DIAGNOSTIC ACCURACY OF FAST SCAN TO DETECT ABDOMINAL FREE FLUID KEEPING CT ABDOMEN & PELVIS AS GOLD STANDARD

Abstract

Background: Emergency room practitioners depend on the focused assessment with sonography for trauma (FAST) scan to evaluate patients with blunt abdominal trauma for free intraperitoneal fluid at their bedside. FAST delivers dependable results, though the accuracy level depends on the operational circumstances. The diagnosis of intra-abdominal injuries alongside free fluid depends on computed tomography (CT) examination of the abdomen and pelvis [1, 2]. The diagnostic accuracy of FAST regarding CT detection of intraperitoneal free fluid in adult blunt-trauma patients was assessed in patients at Combined Military Hospital Rawalpindi.

Methodology: Following their admission to the study over six months, 65 adult blunt-trauma patients received TOSHIBA XARIO 200 ultrasound for FAST immediately preceding (≤2 h) GE OPTIMA-CT 660 contrast-enhanced CT scanning. The study employed qualified emergency physician operators to perform FAST examinations while maintaining blind awareness of CT results and the radiologists followed a similar procedure when interpreting CT data without viewing FAST findings. The study established diagnostic precision through sensitivity, specificity, PPV, NPV, overall accuracy statistics with their corresponding 95% confidence intervals. The designed sample size was intended to measure an 85% ± 5% sensitivity range with 80% power at a significance level of α = 0.05 [3].

Results: The CT examination showed 26/65 (40.0%) cases with free fluid and 39/65 (60.0%) cases without free fluid. Thirty-one of sixty-five patients (25 cases) received positive FAST results, while forty patients received negative results (both results were confirmed by expert assessment). Results demonstrated FAST obtained sensitivity rates at 84.6% (95% CI 65.1–95.6) with specificity at 92.3% (95% CI 79.1–98.4) along with PPV at 88.0% (95% CI 68.8–97.5) and NPV at 90.0% (95% CI 76.3–97.2) and overall accuracy was established at 89.2% (95% CI 78.1–95.8). The time needed for FAST completion was 5 min (IQR 4–7) but obtaining a CT report took 45 min (IQR 40–60) (p < 0.001). No adverse events occurred.

Conclusions: The ability of the TOSHIBA XARIO 200 used at CMH Rawalpindi to diagnose free fluids in blunt abdominal trauma cases demonstrates good ability to detect such fluids with high specificity and sensitivity at the bedside. GE OPTIMA-CT 660 CT procedures must be conducted after a negative FAST result but before the clinical doubt disappears. The initial assessment of FAST represents a valuable method to screen stable blood pressure patients.

The examination methods of FAST, along with ultrasound and CT abdomen, demonstrate strong diagnostic precision in detecting free fluid among patients who suffered blunt trauma injuries.