Over reliance on computed tomography imaging in patients with severe abdominal injury: is the delay worth the risk?

Computed tomography (CT) has a high sensitivity and specificity for detecting abdominal injuries. Expeditious abdominal imaging in "quasi-stable" patients may prevent negative laparotomy. However, the significance of potential delay to laparotomy secondary to abdominal imaging remains unknown. We sought to analyze whether the use of abdominal CT (ABD CT) in patients with abdominal injury requiring laparotomy results in a significant delay and a higher risk of poor outcome.

A retrospective analysis of data from the National Trauma Data Bank (version 7.1) was performed. Inclusion criteria were adult patients (age>14 years), a scene admission (nontransfer), hypotension on arrival (emergency department systolic blood pressure<90 mm Hg), an abdominal Abbreviated Injury Scale (AIS) score>3, and undergoing a laparotomy within 90 minutes of arrival. Patients with severe brain injury (head AIS score>3) were excluded. The independent mortality risk associated with a preoperative ABD CT was determined using logistic regression after controlling important confounders.

This cohort of patients (n=3,218) was significantly injured with a median Injury Severity Score of 25 ([interquartile range, 16-34]). Patients who underwent ABD CT had similar Glasgow Coma Scale scores, a lower head AIS, longer time delays to the operating room, and a higher crude mortality (45% vs. 30%; p=0.001). Logistic regression revealed that ABD CT was independently associated with more than a 70% higher risk of mortality (odds ratios, 1.71; 95% CI, 1.2-2.2; p<0.001). When stratified by injury mechanism, intubation status and whether or not a head CT was performed, the mortality risk remained significantly increased for each subgroup. When the laparotomy was able to occur within 30 minutes of arrival, an ABD CT was independently associated with more than a sevenfold higher risk of mortality (odds ratios, 7.6; p=0.038).

Delay secondary to abdominal imaging in patients who require operative intervention results in an independent higher risk of mortality. ABD CT imaging is an important and useful tool after injury; however, these results suggest that delay caused by overreliance on ABD CT may result in poor outcome in specific patients. Clinicians who take care of critically injured patients should be aware of and understand these potential risks.