Abstract:Objective To investigate the influences of CO₂ pneumoperitoneum on regional cerebral oxygen saturation（rScO₂）and S-100β protein in elderly patients undergoing retroperitoneal laparoscopic radical nephrectomy. Methods Fifty-five elderly patients undergoing retroperitoneal laparoscopic radical nephrectomy from May 2018 to March 2019 were included,whose rScO₂ was monitored by FORE-SIGHT non-invasive near-infrared spectroscopy.The intraoperative pneumoperitoneum pressure was 15 mm Hg.Pulse oxygen saturation (SpO₂),heart rate (HR),rScO₂ and mean artery pressure (MAP) were recorded respectively at each time point of entering operating room (T₀ ),5 min before CO₂ pneumoperitoneum (T₁),10 min after CO₂ pneumoperitoneum(T₂),30 min after CO₂ pneumoperitoneum (T₃),60 min after CO₂ pneumoperitoneum (T₄),10 min after CO₂ pneumopeeritoneum(T₅).Immediate blood gas analysis (pH) PaO₂,PaCO₂,hemoglobin(Hb)and other data at T₀-T₅ were detected and recorded.At T₀ -T₄,S-100β protein levels in plasma of internal jugular vein were determined immediately. Results There were significant differences in S-100 β protein,rScO₂,PaCO₂,pH and PaO₂ at T₀ to T₅ (all P<0.01),but no significant differences in MAP,HR,SpO₂ and Hb at these time points (all P>0.05).Compared with T₀,rScO₂ significantly increased at T₄-T₅,and S-100β protein level increased at T₄;compared with T₀-T₁,pH value significantly decreased at T₃-T₅,and PaCO₂ increased statistically at T₂-T₅(all P<0.05). ConclusionIn the elderly patients receiving retroperitoneal laparoscopic radical nephrectomy,CO₂ pneumoperitoneum significantly increase rScO₂,and the levels of S-100β protein in cervical venous blood and PaCO₂ also increase gradually with the prolongation of CO₂ pneumoperitoneum.