Mechanical ventilation

Prostatectomy

Positive end-expiratory pressure

Oxygenation

Tidal volume

Anesthesia

Internal medicine

Prostate

Respiratory system

Medicine

Atelectasis

Laparoscopic radical prostatectomy

Cancer

Lung

British Journal of Anaesthesia

<h2>Abstract</h2><h3>Background</h3> Robot-assisted laparoscopic radical prostatectomy requires general anaesthesia, extreme Trendelenburg positioning and capnoperitoneum. Together these promote impaired pulmonary gas exchange caused by atelectasis and may contribute to postoperative pulmonary complications. In morbidly obese patients, a recruitment manoeuvre (RM) followed by individualised PEEP improves intraoperative oxygenation and end-expiratory lung volume (EELV). We hypothesised that individualised PEEP with initial RM similarly improves intraoperative oxygenation and EELV in non-obese individuals undergoing robot-assisted prostatectomy. <h3>Methods</h3> Forty males (age, 49–76 yr; BMI <30 kg m<sup>−2</sup>) undergoing prostatectomy received volume-controlled ventilation (tidal volume 8 ml kg<sup>−1</sup> predicted body weight). Participants were randomised to either (1) RM followed by individualised PEEP (RM/PEEP<sub>IND</sub>) optimised using electrical impedance tomography or (2) no RM with 5 cm H<sub>2</sub>O PEEP. The primary outcome was the ratio of arterial oxygen partial pressure to fractional inspired oxygen (<i>P</i>ao<sub>2</sub>/F<sub>i</sub>o<sub>2</sub>) before the last RM before extubation. Secondary outcomes included regional ventilation distribution and EELV which were measured before, during, and after anaesthesia. The cardiovascular effects of RM/PEEP<sub>IND</sub> were also assessed. <h3>Results</h3> In 20 males randomised to RM/PEEP<sub>IND</sub>, the median PEEP<sub>IND</sub> was 14 cm H<sub>2</sub>O [inter-quartile range, 8–20]. The <i>P</i>ao<sub>2</sub>/F<sub>i</sub>o<sub>2</sub> was 10.0 kPa higher with RM/PEEP<sub>IND</sub> before extubation (95% confidence interval [CI], 2.6–17.3 kPa; <i>P</i>=0.001). RM/PEEP<sub>IND</sub> increased end-expiratory lung volume by 1.49 L (95% CI, 1.09–1.89 L; <i>P</i><0.001). RM/PEEP<sub>IND</sub> also improved the regional ventilation of dependent lung regions. Vasopressor and fluid therapy was similar between groups, although 13 patients randomised to RM/PEEP<sub>IND</sub> required pharmacological therapy for bradycardia. <h3>Conclusion</h3> In non-obese males, an individualised ventilation strategy improved intraoperative oxygenation, which was associated with higher end-expiratory lung volumes during robot-assisted laparoscopic prostatectomy. <h3>Clinical trial registration</h3> DRKS00004199 (German clinical trials registry)

Individualised positive end-expiratory pressure guided by electrical impedance tomography for robot-assisted laparoscopic radical prostatectomy: a prospective, randomised controlled clinical trial