ObjectivePaediatric cardiac surgery has a low error tolerance and demands high levels of cognitive and technical performance. Growing evidence suggests that further improvements in patient outcomes depend on system factors, in particular, effective team skills. The hypotheses that small intraoperative non-routine events (NREs) can escalate to more serious situations and that effective teamwork can prevent the development of serious situations were examined to develop a method to assess these skills and to provide evidence for improvements in training and performance. MethodsThis mixed-method design, using both quantitative and qualitative measures, relied on trained human factor observers who observed and coded NREs and teamwork elements from the time of patient arrival into the operating room to patient handover to the intensive care unit. Real-time teamwork observations were coupled with microsystem preparedness measures, operative duration, assessed difficulty of the operation and patient outcome measures. Behaviour was rated based on whether it hindered or enhanced teamwork. Results40 paediatric cardiac surgery cases were observed. Surgeons displayed better teamwork during complicated procedures, particularly during the surgical bypass/repair epoch. More procedural NREs were associated with a more complicated postoperative course (Muncomplicated=9.08; Mminor complications=11.11; Mmajor morbidity=14.60, F(2,26)=3.46, p<0.05). Procedural NREs decreased substantially over time (M1=13.5; M2=7.1, F(1,37)=33.07, p<0.001). ConclusionsStructured observation of effective teamwork in the operating room can identify substantive deficiencies in the system and conduct of procedures, even in otherwise successful operations. High performing teams are more resilient displaying effective teamwork when operations become more difficult.