Is fasting still necessary prior to contrast-enhanced computed tomography? A randomized clinical study.

Objectives: There is very limited evidence to support the common practice of preparative fasting prior to contrast-enhanced computerized tomography (CT). This study examined the effect of withholding fasting orders, prior to contrast-enhanced CT, on the incidence of aspiration pneumonitis and adverse gastrointestinal symptoms.

Methods: This randomized controlled trial enrolled hospitalized patients referred for non-emergency, contrast-enhanced CT scan to either at least 4 h of fasting or to an unrestricted consumption of liquids and solids up to the time of CT. The primary outcome was incidence of aspiration pneumonitis and the secondary outcomes were rates of adverse gastrointestinal symptoms (nausea and/or vomiting).

Results: After excluding participants with incomplete follow-up, a total of 1080 participants were assigned to the fasting group and 1011 were assigned to the non-fasting group. Aspiration pneumonitis was not identified in either group. The mean time of fasting in the fasting group was 8.4 ± 1.6 h. Rates of nausea and vomiting were not statistically different between the fasting group compared with the non-fasting group, 6.6% vs. 7.6% (p = 0.37) and 2.6% vs. 3.0% (p = 0.58), respectively. A subgroup analysis of patients who were required to drink oral contrast agent (n = 1257) showed that rates of nausea and vomiting were not statistically different between the fasting and non-fasting groups, 6.8% vs. 8.0% (p = 0.42) and 2.6% vs. 3.6% (p = 0.3), respectively.

Conclusions: Withholding fasting orders prior to contrast-enhanced CT was not associated with a greater risk of aspiration pneumonitis or a significant increase in rates of adverse gastrointestinal symptoms.

Trial Registration: ClinicalTrials.gov : NCT03533348 KEY POINTS: • Is fasting necessary prior to contrast-enhanced computed tomography (CT)? • In this randomized clinical study including 2091 participants referred to non-emergency contrast-enhanced CT scan, withholding preparative fasting was not associated with a greater risk of aspiration pneumonitis or clinically significant increase in rates of adverse gastrointestinal symptoms. • Eating and drinking prior to contrast-enhanced CT can be allowed and are not associated with an increased risk of aspiration pneumonitis.