Early ultrasound in acute appendicitis avoids CT in most patients but delays surgery and increases complicated appendicitis if nondiagnostic - A retrospective study.

BACKGROUND

We determined whether increasing early imaging (in the emergency department) was associated with earlier surgery and a decrease in complicated appendicitis.

METHODS

Retrospective study; 3013 operations between 12/2006-12/2016.

RESULTS

Early imaging increased from 13.1% to 74.1%, mostly due to increasing use of ultrasound. Negative appendectomies decreased from 10.7% to 5.1% (p < 0.001). Ultrasound was diagnostic in 80.5%. The false positive rate of ultrasound was 4%. Median time to surgery following positive ultrasound was 7.4 h (IQR 5.8-9.4), shorter compared to no early imaging (13.3 h, IQR 7.2-20.0; p < 0.001). However, median time to surgery following inconclusive and negative ultrasound was 11.5 h (IQR 8.7-16.1) and 17.0 h (IQR 10.3-26.7) respectively. The incidence of complicated appendicitis was 40% and 37.7%, higher than 21.5% in patients with positive US (p < 0.001).

CONCLUSIONS

Early imaging resulted in earlier surgery but did not reduce the incidence of complicated appendicitis. Ultrasound averted the need for CT in the majority of patients. When ultrasound was negative or inconclusive, time to surgery was delayed and the rate of complicated appendicitis higher.