A retrospective evaluation of point of care ultrasound for acute cholecystitis in a tertiary academic hospital setting

Abstract

Background In 2008 the Council of Emergency Medicine Residency Directors delineated consensus recommendations for training in biliary ultrasound for the “detection of biliary pathology”. Objectives While studies have looked at the accuracy of emergency provider performed clinical ultrasound (ECUS), we sought to evaluated if ECUS could be diagnostic for acute cholecystitis and thus obviate the need for follow-up imaging. Method We reviewed all ECUS performed between 2012 and 2017 that had a matching radiology performed ultrasound (RADUS) and a discharge diagnosis. 332 studies were identified. The sensitivity and specificity of both ECUS and RADUS were compared to the patient’s discharge diagnosis. The agreement between the ECUS and RADUS was assessed using an unweighted Cohen’s Kappa. The time from patient arrival to diagnosis by ECUS and RADUS was also compared. Results Using discharge diagnosis as the gold standard ECUS was 67% (56–78%) sensitive, 88% (84–92%) specific, NPV 90% (87–95%), PPV 60% (50–71%), +LR 5.6 (3.9–8.2), −LR 0.37 (0.27–0.52) for acute cholecystitis. RADUS was 76% (66–87%) sensitive, 97% (95–99%) specific, NPV 95% (092–97%), PPV 86% (76–95%), +LR 25.6 (12.8–51.4), and −LR 0.24 (0.15–0.38). ECUS was able to detect gallstones with 93% (89–96%) sensitivity and 94% (90–98%) specificity leading to a NPV 90% (85–95%), PPV of 95% (92–98%), +LR 14.5 (7.7–27.4), −LR 0.08 (0.05–0.13). The unweighted kappa between ECUS and RADUS was 0.57. The median time between obtaining ECUS vs. RADUS diagnosis was 124 min. Conclusions ECUS can be beneficial in ruling out acute cholecystitis, but lacks the test characteristics to be diagnostic for acute cholecystitis.

Point‐of‐care ultrasound to diagnose acute cholecystitis in the emergency department: A scoping review

“…Seven prospective observational studies compared both POCUS and RADUS against a reference standard for the diagnosis of acute cholecystitis (Table 2). 11,32,42–46 In two out of seven studies, the POCUS operator was a surgeon 43,45 . In the remaining five studies, the POCUS operator was an ED doctor 13,34,42,44,46 .…”

“… 11,32,42–46 In two out of seven studies, the POCUS operator was a surgeon 43,45 . In the remaining five studies, the POCUS operator was an ED doctor 13,34,42,44,46 . Of the seven studies, four reported the accuracy of a mixture of secondary signs 11,42,43,46 .…”

“…When POCUS and RADUS were compared against a reference standard, POCUS was found to be less accurate than RADUS in most cases, with the conclusion drawn that POCUS is accurate enough to rule in or out cholelithiasis, but confirmatory imaging would still be required when evaluating acute cholecystitis. 11,32,[42][43][44][45][46] The degree of operator experience is likely to be a considerable factor in this discrepancy. Summers et al 11 showed similar accuracy of POCUS when compared to RADUS in diagnosing acute cholecystitis and its secondary signs, with POCUS sensitivity and specificity even surpassing that of RADUS in detecting acute cholecystitis overall.…”

“…43,45 In the remaining five studies, the POCUS operator was an ED doctor. 13,34,42,44,46 Of the seven studies, four reported the accuracy of a mixture of secondary signs. 11,42,43,46 The reference standards used included surgical and pathology reports in two studies, 11,46 pathology report in one study, 45 discharge diagnosis in two studies, 42,44 a combination of pathology report and discharge diagnosis in one study 43 and clinical follow-up in one study.…”

“…32 Five of the seven studies found POCUS to be inferior to RADUS in diagnosing acute cholecystitis or its secondary signs, with POCUS sensitivity lower than that of RADUS. [42][43][44][45][46] Notably, the two studies that found POCUS to have the lowest accuracy in diagnosing acute cholecystitis both included inexperienced ultrasound operators and were of comparatively small sample sizes. 44,46 Of the two studies that found POCUS to be more accurate, the reported POCUS diagnostic parameters were marginally superior to that of RADUS.…”