Human Perception: The Way We See Things

Abstract

The anesthetist decided to extubate his patient and first needed to test the patient’s ability to breathe spontaneously. Because of a handling error, the anesthesia machine was not switched into a spontaneous breathing mode, but instead the machine continued to mechanically ventilate the patient. In the mistaken conviction that the patient was breathing on his own, the anesthetist interpreted his clinical observation and the information gathered from his monitor as signs of adequate spontaneous breathing. He saw regular and deep chest excursions, the flawless pattern of the capnography curve and an expiratory minute volume close to what he expected. This evidence reinforced his conviction that the patient could be safely extubated. Other minor problems arose that diverted some of his attention for a short while and he did not realize that his monitor was showing additional ventilation curves that contradicted current assumption (e.g., the pressure/time curve and the flow/time curve). Because he accepted his perception as being in agreement with his working hypotheses of a spontaneously breathing patient, a critical re-examination of the situation did not occur until the patient had serious problems.