TY - JOUR
AU - MD, Sharmila Dissanaike,
AB - Abstract Optimal nutrition is essential to the recovery of burned patients. The authors evaluated the efficacy of an aggressive nutrition delivery protocol. The following protocol was implemented: initiation of tube feeds within 4 hours, acceleration to goal rate within 8 hours, and tolerance of gastric residual volumes of 400 ml. Patients on the protocol formed the study group whereas patients admitted immediately before implementation served as controls for a study period of 7 days after admission. Outcome variables included ileus, prokinetic medication use, intensive care unit and overall length of stay, ventilator days and mortality. Variables were compared using bivariate analysis. The 42 study subjects and 34 controls were similar at baseline. Time to initiation was similar (6.8 vs 9.4 hours; P = .226), however, goal rate was achieved much sooner in the study group (11.2 vs 20.9 hours; P < .001). Number of hours spent at goal was different on days 1 and 2 (6.62 vs 2.74, P = .003 and 17.24 vs 13.18, P = .032) with no difference thereafter. Residual volumes in the study group were higher from day 2 onward, and remained increased throughout the study period (401 vs 234 ml average; P = .449). Clinical ileus was much more common in the study group (8 cases vs 1, P = .037). There was no difference in length of stay or mortality. The protocol was successfully implemented and resulted in early achievement of goal tube feed rates. However, this resulted in tube feed intolerance as manifested by more cases of clinical ileus. Burn injured patients have the highest metabolic demand of all critically ill or injured patients.1,2 Burn injury results in an increase in the hypothalamus set-point for the production of endogenous catecholamines, cortisol, and other glucocorticoids resulting in hypermetabolism.1,3 Symptoms of the stress response include a hyperdynamic cardiovascular system, accelerated gluconeogenesis and glycogenolysis, increased lipolysis and proteolysis, increased thermogenesis, higher insulin resistance, and loss of lean body mass and body weight.1 This hypermetabolic response results in weight loss, poor wound healing, muscle wasting, growth retardation in children, and worsened immune function.3,4 The provision of adequate nutrition can help ameliorate these adverse effects; however, adequate nutrition in this setting requires much higher caloric and protein intakes than is usual in the intensive care unit (ICU) environment. For example, an adult patient burned more than 50% of their TBSA will require upward of 5000 calories per day.3,5 Provision of early nutrition therapy can reduce disease severity, prevent complications, decrease length of stay, and improve outcomes. Enteral nutrition is preferred over parenteral nutrition whenever possible.1,–7 Early nutrition is typically defined as initiation of feeds within the first 24 hours of hospitalization.1,3,–7 Patients with large burn sizes or requiring mechanical ventilation may require enteral nutrition alone or in combination with oral feeding to meet their high requirements.3,5 The goal of nutrition supplementation is to promote wound healing, prevent infection, and attenuate the loss of muscle mass during critical illness associated with increased mortality and poorer long-term outcomes among survivors.1,2 Clinical guidelines have been established for the assessment, provision, and monitoring of nutrition for burn victims, with nurse-driven protocols considered best practice.6,7 Longstanding practice for enteral nutrition has included the routine monitoring of gastric residual volumes (GRV) by nursing staff, using the residual volume as a surrogate measure of gastric emptying. The evidence supporting the use of GRV to assess tolerance leaves much to be desired,8,–10 although it has been routine practice in many centers for decades. High GRV measurements result in cessation of enteral tube feedings in up to 45% of patients receiving enteral nutrition.11 According to the American Society for Parenteral and Enteral Nutrition guidelines, inappropriate cessation of enteral nutrition should be avoided unless GRV is greater than 500 ml in the absence of other signs of intolerance.7 Standard practice, for many years, has also been to withhold tube feeds during operations and certain bedside procedures. Because severely burned patients typically require multiple operations and procedures, this has significant implications for nutrition delivery. Recent literature suggests that enteral nutrition can be continued without increased risk of aspiration during surgery unless the patient is prone. However, the airway must be protected by a cuffed endotracheal tube.12 On the basis of these findings we created an aggressive protocol for nutrition in severely burned patients, which involved reducing time to initiation, accelerating faster, tolerating higher GRV, and continuing tube feeding during operations and procedures. We hypothesized that this aggressive enteral tube feed protocol would result in improved clinical outcomes in critically ill burn patients. METHODS Setting The study was conducted at an American Burn Association–verified regional burn center located in an academic teaching hospital serving an adjacent urban population as well as a large rural population spread over a 300-mile radius draw-area. Nutrition Protocol The aggressive nutrition protocol consisted of a four-tiered bundle (Figure 1): Figure 1. View largeDownload slide Burn intensive care unit enteral nutrition algorithm. Figure 1. View largeDownload slide Burn intensive care unit enteral nutrition algorithm. Enteral nutrition was initiated within 4 hours of admission to the burn ICU. Rapid acceleration to goal tube feed rates within 8 hours of admission. GRVs of 400 ml were tolerated before adjusting the rate of tube feeding. Patients were fed continuously during operations, procedures, and wound care. Study Design A retrospective cohort study design was used. Adult patients aged 18 to 89 years admitted to the burn center ICU with severe burn or inhalation injury requiring enteral nutrition support were included in the study. The study group consisted of patients who were initiated on the aggressive tube feeding protocol starting March 1, 2011 until April 30, 2012. The control group consisted of a matched group of patients who were admitted during the 12-month period immediately before initiation of the protocol. The study period consisted of the first 7 days after admission. Demographic data recorded included age, race, sex, TBSA, presence of inhalation injury, time to hospital, and time to the burn center. Recorded values for nutrition parameters included: time to initiation of tube feeding, time to achieving goal rate prescribed, hours spent at goal rate prescribed, percentage of goal rate achieved compared with prescribed rate, GRV per 24-hour period, number of operating room procedures during study period, presence of ileus as documented in the medical record and/or on abdominal radiograph, and use of prokinetic agents. Nutritional parameters and feeding rates were recorded for the 7-day study period only. Clinical outcomes data include ICU length of stay, hospital length of stay, use of vasopressors, antibiotic days, ventilator days, and in-hospital mortality. Clinical outcomes were evaluated for the entire length of hospital admission. Subjects expiring or completing tube feeding during the study period were removed from analysis. Chi-square test was used for proportions and Student's t-test or Mann–Whitney U test were used to analyze continuous variables. All analyses were performed using SPSS v. 20 (Chicago, IL). RESULTS A total of 76 patients were included in the study: 42 study subjects and 34 control subjects. The groups were well matched (Table 1), with an average age of 45.6 vs 47.7 years. Average burn size was 27 vs 30% TBSA, with 41 and 45% of patients having concomitant inhalation injuries. The average time to hospital was approximately 4.5 hours in both groups, with time to arrival at the burn center being about 5.5 hours. On average each subject had one operation during their study period, irrespective of group (P = .263). Table 1. Patient characteristics View Large Table 1. Patient characteristics View Large The time to initiation of tube feeding was improved with the protocol (5.9 vs 8.7 hours,P = .025). The time to achievement of goal rate was reduced to 10.2 vs 21.1 hours (P = .001). The number of hours that tube feeding was delivered at the prescribed rate was significantly improved in the study population on days 1 and 2 of the study (6.62 vs 2.74 hours, P = .042; 17.24 vs 13.18 hours, P = .110, respectively). However, the number of hours remained similar thereafter (Figure 2). The total percentage of the prescribed regimen achieved showed a similar pattern, with greater nutrition provided to the study group on the first day (54.2 vs 35.9%,P = .011), with no significant differences noted later in the study period (Figure 3). The proportion of overall tube feeds delivered during the entire study period as compared with goal rates was 74% in the aggressive protocol group vs 71% (P = .392) in the control group. The total daily GRV was similar on day 1 (P = .760) but was higher in the study group from day 2 onward as depicted in Figure 4. Figure 2. View largeDownload slide Hours spent at goal rate prescribed for tube feeding. Figure 2. View largeDownload slide Hours spent at goal rate prescribed for tube feeding. Figure 3. View largeDownload slide Percentage of goal rate achieved. Figure 3. View largeDownload slide Percentage of goal rate achieved. Figure 4. View largeDownload slide Total daily residual volume. Figure 4. View largeDownload slide Total daily residual volume. Clinical outcomes were not significantly different between groups, with similar hospital length of stay, mortality, use of vasopressors, and antibiotic days (Table 2). Ventilator days trended toward being lower in the study group at 9.1 vs 14.6 days (P = .07) in the control group. Table 2. Clinical outcomes View Large Table 2. Clinical outcomes View Large An increase in the incidence of clinical ileus was manifested in eight cases in the study group and one in the control (P = .037) group. There was no difference in the use of prokinetic medications (P = .241). Use of stool softeners and laxatives were equal at 70%. DISCUSSION The aggressive nutrition protocol used in this study did not improve clinical outcomes but did increase the incidence of ileus. Additionally, it was seen that a prolonged period of tube feed intolerance occurred in patients who received the aggressive protocol, which negated the benefits of the early acceleration to goal rates. As a result, after the first 48 hours from burn injury, total nutrition provided was essentially the same in both groups. Several possible reasons for the reduced tolerance of tube feeds were noted. It is likely a combination of factors including the route of feeding, timing of feeding, and amount of feeding. Standard practice at our institution is to feed via the gastric route. Recommendations from the American and European Society for Parenteral and Enteral Nutrition indicate no clinical difference in jejunal vs gastric feeding for patients suffering critical illness.7,13 Jejunal feeding may decrease the incidence of reflux and aspiration but meta-analysis suggests little effect on incidence of pneumonia.7 In addition, patients fed directly in the small bowel may have an increased incidence of diarrhea as opposed to those fed via the gastric route, which additionally provides prophylaxis for stress ulcers.14 Although it is possible that the gastric feeding resulted in higher residual volumes, this should have applied equally to both groups, and is therefore unlikely to be the explanation for the study findings. The timing of initiation during the acute phase of burn resuscitation may have proven too aggressive in this severely burned population; shifting the goal toward initiation between 24 and 48 hours may improve tolerance. Using slow constant rate feeding (usually 10–30 ml/hr) to prevent added stress to intestinal blood flow and mucosal atrophy is another method that has been studied in other populations.7 Slowing the acceleration to goal and maintaining the patient on low rates during the first 24 to 48 hours is a potential option. In this study, using higher GRV of 400 ml did not significantly change the amount of tube feeding received by the patients; therefore it is unclear whether this aspect of the protocol was necessary. Finally, the use of prokinetics was not routine, but given on an “as needed” basis at physician discretion. It is possible that coupling the nutrition delivery with early use of motility agents may have improved tolerance of tube feeds. Given the lack of difference in total nutrition delivered at the end of the 7-day study period, it is not surprising that there was no difference in clinical outcomes between study and control groups in this study. Additionally, both study and control groups had tube feeds initiated within 24 hours, thus falling within the “early” nutrition period by standard definitions and further reducing the disparity between groups. It is possible that had we monitored feeding rates for a period longer than 7 days some clinical differences between groups might have been noticed; however given the confluence of the feeding curves it would be physiologically and statistically unlikely. Finally, improvements in mortality and length of stay that have occurred at burn centers over the past decade have resulted in a reduced sensitivity of these variables as outcome markers. The reduction in ventilator days in the study group was an intriguing finding that narrowly missed statistical significance. However, we do not believe that this was directly related to the nutrition protocol. As in many centers across the country, there was an increased emphasis on avoiding overresuscitation at our burn center during the year that the study cohort was drawn from, and a protocol was initiated to that effect which included high-dose intravenous vitamin C and a nurse-driven automatic titration protocol for resuscitation fluid. It is probable that the trend toward reduced ventilator days was a result of these changes, thus highlighting the pitfalls of drawing conclusions from retrospective studies with historical controls in this highly complex, critically ill patient population. Initiating enteral support in the very early stages of burn injury is not a new idea. Animal studies conducted by Mochizuki et al15 in 1984 demonstrated that feeding as early as 2 hours postinjury may prevent burn hypermetabolism from manifesting. Gianotti et al16 demonstrated in 1994 that immediate enteral feeding in guinea pigs was helpful in preserving gut barrier function and decreasing bacterial translocation while decreasing metabolism. It is clear that gut barrier function is important in the prevention of sepsis related to bacterial translocation. Consequently, measures to promote healthy gut integrity are important to the management of the burn-injured patient.14,17 Feeding the critically injured burn patient as soon as possible may have a positive effect on splanchnic blood flow and support the gut barrier.17 However, there is little clinical data regarding the optimal timing and rate of feeding in human burn victims. Moreover, associations between hypoperfusion of the splanchnic circulation in conjunction with hypotension and shock leading to intestinal necrosis have been made,4 suggesting the downside to overly aggressive feeding. The increased incidence of ileus observed in this study may be a manifestation of splanchnic hypoperfusion because of excessive demand during the peak period of burn hypermetabolism. Prospective studies are needed to identify the exact timing of safe and effective initiation of enteral feeding in the burn injured patient to provide nutritional support and attenuate the hypermetabolic response to burn injury without further compromising intestinal function. This study has several limitations that are primarily associated with the use of a retrospective review with a historical cohort study design, as mentioned above. It is possible that a small sample size resulted in a type II error, and that a larger cohort would have shown differences in outcome. Reliance on the medical record to determine the occurrence of ileus precludes judgment on the actual clinical significance of this finding. The study period was limited to 7 days after admission in a population with a much longer total hospital stay; therefore it is possible that outcomes would have been different if data had been collected for a longer period. Differences in type of tube feed were not recorded, although the standard options in the burn center did not change during this time period. Episodes of emesis were not recorded. Given the innumerable interventions and complexity of the healthcare process in this population, there are many potential confounders that were not studied; therefore the findings reported should be viewed as hypothesis-generating, rather than a basis on which to alter clinical practice. However these results may aid in developing future clinical studies on the optimal timing and delivery of enteral nutrition in burn patients. CONCLUSION An aggressive nutrition protocol did not improve clinical outcomes but increased the occurrence of ileus in a cohort of severely burned patients. Further prospective research is needed to develop tube feeding regimens that optimize nutrition delivery without adverse effects. REFERENCES 1. Lee JO, Benjamin D, Herndon DN. Nutrition support strategies for severely burned patients. Nutr Clin Pract. 2005;20:325–30. 2. Flynn MB. Nutritional support for the burn-injured patient. Crit Care Nurs Clin North Am. 2004;16:139–44. 3. Chan MM, Chan GM. Nutritional therapy for burns in children and adults. Nutrition. 2009;25:261–9. 4. Gottschlich MM, Jenkins ME, Mayes T, Khoury J, KAgan RJ, Warden GD. An evaluation of the safety of early vs delayed enteral support and effects on clinical, nutritional, and endocrine outcomes after severe burns. J Burn Care Rehabil. 2002;23:401–15. 5. Wasiak J, Cleland H, Jeffrey R. Early versus delayed enteral nutrition support for burn injuries (Review). The Cochrane Library. 2009;1. 6. Windle EM. Nutrition support in major burn injury: case analysis of dietetic activity, resource use and cost implications. J Hum Nutr Diet. 2008;21:165–73; quiz 174–6. 7. McClave SA, Martindale RG, Vanek VW, et al. Guidelines for the provision and assessment of nutrition support therapy in the adult critically ill patient: Society of Critical Care Medicine and American Society for Parenteral and Enteral Nutrition. J Parenter Enteral Nutrition. 2009;33:277–14. 8. Poulard F, Dimet J, Martin-Lefevre L, et al. Impact of measuring residual gastric volume in mechanically ventilated patients receiving early enteral feeding: a prospective before-after study. J Parenter Enteral Nutrition. 2009;34:125–30. 9. McClave SA, Snider HL. Clinical use of gastric residual volumes as a monitor for patients on enteral tube feeding. J Parenter Enteral Nutrition. 2002;26:S43–50. 10. Montejo JC, Miñambres E, Bordejé L, et al. Gastric residual volume during enteral nutrition in ICU patients: the REGANE study. Intensive Care Med. 2010;36:1386–93. 11. McClave SA, Lukan JK, Stefater JA, et al. Poor validity of residual volumes as a marker for risk of aspiration in critically ill patients. Crit Care Med. 2005;33:324–30. 12. Endorf FW, Ahrenholz D. Burn management. Curr Opin Crit Care. 2011;17:601–5. 13. Kreymann KG, Berger MM, Deutz NE, et al.DGEM (German Society for Nutritional Medicine); ESPEN (European Society for Parenteral and Enteral Nutrition). ESPEN guidelines on enteral nutrition: intensive care. Clin Nutr. 2006;25:210–23. 14. Prelack K, Dylewski M, Sheridan RL. Practical guidelines for nutritional management of burn injury and recovery. Burns. 2007;33:14–4. 15. Mochizuki H, Trocki O, Dominioni L, Brackett KA, Joffe SN, Alexander JW. Mechanism of prevention of postburn hypermetabolism and catabolism by early enteral feeding. Ann Surg. 1984;200:297–10. 16. Gianotti L, Nelson JL, Alexander JW, Chalk CL, Pyles T. Post injury hypermetabolic response and magnitude of translocation: prevention by early enteral nutrition. Nutrition. 1994;10:225–31. 17. Magnotti LJ, Deitch EA. Burns, bacterial translocation, gut barrier function, and failure. J Burn Care Rehabil. 2005;26:383–91. Copyright © 2013 by the American Burn Association,
TI - A Protocol of Early Aggressive Acceleration of Tube Feeding Increases Ileus Without Perceptible Benefit in Severely Burned Patients
JF - Journal of Burn Care & Research
DO - 10.1097/BCR.0b013e3182a2a86e
DA - 2013-09-01
UR - https://www.deepdyve.com/lp/oxford-university-press/a-protocol-of-early-aggressive-acceleration-of-tube-feeding-increases-005dNSDb9i
SP - 515
EP - 520
VL - 34
IS - 5
DP - DeepDyve
ER -