A simplified approach to the management of gastric residual volumes in critically ill mechanically ventilated patients: a pilot prospective cohort study.

Background: Enteral nutrition in the critically ill patient is often complicated by gastrointestinal intolerance, manifested by a large gastric residual volume. The frequency of GRV assessment and the intolerant level above which feeding is stopped is controversial.

Objectives: To evaluate a novel approach to EN by allowing high GRV and once-daily assessment that was correlated with the paracetamol absorption test.

Methods: We conducted a pilot prospective study in an 18 bed general intensive care unit. The study group comprised 52 consecutive critically ill mechanically ventilated patients. Enteral nutrition was started at full delivery rate. Once-daily assessment of GRV with three consecutively repeated threshold volumes of 500 ml was performed before stopping EN. The paracetamol absorption test was performed and correlated to GRV. Patients were divided into two groups: low GRV (< 500 ml) and high GRV (at least one measurement of GRV > 500 ml). Clinical outcome included maximal calories delivered, incidence of pneumonia, ICU length of stay, and ICU and hospital mortality.

Results: There were 4 patients (9.5%) with ventilator-associated pneumonia in the low GRV group and 3 (30%) in the high GRV group (P = 0.12). GRV was inversely correlated to paracetamol absorption; however, neither GRV nor paracetamol absorption was associated with the development of pneumonia. Both groups had similar ICU length of stay (11.0 +/- 8.2 vs. 13.8 +/- 14.4 days, P = 0.41), and similar ICU (21% vs. 40%, P = 0.24) and hospital mortality (35% vs. 40%, P = 1.0).

Conclusions: In critically ill mechanically ventilated patients, allowing larger gastric residual volumes, measured once daily, enables enteral feeding with fewer interruptions which results in high calorie intake without significant complications or side effects.