The spectrum of patient monitoring techniques and equipment presently available in the operating room is reviewed from the anesthetist's viewpoint. Although electronic monitoring instruments are becoming more sophisticated with self-contained microprocessors or computer interfaces, few are designed for performance specifically within the hostile environment of the operating room. Intraoperative patient monitoring equipment lacks interchangeable transducers, facilities for automatic collection of physiological data, and methods for the display of trends in the patient's condition. Event recording during anesthesia depends upon the time-honored but inefficient handmade record of the anesthetist. Within the context of developing a computer-assisted monitoring and display system, this commentary presents the physician's perspective of instrumentation limitation and successes.