Gut function in the intensive care unit - What is 'normal'?

BACKGROUND

Management of gut function in the intensive care unit (ICU) is often protocol-driven. Protocols for enteral feeding or bowel management are based on assumptions about what is 'normal' gastrointestinal motility during critical illness or in the early postoperative period, although 'normal' has not been well described in this group.

OBJECTIVES

This study aimed to describe aspects of gut function based on an audit of current ICU patients.

METHODS

A retrospective medical audit of 100 recent consecutive ICU patients was conducted to obtain data on gut function parameters in the critically ill or postoperative population.

RESULTS

The audit indicated that delayed gastric emptying is common in the ICU. Regardless of the definition volume used, large gastric aspirates occurred in most enterally fed patients. Patient positioning was a significant influence, with a bed angle <30° associated with increased gastric aspirates (p = 0.0002). Constipation was more common among enterally fed patients than among orally fed ones (p = 0.001) and was associated with opioids (p = 0.009). Diarrhoea was associated with antibiotic use (p = 0.047). For enterally fed patients, the first bowel motion in the ICU occurred on average day 4.60 (standard deviation, 2.78), compared to day 2.72 (standard deviation, 1.67) for orally fed patients (p = 0.0001).

CONCLUSION

Alteration of upper and lower gastrointestinal motility is common in critically ill and early postoperative patients. Care should be taken in interpreting protocols that relate to gut function to avoid unnecessary interventions or interruptions to nutritional therapy.