Randomization and Blinding
SENSITIVITY
To reduce contamination effects and improve protocol adherence, ORs (rather than patients) were randomized 1:1 to the control or intervention group each day using centrally generated sequences. All patients in each OR for that day had the same treatment assignment. Operating room randomization was balanced on a 1:1 ratio for each day; however, because some ORs had no cases on some days, the allocation ratio varied randomly, with a mean of 1. Randomization was included in the ACT display interface. Patients received either usual intraoperative care comprising medical direction from the anesthesia care team (control group) or usual care augmented by telemedicine decision support from the ACT (intervention group).Patients were blinded to group allocation. Operating room clinicians were unblinded if contacted by the ACT but were not aware of their allocation otherwise. Clinicians in the ACT monitored patients in the control group but did not contact intraoperative clinicians unless there was a patient safety issue necessitating immediate action, such as failure to deliver an anesthetic agent. There were no changes to OR staffing based on group allocation. Patients with another surgical procedure within 30 days after an index operation were analyzed according to their previous treatment assignment. Because the interface did not track individual-level previous randomizations, in subsequent procedures, patients received the treatment per the new OR day’s independent randomization. Surgical procedures received more than 30 days after an index operation were analyzed according to the new randomization. This strategy was chosen in the protocol to reduce contamination effects due to ACT-assisted management plans carried over to subsequent procedures. Sensitivity analyses excluded previous treatment assignments and used only the first operation in a 30-day window.