Objectives: To describe current enteral nutrition-prescribing practices for critically ill patients, and to identify factors associated with initiation of, and tolerance to, enteral nutrition.
Design: A prospective, cohort study.
Setting: Two tertiary care medical-surgical intensive care units (ICU) in Ontario, Canada.
Patients: We enrolled 99 consecutive patients who were expected to stay in the ICU for > 3 days and who were unable to tolerate oral nutrition. We followed patients for 21 days or until they tolerated enteral nutrition, tolerated oral nutrition, were discharged from the ICU, or died.
Measurements and main results: We recorded time elapsed from ICU admission to initiation and tolerance of enteral feedings, and examined factors associated with these events. We defined tolerance as receiving 90% of estimated daily energy requirements for > 48 hrs without gastrointestinal dysfunction (i.e., high gastric residuals, vomiting, diarrhea, abdominal distention). Seventy-three (74%) of 99 patients were started on enteral feedings an average 3.1 days (range 1 to 18) after ICU admission. Of 26 patients never started on enteral nutrition, three (12.5%) patients eventually tolerated oral nutrition, 14 (54.0%) patients were discharged from the ICU, and seven (27.0%) patients died. Reasons for not initiating enteral nutrition included absence of bowel sounds (27.0%), high nasogastric drainage (16.9%), contraindication to enteral nutrition (16.7%), tolerance of oral nutrition (6.8%), and no apparent reason (5.1%). Abdominal surgery, use of vasoactive drugs, and admission to one hospital made initiation of enteral nutrition less likely, whereas presence of bowel sounds and admission to the other hospital made initiation of enteral nutrition more likely. Thirty-five (42.9%) of 73 patients started on enteral nutrition achieved tolerance of the regimen. The average time from ICU admission to tolerance of feedings was 5.8 days (range 1 to 14). Once started on enteral nutrition, the most common reasons for decreasing or discontinuing feedings included high gastric residuals (51.0%), mechanical feeding tube problems (15.4%), medical or surgical procedures (5.4%), and vomiting (5.1%). Use of paralytic agents and the presence of high gastric residuals were associated with intolerance. Of 38 patients who did not achieve tolerance, 20 (52.6%) patients were discharged from the ICU, eight (21.0%) patients died, and eight (21.0%) patients eventually tolerated oral nutrition.
Conclusions: Enteral nutrition is not started in all eligible ICU patients. Approximately half of those patients receiving enteral nutrition achieved tolerance of the regimen. Gastrointestinal dysfunction causing intolerance to enteral nutrition is a common reason for not starting, or discontinuing, feedings.