The surgical domain can be seen as more complex and high risk in its delivery of care than other non-interventional specialities. It is therefore not surprising that in the majority of studies of adverse events in healthcare, at least 50% occurred within the surgical domain and the majority of these in the operating theatre. Furthermore, at least half of these adverse events were also deemed preventable. Just as the multiple studies in the developed world have similar figures for adverse events in hospitalised patients across all specialities, there appears to be a similar rate of harm in surgery. A review of 14 studies, incorporating more than 16000 surgical patients, quoted an adverse event occurring in 14.4% of surgical patients. This was not simply minor harm; a full 3.6% of these adverse events were fatal, 10% severe and 34% moderately harmful. Gawande, a surgeon from Boston, made one of the first attempts to clarify the source of these adverse events.

This paper pioneered the concept that the majority of these adverse events were not due to lack of technical expertise or surgical skill on the part of the surgeon, finding instead that ‘systems factors’ were the main contributing factor in 86% of adverse events. The most common system factors quoted were related to the people involved and how they were functioning in their environment. Communication breakdown was a factor in 43% of incidents, individual cognitive factors (such as decision-making) were cited in 86%, with excessive workload, fatigue and the design or ergonomics of the environment also contributing.

These findings were confirmed in the systematic review of surgical adverse events, where it was found that errors in what were described as ‘nonoperative management’ were implicated in 8.32% of the study population versus only 2.5% contributed to by technical surgical error. In accordance with other high-risk industries, such as commercial aviation, the majority of these adverse events are therefore not caused by failures of technical skill on the part of the individual surgeon, but rather lie within the wider healthcare team, environment and system. Lapses and errors in communication, teamworking, leadership, situational awareness or decision-making all feature highly in post-hoc analysis of surgical adverse events. This knowledge of error causation has been prominent and acknowledged in most other high-risk industries for many years, but it is only recently that healthcare has appreciated this.