3 evidence that enhanced oral care may reduce rates of non-ventilator hospital-acquired pneumonia compared to standard oral care in mixed brain injury populations.

There is level 1b evidence that povidone-iodine may be effective for reducing the incidence of ventilator-associated pneumonia compared to placebo post stroke or ABI.

There is level 1b evidence that 0.2% chlorohexidine gel is beneficial for reducing nosocomial infections and hospital length of stay compared to placebo in non-ABI populations.

There is level 1b evidence that oral care may reduce rates of pneumonia, febrile days, and pneumonia-related deaths in mixed populations.

5.6 Nutritional Management

Ensuring patients with ABI have adequate nutrition is an important part of their medical management (Denes, 2004), as it has a critical impact on the patient’s recovery process and final outcome (Elovic, 2000). Denes (2004) stated that rehabilitation problems associated with severely malnourished patients with ABI include an increased occurrence of complications, a greater challenge in patient mobilization, an increased frequency for the need to operate on contractures, and a longer length of stay in a rehabilitation unit. Despite clinicians’ efforts several factors make it difficult to avoid malnutrition in patients with ABI, beginning with the metabolic changes that occur post injury (Elovic, 2000). Post ABI, the damage to the metabolic control center causes more severe and protracted systematic responses than seen in many other forms of injuries. The former is a possible consequence of the change in feedback mechanisms post injury and the brain’s critical role in triggering the metabolic response (Young et al., 1992).

Secondary to ABI, a catabolic and counter regulatory hormone (glucagon and cortisol cortical increase takes place (Loan, 1999). Deficiencies of follicle-stimulating hormones, luteinizing hormone, and growth hormone (GH) indicate alteration in the hypothalamic-pituitary feed-back mechanism that normally regulates metabolism (Loan, 1999). As a result of hypermetabolism and hypercatabolism, both energy and protein requirements will be elevated in the first several weeks following injury. Negative energy and nitrogen balance, which may exceed 30 grams per day, have been reported within the first week following injury (Bruder et al., 1994; Weekes & Elia, 1996; Wilson et al., 2001; Young et al., 1985). Unfortunately, although muscle wasting occurs as a consequence of bed rest and immobilization, only a portion of these losses are responsive to nutritional interventions (Behrman et al., 1995).

A case control study examined the cost associated with enteral nutrition (EN) compared to parenteral nutrition (PN) treatment (Ott et al., 1999). It was found that on average the cost of PN was almost double of the cost of EN. However, it should be emphasized that cost is not a sufficient determinant of which treatment should be allocated to an individual as that is determined by their physiological state and their ability to absorb nutrients.

Incidence of Malnutrition

The incidence of malnutrition following ABI is difficult to estimate as there are no consistent criteria used, and relatively few studies have examined the issue. Given that ABI tends to occur in younger, previously healthy individuals, it is unlikely that pre-existing nutritional deficits are prevalent at the time of injury. Therefore, declines in nutritional parameters are most likely directly related to the metabolic effects of the injury. Brooke et al. (1989) reported an average weight loss of 13.2 kg from injury to rehabilitation admission, while Weekes and Elia (1996) reported 9.8 kg of weight loss from the time of injury to day 19 in four previously healthy young males. In the early rehabilitation phase, a substantial amount of patients are underweight (approximately 60%) (Brooke et al., 1989; Haynes, 1992); however, obesity has also been reported among patients, typically in the chronic phase of recovery (Henson et al., 1993). Another factor which can contribute to malnutrition or dehydration following an ABI is diarrhea, which has been shown to occur in rates as high as 70% in those receiving enteral nutrition, and in relation to the use of antibiotics for over 1-week (Vieira et al., 2018). Of the individuals who had diarrhea, they were also seen to have longer stays in the ICU and were attributed to enteral nutrition intolerance (Vieira et al., 2018).

Hypermetabolism Post ABI

Hypermetabolism is a well-known metabolic sequelae of ABI. Hypermetabolism has been defined as an increase in metabolic rate above that which is predicted using equations, which take into account age, sex, height, and weight (Souba & Wilmore, 1999). The hypermetabolic state, which is characterized by increased oxygen consumption and nitrogen excretion following injury, is thought to be mediated by an increase in i) counterregulatory hormones such as epinephrine, norepinephrine and cortisol, ii) corticosteroids, and iii) proinflammatory mediators and cytokines (Pepe & Barba, 1999). Tremendous variability has been reported regarding the magnitude of the hypermaetabolic state post ABI. The variations are likely due to the timing of the measurements, patient characteristics (i.e., initial level of injury, concomitant infections) and management (i.e., craniotomy, intubation and sedation and/or barbiturate use, ambient temperature).

Resting Energy Expenditure (REE) represents the amount of calories required for a 24-hour period by the body during a non-active period.  Young et al. (1985) found REE to decrease consistently over time post ABI (151% to 116% over 22-day evaluation). Bruder et al. (1994) compared REE in patients with ABI who were weaned off from sedation, while others were re-sedated. REE increased to 143% of predicted values in those who were weaned from sedations, while the increases in REE were only 122% of predicted values in those who received additional sedation (Bruder et al., 1994), demonstrating that sedation can impact metabolic rates. Barbiturate use as it relates to REE was examined by Dempsey et al. (1985); the findings showed that mean REE was significantly lower during barbiturate therapy than without barbiturate therapy, when it was administered to those with failing intracranial pressure (ICP) (p<0.01). Other factors that affected REE after head injury were evaluated by Robertson et al. (1984). The authors found that patients with GCS 4-5 had the highest REE at 168±53% of expected values, and was lowest in patients with GCS 6-7 at 129±31% of expected values (Robertson et al., 1984).

The evidence suggests that patients with ABI are often hypermetabolic, with significantly higher resting energy expenditure in the acute period following the injury. Continued research in this area will help to establish meaningful guidelines regarding use of barbiturates and sedations as modifiable factors.

Fluid Consumption and the Frazier Free Water Protocol

To increase fluid consumption and decrease the risk of dehydration, the Frazier Free Water Protocol allows patients who are receiving thickened liquids to be given regular, thin water in between meals. Thickened fluids do not quench thirst in the same way that regular thin water does. Therefore, the regular water, in combination with the recommended thickened fluids, works to assist some patients in better meeting their daily hydration needs. Patients who are NPO are often permitted to have water (following screening) and those who have found success using various postural changes are asked to use postural maneuvers when drinking water. The Frazier Free Water protocol states that, by policy, water is allowed for any patient NPO or on a dysphasic diet (Panther, 2005).

5.6.1 Enteral Nutrition

Key Points

Enteral nutrition may not reduce weight loss in individuals post ABI.

For those with ABI and being provided with enteral nutrition, energy expenditure levels may be beyond those predicted by equations.

EN consists of delivering complete nutritional requirements directly into the stomach, duodenum, or jejunum using a gastroenteric tube. EN is beneficial when patients are unable to ingest nutrients independently but their bodily functions still allow for the digestion of food. However, post-ABI caloric and nutrient requirements may not always be met and PN is used as supplementation. Patients should be routinely monitored for signs of malnutrition and dehydration. Studies examining the efficacy of enteral nutrition are presented in Table 5.14.

Discussion

To date only two studies have looked at the general effectiveness of EN in an ABI population (Clifton et al., 1984; Horn et al., 2015). It was found that EN, when compared to no EN, resulted in trends towards smaller weight changes, improved FIM scores (motor and cognitive function), and longer length of stay, although these between-group differences did not reach statistical significance (Horn et al., 2015). Clifton et al. (1984) examined the REE of those being treated with EN and found that REE was higher than predicted, specifically with those patients who were not sedated. Further research is needed to better understand any potential benefits of EN outside of direct caloric or weight measures.

Conclusions

There is level 2 evidence that enteral nutrition may not reduce weight loss or improve FIM scores compared to no EN in patients post ABI.

There is level 4 evidence that patients with ABI may expend more energy when on enteral nutrition than predicted by equations, and that this effect may be greater for non-sedated individuals.

5.6.1.1 Timing

Key Points

Early enteral nutrition may be more beneficial than standard or late enteral nutrition for several patient outcomes post ABI.

Early enteral feeding (EEF) is desirable as a means to prevent intestinal mucosal atrophy and to preserve gut integrity. Although, as previously noted, feeding intolerance occurs frequently. The following table presents literature surrounding the timing of enteral feeding (Table 5.12).

Discussion

Chourdakis et al. (2012) compared delayed enteral feeding with EEF in 59 individuals post severe TBI. Although rates of complications were comparable between groups, the length of feeding for the EEF group was significantly shorter than the length of feeding for the delayed group. Hormonal measurements also indicated that those in the early group showed significant improvements on several hormonal measures (Chourdakis et al., 2012).

Minard et al. (2000) and Azim et al. (2016) found that timing of enteral feeding had no significant impact on mortality, number of infections, ventilator days, or incidence of pneumonia. Chaudhry et al. (2017) looked at inpatients who received early, standard, or late percutaneous endoscopic gastronomy (PEG) for nutritional support post ABI. Their results showed that late PEG was associated with a higher comorbidity index, longer LOS, and more complications compared to early PEG.

In a prospective study comparing total EN at various time points (within 3 days, 4-7 days, and after 7 days) there were unfavourable outcomes associated with total EN after 3 days (Dhandapani et al., 2012). Those who began later lost significantly more mid-arm circumference and mid arm muscle circumference and had worse malnutrition. At the third and sixth month follow-ups, those receiving total EN within the first 7 days were more likely to have favourable outcomes on the GOS (Dhandapani et al., 2012).

A Cochrane review by Yanagawa et al. (2000) identified six RCTs that addressed the timing to initiation of feeding and mortality as an outcome. The relative risk for death associated with early nutritional support was 0.71 (95% CI 0.43-1.16). The pooled relative risk from three trials, which also assessed death and disability, for early feeding was 0.75 (0.50-1.11). Although the results were not statistically significant, it was concluded that early feeding may be associated with a trend towards better outcomes in terms of survival and disability (Yanagawa et al., 2000).

Conclusions

There is level 1b evidence that early enteral nutrition may improve the hormonal profile of patients with TBI compared to delayed enteral feeding.

There is level 2 evidence that early versus late enteral feeding has a similar effect on mortality, number of infections, ventilator days, or incidence of pneumonia in patients with ABI.

There is level 2 evidence that early enteral nutrition may improve energy and nitrogen intake compared to standard enteral nutrition in ABI populations.

There is level 4 evidence that late percutaneous endoscopic gastrostomy may be associated with a higher comorbidity index, longer length of stay, and more complications compared to early percutaneous endoscopic gastrostomy in patients with ABI.

There is level 2 evidence that late total enteral feeding can result in reduced arm circumference, worse malnutrition, and more disability compared to early total enteral feeding in patients with ABI.

5.6.1.2 Administration

Key Points

There may be an increased risk of developing pneumonia in ventilated stroke and head injury patients fed by a nasogastric tube.

Surgical feeding tube placement strategies can reduce the number of unnecessary surgical feeding tubes. 

Early enteral feeding has been associated with improved outcomes, however, the effectiveness of the intervention may vary depending on the mode of feeding. Nasogastric feeding tubes have been associated with increased incidence of pneumonia, while theoretically, feeding tubes placed more remotely decrease the risk. Gastronomies are proven to be a safe and dependable process used to provide enteral access for meeting nutritional needs of patients with ABI and delivering essential medications (Harbrecht et al., 1998).

Discussion

One study has examined the effect of early gastrostomy compared to nasogastric tubes on ventilator-associated pneumonia post head injury or stroke. Kostadima et al. (2005) found that those who received a nasogastric tube had significantly higher rates of pneumonia compared to the gastrostomy group at the end of the second and third weeks of treatment. However, no other significant differences were found in terms of LOS, ventilation days, or mortality. Further research should be conducted to examine the effect of type of EN on patient outcomes in ABI populations.

Another study found that after implementation of a new Surgical Feeding Tube (SFT) placement strategy, the percentage of unnecessary SFTs significantly decreased from 25% to 8% (Marcotte et al., 2018). In addition, significant predictors of necessary SFTs were identified and included increasing age, head injury, cervical spinal cord injury and need for a tracheostomy.

Conclusions

There is level 1b evidence that the risk of developing pneumonia is higher among ventilated patients (stroke and head injury) fed by a nasogastric tube compared with a gastrostomy tube.

There is level 3 evidence that a specific surgical feeding tube placement strategy can reduce the number of unnecessary surgical feeding tube placements.

5.6.1.3 Enhanced Feeding Solutions

Key Points

There is conflicting evidence as to whether immune enhanced enteral feeding solutions reduce infection rates, ventilator dependency, GCS, and hospital length of stay in patients post-ABI.

EN feeding solutions enriched with immune-enhancing nutrients may decrease the occurrence of sepsis and reduce the inflammatory response. Theoretically, glutamine is thought to enhance gut mucosal and immune cell function through its antioxidant properties, while probiotic bacteria could favorably alter the intraluminal environment, competing for nutrients and adhesion sites with pathogenic bacteria. These co-operative actions may reduce the rate of bacterial translocation and, thus, decrease both the incidence of infection and the length of hospitalization (Falcao de Arruda & de Aguilar-Nascimento, 2004). Studies examining the effects of enhanced enteral nutrition are presented in Table 5.14.

Discussion

A RCT comparing standard diet to glutamine and probiotic enhanced diet in brain injured patients showed lower infection rates in the enhanced diet group, as well as decreased length of stay (LOS) and ventilator days for those on enhanced diets (Falcao de Arruda & de Aguilar-Nascimento, 2004). Painter et al. (2015) reviewed patients given either immune enhancing nutrition (IEN) or standard formula. Surprisingly, patients with IEN had longer LOS in ICU (p=0.02) and more days on ventilator than SF, but were less likely to have bacteremia (p<0.05). This conflicts with two other RCTs, one of which found that enhanced EN feeding resulted in earlier discharge and fewer infections in patients with ABI (Taylor et al., 1999). Taylor et al. (1999) also found that those receiving enhanced EN, compared to standard EN, met significantly more of their daily nitrogen and energy requirements. The other RCT by Jia et al. (2018), it was found that sequential enhanced enteral feeding resulted in significantly higher protein levels and GCS scores 14 days post-treatment.

Brain injury patients have higher energy and protein expenditures and are prone to infections, thus supplementing diet and enhancing feeding solutions may be a feasible option to consider when improving outcomes.

Conclusions

There is conflicting evidence regarding whether or not enhanced enteral nutrition can reduce the incidence of infection, ventilator dependency period, or length of stay compared to standard formula nutrition in patients post ABI.

5.6.1.4 Metoclopramide

Key Points

The use of metoclopramide to aid in gastric emptying may not be effective post TBI.

Individuals who sustain a severe TBI often show signs of gastroparesis. For many individuals with a severe ABI, their energy requirements may reach 60% more than predicted. Metoclopramide has been used and continues to be used to enhance the effectiveness of enteral nutrition, despite its limited success and the inconsistent findings supporting its use (Nursal et al., 2007).

Discussion

A single RCT by Nursal et al. (2007) compared a treatment group receiving 10 mg of metoclopramide per day for five days to a control group receiving placebo. All patients were receiving EN through a nasogastric feeding tube. When looking at the absorption parameters of the two groups, a small non-significant difference was found, with the levels in the treatment group being slightly more pronounced. Overall, the study showed no advantages of metoclopramide in a TBI population.

Conclusions

There is level 1b evidence that metoclopramide may not be effective compared to placebo for gastric emptying in patients with TBI.

5.6.2 Total Parenteral Nutrition

Key Points

Parenteral nutrition with a continuous infusion of insulin may lower blood glucose levels in ABI populations.

The evidence regarding which method of feeding (EN or PN) is optimal to deliver nitrogen, meet required energy expenditures, nutritional goals and prevent complications (e.g. diarrhea and pneumonia) is conflicting.

Further research is needed to clarify the effect of both feeding routes on nitrogen balance and albumin levels post ABI.

Total Parenteral Nutrition (TPN) provides complete nutrition intravenously. Usually, TPN is initiated when a patient’s stomach or bowel is not functioning properly (American Society for Parenteral and Enteral Nutrition, 2018). TPN feeding solution includes all essential vitamins and minerals, as well as  protein, carbohydrates, fats, and electrolytes (Mousavi et al., 2014). If a patient requires TPN to meet their nutritional and caloric requirements, it is essential to initiate TPN as quickly as possible, as a delay in nutrition can result in severe complications, delayed discharge and rehabilitation.

Discussion

Fan et al. (2016) conducted a prospective controlled trial comparing EN versus PN versus combined EN and PN. Total serum protein, prealbumin, and hemoglobin were significantly decreased in the PN group (p<0.01), which corresponds to a degradation in nutritional status; in the EN and EN+PN groups, total serum and protein levels significantly increased (p<0.01) after nutritional treatment. Therefore, the authors suggest a combination of EN+PN to improve prognosis and nutritional status for patients post injury.

A RCT assessing the effect of glycemic control on PN complications in hospitalized patients with brain injury demonstrated that treatment using an insulin infusion significantly decreased blood glucose levels when compared to a conventional glucose treatment (Mousavi et al., 2014). The experimental group also had significantly lower concentrations of C-reactive protein and  triglycerides compared to the control group (Mousavi et al., 2014). The study authors concluded that although more research is needed, insulin infusions improved some parenteral nutrition complications (Mousavi et al., 2014).

With respect to nitrogen balance, Justo Meirelles and de Aguilar-Nascimento (2011) also evaluated the effects of EN and PN in 22 patients with moderately severe TBI and found that parenteral nutrition delivered nitrogen more effectively. Both groups received increasing quantities of nitrogen each day, with those in the total parenteral nutrition (TPN) group receiving significantly more. Despite the increased daily loss of nitrogen, all patients showed significant improvement in nitrogen balance as a result of nutritional therapy (Justo Meirelles & de Aguilar-Nascimento, 2011). Nataloni et al. (1999) studied the effects of EN, PN, or both in a group of patients with ABI while in the intensive care unit. Even though there was a negative nitrogen balance in all groups, all showed improvement over the course of the study, however a positive nitrogen balance was only seen in the enteral group. Furthermore, other studies have found no difference in nitrogen balance between PN and EN (Borzotta et al., 1994; Hadley et al., 1986; Hausmann et al., 1985).

Young and colleagues investigated the effects of TPN versus EN administration on ICP levels in 95 severely brain-inured patients. Participants were randomly assigned to receive TPN or EN and ICP pressure was monitored, as well as serum glucose levels and hyperosmolality. No significant differences were observed between groups in relation to ICP levels or hyperosmolality, suggesting that EN and TPN can be administered safely to severely brain injured patients without causing serum hyperosmolality or affecting ICP therapy.

Hausmann et al. (1985) conducted a RCT to investigate the effects of combined EN and PN compared to TPN on protein catabolism. Findings from the study noted a difference in nitrogen balance between the two feeding regimes, however, these differences were not significant. The combination (EN and PN) group did have significantly higher protein concentrations compared to the TPN group. Although, no other relevant differences in the metabolic data or mortality between each of these treatment groups was found (Hausmann et al., 1985).

Conclusions

There is level 1b evidence that insulin infusions significantly decrease blood glucose levels in patients with TBI.   

There is level 2 evidence that TPN delivered nitrogen more efficiently than EN therapy. However, both groups showed a significant improvement in nitrogen balance as a result of nutritional therapy.

There is level 2 evidence that enteral feeding post ABI may be effective for improving nitrogen balance, while also increasing serum pre-albumin and RBP levels compared to parenteral nutrition and enteral plus parenteral nutrition.

There is level 2 evidence that patients treated with TPN or EN had no differences in nitrogen balance, energy expenditures, meeting nutritional goals and frequency of infections. However, enteral feeding post ABI may lead to decreased rates of hyperglycemia and diarrhea compared to parenteral nutrition.

There is level 2 evidence that intracranial pressure and serum osmolality are not affected by TPN or EN interventions.

There is level 2 evidence that patients receiving EN or PTN had no significant changes in nitrogen balance, although, EN may be more effective in reducing nitrogen intake and nitrogen loss, when compared to PN post ABI.

There is level 2 evidence that parenteral nutrition post ABI reduces the amount of regurgitated gastric fluid compared to combined enteral and parenteral nutrition post ABI, however, nitrogen balance could not be reached for either PN or combined EN and PN post ABI.

There is level 2 evidence that enteral feeding post ABI may reduce mean intake of nitrogen compared to parenteral nutrition post ABI.

There is level 2 evidence that enteral feeding post ABI may increase serum protein, the rate of aspirated pneumonia and diarrhea when compared to parenteral nutrition or combined enteral-parenteral nutrition post ABI.

5.6.2.1 Timing

Key Points

Early parenteral nutrition support of patients with ABI may improve immunologic function.

Early PN support provided directly following injury could assist in the maintenance of immunocompetence and help reduce the incidence of infection following ABI (Sacks et al., 1995). Studies investigating the timing of parenteral feeding for nutritional management post ABI are listed below (Table 5.17).

Discussion

A study by Sacks et al. (1995) found that in individuals with closed head injuries, early PN nutrition was beneficial in modifying immunologic function. More specifically, it aided in improving CD4 cells, CD4-CD8 ratios, and T-lymphocyte responsiveness to Con A. Further research is warranted to determine if this is a consistent effect of early versus late PN (Sacks et al., 1995).

Conclusions

There is level 2 evidence that early parenteral nutrition support may improve immunologic function compared to delayed parenteral nutrition in patients with closed head injury.

5.6.3 Combination or Comparative Nutrition Administration Strategies

Key Points

The evidence regarding which method of feeding (EN or PN or combined EN + PN) is optimal to deliver nitrogen, meet required energy expenditures, nutritional goals and prevent complications (e.g. diarrhea and pneumonia) is conflicting.

Further research is needed to clarify the effect of combined feeding routes on nitrogen balance and albumin levels post ABI.

Combined enteral-parenteral nutrition post ABI may lead to nutritional independence by 6 months post injury.

Often times it is necessary to use both EN and PN administration strategies to ensure that an individual is meeting their caloric needs. For this reason, many studies measure their combined effect, these studies are listed below in Table 5.18.

Discussion

Fan et al. (2016) conducted a prospective controlled trial comparing EN versus PN versus combined EN and PN. Total serum protein, prealbumin, and hemoglobin were significantly decreased in the PN group (p<0.01), which corresponds to a degradation in nutritional status; in the EN and EN+PN groups, total serum and protein levels significantly increased (p<0.01) after nutritional treatment. Therefore, the authors suggest a combination of EN+PN to improve prognosis and nutritional status for patients post injury.

A case control conducted by Krakau et al. (2007) found that 68% of patients who had sustained an ABI showed signs of malnutrition within the first two months of injury. When first admitted to hospital, all patients initially received nutrition parenterally for the first 19 days following injury. The majority of these patients (86%) then received EN (Krakau et al., 2007).

A RCT by Rapp et al. (1983) investigating EN versus PN demonstrated a significant difference in overall nitrogen balance between groups, in favour of PN (p=0.002). Other studies have found no difference in nitrogen balance between PN and EN (Borzotta et al., 1994; Hadley et al., 1986; Hausmann et al., 1985).

They also reported fewer deaths occurring among individuals receiving TPN compared to standard EN (0 versus 44%, p<0.0001). However, there were no significant differences in terms of serum albumin levels over time. This is contrary to a later study which found that patients who received EN showed significant increases in serum pre-albumin and retinol-binding protein compared to the PN or combined EN and PN (Nataloni et al., 1999).

Hausmann et al. (1985) conducted a RCT to investigate the effects of combined EN and PN compared to TPN on protein catabolism. Findings from the study noted the difference in the nitrogen balance between the two feeding regimes; however, these differences were not significant. The combination EN and PN group did have significantly higher protein concentrations compared to the TPN group, but no other relevant differences in the metabolic data or mortality between each of these treatment groups was found (Hausmann et al., 1985).

Conclusions

There is level 2 evidence that patients treated with TPN or EN had no differences in nitrogen balance, energy expenditures, meeting nutritional goals and frequency of infections. However, enteral feeding post ABI may lead to decreased rates of hyperglycemia and diarrhea compared to parenteral nutrition.

There is level 2 evidence that parenteral nutrition post ABI reduces the amount of regurgitated gastric fluid compared to combined enteral and parenteral nutrition post ABI, however, nitrogen balance could not be reached for either PN or combined EN and PN post ABI.

There is level 2 evidence that enteral feeding post ABI may reduce mean intake of nitrogen compared to parenteral nutrition post ABI.

There is level 2 evidence that enteral feeding post ABI may increase serum protein, the rate of aspirated pneumonia and diarrhea when compared to parenteral nutrition or combined enteral-parenteral nutrition post ABI.

There is level 3 evidence that combined enteral-parenteral nutrition post ABI leads to nutritional independence by 6 months post injury.

5.6.4 Other Nutritional Interventions

5.6.4.1 Zinc Supplementation

Key Points

Zinc supplementation in the immediate post-injury period may improve neurological recovery and visceral protein concentrations, but not mortality rates, in patients with ABI.

Zinc is an essential element for humans as it is important for normal nucleic acid and protein metabolism (McClain et al., 1986). Moderate zinc deficiency has been associated with cell death. Serum hypozincemia and increased urinary zinc excretion are common following head injury and are thought to be an adaptive response to inhibit the proliferation of infective organisms. Levels of serum albumin, the major transport carrier for zinc, are also markedly depressed following brain injury and likely help to explain a portion of the reductions in serum zinc levels. Urinary excretion of zinc appears to be proportional to the severity of head injury (Levenson, 2005). As such, two studies investigating the use of zinc supplementation following an ABI are presented below (Table 5.19).

Discussion

Two RCTs examined the effect of zinc supplementation following ABI (Khazdouz et al., 2018; Young et al., 1996). An improvement in protein synthesis and neurological recovery (measured via GCS) in patients who received supplementation was reported, in comparison to matching placebo tablet (Young et al., 1996). Surprisingly, there were no differences in either the serum or cerebrospinal fluid zinc concentrations between the groups. In contrast, Khazdouz et al. (2018) found that zinc supplementation increased GCS scores, plasma zinc concentrations, and zinc excretory concentrations. Although there were no significant differences found in terms of GOS scores or mortality, individuals in the zinc supplementation group experienced shorter LOS (Khazdouz et al., 2018).

Conclusions

There is level 1a evidence that zinc supplementation may improve neurological recovery as measured by the Glasgow Coma Scale in patients with ABI.

5.6.4.2 Growth Hormone

Key Points

Growth hormones may enhance nutritional repletion, however, the evidence is conflicting regarding improvements in nitrogen balance, in patients post ABI.

Anabolic agents have been proposed as a means to improve lean body mass (Behrman et al., 1995). It has been reported that GH mobilizes fat stores and enhances whole body and liver mitochondrial protein stores (Maddaiah et al., 1973; Merimee & Rabin, 1973). It is believed that GHs exert their effects via Insulin-like Growth Factor-I (IGF-I), which is synthesized in the liver (Phillips & Vassilopoulou-Sellin, 1980). Several studies in non-stressed postoperative patients have demonstrated improvements in nitrogen balance following the use of GH (Manson et al., 1988; Manson & Wilmore, 1986; Ponting et al., 1988). However, the effects of GHs on the nutritional parameters of injured patients have not been well established. As such, existing studies examining this topic are presented in Table 5.20.

Discussion

In a study conducted by Behrman et al. (1995), GH treatments administered to patients who were completely immobilized did not improve nitrogen balance. The adjuvant recombinant human GH did, however, improve constitutive serum protein concentrations and the patients’ prognostic nutritional index (Behrman et al., 1995). Conversely, another RCT found that individuals who were administered IGF-I/GH had a higher nitrogen balance per day than those in the control group (1.20±0.84 versus -3.90±0.87) (Hatton et al., 2006). Overall, there was a sustained improvement in metabolic and nutritional status in patients with TBI. Lastly, a study conducted by Devesa et al. (2013) found that GH administration was useful when provided with proper rehabilitation.

Conclusions

There is conflicting evidence regarding whether or not insulin-like growth factor-1/growth hormone is effective for enhancing growth hormone concentration and nitrogen balance compared to placebo in those who have sustained an ABI.

5.6.4.3 Increased Nitrogen Feeds

Key Points

High-protein nitrogen feedings may restore nitrogen losses post ABI.

Following brain injury, nitrogen losses result from the conversion of endogenous protein to energy with the extra stress demand of recovery (Grahm et al., 1989). The attainment of a positive nitrogen balance is complicated because increasing the amount of nitrogen feeding will not be retained, rather it will cause an increased amount of nitrogen excretion (Hadley et al., 1986). Often this positive balance does not occur until the catabolic stimulus begins to subside (Hadley et al., 1986). One study examined nitrogen feeds in ABI populations and is presented in Table 5.21.

Discussion

Following a brain injury, metabolic changes can influence cell turnover, use of substrate, and body composition (Twyman, 1997). Twyman (1997) noted, urinary urea nitrogen levels increased by a factor of three when compared with normal levels, within 10 days following severe head injury. In this study, high-protein nitrogen feeds improved nitrogen balance daily, as well as cumulatively, over the course of the study when compared to low-protein nitrogen feeds. On average, about 5 to 10 g of urea nitrogen are excreted daily in a healthy individual, however, patients with ABI lose a mean of 21 g urinary urea in a single day (Twyman, 1997).

Conclusions

There is level 2 evidence that high-protein nitrogen feedings of approximately 1 g nitrogen/90 calories may be effective for restoring nitrogen losses that occur post ABI compared to low-protein nitrogen feedings.

5.6.4.4 Branched-Chain Amino Acids

Key Points

Branched-chain amino acid supplementation may improve disability scores in patients with ABI.

Branched-Chain Amino Acids (BCAAs), which include leucine, valine, and isoleucine, make up roughly 35% of the human body’s essential amino acids and approximately 14% of skeletal muscle amino acids (Aquilani et al., 2005). Following intake of a meal, amino acid skeletal muscle uptake is comprised of 50% or more BCAAs (Aquilani et al., 2005). Amino acids are not just nutritionally beneficial, but they may also impact cognitive function (Aquilani et al., 2005). It is thought that the BCAAs improve cognitive functioning by providing substrates and increasing brain insulin availability (Aquilani et al., 2005). One study examining this topic is presented in Table 5.22.

Discussion

To date only one RCT has examined the effect of BCAAs on patient outcomes in an ABI population. Aquilani et al. (2005) supplemented patients with 19.6g of BCAAs daily for 15 days and found that disability rating scale scores significantly improved in the BCAA group when compared to placebo. In addition, the total amount of BCAAs at baseline significantly improved in patients receiving BCAA supplementation, including leucine, isoleucine, valine, and tyrosine.

Conclusions

There is level 2 evidence that branched-chain amino acid supplementation may improve disability scores compared to placebo in patients with ABI.

5.7 Conclusion

Treatment of dysphagia and nutritional status post ABI remains understudied. Although there are several available interventions to treat dysphagia and malnutrition post stroke, there is limited clinical evidence to support their effect specifically within an ABI population. This module has demonstrated that both nutrition and oral care are of the utmost importance when maximizing recovery gains following ABI. According to the Canadian Dental Association (2009), diabetes, hypertension, circulatory problems, cognitive and mental health impairments, and stroke are only a few of the common systemic diseases that can negatively affect individuals’ oral health as they age. The Canadian Dental Association emphasizes the importance of teaching preventative habits, such as an appropriate diet and patient-specific oral hygiene techniques, to prevent infection and decay.

Until an ABI-specific research knowledge base regarding effective rehabilitative interventions is established for dysphagia, aspiration, oral care, and malnutrition, therapeutic management will continue to be guided by extrapolation from the stroke literature. As such, further research is needed to better determine the appropriateness of generalizing post-stroke dysphagia rehabilitation practices to an ABI population.

Summary


There is Level 2 evidence that providing oral hygiene education to patients post TBI results in a significant reduction of dental plaque, measured by the Plaque Index Score.

There is level 3 evidence that enhanced oral care may reduce rates of non-ventilator hospital-acquired pneumonia compared to standard oral care in mixed brain injury populations.

There is level 1b evidence that povidone-iodine may be effective for reducing the incidence of ventilator-associated pneumonia compared to placebo post stroke or ABI.

There is level 1b evidence that 0.2% chlorohexidine gel is beneficial for reducing nosocomial infections and hospital length of stay compared to placebo in non-ABI populations.

There is level 1b evidence that oral care may reduce rates of pneumonia, febrile days, and pneumonia-related deaths in mixed populations.

There is level 2 evidence that TPN delivered nitrogen more efficiently than EN therapy. However, both groups showed a significant improvement in nitrogen balance as a result of nutritional therapy.

There is level 2 evidence that enteral feeding post ABI may be effective for improving nitrogen balance, while also increasing serum pre-albumin and RBP levels compared to parenteral nutrition and enteral plus parenteral nutrition.

There is level 2 evidence that patients treated with TPN or EN had no differences in nitrogen balance, energy expenditures, meeting nutritional goals and frequency of infections. However, enteral feeding post ABI may lead to decreased rates of hyperglycemia and diarrhea compared to parenteral nutrition.

There is level 2 evidence that intracranial pressure and serum osmolality are not affected by TPN or EN interventions.

There is level 2 evidence that patients receiving EN or PTN had no significant changes in nitrogen balance, although, EN may be more effective in reducing nitrogen intake and nitrogen loss, when compared to PN post ABI.

There is level 2 evidence that enteral feeding post ABI may reduce mean intake of nitrogen compared to parenteral nutrition post ABI.

There is level 3 evidence that enteral feeding post ABI may be effective for meeting energy and protein requirements, while also contributing to a smaller protein deficit, compared to oral feeding post ABI.

There is level 2 evidence that enteral feeding post ABI may increase serum protein, the rate of aspirated pneumonia and diarrhea when compared to parenteral nutrition or combined enteral-parenteral nutrition post ABI.

There is level 1b evidence that early enteral nutrition may improve the hormonal profile of patients with TBI compared to delayed enteral feeding.

There is level 2 evidence that early versus late enteral feeding has a similar effect on mortality, number of infections, ventilator days, or incidence of pneumonia in patients with ABI.

There is level 2 evidence that early enteral nutrition may improve energy and nitrogen intake compared to standard enteral nutrition in ABI populations.

There is level 4 evidence that late percutaneous endoscopic gastrostomy may be associated with a higher comorbidity index, longer length of stay, and more complications compared to early percutaneous endoscopic gastrostomy in patients with ABI.

There is level 2 evidence that late total enteral feeding can result in reduced arm circumference, worse malnutrition, and more disability compared to early total enteral feeding in patients with ABI.

There is level 2 evidence that standard enteral nutrition or high protein formulas (greater than 20% of calories from protein) resulted in better FIM motor and FIM cognitive scores at discharge and less weight loss than similar patients not receiving enteral nutrition.

There is level 4 evidence that patients with ABI may expend more energy when on enteral nutrition than predicted by equations, and that this effect may be greater for non-sedated individuals.

There is level 1b evidence that the risk of developing pneumonia is higher among ventilated patients (stroke and head injury) fed by a nasogastric tube compared with a gastrostomy tube.

There is level 3 evidence that a specific surgical feeding tube placement strategy can reduce the number of unnecessary surgical feeding tube placements.

There is conflicting evidence regarding whether or not enhanced enteral nutrition can reduce the incidence of infection, ventilator dependency period, or length of stay compared to standard formula nutrition in patients post ABI.

There is level 1b evidence that metoclopramide may not be effective compared to placebo for gastric emptying in patients with TBI.

There is level 2 evidence that parenteral nutrition post ABI reduces the amount of regurgitated gastric fluid compared to combined enteral and parenteral nutrition post ABI, however, nitrogen balance could not be reached for either PN or combined EN and PN post ABI.

There is level 2 evidence that early parenteral nutrition support may improve immunologic function compared to delayed parenteral nutrition in patients with closed head injury.

There is level 3 evidence that combined enteral-parenteral nutrition post ABI leads to nutritional independence by 6 months post injury.

There is level 1a evidence that zinc supplementation may improve neurological recovery as measured by the Glasgow Coma Scale in patients with ABI.

There is conflicting evidence regarding whether or not insulin-like growth factor-1/growth hormone is effective for enhancing growth hormone concentration and nitrogen balance compared to placebo in those who have sustained an ABI.

There is level 2 evidence that high-protein nitrogen feedings of approximately 1 g nitrogen/90 calories may be effective for restoring nitrogen losses that occur post ABI compared to low-protein nitrogen feedings.

There is level 2 evidence that branched-chain amino acid supplementation may improve disability scores compared to placebo in patients with ABI.

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