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

Abstract

Background: 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 nonobese individuals undergoing robot-assisted prostatectomy. Methods: Forty males (age, 49e76 yr; BMI <30 kg m À2 ) undergoing prostatectomy received volume-controlled ventilation (tidal volume 8 ml kg À1 predicted body weight). Participants were randomised to either (1) RM followed by individualised PEEP (RM/PEEP IND ) optimised using electrical impedance tomography or (2) no RM with 5 cm H 2 O PEEP. The primary outcome was the ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO 2 /F i O 2 ) 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 IND were also assessed. Results: In 20 males randomised to RM/PEEP IND , the median PEEP IND was 14 cm H 2 O [inter-quartile range, 8e20]. The PaO 2 / F i O 2 was 10.0 kPa higher with RM/PEEP IND before extubation (95% confidence interval [CI], 2.6e17.3 kPa; P¼0.001). RM/ PEEP IND increased end-expiratory lung volume by 1.49 L (95% CI, 1.09e1.89 L; P<0.001). RM/PEEP IND also improved the regional ventilation of dependent lung regions. Vasopressor and fluid therapy was similar between groups, although 13 patients randomised to RM/PEEP IND required pharmacological therapy for bradycardia. Conclusion: 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. Clinical trial registration: DRKS00004199 (German clinical trials registry)

Individualized versus Fixed Positive End-expiratory Pressure for Intraoperative Mechanical Ventilation in Obese Patients: A Secondary Analysis

“…Furthermore, our results cannot be fully transferred to other patient populations or to laparoscopic procedures with different patient positioning, even if a recent publication found that comparable individualized PEEP values are necessary in normal-weight patients undergoing laparoscopic surgery in extreme Trendelenburg positioning. 32 Our study was neither designed nor powered to investigate the impact of an individualized PEEP strategy on the incidence of postoperative pulmonary complications. Considering the slightly higher rate of hemodynamic complications and the time needed for the PEEP titration, we strongly encourage (1) testing whether an individualized PEEP strategy also translates into a lower rate of postoperative pulmonary complications, and (2) searching for alternative methods for individualization of mechanical ventilation that would be more applicable in clinical routine.…”

Regional ventilation distribution in healthy lungs: can reference values be established for electrical impedance tomography parameters?

“…Similar questions need to be answered for other EITbased parameters, such as the global inhomogeneity (GI) index (20) and regional ventilation delay (RVD) (21), to assess the spatial and temporal ventilation distribution. The GI and RVD were proposed to guide PEEP optimization (4,22) and weaning from ventilation (23). Standard reference values for these parameters may aid in the clinical application of EIT.…”

Effects of individualized high positive end-expiratory pressure and crystalloid administration on postoperative pulmonary function in patients undergoing robotic-assisted radical prostatectomy: a prospective randomized single-blinded pilot study

“…Inadequately low PEEP values during laparoscopic surgery (in STP) favor the development of atelectasis and decreases pulmonary ventilation and oxygenation. Two current studies using electrical impedance tomography during RALP shows that a PEEP with 14 to 15 cmH 2 O improves oxygenation in non-obese individuals [32,33].…”