Pharmacologic Management of Constipation in the Critically Ill Patient

Asad E. Patanwala, Pharm.D.; Jacob Abarca, Pharm.D., M.S.; Yvonne Huckleberry, Pharm.D.; Brian L. Erstad, Pharm.D., FCCP


Pharmacotherapy. 2006;26(7):896-902. 

In This Article

Abstract and Introduction

Study Objective: To compare the effectiveness of common laxatives in producing a bowel movement in patients admitted to a medical intensive care unit (MICU).
Design: Retrospective medical record review.
Setting: MICU of an academic medical center.
Patients: Ninety-five patients admitted to the MICU from July 1–October 31, 2004.
Measurements and Main Results: Fifty patients satisfied the inclusion criteria. Patient-specific data such as age, weight, sex, length of MICU stay, Acute Physiology and Chronic Health Evaluation (APACHE) II score, dietary intake, opioid intake, laxative intake, and bowel movements were recorded during the first 96 hours of admission. Logistic regression analysis was used to compare patients who did and did not have a bowel movement. Of the 50 patients, 25 did not have a bowel movement during the first 96 hours of MICU admission. Patients given a stimulant laxative (senna, bisacodyl) and/or an osmotic laxative (lactulose, milk of magnesia) were more likely to have a bowel movement (odds ratio [OR] 26.6, 95% confidence interval [CI] 3.2–221, p=0.002). Opioid intake, expressed as logarithmic morphine equivalents, was negatively associated with occurrence of a bowel movement (OR 0.76, 95% CI 0.59–0.97, p=0.027). Disease severity, as determined by APACHE II score, was also negatively associated with a bowel movement (OR 0.84, 95% CI 0.7–0.99, p=0.04).
Conclusion: Critically ill patients have a high frequency of constipation, and opioid therapy is a significant risk factor. Routine administration of stimulant or osmotic laxatives should be considered for this patient population.

The epidemiology of constipation in the general population depends on the definition of constipation. In an effort to introduce uniform standards to clinical research, a consensus definition of constipation was developed.[1,2] This definition incorporates several components, such as straining, hard stools, feelings of incomplete evacuation, and three or fewer bowel movements/ week. United States and British community-based population surveys have estimated that the prevalence of constipation varies from 2–28% depending on the definition used. However, little data exist regarding prevalence of constipation in critically ill patients. In this population, measurement of bowel consistency is highly subjective, and symptomatic constipation cannot be ascertained accurately.

Constipation has been defined as the lack of a bowel movement for 3 consecutive days, and the frequency has been found to be as high as 83% in critically ill patients.[3] Risk of constipation is increased in critically ill patients due to immobility, inability to act or respond to the urge to defecate, and opioid use, which can result in abdominal distension, vomiting, restlessness, gut obstruction, and perforation. Constipation also has been implicated in prolonged mechanical ventilation and in delayed start of enteral nutrition.

Implementation of an inpatient constipation protocol in non–intensive care patients has reduced the frequency of constipation.[4] This protocol involves risk assessment and dietary interventions that often would not apply to intensive care patients. Little information has been published regarding management of constipation in critically ill patients.

Several therapeutic modalities are available to the intensive care clinician for treating consti-pation. However, due to the lack of published literature, questions still exist regarding the optimal use of laxatives for intensive care patients. Therefore, we compared the effectiveness of common laxatives in producing a bowel movement in patients admitted to a medical intensive care unit (MICU).


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