We relate an incident that occurred during a thyroid resection performed for malignant disease. Following excision of the specimen, the surgical field was irrigated using 30 mL of normal saline at ambient room temperature (24°C). An immediate asystole followed that responded to a combination of cardiac massage and pharmacologic intervention by the anesthetist. Given the absence of any other likely cause, we ascribed the event to the normal functioning of the carotid body.
Chemoreceptor and baroreceptor functions of the carotid body are well recognized. As a chemoreceptor, the carotid bodies are sensitive to alterations in PO2, PCO2, pH, and temperature.1-3 We hypothesize that the asystole occurred as a direct response to stimulation of the carotid body by the cold saline. This irrigation was performed gently and we were therefore not inclined to think that it could have been the result of baroreceptor activation. We believe that the