Intraoperative automated ST segment analysis: a reliable 'black box'?
OBJECTIVE
To review the application of intraoperative computerized ST analysis and its potential impact on postoperative outcomes.


METHODS
Existing anaesthesia and cardiology literature.


RESULTS
Computerized ST analysis was introduced into the operating room using exercise electrocardiographic (ECG) systems. In spite of sophisticated algorithms, errors do occur. Downsloping or horizontal ST depression are the classical criteria for ischaemia. Although algorithms have been developed and evaluated in exercise stress testing, only limited evaluation has been carried out in the operating room. This may be a concern since circumstances in the operating room may frequently lead to false positives. Similarly, studies suggest that all myocardial ischaemia may not exhibit ST changes. The diagnostic accuracy of ST depression in exercise stress testing also cannot be assumed in the operating room. Finally, if ST analysis is applied widely, without considering the population or disease prevalence, misdiagnosis may occur.


CONCLUSIONS
Given the number of anaesthetic tasks at-hand, on-line computerized ST analysis in the operating room can be a useful asset. The technology has its problems and should be applied with an understanding of its limitations and potential for errors. It should be applied in the operating room within the context of the population and disease prevalence.
Department of Anaesthesia, Hamilton Civic Hospitals, McMaster University, Ontario, Canada. yangh@FHS.McMaster.CA
H
H
Yang
D003951:Diagnostic Errors; D004562:Electrocardiography; D005080:Exercise Test; D006801:Humans; D016343:Monitoring, Intraoperative; D012815:Signal Processing, Computer-Assisted