BACKGROUND: An anesthesia preinduction checklist (APIC) to be performed before anesthesia induction was introduced and evaluated with respect to 5 team-level outcomes, each being a surrogate end point for patient safety: information exchange (the percentage of checklist items exchanged by a team, out of 12 total items); knowledge of critical information (the percentage of critical information items out of 5 total items such as allergies, reported as known by the members of a team); team members' perceptions of safety (the median scores given by the members of a team on a continuous rating scale); their perception of teamwork (the median scores given by the members of a team on a continuous rating scale); and clinical performance (the percentage of completed items out of 14 required tasks, e.g., suction device checked). METHODS: A prospective interventional study comparing anesthesia teams using the APIC with a control group not using the APIC was performed using a multimethod design. Trained observers rated information exchange and clinical performance during on-site observations of anesthesia inductions. After the observations, each team member indicated the critical information items they knew and their perceptions of safety and teamwork. RESULTS: One hundred five teams using the APIC were compared with 100 teams not doing so. The medians of the team-level outcome scores in the APIC group versus the control group were as follows: information exchange: 100% vs 33% (P < 0.001), knowledge of critical information: 100% vs 90% (P < 0.001), perception of safety: 91% vs 84% (P < 0.001), perception of teamwork: 90% vs 86% (P = 0.028), and clinical performance: 93% vs 93% (P = 0.60). CONCLUSIONS: This study provides empirical evidence that the use of a preinduction checklist significantly improves information exchange, knowledge of critical information, and perception of safety in anesthesia teams-all parameters contributing to patient safety. There was a trend indicating improved perception of teamwork. The WHO Guidelines for Safe Surgery also encourage a formal inspection of the anesthetic equipment, breathing circuit, medications, and a patient's anesthetic risk before each case.The reason for introducing the separate anesthesia preinduction checklist (APIC), in addition to the already introduced WHO surgical safety checklist, was that the WHO surgical safety checklist contains only a few supercritical anesthesia items (e.g., checks of saturation sensor, but not electrocardiogram or blood pressure monitoring).In this study, we sought to evaluate whether the APIC complementing the WHO surgical safety checklist is suited to improve 5 team-level outcomes, each shown to be critical surrogate end points for patient safety: information exchange, knowledge of critical information, team members' perceptions of both safety and teamwork, and clinical performance. Figure 1 outlines the series of subitems assessed for the outcome scores: information exchange, knowledge of critical information, and clinical performance...