Purpose: To evaluate the evidence on the value of preparative fluid fasting for patients undergoing elective computed tomography (CT) with intravenous administration of contrast material and to survey leading institutions in a number of countries on their current policies in this regard.
Materials and methods: This study qualified for exempt status by the institutional review board. First, 20 keyword combinations were entered into Medline to ascertain the correlation between fluid ingestion preceding contrast material-enhanced CT and development of aspiration pneumonia. The numbers of patients were summed up to estimate incidence of aspiration pneumonia attributable to ingestion of clear inert fluid before contrast-enhanced CT examination. Second, a multinational survey was conducted about the length of preparative fasting protocols, if any, for fluids and solids that they recommend to patients before elective non-gastrointestinal contrast-enhanced CT.
Results: Aspiration was not noted in any of 2001 patients (13 studies in the literature) who underwent contrast-enhanced CT after fluid ingestion. Data were available from 69 (86.3%) of 80 institutions queried (17 Korean, 14 U.S., 11 French, 10 Australian, 10 German, and seven Egyptian hospitals). Two-thirds (14 of 21 [66.7%]) of the French and German hospitals had a no-restriction policy for both fluids and solids, while Australian hospitals had a policy liberal about fluids (no restrictions in eight of 10 [80%]) only. Policies on fluids were variable in Korea, the United States, and Egypt (restrictions of 0-8 hours, 0-4 hours, and 0-6 hours, respectively), as were policies on solids in Korea, the United States, Australia, and Egypt (restrictions of 0-8 hours, 0-6 hours, 0 to 4-6 hours, and 0 hours to overnight, respectively). The length of fasting was longer for solids than for fluids in 20 hospitals.
Conclusion: There is little evidence that ingestion of clear inert fluid prior to contrast-enhanced CT is a cause of aspiration pneumonia; the length of fasting is variable in any country, being much longer in some hospitals than in others.