Effects of laparoscopic radical prostatectomy on intraoperative autonomic nervous system control of hemodynamics.

Background: Laparoscopic radical prostatectomy induces hemodynamic changes that have been supposed due to autonomic nervous system activity. The aim of this study is to measure the sympathetic and vagal modulation on hemodynamic response to steep Trendelenburg and pneumoperitoneum for laparoscopic surgery.

Methods: Autonomic nervous system modulation was assessed noninvasively through heart rate variability and arterial pressure variability analysis in patients undergoing elective laparoscopic radical prostatectomy and in awake volunteers during head-down tilt.

Results: Forty patients and 14 awake volunteers were studied. The induction of general anesthesia significantly decreased the heart rate, arterial pressure, vagal modulation, and sympathetic modulation. Steep Trendelenburg increased vagal and sympathetic modulation both in anesthetized and awake subjects. Pneumoperitoneum increased arterial pressure without effect on autonomic nervous system control in anesthetized patients.

Conclusions: Hemodynamic changes occurring during laparoscopic radical prostatectomy reveal autonomic response to the challenges (i.e. general anesthesia and head down position), and non-neurally mediated increase of arterial pressure caused by pneumoperitoneum. This study supports the notion that during laparoscopic radical prostatectomy the association between the vagal stimulation due to Trendelenburg positioning and sympathetic withdrawal caused by general anesthesia could lead to severe bradycardia and cardiac arrest in risky patients.