Incidence and pattern of intraoperative hemodynamic response to endoscopic third ventriculostomy

Background: In patients undergoing endoscopic third ventriculostomy (ETV), various cardiovascular changes occur in the intraoperative period. Aim: We tried to determine a pattern in these changes and their relation to different surgical steps. Materials and Methods: A total of 260 patients were studied over a period of six years. Heart rate and mean arterial pressures were recorded before introduction of the endoscope and thereafter at various stages of the operation. Results: Tachycardia was the predominant observed abnormality in 20% of patients, occurring mostly during manipulations and irrigation in the third ventricle (TV). Bradycardia was seen in 12% of patients, more often during fenestration of the floor of the third ventricle. Conclusions: Tachycardia observed during ETV may be related to hypothalamic stimulation or a rise in intracranial pressure and bradycardia may be due to stimulation of the hypothalamus or the third cranial nerve. Anticipation of these cardiovascular changes during the relevant steps of the operation can help in taking appropriate corrective action, thus preventing potentially serious complications of ETV.