Randomised controlled trial of ultrasonography in diagnosis of acute appendicitis, incorporating the Alvarado score.

OBJECTIVES: To determine whether diagnosis by graded compression ultrasonography improves clinical outcomes for patients with suspected appendicitis.

DESIGN: A randomised controlled trial comparing clinical diagnosis (control) with a diagnostic protocol incorporating ultrasonography and the Alvarado score (intervention group).

SETTING: Single tertiary referral centre.

PARTICIPANTS: 302 patients (age 5-82 years) referred to the surgical service with suspected appendicitis. 160 patients were randomised to the intervention group, of whom 129 underwent ultrasonography. Ultrasonography was omitted for patients with extreme Alvarado scores (1-3, 9, or 10) unless requested by the admitting surgical team.

MAIN OUTCOME MEASURES: Time to operation, duration of hospital stay, and adverse outcomes, including non-therapeutic operations and delayed treatment in association with perforation.

RESULTS: Sensitivity and specificity of ultrasonography were measured at 94. 7% and 88.9%, respectively. Patients in the intervention group who underwent therapeutic operation had a significantly shorter mean time to operation than patients in the control group (7.0 v 10.2 hours, P=0.016). There were no differences between groups in mean duration of hospital stay (53.4 v 54.5 hours, P=0.84), proportion of patients undergoing a non-therapeutic operation (9% v 11%, P=0.59) or delayed treatment in association with perforation (3% v 1%, P=0.45).

CONCLUSION: Graded compression ultrasonography is an accurate procedure that leads to the prompt diagnosis and early treatment of many cases of appendicitis, although it does not prevent adverse outcomes or reduce length of hospital stay.