Objectives To evaluate the effectiveness of aviation-style teamwork training in improving operating theatre team performance and clinical outcomes.

Setting 3 operating theatres in a UK district general hospital, 1 acting as a control group and the other 2 as the intervention group.

Participants 72 operations (37 intervention, 35 control) were observed in full by 2 trained observers during two 3-month observation periods, before and after the intervention period.

Interventions A 1-day teamwork training course for all staff, followed by 6 weeks of weekly in-service coaching to embed learning.

Primary and secondary outcome measures We measured team non-technical skills using Oxford NOTECHS II, (evaluating the whole team and the surgical, anaesthetic and nursing subteams, and evaluated technical performance using the Glitch count. We evaluated compliance with the WHO checklist by recording whether time-out (T/O) and sign-out (S/O) were attempted, and whether T/O was fully complied with. We recorded complications, re-admissions and duration of hospital stay using hospital administrative data. We compared the before–after change in the intervention and control groups using 2-way analysis of variance (ANOVA) and regression modelling.

Results Mean NOTECHS II score increased significantly from 71.6 to 75.4 in the active group but remained static in the control group (p=0.047). Among staff subgroups, the nursing score increased significantly (p=0.006), but the anaesthetic and surgical scores did not. The attempt rate for WHO T/O procedures increased significantly in both active and control groups, but full compliance with T/O improved only in the active group (p=0.003). Mean glitch rate was unchanged in the control group but increased significantly (7.2–10.2/h, p=0.002) in the active group.

Conclusions Teamwork training was associated with improved non-technical skills in theatre teams but also with a rise in operative glitches.