Effect of oral contrast administration for abdominal computed tomography in the evaluation of acute blunt trauma

Abstract

Study objective: To determine how frequently oral contrast medium (OC) is essential for computed tomography (CT) diagnosis of blunt intraabdominal injury and to quantify the delay associated with OC administration and the incidence of adverse effects.

Methods: This retrospective chart review, with prospective reevaluation of CT scans for diagnostic value of OC, took place in a university teaching hospital and Level l trauma center. Participants were blunt-trauma victims admitted between June 1, 1988, and November 1, 1993, who had abdominal CT as part of their initial evaluation. Trauma registry records were used to identify study patients. Available charts and CTs were reviewed for all patients with intestinal/mesenteric and pancreatic injuries. Randomly selected cases of liver injury, spleen injury, and no intraabdominal injury were also reviewed. Blinded CT scans were reevaluated for quality of bowel opacification and value of OC to diagnostic impression.

Results: During the study period, 2,162 blunt-trauma patients had an abdominal CT; 297 intraabdominal injuries were diagnosed in 248 patients. Full review was done on 124 charts, and 70 CT scans were reevaluated. Thirty-one (100%) of 31 liver and spleen injuries were diagnosed on CT, and OC was considered essential in none of these studies. One (4.5%) of 22 intestinal and mesenteric injuries was seen on CT, but this was the only such injury treated nonoperatively. None of 21 surgically confirmed intestinal/mesenteric injuries was seen on CT. Free air or free OC was seen in none of 7 cases of intestinal perforation. OC was judged essential in none of 20 scans in patients without intraabdominal injury. On 2 scans. OC was considered essential for the radiographic diagnosis. One of these was a normal pancreas at exploration (radiographic false-positive result). The only pancreatic injury requiring specific surgical treatment was missed on CT. Twenty-one percent of patients required placement of nasogastric tube for contrast administration after failing oral administration, and 23% vomited OC. One of 124 had documented aspiration of OC. Average additional time incurred in the ED for administration of OC was 144 minutes.

Conclusion: OC is rarely essential for CT diagnosis of intraabdominal injury. It may improve sensitivity for pancreatic injury, but it does not help identify injuries requiring surgical treatment. Even with OC, CT is insensitive for intestinal injury. Vomiting and aspiration are significant risks. Use of OC adds a significant amount of time to ED evaluation. Adverse effects of OC administration, in this setting, may outweigh its benefits.