Enteral nutrition feeding in burn injury patients

Burn injury causes a persistent hypermetabolic state and increases catabolism that results in systemic biomolecular changes. It results in profound physiological alterations, such as increased muscle catabolism, hepatic steatosis, higher susceptibility to infections, multiple organ dysfunction, insulin resistance, and sepsis. The metabolic rate of these patients can be greater than twice the normal rate.1 Adequate nutrition support is the most important aspect of the treatment of burn injury patients. If these energy requirements are not fulfilled, it causes poor wound healing, immune dysfunction, increasing infection, and even death.2 Immediate and aggressive administration of enteral nutrition in combination with special nutrients can significantly reduce the duration of systemic inflammatory response, attenuate hypermetabolism, decrease the incidence of multiple organ failure, and improve the outcome in burn injury patients.3 A major determining factor of the outcome is time to treatment, and any delays in resuscitation lead to poorer outcomes. While the patients suffering from burn injury, there is significant gut mucosal damage and increased bacterial translocation followed by decreased nutrient absorption. Optimal nutrition support for the burn injury patient is best accomplished by early (less than 24 hours after injury) initiation of enteral nutrition. Early enteral feeding of mixed nutritional agents in addition to conventional therapy can modulate the hypermetabolic status and then effectively promote the repair of impaired intestinal mucosal barrier, protect the integrity of intestinal mucosa, alleviate inflammatory response, and obtain better prognosis in terms of survival in burn injury patients.4 For nutrition support of the burn injury patients, the enteral route is better than parenteral route because of lower energy expenditure, better preservation of immune function, decreased risk of infection, shorter length of hospital stay, and decrease in mortality.4, 5 But adequate enteral nutrition is often hindered by gastrointestinal motility disorders and complications because of burn injury. Burn injury has been shown to relax the fundus, reduce antral motility, and slow gastric emptying due to increase in both sympathetic and opiatergic neural activity and release of systemic inflammatory cytokines.6 Nguyen et al7 found that, after severe burn injury, gastric dysmotility is a frequently encountered problem, deterring early oral or enteral feeding. One of the most important gastrointestinal problems after burn injury is enteral feeding intolerance (EFI). EFI is diagnosed when enteral feeding has to be discontinued due to severe vomiting, high gastric aspiration or more gastric residual volume (GRV), bowel distension, or severe diarrhea.8 Pham et al9 claim that elevated GRVs do not equate gastrointestinal intolerance and do not reflect aspiration risk, and they advocate that a GRV threshold of 500 mL should be used to optimize the benefits of enteral nutrition in the burn intensive care unit (ICU). One of the factors associated with EFI, especially with diarrhea, is tube or enteral feeding.10 The composition of tube feeding is not necessarily the primary cause of EFI in critically ill patients as many other factors may be involved. GRV is likely to be affected when administering hyperosmolar medications as hyperosmolar solutions inhibit gastric emptying, thereby increasing GRV and then inducing EFI. Whether enteral feeding access should initially be through a nasogastric tube or nasoduodenal tube in severe burn injury patients remains controversial. Among less severely ill patients, no differences existed between the nasogastric feeding and nasoduodenal feeding groups in daily energy and protein intake, feeding complications, length of ICU stay, and nitrogen balance.11 Huang et al11 also found that, among more severely ill patients, the nasogastric feeding group experienced lower energy and protein intake, more tube feeding complications, longer ICU stay, and poorer nitrogen balance than the nasoduodenal feeding group. In burn injury patients with delayed gastric emptying, nasoduodenal feeding is a preferred method of providing adequate enteral nutrition. There are several strategies used to improve the tolerance and hence adequacy of enteral nutrition delivery in the critically ill patients. One of the most widely used strategies is that of prokinetic medication administration, most commonly metoclopramide and erythromycin.12 The effectiveness and complications of nasoduodenal feeding compared with nasogastric feeding have largely been controversial. Compared with nasogastric feeding, nasoduodenal feeding may reduce the risk of pneumonia.13 But in severe burn injury patients, while EFI has developed, the nasoduodenal tubes become more difficult to set correctly and need to be guided by endoscopy. Therefore, early placement of nasoduodenal tubes may be the optimal method of feeding these patients, particularly for those who may develop gastric stasis. Nasoduodenal feeding is safe, well tolerated, and meets the nutritional requirements of the majority of patients with severe burn injuries, even while nasogastric feeding had failed. Adequate assessment and provision of enteral nutrition is imperative to the care of the severe burn injury patients. There is no consensus regarding the optimal timing, route, amount, and composition of nutritional support for these patients, but most clinic doctors advocate for early enteral nutrition with high-carbohydrate formulas by nasogastric or nasoduodenal tube. In clinical practice, nasogastric feeding is the preferred access of enteral nutrition because it is easier to achieve, more similar to the natural physiological route, and cheaper than nasoduodenal feeding.14 However, patients with critical illness should be fed through the nasoduodenal route if at a high-risk status for aspiration or showing intolerance to gastric feeding.15 For optimizing nutritional support and medical resources, the nasogastric feeding route is recommended for less severely ill patients and the nasaduodenal feeding route for more severely ill patients. If nasogastric feeding failure in less severe burn injury patients, we can change to nasoduodenal feeding to relieve enteral feeding intolerance. In conclusion, enteral nutritional support in burn injury patients must be individualized, and initially, nasoduodenal tube feeding for severe burn injury patients is suggested, which should be closely monitored and adjusted throughout recovery as it is important. Further investigation is needed regarding optimal enteral nutritional support and to determine the optimal feeding route associated with burn injury severity and accurate nutritional endpoints and goals. The author declares no conflict of interest.