Different ventilation techniques and hemodynamic optimization to maintain regional cerebral oxygen saturation (rScO₂)...

The purpose of this study was to assess the changes in regional cerebral oxygen saturation (rScO₂) in response to different ventilation strategies: inspired oxygen concentration (FiO₂), end-tidal carbon dioxide (EtCO₂), 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.

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 FiO₂ 0.4 and EtCO₂ 30 mmHg without PEEP. Study patients were assigned to specific protocol; T0, baseline rScO₂; T1, 5 min following induction; T2, PP/RTP (10 min after pneumoperitoneum and reverse trendelenburg position); T3, PEEP 10 cmH₂O; T4, FiO₂ 1.0; T5, EtCO₂ 40 mmHg and T6, MAP/BL; MAP back to baseline in both groups.

10 min after PP/RTP, there was a significant decrease in rScO₂ in both groups. At T4, with FiO₂ 1.0, there was significant improvement in rScO₂ when compared to T2. At T5, with EtCO₂ 40 mmHg, rScO₂ significantly enhanced when compared to EtCO₂ 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, rScO₂ statistically increased in both groups when compared to T2.

In obese patients, subjected to laparoscopic bariatric surgery in reverse trendelenburg position, adjustment of ventilation strategies and hemodynamic optimization succeeded to improve rScO₂.