Effect of ventilation on cerebral oxygenation in patients undergoing surgery in the beach chair position: a randomized controlled trial

Background Surgery in the beach chair position (BCP) may reduce cerebral blood flow and oxygenation, resulting in neurological injuries. The authors tested the hypothesis that a ventilation strategy designed to achieve end-tidal carbon dioxide ( E C O 2 ′ ) values of 40–42 mm Hg would increase cerebral oxygenation ( S c t O 2 ) during BCP shoulder surgery compared with a ventilation strategy designed to achieve E C O 2 ′ values of 30–32 mm Hg. Methods Seventy patients undergoing shoulder surgery in the BCP with general anaesthesia were enrolled in this randomized controlled trial. Mechanical ventilation was adjusted to maintain an E C O 2 ′ of 30–32 mm Hg in the control group and an E C O 2 ′ of 40–42 mm Hg in the study group. Cerebral oxygenation was monitored continuously in the operating theatre using near-infrared spectroscopy. Baseline haemodynamics and S c t O 2 were obtained before induction of anaesthesia, and these values were then measured and recorded continuously from induction of anaesthesia until tracheal extubation. The number of cerebral desaturation events (CDEs) (defined as a ≥20% reduction in S c t O 2 from baseline values) was recorded. Results No significant differences between the groups were observed in haemodynamic variables or phenylephrine interventions during the surgical procedure. S c t O 2 values were significantly higher in the study 40–42 group throughout the intraoperative period ( P P Conclusions Cerebral oxygenation is significantly improved during BCP surgery when ventilation is adjusted to maintain E C O 2 ′ at 40–42 mm Hg compared with 30–32 mm Hg. Clinical trial registration ClinicalTrials.gov NCT01546636.