Measurement and monitoring of surgical adverse events
The aim of this thesis is to investigate the validity of the measurement and the monitoring of surgical adverse events. Objectives: 1. To select surgical adverse events for detailed evaluation; 2. To investigate events with different epidemiological characteristics and attributes to assess the validity of their measurement and monitoring. Three events were selected: surgical wound infection, anastomotic leak and chronic post-surgical pain. Methods: Four systematic reviews and two epidemiological studies were conducted to investigate surgical wound infection, anastomotic leak and chronic post-surgical pain. A total of 41 definitions of wound infection were identified in the surgical literature, with little evidence of formal theoretical assessment of validity and reliability. Modified versions of Centres for Disease Control (CDC) definitions are currently used by UK nosocomial surveillance systems, although the impact of these modifications has not been evaluated. A total of 56 definitions for anastomotic leak were found. Although a national surgical consensus group proposed a definition for anastomotic leak, no evidence of its use was found in the surgical literature. The cohort study of 435 patients undergoing gastrointestinal surgery found that patients with anastomotic leak had poorer long-term survival at four years postoperatively, although patient numbers were small. The systematic review of chronic pain after cardiac study identified six prevalence studies worldwide, none of which used ‘standard’ definitions proposed by the International Association of the Study of Pain (IASP). A total of 1080 patients undergoing cardiac surgery at one regional cardiothoracic centre were assessed at two years postoperatively; the cumulative prevalence of chronic pain was 39% using a definition based on timing, location and pain characteristics.