Voluntary reporting system in anaesthesia: is there a link between undesirable and critical events?

Background-Reporting systems in anaesthesia have generally focused on criti cal events (including death) to trigger investigations of latent and active errors. The decrease in the rate of these critical events calls for a broa der definition of significant anaesthetic events, such as hypotension and b radycardia, to monitor anaesthetic care. The association between merely und esirable events and critical events has not been established and needs to b e investigated by voluntary reporting systems. Objectives-To establish whether undesirable anaesthetic events are correlat ed with critical events in anaesthetic voluntary reporting systems. Methods-As part of a quality improvement project, a systematic reporting sy stem was implemented for monitoring 32 events during elective surgery in ou r hospital in 1996. The events were classified according to severity (criti cal/undesirable) and nature (process/outcome) and control charts and logist ic regression were used to analyse the data. Results-During a period of 30 months 22% of the 6439 procedures were associ ated with anaesthetic events, 15% of which were critical and 31% process re lated. A strong association was found between critical outcome events and c ritical process events (OR 11.5 (95% confidence interval (CI) 4.4 to 27.8)) , undesirable outcome events (OR 4.8 (95% CI 2.0 to 11.8)), and undesirable process events (OR 4.8 (95% CI 1.3 to 13.4)). For other classes of events, risk factors were related to the course of anaesthesia (duration, occurren ce of other events) and included factors determined during the pre-anaesthe tic visit (risk of haemorrhage, difficult intubation or allergic reaction). Conclusion-Undesirable events are associated with more severe events and wi th pre-anaesthetic risk factors. The way in which information on significan t events can be used is discussed, including better use of preoperative inf ormation, reduction in the collection of redundant information, and more st ructured reporting.