5.10.1 Routes of Nutrient Administration
What would be the indications for enteral feeding? What would be the indications for parenteral feeding?
- Enteral feeding is required when the patient is severely dysphagic, an aspirator, comatose or mechanically ventilated.
- In these situations enteral feeding is the preferred option.
- Parenteral feeding is indicated when enteral feeding is not possible – feeding intolerance due to gastroparesis and ileus as well as increased intracranial pressure.
- Both parenteral and enteral feeding methods of nutrition administration safely and effectively reduce mortality and improve outcome following traumatic head injury; parenteral feeding was associated with .
- There is conflicting evidence that choice of feeding route does not affect nitrogen balance or mortality in post-ABI patients.
- Based on a single RCT, there is Level 2 evidence that TPN can safely be administered without causing serum hypersomolality or influencing intracranial (ICP) pressure levels or ICP therapy in post-ABI patients.
In the early stages of recovery a significant percentage of patients will be comatose and mechanically ventilated, precluding oral feeding. While enteral feeding is the preferred route of nutrient administration, feeding intolerance due to gastroparesis and ileus are common. Enteral feeding has been associated with a decrease in bacterial translocation and a reduced incidence of infection.
Enteral feeding intolerance may be related to increases in intracranial pressure 80. Medications may also play a role in delayed gastric emptying. Although the placement of feeding tubes into the small bowel may theoretically improve tolerance, placement can be difficult and empirical evidence of superiority is lacking. If intolerance is prolonged, parenteral feeding may be indicated 81although the risk of hyperglycemia and cerebral edema are increased.
A Cochrane review authored by Yanagawa et al. 82identified six trials, which compared parenteral versus enteral nutrition. Parental feeding was associated with protection from both death and the combined outcome of death and disability, although the result was not statistically significant. The relative risk for mortality at the end of the follow-up period was 0.66 (0.41-1.07) while two trials noted the relative risk of death and disability as 0.69 (0.40-1.15). Young et al. 66noted that both parenteral and enteral feeding methods of nutrition administration safely and effectively reduce mortality and improve outcome following traumatic head injury.
Nutritional Recommendations (ABIKUS Guidelines 2007 18)
All brain injured patients with significant ongoing impairment or disability should have their nutritional status assessed using a validated method, within 48 hours of admission (onset of injury). (ABIKUS B, adapted from RCP, G52, p.30) (G64-p.26)
Where patients are unable to maintain adequate nutrition orally, nutrition should be provided via nasogastric tube within 48 hours of injury, in collaboration with physician, dietician, nursing staff (ABIKUS A, adapted form RCP G53, p. 30) (G65-p.26)
A dietician trained in the management of brain injury should review nutrition and hydration needs regularly. This should include regularly weighing the patient (ABIKUS C, adapted from RCP, G55, p.30) (G66-p.26)
Nutritional needs may need to be changed according to changing metabolic demands (ABIKUS B, adapted from RCP, G54, p.30) (G67-p.26)
If the patient is unable to take adequate nutrition orally for longer than 2-3 weeks after injury, Percutaneous Endoscopic Gastrostomy (PEG) or similar intervention should be instituted, unless contradicted. (ABIKUS B, adapted from RCP, G56, p.30) (G68-p.26)
5.10.2 Enhanced Enteral Nutrition
What evidence is there of a benefit of enhanced enteral nutrition post ABI?
- There is Level 1 evidence based on a single RCT that enhanced enteral nutrition enriched with immune-enhancing nutrients can reduce the incidence of infection, and reduce both the ventilator dependency period and ICU stay.
Enteral feeding solutions enriched with immune-enhancing nutrients may decrease the occurrence of sepsis and reduce the inflammatory response. Theoretically, glutamine may improve the nutrition of both the gut mucosa and immune cells, while probiotic bacteria could favourably 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 83.
5.10.3 Timing of Enteral Nutrition
What are the benefits of early administration of enteral nutrition post ABI?
- There is Level 2 evidence based on a single RCT that initiating enteral feeding at goal rate will increase the percentage of prescribed energy and protein actually received.
Early enteral feeding is desirable as a means to prevent intestinal mucosal atrophy and to preserve gut integrity, although, as previously noted, feeding intolerance occurs frequently.Three studies examined the effects of early vs. delayed enteral feeding. A Cochrane review authored by Yanagawa et al. 82 identified six RCTs, which addressed the timing to initiation of feeding and assessed 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 RR 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, the authors concluded that early feeding may be associated with a trend towards better outcomes in terms of survival and disability.
5.10.4 Timing of Parenteral Nutrition
What are the benefits of early administration of parenteral nutrition post ABI?
- There is Level 2 evidence that early parenteral nutrition support of closed head-injury patients appears to modify immunologic function by increasing CD4 cells, CD4-CD8 ratios, and T-lymphocyte responsiveness to Con A.
Early parenteral nutrition support provided directly following injury could assist in the maintenance of immunocompetence and help reduce the frequency of the incidence of infection following acquired brain injury 84. In a study conducted by Sacks et al.84a significant increase in total CD4 cell counts and CD4% for early PN versus delayed PN at day 14 (p<0.05) was found. From baseline to day 14, following Con A stimulation, an improved lymphocyte response was demonstrated in the early PN group (p<0.05). The CD4-CD8 ratio significantly increased from baseline to day 12 in the early PN group (p<0.05).
5.10.5 Types of Enteral Feeding Tubes
What evidence for one type of enteral feeding tube over another?
There is Level 1 evidence that the risk of developing pneumonia is higher among ventilated patients fed by a naso-gastric tube compared with a gastrostomy tube.
- There is Level 2 evidence that early naso-jejunal hyperalimentation improves caloric intake, nitrogen intake, nitrogen balance, bacterial infection and days of stay in the intensive care unit in post-ABI patients.
Early enteral feeding has been associated with improved outcome.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 proved to be a safe and dependable process used to provide enteral access for meeting nutritional needs of ABI patients and delivering essential medications 85.