Fig. 2

Blinding set-up. Blinding study drug entails unique considerations because propofol is a white intravenous infusion while isoflurane is a clear colorless volatile liquid that is administered via a specialized inhalational delivery device, the Sedaconda ACD. Plastic wraps are used to cover the propofol bottle and infusion line (or their dummy equivalent), as well as the Sedaconda ACD (or heat-moisture exchanger) placed inline with the ventilator circuit. A volatile anesthetic scavenger is placed on the ventilator exhaust and gas sampling monitor connected to the ACD or heat-moisture exchanger in both arms (not shown). The gas sampling monitor displays only end-tidal carbon dioxide by default to preserve blinding, though the study team can access additional data views as needed for periodic recording of end-tidal isoflurane concentration in patients assigned to the intervention arm