Nutrient intake is considered part of the global resuscitation

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1 Prospective Randomized Control Trial of Intermittent Versus Continuous Gastric Feeds for Critically Ill Trauma Patients Jana B. A. MacLeod, MD, Jennifer Lefton, RD, CNSD, Doug Houghton, MSN, Christina Roland, MD, James Doherty, MD, Stephen M. Cohn, MD, and Erik S. Barquist, MD Background: This study compared an intermittent feeding regimen (one-sixth of daily needs infused every 4 hours) with a continuous (drip) feeding regimen for critically ill trauma patients. There were two outcome variables: time to reach goal volume and the days on 100% of caloric needs via an enteral route in the first 10 days of the intensive care unit stay. Adverse events were also tallied. Methods: A prospective randomized trial was conducted in the trauma intensive care unit in a university Level I trauma center. A total of 164 trauma patients, 18 years of age and older were admitted to the trauma intensive care unit with a noninjured gastrointestinal tract and required more than 48 hours of mechanical ventilation. Patients were randomized to receive enteral nutrition via an intermittent feeding regimen versus a continuous feeding regimen. A single nutritionist calculated caloric and protein goals. A strict protocol was followed where hourly enteral intake, interruptions and their causes, diarrhea, and pneumonia were recorded, as well as standard guidelines for intolerance. Results: A total of 164 patients were randomized and 139 reached their calculated nutritional goal within 7 days. There were no statistical differences in complications of tube feeding. The patients intermittently fed reached the goal faster and by day 7 had a higher probability of being at goal than did the patients fed continuously ( , p 0.01). Intermittent patients maintained 100% of goal for 4 of 10 days per patient (95% CI ) as compared with the drip arm goal for only 3 of 10 days per patient (95% CI ). Conclusions: Patients from both the intermittent and continuous feeding regimens reached the goal during the study period of 7 days but the intermittent regimen patients reached goal enteral calories earlier. The intermittent gastric regimen is logistically simple and has equivalent outcomes to a standard dripfeeding regimen. Key Words: Nutrition, Enteral feeding, Outcome, Trauma, Randomized prospective clinical trial, Human, Critical illness. J Trauma. 2007;63: Nutrient intake is considered part of the global resuscitation of trauma patients. Once patients have been adequately resuscitated, enteral feedings are considered standard treatment of the critically ill trauma patients. 1 3 Enteral nutrition is preferred even in patients postlaparotomy and with open abdomens. 4 6 However, several studies have demonstrated suboptimal achievement of enteral goal nutrient intake. DeJonghe et al. reported significantly lower calories delivered when comparing enteral versus parenteral nutrition. 7 McClave et al. showed that only 51.6% of the nutritional goal was actually delivered to intensive care unit (ICU) patients. 8 The authors identified the practice of interrupting continuous feeds for the performance of procedures and diagnostics as a major factor contributing to the inability to maintain nutritional goals. Submitted for publication April 3, Accepted for publication September 26, Copyright 2007 by Lippincott Williams & Wilkins, Inc. From the Department of Surgery (J.B.A.M.), Emory University, Atlanta, Georgia; the Department of Surgery (J.L., D.H., C.R., E.S.B.), University of Miami, Miami, Florida; Advocate Christ Medical Center (J.D.), Oak Lawn, Illinois; and the Department of Surgery (S.M.C.), University of Texas Health Science Center, San Antonio, Texas. Address for reprints: Erik Barquist, MD, FACS, FCCM, 9380 SW 150th Street, Suite 100, Miami, FL 33176; ebarquis@med.miami.edu. DOI: /01.ta Enteral nutrition can be administrated either as a continuous infusion or as an intermittent feeding. A number of randomized controlled trials have compared continuous and intermittent feedings These studies showed comparable patient tolerance and safety between the two approaches. No previous study compared continuous with intermittent feedings for impact on the time to the prescribed caloric goal or maintenance of that goal. Any need for interruption of continuous tube feeds will affect total daily intake, because there is no way to make up for the interruption. We hypothesized that the intermittent enteral feeding route would optimize caloric intake in the first 7 days of critical illness as compared with continuous tube feedings, as the intermittent route is not impacted by treatment and diagnostic interruptions that occur in the critical care unit. PATIENTS AND METHODS A total of 164 patients admitted to the trauma intensive care unit (TICU) who were ordered by the staff intensivists to start enteral nutrition were randomized to one of two feeding regimens arms: intermittent or continuous. A single nutritionist calculated caloric and protein goals using 25 kcal/kg (ideal body weight) for caloric need. Protein was dosed at 1.5 gm/kg for each patient entered in the study. Randomization was performed using computer-generated random numbers kept individually in sealed envelopes. The investigational review Volume 63 Number 1 57

2 board (IRB) granted approval for the study protocol with waiver of consent. Inclusion criteria were age 18 years of age, a functional gastrointestinal (GI) tract, and planned mechanical ventilation for more than 48 hours. Patients were excluded if they met any of the following criteria: previous gastrectomy, massive intestinal resection with less than 200 cm of small intestine remaining, premorbid history of malabsorptive or motility or other GI disorder, morbid obesity (defined as body mass index [BMI] 35), any contraindication to oral or nasal tube placement, or if nutritional support had been initiated before admission to the TICU. The feeding regimens were initiated following a strict protocol for a predefined study period of 7 days using a Corpak 125 cm long 10F feeding tube (Viasys Healthcare, Conshohocken, PA) with a 18F Salem sump NG tube (Tyco Healthcare, Mansfield, MA) for residuals (Table 1). All patients were fed using a standard 1.0 cal/ml, high nitrogen formula. The intermittent protocol involved initial feeds of 100 ml every 4 hours. This was repeated twice and, if tolerated, they were advanced by 100 ml every 8 hours to the volume goal, determined by dividing the 24-hour goal by six. Each intermittent feeding was delivered via an enteral feeding pump during a 30- to 60-minute period of time. The NG/OG was clamped between feeding administration. Gastric residual volumes (GRVs) were checked every 4 hours before each intermittent feeding. The second arm, the continuous protocol, delivered a prescribed hourly volume based on 24-hour calculated goal. The volume was started at 20 ml/h for 8 hours and advancement was made in 20 ml/h increments every 8 hours to reach the volume goal. GRVs were checked every 4 hours. No materials outside of standardized enteral feeding care were utilized. For both arms, GRVs of 200 ml were considered markers of good tolerance and the protocol was advanced accordingly. Feeding intolerance was defined as aspiration of GRV 200 ml, excessive abdominal distension, vomiting, regurgitation, or tube feeds suctioned from the oropharynx and/or the airway. If feeding intolerance was diagnosed using these criteria then changes in enteral feeding were determined by a defined protocol as shown in Table 1. In this protocol, if feeding intolerance was diagnosed then feedings were held for 6 hours and restarted at the next lowest rate. If feedings were not tolerated a second time, they were held for another 6 hours and then restarted. Failure to successfully reestablish tolerance to enteral feeding for 12 consecutive hours mandated an additional 12-hour rest period for a total of 24 hours. Feedings were then restarted at the lowest rate for that protocol (100 ml bolus or 20 ml/h). Three consecutive failures were considered an enteral feeding failure and further decisions in regard to nutritional support were made by the appropriate attending physician on a case by case basis. The bedside nursing staff followed the protocol and performed data collection hourly. Daily validation of the data were performed by one of two authors using pump readings, direct patient clinical observation, and ICU flow sheets. All patient s data, whether they reached the goal in the defined study period or not, were entered for final analysis. A number of secondary endpoints were collected. They include the number of days on full enteral caloric support, time to initiation of enteral feeds, total time of tolerance of nutritional goal, onset of diarrhea, and incidence of pneumonia at 14 days (Centers for Disease Control and Prevention [CDC] definition). Demographic data, Acute Physiology and Chronic Health Evaluation (APACHE) II, Injury Severity Score (ISS), ICU days and disposition were collected. Data were expressed as the mean SEM for quantitative variables and proportions for categorical and binary variables. Statistical methods for comparison between groups used Student s t test for continuous variables and 2 test of proportions for categorical variables. Time to event data were analyzed and compared using Kaplan Meier curves and log rank sum tests to determine statistical significance between the curves. All tests for statistical significance were deter- Table 1 Enteral Feeding Protocol for Both Arms: Intermittent and Continuous. Time Gastric Residual Aspirate Intermittent Continuous Arm 0h 200 ml 3 Initiate 100 ml during mins 20 ml/h 200 ml 3 Hold tube feeds and recheck aspirate 4h 200 ml 3 Continue 100 ml during mins 20 ml/h 8h 200 ml 3 Increase 200 ml during mins 40 ml/h 12 h 200 ml 3 Continue 200 ml during mins 40 ml/h 16 h 200 ml 3 Increase 300 ml during mins 60 ml/h 20 h 200 ml 3 Increase 300 ml during mins 60 ml/h 24 h 200 ml ml during mins 80 ml/h Continue until goal reached Every 4 h 58 July 2007

3 Gastric Feeds for Critically Ill Trauma Patients Fig. 1. Trial profile. mined using an alpha level of All analyses were performed using Intercooled Stata Version 8.0 (Stata Corp., College Station, TX). RESULTS A total of 164 patients were enrolled in the study (Fig. 1). Four patients were randomized, two to each intervention arm, but did not have adequate data collection to be included in the analysis because of transfer to ICUs not involved in the study. Of the remaining 160 patients, 79 were randomized to the intermittent feeding regimen and 81 to the continuous feeding regimen. Blunt injuries accounted for 84.4% of the cases, 70.6% were male with a mean age of 46.5 (SD 20.3) years. There were 17 deaths, for a mortality rate of 6.5%. Table 2 shows there were no statistically significant differences across demographic characteristics for the two groups. There were 21 patients who did not reach the goal within the study period. Of these 21 patients, 8 died, whereas 6 had extubation before day 7 and were sent to the floor on a diet. The remaining cases included one patient with GI bleed, one patient with severe ileus, two patients who had intolerance to gastric feeding requiring small bowel feeding tube, and three patients whose enteral regimen protocol was not followed. Five of the six patients with an open abdomen reached goal enteral intake in the first 7 days of their ICU stay. The total calorie intake for the entire group in each arm (including all patients enrolled) as a percentage of the total required calories for the first 7 days of their ICU stay was Fig. 2. Kaplan Meier curve for cumulative incidence of achievement of 100% goal per 24-hour time period for the two intervention groups, intermittent and continuous. equivalent: 60.2% (SEM 4.2%) for intermittent as compared with 58.3% (SEM 4.0%) for continuous (p 0.05). The Kaplan Meier curve generated using the time to reach 100% nutrition per every 24-hour period showed that the intermittent patients reached the goal faster. In Figure 2, the log rank sum test shows that the intermittent regimen patients, by day 7, had a higher probability of being at goal than did the continuous regimen patients ( , p 0.01). There was no difference in the occurrence of diarrhea, emesis, or pneumonia between the two groups (Table 3). Many of the patients in the study reached the goal enteral caloric intake on only 1 or 2 days of the study and then subsequently, tolerated less than this amount of intake. For this reason, we also calculated the likelihood that a patient would remain on goal nutrition having tolerated it for at least one day. We measured the maintenance of enteral feeds at goal by calculating a ratio of the total number of days that the goal was maintained at 100% out of every 10 days of total postgoal enteral feeding per patient in each arm of the study. The intermittent regimen patients maintained goal level of enteral nutrition for 4 days per patient (95% CI ) as compared with the Table 2 Study Patient Demographics by Randomized Intervention Group Intermittent Feeding Regimen (N 79) Continuous Feeding Regimen (N 81) p Value for a Difference Between Groups Age (in yrs), mean SEM GCS, median (range*) 8 (6 11) 9 (6 11) 0.92 Gender: male, n (%) 53 (67) 60 (74) 0.33 ISS, median (range*) 29 (22 38) 29 (20 38) 0.87 APACHE II at randomization, median (range*) 12 (9 16) 14 (10 17) 0.46 Presence of open abdomen, n (%) 4 (5.1) 2 (2.5) 0.39 Blunt injury, n (%) 70 (89) 65 (80) 0.15 Length of ICU stay (in days), mean SEM Time to initiation of enteral nutrition (in days), mean SEM SEM, standard error of the mean. * Interquartile range (25% to 75%). Volume 63 Number 1 59

4 Table 3 Nutritional Outcomes and Adverse Events by Randomized Intervention Group Intermittent Feeding Regimen (N 79) Continuous Feeding Regimen (N 81) p Value for a Difference Between Groups Onset of diarrhea, n (%) 5 (6.3) 3 (3.7) 0.45 ICU mortality rate, n (%) 11 (13.9) 6 (7.4) 0.18 Patients extubated prior to day 5 (6.3) 7 (8.6) of study, n (%) New onset pneumonia, n (%) 38 (48) 33 (41) 0.45 drip arm patients, which maintained goal for only 3 days per patient (95% CI ). DISCUSSION The present study confirms the findings of previous authors that suggest no difference in serious complication rates between continuous and intermittent feedings The increased frequency and duration of diarrhea observed by Ciocon et al. in patients receiving intermittent feedings was not demonstrated in our patients. 11 The difference may be a result of the age difference between the two populations investigated, because our intermittent group feeding regimens were identical. Review of the data from individual test subjects identified feeding interruption in the continuous feeding regimen as a major source of the difference between the groups. Interruptions were most commonly caused by preoperative holding of tube feeds. This is consistent with other studies in the literature, which reported similar difficulties. 7,8 Intermittent regimens represent a logistically simple method by which delivery of nutritional intake may continue uninterrupted despite the necessity for multiple procedures and diagnostics that traditionally require discontinuance of continuous enteral feeds. Our study suggests that gastric enteral feeding can be performed via an intermittent feeding regimen without increasing complication rates. When studied in ICUs with experience in gastric feeding, nutrition delivered to the stomach does not have an increased complication rate when compared with that of small bowel delivery Further studies to investigate whether this method of administration actually improves nutritional status of the patient are needed. This study has limitations. There is a possibility of ascertainment bias because the study was not and could not be blinded. Even though the nurses the recorded the hourly enteral feed amount on the data sheet and the nurse was aware of the patient s group in the study, this amount was validated every 24 hours by the total on the patient s feeding pump by one of the study teams. Therefore, it was unlikely that an inaccurate amount was entered based on a nursing bias toward one route of feeding compared with the other. There is no data on nutritional outcomes because we did not measure prealbumin levels or other markers of nutritional status. The percentage of total caloric estimated need delivered between the two groups was not statistically different because of the time-insensitive nature of this global calculation. The Kaplan Meier curve demonstrates that the greatest difference between the groups occurred on days 4 and 5 after traumatic injury. There was a nonsignificant trend to a higher mortality in the intermittently fed group. The temporal distribution of the deaths and the equal distribution of pneumonia across the groups make a real difference between groups unlikely. This observed difference in mortality rates would occur 18% of the time because of random chance. CONCLUSIONS In a critically ill trauma population, patients fed an intermittent regimen received goal enteral nutrition more quickly and were more likely to remain at goal enteral caloric intake than were patients fed with continuous feeding regimens. The clinical significance of this increased caloric delivery is not known. REFERENCES 1. 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