Different ventilation techniques and hemodynamic optimization to maintain regional cerebral oxygen saturation (rScO2) during laparoscopic bariatric surgery: a prospective randomized interventional study

Purpose The purpose of this study was to assess the changes in regional cerebral oxygen saturation (rScO 2 ) in response to different ventilation strategies: inspired oxygen concentration (FiO 2 ), end-tidal carbon dioxide (EtCO 2 ), and positive end expiratory pressure (PEEP) in addition to optimizing mean arterial pressure (MAP) in obese patients subjected to laparoscopic bariatric surgery in the reverse trendelenburg position. Methods 50 obese patients were randomly assigned into one of two groups. Each group is 25 patients. Control patients subjected to a ventilation strategy aimed to maintain FiO 2 0.4 and EtCO 2 30 mmHg without PEEP. Study patients were assigned to specific protocol; T0, baseline rScO 2 ; T1, 5 min following induction; T2, PP/RTP (10 min after pneumoperitoneum and reverse trendelenburg position); T3, PEEP 10 cmH 2 O; T4, FiO 2 1.0; T5, EtCO 2 40 mmHg and T6, MAP/BL; MAP back to baseline in both groups. Main results 10 min after PP/RTP, there was a significant decrease in rScO 2 in both groups. At T4, with FiO 2 1.0, there was significant improvement in rScO 2 when compared to T2. At T5, with EtCO 2 40 mmHg, rScO 2 significantly enhanced when compared to EtCO 2 30 mmHg. At T4 and T5, we observed highly significance difference between both groups. At the end of the procedure and when MAP increased back to baseline (T6) in both groups, rScO 2 statistically increased in both groups when compared to T2. Conclusion In obese patients, subjected to laparoscopic bariatric surgery in reverse trendelenburg position, adjustment of ventilation strategies and hemodynamic optimization succeeded to improve rScO 2 .