Constipation in the ICU: How Common? How Important?
Abstract & Commentary
By David J. Pierson, MD, Editor, Professor, Pulmonary and Critical Care Medicine, Harborview Medical Center, University of Washington, Seattle, is Editor for Critical Care Alert.
Synopsis: In this 6-month observational study in a surgical ICU, constipation occurred in 70% of patients who spent more than 3 days in the unit, did not appear to affect any outcome, and was less common among patients who received early enteral nutrition.
Source: Nassar AP Jr, et al. Constipation in intensive care unit: Incidence and risk factors. J Crit Care 2009 Jul 8; Epub ahead of print.
Nassar and colleagues at the University of São Paulo in Brazil investigated the incidence, associations, and outcomes of constipation among all patients admitted to their 14-bed surgical ICU during a 6-month period. They excluded patients who spent less than 3 days in the unit or who had undergone bowel surgery, and defined constipation as the absence of a bowel movement for at least 3 days. They looked at patient age and sex, the type of admission (postoperative, non-operative transfer from floor, or trauma), APACHE II score, and the use of opioids, antibiotics, and mechanical ventilation, as well as mortality, length of stay, and days free of mechanical ventilation. In the ICU in question, laxatives and other measures for promoting bowel movements were not routinely used.
After a priori exclusions, 106 patients fulfilled the entry criteria. Their mean age was 61, 64% were male, and the mean APACHE II score was 18. Sixty percent of the patients were admitted from the operating room, and 45% had undergone operations on the gastrointestinal tract. Thirty-six percent were admitted for non-operative reasons and 5% following trauma. Of the total, 72% of the patients were intubated upon ICU admission. Overall mortality was 38% in the ICU and 46% in the hospital.
A total of 73 patients (70%) had no bowel movement in at least 3 days in the ICU; none of these had been given laxatives or fecal emollients. There was no difference between constipated and non-constipated patients with respect to any of the variables examined except the early use of enteral nutrition. Enteral feeds had been started within 24 hours in 33 patients, 19% of those who were constipated and 58% of those who were not constipated (P < 0.01). Logistic regression analysis showed that the only variable independently associated with constipation was early enteral nutrition, with an odds ratio of 0.16 (95% confidence interval, 0.05-0.45; P < 0.001).
Commentary
This study shows that, in the investigators' ICU and under the conditions examined, constipation was very common and not obviously associated with complications, length of stay, or other outcomes. It is a fairly small study, however, and not really powered to demonstrate many such differences. Importantly, however, there was a clear association between the early use of enteral feeding and the return of bowel function.
Aside from its size, the study has some other limitations that affect its generalizability. It was done in a single institution and only in surgical patients, and whether constipation is a greater or lesser problem in the medical ICU or in other patient populations is uncertain. Early enteral feeding was used in only one-third of the patients, and at the discretion of the managing physicians, so we cannot know whether it was preferentially used in patients who were less ill or otherwise less likely to have constipation, or whether starting more patients on enteral feeding would have decreased the incidence of constipation. Although the authors did not find differences in the use of opioids among constipated and non-constipated patients, the paper does not report the quantities of narcotic used. The agent used in the study ICU was fentanyl, which may have less effect on bowel function than morphine. And no patient in the study who developed constipation had received laxatives or fecal emollients, so that the potential effect of specific efforts to prevent constipation was not addressed.
Admittedly, constipation is not a major problem in comparison with most others dealt with in the ICU. Nonetheless, it can be distressing for patients, and the absence of bowel activity after 3 or more days is one more problem the bedside nurse must contend with and discuss during bedside rounds. This study focuses our attention on a practical issue and provides additional evidence for the benefits of early enteral nutrition in critically ill patients.
Nassar and colleagues at the University of São Paulo in Brazil investigated the incidence, associations, and outcomes of constipation among all patients admitted to their 14-bed surgical ICU during a 6-month period.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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