title: Continuous versus bolus tube feeds: Does the modality affect glycemic variability, tube feeding volume, caloric intake, or insulin utilization?
abstract: BACKGROUND
  Enteral nutrition (EN) is very important to optimizing outcomes in critical illness. Debate exists regarding the best strategy for enteral tube feeding (TF), with concerns that bolus TF (BTF) may increase glycemic variability (GV) but result in fewer nutritional interruptions than continuous TF (CTF). This study examines if there is a difference in GV, insulin usage, TF volume, and caloric delivery among intensive care patients receiving BTF versus CTF. We hypothesize that there are no significant differences between CTF and BTF when comparing the above parameters.
  
  
  METHODS
  Prospective, randomized pilot study of critically ill adult patients undergoing percutaneous endoscopic gastrostomy (PEG) placement for EN was performed between March 1, 2012 and May 15, 2014. Patients were randomized to BTF or CTF. Glucose values, insulin use, TF volume, and calories administered were recorded. Data were organized into 12-h epochs for statistical analyses and GV determination. In addition, time to ≥80% nutritional delivery goal, demographics, Acute Physiology and Chronic Health Evaluation II scores, and TF interruptions were examined. When performing BTF versus CTF assessments, continuous parameters were compared using Mann-Whitney U-test or repeated measures t-test, as appropriate. Categorical data were analyzed using Fisher's exact test.
  
  
  RESULTS
  No significant demographic or physiologic differences between the CTF (n = 24) and BTF (n = 26) groups were seen. The immediate post-PEG 12-h epoch showed significantly lower GV and median TF volume for patients in the CTF group. All subsequent epochs (up to 18 days post-PEG) showed no differences in GV, insulin use, TF volume, or caloric intake. Insulin use for both groups increased when comparing the first 24 h post-PEG values to measurements from day 8. There were no differences in TF interruptions, time to ≥80% nutritional delivery goal, or hypoglycemic episodes.
  
  
  CONCLUSIONS
  This study demonstrated no clinically relevant differences in GV, insulin use, TF volume or caloric intake between BTF and CTF groups. Despite some shortcomings, our data suggest that providers should not feel limited to BTF or CTF because of concerns for GV, time to goal nutrition, insulin use, or caloric intake, and should consider other factors such as resource utilization, ease of administration, and/or institutional/patient characteristics.
authors.affiliation: Department of Surgery, Ohio State University College of Medicine, Columbus, Ohio, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Evans
authors.affiliation: Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors.forename: Rachel
authors.initials: R
authors.lastname: Forbes
authors.affiliation: Department of Surgery, Ohio State University College of Medicine, Columbus, Ohio, USA.
authors.forename: Christian
authors.initials: C
authors.lastname: Jones
authors.affiliation: Department of Surgery, Ohio State University College of Medicine, Columbus, Ohio, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Cotterman
authors.affiliation: Department of Surgery, Ohio State University College of Medicine, Columbus, Ohio, USA.
authors.forename: Chinedu
authors.initials: C
authors.lastname: Njoku
authors.affiliation: Department of Anesthesiology, Ohio State University College of Medicine, Columbus, Ohio, USA.
authors.forename: Cattleya
authors.initials: C
authors.lastname: Thongrong
authors.affiliation: Department of Anesthesiology, Ohio State University College of Medicine, Columbus, Ohio, USA.
authors.forename: David
authors.initials: D
authors.lastname: Tulman
authors.affiliation: Department of Anesthesiology, Ohio State University College of Medicine, Columbus, Ohio, USA.
authors.forename: Sergio D
authors.initials: SD
authors.lastname: Bergese
authors.affiliation: Department of Clinical Nutrition, Ohio State University College of Medicine, Columbus, Ohio, USA.
authors.forename: Sheela
authors.initials: S
authors.lastname: Thomas
authors.affiliation: Department of Anesthesiology, Ohio State University College of Medicine, Columbus, Ohio, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Papadimos
authors.affiliation: Department of Research and Innovation, St. Luke's University Hospital, Bethlehem, Pennsylvania, USA.
authors.forename: Stanislaw P
authors.initials: SP
authors.lastname: Stawicki
keywords: Continuous tube feeding; enteral nutrition; glycemic variability; intermittent tube feeding; percutaneous endoscopic gastrostomy; tube feeding