The DELAY Trial will compare immediate (< 6 hours from decision to operate) to delayed (Surgery to take place the following morning) appendectomy in adult patients presenting to the emergency department with suspected acute appendicitis. The primary outcome will be 30 day postoperative complications.

This randomized controlled trial is designed to assess the effect of timing of surgery on surgical complications in patients undergoing appendectomy for acute appendicitis at one of two participating institutions.

Early appendectomy in patients diagnosed with acute appendicitis has been a mainstay of treatment. Timely intervention is recommended to avoid the risks associated with perforated appendicitis, which has been shown to increase the risk of post-operative complications compared to non-perforated appendicitis. However, some studies have suggested that delaying appendectomy does not increase complications. Several studies have also assessed the safety of nighttime operating with conflicting results. Some suggest that delaying surgery until daytime is safe.

This study is a prospective, randomized controlled trial with blinding of the outcome assessors. Eligible participants will be adult patients diagnosed with acute appendicitis with an expected operative start time between 2000-0400. Patients randomized to the intervention group will have delayed surgery after 0530 the following morning to avoid nighttime operating. Patients randomized to the control group will receive immediate surgery within 6 hours of the decision to operate. The follow up period will be a minimum of 30 days. Independent outcome assessors will assess patients during their postoperative course in hospital as well as in the outpatient follow up clinic.

The primary outcome for this study is complication occurring within 30 days of surgery. Complication includes any of the following: mortality, readmission to hospital, emergency department (ED) visit, percutaneous drain insertion, reoperation, prolonged hospital stay greater than 7 days, and a predefined list of postoperative complications. Secondary outcomes include perforated appendicitis, operative time, and length of stay.

Inclusion Criteria:

• Adult patients ≥ 18 years of age
• Imaging confirmed diagnosis of appendicitis (ultrasound or CT or MRI)
• Expected time of operation between 2200 - 0400 and occurs within 6 hours of the decision to operate

Exclusion Criteria:

• Patients with hemodynamic instability
• Patients with suspected sepsis
• Unknown diagnosis
• Presence of abscess on CT Scan
• Diagnosis of missed appendicitis
• Pregnancy
• Patients who are not surgical candidates
• Patients who are not competent to sign consent

Outcome assessors will be blinded to the intervention.