Abstract A computerized monitoring system has been described that can noninvasively obtain, process, display, and print out the vital signs contained on the standard anesthesia chart. This information was acquired during general surgical operations with a reliability and accuracy approaching that of anesthesia residents. More importantly, these data were collected with greater frequency, especially during events when the anesthesiologist was otherwise fully occupied with patient care. Although subjective bias is present in the interpretation of the anesthesia chart data when examining the discrepancies between man and the computerized system, we believe that significant changes in vital signs occurred and that they were frequently unnoticed or underestimated by man. Specifically, smoothing of irregular data or interpolation for missing data appeared to be human traits unmasked by this computerized system. Although a statistical significance cannot be assigned to these differences, the finding of 43 episodes in 100 cases implies that the incidence of these occurrences is not trivial. It also appears that during time of intense activity by the anesthesiologist, an automated system is more likely to detect significant physiologic changes as it is not clinically distracted. Accordingly, we believe that real-time computer generation of future anesthesia records will improve patient care by documenting significant changes that are often not observed under the current clinical system.