Accuracy and utilization patterns of intraabdominal imaging for major trauma in pregnancy

Imaging protocols for major maternal trauma during pregnancy are not standardized, and it is uncertain whether focused assessment with sonography for trauma or computed tomography of the abdomen/pelvis is preferred for detecting intraabdominal hemorrhage.

This study aimed to estimate the accuracy of focused assessment with sonography for trauma compared with computed tomography of the abdomen/pelvis, validate imaging accuracy with clinical outcomes, and describe clinical factors associated with each imaging mode.

A retrospective cohort study of pregnant patients evaluated for major trauma at one of two Level 1 trauma centers between 2003 and 2019. We identified 4 imaging groups: no intraabdominal imaging, focused assessment with sonography for trauma only, computed tomography of the abdomen/pelvis only, and both focused assessment with sonography for trauma and computed tomography of the abdomen/pelvis. The primary outcome was a composite maternal severe adverse pregnancy outcome, including death and intensive care unit admission. We estimated sensitivity, specificity, and positive and negative predictive values of focused assessment with sonography for trauma for hemorrhage with computed tomography of the abdomen/pelvis as the reference standard. We performed analysis of variance and chi-square tests to compare clinical factors and outcomes across imaging groups. Multinomial logistic regression was used to estimate associations between selected imaging mode and clinical factors.

Of 119 pregnant trauma patients, 31 (26.1%) experienced a maternal severe adverse pregnancy outcome. Intraabdominal imaging modes included none in 37.0%, focused assessment with sonography for trauma only in 21.0%, computed tomography of the abdomen/pelvis only in 25.2%, and both modes in 16.8%. With computed tomography of the abdomen/pelvis as the reference, focused assessment with sonography for trauma had sensitivity, specificity, positive predictive value, and negative predictive value of 11%, 91%, 50%, and 55%, respectively. One patient had a maternal severe adverse pregnancy outcome with a positive focused assessment with sonography for trauma and negative computed tomography of the abdomen/pelvis, and 2 patients with a positive computed tomography of the abdomen/pelvis did not have an adverse outcome. Use of computed tomography of the abdomen/pelvis with or without focused assessment with sonography for trauma was associated with a higher injury severity score, lower systolic blood pressure nadir, higher motor vehicle collision speed, and higher rates of hypotension, tachycardia, bone fracture, maternal severe adverse pregnancy outcome, and fetal demise. The association of computed tomography of the abdomen/pelvis use with higher injury severity score, tachycardia, and lower systolic blood pressure nadir persisted in multivariable analysis. With each 1-point increase in the injury severity score, there was an 11% higher likelihood of using computed tomography of the abdomen/pelvis over focused assessment with sonography for trauma for intraabdominal imaging.

The sensitivity of focused assessment with sonography for trauma in detecting intraabdominal hemorrhage in pregnant trauma patients is poor, and computed tomography of the abdomen/pelvis has a low false-negative rate. Providers seem to prefer computed tomography of the abdomen/pelvis to focused assessment with sonography for trauma in patients with the most severe trauma. Computed tomography of the abdomen/pelvis with or without focused assessment with sonography for trauma is more accurate than focused assessment with sonography for trauma alone.