Effects of positive end-expiratory pressure on intracranial pressure during pneumoperitoneum and Trendelenburg position in a porcine model*

Abstract

IntroductionRobot-assisted laparoscopic surgery has developed greatly and is becoming a standard technique for radical prostatectomy. It is widely preferred for pelvic surgeries because of its important advantages that minimize postoperative morbidity and mortality. Robotic surgeries in the pelvic region, including radical prostatectomy, rectum resection, and gynecologic procedures, usually require a steep Trendelenburg position and carbon dioxide pneumoperitoneum to secure the surgical field. Pneumoperitoneum combined with steep Trendelenburg position may cause significant changes in cardiovascular, respiratory, and neurophysiological parameters (1,2). Both the increase in abdominal pressure as a result of carbon dioxide insufflation and the head-down position have been shown to impair respiratory functions during the procedure by pushing the diaphragm upward and reducing lung volume and respiratory compliance, thus inducing atelectasis formation (3,4).Background/aim: This study was undertaken to evaluate the effects of positive end-expiratory pressure (PEEP) levels on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) and to determine the appropriate PEEP level during steep Trendelenburg position combined with pneumoperitoneum. Materials and methods:Ten pigs were included in this study. Pneumoperitoneum and Trendelenburg position were maintained and PEEP titration was initiated. Arterial pressure, heart rate, arterial blood gas, ICP, and CPP were recorded at the following time points: baseline (T0), 30 min after positioning and pneumoperitoneum (T1), PEEP 5 (T2), PEEP 10 (T3), PEEP 15 (T4), and PEEP 20 (T5).Results: MAP significantly increased at T1 compared to T0 and decreased at T4 and T5 compared to T1. ICP was 9.5 mmHg and CPP was 69.3 mmHg at T0. CO 2 insufflation and steep Trendelenburg position did not cause any significant difference in ICP and CPP. ICP increased and CPP decreased significantly at T4 and T5 compared to both T0 and T1. PaO 2 and PaO 2 /FiO 2 decreased significantly at T1 and T2 compared to T0, while both increased significantly at T3, T4, and T5 compared to T1. Conclusion:PEEP of 10 cmH 2 O was effective for providing oxygenation while preserving hemodynamic stability, ICP, and CPP in this model.

The effects of positive end-expiratory pressure (PEEP) application on optic nerve sheath diameter in patients undergoing laparoscopic cholecystectomy: a randomized trial

“…In a recent study performed by Bedirli et al 18 on pigs, the authors reported that PEEP pressure at 10 cmH 2 O maintained the intracranial pressure and brain perfusion pressure in laparoscopic surgery performed with the aid of pneumoperitoneum. In their study, PEEP pressures of 15 cmH 2 O and 20 cmH 2 O were shown to increase intracranial pressure and significantly decrease brain perfusion pressure.…”