Feasibility of pneumoperitoneum diagnosis using point-of-care ultrasound: a pilot study using a fresh cadaver model.

Abstract

To assess the accuracy of point-of-care ultrasound (PoCUS) in the hands of two trained and blinded emergencyphysicians (EPs) in detecting very small amounts of free intraperitoneal air injected intra-abdominally, using a fresh humancadaver model. Fifteen cadavers were injected on 3 occasions with predefined quantities of free intraperitonealair ranging from 0-10 mL. Seven cadavers were injected in the mid-epigastrium (ME), while 8 were injected inthe left lower quadrant (LLQ). Each cadaver was scanned after each of the 3 injections by 2 trained and blinded EPs, resultingin 45 scans per sonographer. Scans were performed using previously validated and standardized techniques. All scans wererecorded, time-stamped and labeled. For each scan the sonographers indicated "yes" or "no" to whether pneumoperitoneumwas detected. A chi square analysis was performed to determine the sensitivity and specificity of PoCUS utilized by each sonographerof pneumoperitoneum based on the location and volume of air injected. Free air (0.25-10 mL) injected intothe ME was successfully diagnosed in 36/42 instances (86% sensitivity), but only detected in 10/36 instances when injectedinto the LLQ (28% sensitivity). Both EPs detected all air injections of ≥2 mL into the ME. Detection of free airoriginating from the midepigastric region may become a future PoCUS indication for adequately trained EPs.