Fasting before contrast-enhanced CT in the emergency department and risk of aspiration pneumonia

We aimed to assess the necessity of preparative fasting for contrast-enhanced abdominopelvic computed tomography (CT) in the emergency department to prevent emetic complications including aspiration pneumonia. This retrospective, observational, single-center study included patients who underwent contrast-enhanced abdominopelvic CT in the emergency department from January 2015 to December 2022. In a predefined subgroup of 5170 examinations performed between January and June 2022, fasting status was inferred from CT-based stomach content assessment. Patients were categorized into fasting and non-fasting groups based on a collapsed stomach or stomach distension with fluid and food materials. Risk factors of iodinated contrast media-related adverse drug reactions (ADRs) were analyzed with inverse probability of treatment weighting to adjust for confounding factors. Among 81,886 examinations, 806 acute ADRs (0.98%) were reported. The incidences of nausea, vomiting, and nausea or vomiting were 0.25%, 0.21%, and 0.32%, respectively. No cases of aspiration pneumonia were noted. Among 5170 examinations, symptoms of ADR were analyzed, revealing an overall ADR incidence of 0.52% in the fasting group and 0.96% in the non-fasting group (odds ratio [OR] 1.85; 95% confidence interval [CI]: 0.90–3.82; P  = .097). The incidence of nausea or vomiting was 0.18% and 0.44% in the fasting and non-fasting groups, respectively (OR 2.41; 95% CI: 0.78–7.50; P  = .128). The result was consistent in inverse probability of treatment weighting, overall ADR incidence of 0.52% in the fasting group and 0.92% in the non-fasting group (OR 1.77; 95% CI: 0.85–3.68; P  = .125). No statistically significant difference in iodinated contrast media-related ADR was observed between the fasting and non-fasting groups, and no cases of aspiration pneumonia were identified.