Preparative Fasting Orders for Medical/Surgical Interventions and Imaging Studies: Time to Review and Revise!

Abstract

Purpose of the review: Preparative fasting orders arose out of a purported need to enhance imaging studies, reduce interference of food with intended medical/surgical interventions, and protect the patient from vomiting and aspiration pneumonia. This review discusses the frequency, appropriateness, and efficacy of fasting orders in meeting those needs and whether their use should be modified in the future.

Recent findings: Nil per os (NPO) orders are overused, as they are often inappropriate, typically excessive, and routinely create barriers which may increase risk for patients. Fasting orders are used more often for medical procedures than for surgical operations or imaging studies. One fourth of NPO orders are inappropriate, and the intended procedure or study is canceled 20% of the time usually for a change in plans or scheduling error and rarely because of patient eating. Nausea/vomiting associated with contrast media or imaging studies is rare, self-limited, and not linked to preparatory fluid or food ingestion. Prolonged fasting reduces patient cooperation and satisfaction, and may contribute to a higher rate of complications. Each institution should review and revise preparative fasting orders. Drinking of fluids should be allowed without restriction. Truncated periods of solid food restriction may be required due to technical reasons related to specific imaging studies, and for procedures or surgical operations which require sedation or general anesthesia. Inappropriate and prolonged fasting should be avoided, as they create barriers to adequate nutritional therapy and impose added risk with regard to patient outcomes.

Keywords: Aspiration; Contrast-enhanced computerized tomography; Fasting; Ileus; Nausea/vomiting; Nil per os; Pneumonia.