Postcesarean Delivery Use of a Modified FAST (Focused Assessment with Sonography for Trauma) Examination

A modified FAST (Focused Assessment with Sonography for Trauma) examination is increasingly being used in obstetrics as a rapid and low-cost tool to assess postoperative patients with possible intra-abdominal bleeding. The purpose of this study was to evaluate whether a modified FAST examination reliably detects, or excludes, intra-abdominal free fluid in postcesarean delivery obstetric patients when compared with gold-standard imaging, such as computed tomography or magnetic resonance imaging, or intraoperative findings on abdominal re-exploration.

This was a retrospective cohort study of patients who underwent cesarean delivery at a single institution between 2015 and 2020. The primary outcome was presence or absence of abdominal free fluid detected by modified FAST examination that was confirmed on formal imaging or abdominal re-exploration. Positive and negative predictive values, sensitivity, and specificity were calculated for modified FAST examination compared with gold-standard imaging or intraoperative findings on abdominal re-exploration.

Of the 35 patients with true-positive results, 16 (45.7%) had formal imaging only, 16 (45.7%) had abdominal re-exploration only, and three (8.6%) had both formal imaging and abdominal re-exploration.

Our analysis indicates that a modified FAST examination is a valid test for identifying intra-abdominal free fluid after cesarean delivery and supports its use in clinical decision making in obstetrics.