Alarms in the operating room.

Historically anaesthetists employed only their senses to monitor patients during the conduct of anaesthesia. Recent developments have made the continuous watching of patient, devices, and every instrumental display virtually impossible. Hearing is an essential communication channel between instrument and user. The human auditory system responds most to the timing of sound stimuli so that a transient increase in firing of auditory neurons may be produced by the termination of sound as well as by its inception. However, instruments are usually equipped with warning noises which need to be interpreted by the user and characteristic sounds which are suitable for the operating room environment have been designed. ~'2 Loudness can be regulated automatically according to environmental noise 3 although this seems to be unnecessary in a medical environment. Automated voice messages that can conform to an almost infinite variety of information requirements 4 are possible but await application to our needs. Although audible alarms are necessary and have been credited with saving lives some anaesthetists deliberately disarm them. 5 This implies that they do not believe that audible alarms increase patient safety. Thus the discovery by Loeb e t al . 6 and Finley and Cohen reported in this journal that some anaesthetists could not identify audible alarms is not surprising. The recognition performance of the subjects would probably be better in their own operating rooms because several communication channels are used simultaneously for tasks in real world situations. The wide disparity between laboratory and real life situations does not justify speculation about the clinical performance of these subjects and the experimental design precludes application to anaesthetists in general. Nevertheless, these investigations draw our attention to an increasingly important aspect of contemporary anaesthesia communication of urgent information from instrument to anaesthetist. There are many complaints about traditional warning devices which include the aggravation of false alarms, the wide variety of alarms as well as difficulty in their interpretation. However, research and development continue to encourage the consistent and effective use of audible alarms. For example, "smart" monitoring systems automatically collect and analyze data before communicating 7-9 and these aid diagnosis and reduce the number of false alarms. In other arrangements the variety has been reduced in a unified system that confines individual warnings to four or five categories, according to physiology, or anaesthesia delivery. In another, the sensitivity of a single warning channel can be reduced, to Encouraging though this is there are some concerns particularly with regard to a reduction in sensitivity to decrease the number of false alarms. A shift to a more conservative criterion is likely to reduce the number of serious situations that will be detected. Smart alarms are an attractive way to improve both the quality of the anaesthetist's working environment and his performance during periods of decreased vigilance and we await reports of clinical testing of such systems. Industry has responded to the needs of the users and there is an urgent need to evaluate these "smart" systems in anaesthesia equipment. Study design methods already exist. I= In the meantime, a consortium funded by the Commission of the European Communities has established the Advanced Information in Medicine Programme (AIM). This collaboration of experts, including clinicians, is developing information management and decision support for high patient dependency environments such as operating rooms. Ergonomics is not a newcomer to clinical anaesthesia journals. 12-1a The evolution of technology to assist human sensing of patients' needs demands that we take an academic interest in our interaction with the instruments we use. Such considerations are essential for the neophyte and expert, for old and young. Not only will knowledge help anaesthetists to purchase carefully and critically from an industry that is increasingly responsive to their needs but it will ensure that the present displays, controls, and patients are arranged in the best interests of patient safety.