Adverse Effects Monitoring

Hypotension is defined as blood pressure below 75% of the preoperative baseline and is listed as a monitored adverse effect. Respiratory depression is defined as a respiratory rate below 12 breaths per minute with shallow breathing. Serious adverse events must be reported in writing to the sponsor and site ethics committee within 24 hours. Antiemetic prophylaxis is guided by the Apfel risk score; patients with more than two risk factors receive three antiemetics. Pruritus is measured using the Peak Pruritus Numeric Rating Scale, ranging from 0 for no itch to 10 for worst imaginable itch. A Data Monitoring Committee comprising ethicists, clinicians and statisticians meets quarterly to assess serious adverse events and advise on whether the trial should continue.