Low Tidal Volume Positive End-Expiratory Pressure versus High Tidal Volume Zero-Positive End-Expiratory Pressure and Postoperative Pulmonary Functions in Robot-Assisted Laparoscopic Radical Prostatectomy

Abstract

<b><i>Objective:</i></b> The aim was to compare the effects of low tidal volume (V<sub>T</sub>) and moderate positive end-expiratory pressure (PEEP) with high V<sub>T</sub> and zero end-expiratory pressure (ZEEP) on postoperative pulmonary functions and oxygenation in patients undergoing robot-assisted laparoscopic radical prostatectomy. <b><i>Subjects and Methods:</i></b> Forty-four patients were randomized into low V<sub>T</sub>-PEEP and high V<sub>T</sub>-ZEEP groups. The patients were ventilated with a V<sub>T</sub> of 6 mL/kg and 8 cm H<sub>2</sub>O PEEP in the low V<sub>T</sub>-PEEP group and a V<sub>T</sub> of 10 mL/kg and 0 cm H<sub>2</sub>O PEEP in the high V<sub>T</sub>-ZEEP group. Preoperative and postoperative spirometric measurements were done and chest X-rays were evaluated using the radiological atelectasis score (RAS). <i>p</i> < 0.05 was considered statistically significant. <b><i>Results:</i></b> The intraoperative and postoperative arterial partial pressure of oxygen and arterial oxygen saturation values were significantly higher in the low V<sub>T</sub>-PEEP group than in the high V<sub>T</sub>-ZEEP group. At all times, the arterial-to-alveolar oxygenation gradients were significantly lower in the low V<sub>T</sub>-PEEP group than in the high V<sub>T</sub>-ZEEP group. Preoperative RAS were similar in both groups, but the postoperative RAS was significantly lower in the low V<sub>T</sub>-PEEP group (<i>p</i> < 0.001). Forced vital capacity, forced expiratory volume in 1 s, and peak expiratory flow rate recorded postoperatively were significantly lower in the high V<sub>T</sub>-ZEEP group (<i>p</i> < 0.001). <b><i>Conclusions:</i></b> Postoperative pulmonary functions were less impaired in patients ventilated with a V<sub>T</sub> of 6 mL/kg and 8 cm H<sub>2</sub>O PEEP than in patients ventilated with a V<sub>T</sub> of 10 mL/kg and ZEEP.