Surgeon-performed ultrasound and timing of surgery in acute cholecystitis

Abstract

Introduction: The use of bedside ultrasound has increased, as equipment has become accessible, user friendly, and ultrasound education is expanding in many specialties. The aim of this project was to validate surgeon-performed ultrasound and to optimise the surgical treatment for patients with acute cholecystitis, in particular in planning timing of surgery.

Methods: Papers I-III represent prospective clinical studies where patients with gallstones, acute cholecystitis or appendicitis were included. Sensitivity, specificity, accuracy, and predictive values of surgeon-performed ultrasound were calculated for these diagnoses. Radiologist-performed ultrasound was used as reference for the diagnosis of gallstones (Paper I). In acute cholecystitis, internationally accepted criteria for the diagnosis were used as reference, and in appendicitis, operation logs were used to verify the diagnosis (Paper II). In Paper III, patients with diagnosed acute cholecystitis were included and followed with repeated daily ultrasounds, during admission. The study had a descriptive design, where measures of the gallbladder wall, gallbladder volume, and gallbladder wall oedema were followed over time. Paper IV consists of a register-based cohort study with retrospectively analysed data from the National Register for Gallstone surgery. Out-of-hours surgery was considered independent variable and the primary outcome was any complication within 30 days. Secondary outcomes were proportion of open procedures and operative time exceeding two hours. Logistic regression models were used to adjust for confounders.

Results: Papers I and II. Sensitivity for surgeon-performed ultrasound was 88.2% in diagnosing gallstones. Specificity was 99.0% and the accuracy was 94.4%. The sensitivity for surgeon-performed ultrasound in diagnosing acute cholecystitis was 60.0%, specificity 98.6%, and accuracy 93.9%. For appendicitis the sensitivity was 53.3%, specificity 89.7%, and accuracy 77.3%. Paper III. The gallbladder volume and gallbladder wall thickness were mostly stable over time, with a slight tendency to decrease among the 37 patients that received repeated examinations. The presence of gallbladder wall oedema did not change over time. Paper IV. Out-of-hours cholecystectomy did not result in a higher proportion of complications 15.6% versus 13.6% (adjusted odds ratio 1.12 (95% CI 0.99-1.28)), but in a higher proportion of open procedures 37.9% versus 28.9% (adjusted odds ratio 1.39 (1.25-1.54)). There was a lower proportion of long procedures out of hours, 40.4% versus 55.8% (adjusted odds ratio 0.63 (0.58-0.69)).

Conclusion: Surgeon-performed ultrasound can be used to diagnose gallstones with high accuracy. Diagnosing acute cholecystitis and appendicitis with ultrasound is more challenging, but examinations with a positive test can help to confirm a clinically suspected diagnosis. The use of ultrasonography in preoperative risk scoring for acute cholecystitis needs to be further evaluated. Out-of-hours surgery for acute cholecystitis is not associated with a higher risk of complications, but with a higher proportion of open procedures.