Bradycardia and sinus arrest following saline irrigation of the brain during epilepsy surgery

Adverse cardiac events during the intraoperative period are life-threatening. The authors report three episodes of severe bradycardia and sinus arrest that occurred in a patient undergoing anterior temporal lobectomy and amygdalo-hippocampectomy for the treatment of epilepsy. The first episode occurred during resection of the amygdala; the other two episodes were observed during subsequent irrigation of the exposed brain structures, most likely the brain stem structures, because of a rent that the surgeon had deliberately made into the basilar cistern for better anatomic appreciation of the structures to be excised. The patient responded well to treatment with no adverse outcomes. The probable mechanisms leading to this event are discussed; the authors excluded insular cortex stimulation, the effects of the anesthetic drugs used, and venous air embolism as a cause of bradycardia and sinus arrest. The amygdala resection was the most likely cause of the first episode of bradycardia; the second episode of bradycardia and sinus arrest occurred because of inadvertent stimulation of brain structures by the high temperature (42 degree C) of the saline used for irrigation. To counter its effects, saline irrigation at room temperature (20 degree C) was started, and this caused the third episode of bradycardia, most likely because of "temperature shock" of the exposed brain. Prompt communication with the surgical team and vigilance are crucial for the appropriate management of such an incident, which may pose a threat to life. Avoiding irrigation of the exposed brain with high-temperature saline may prevent such an incident.