A Study on the Correlation between End-Tidal Positive Pressure and Cerebral Oxygen Saturation in Elderly Patients Undergoing Thoracoscopic Surgery with One-Lung Ventilation

doi:10.3969/j.issn.1004-5775.2025.04.015

Abstract：Objective: To explore the correlation between end-tidal positive pressure (PEEP) and cerebral oxygen saturation (rSO2) in elderly patients undergoing thoracoscopic surgery with one-lung ventilation. Methods: Clinical data of 81 elderly patients with lung cancer who underwent elective thoracoscopic surgery at Baofeng County People's Hospital, Pingdingshan City, Henan Province from July 2020 to July 2022 were retrospectively analyzed. According to the order of admission, the patients were divided into three groups, each with 27 cases. During one-lung ventilation, tidal volume was set at 5 mL/kg for all three groups. Group A (PEEP=0 cmH2O), Group B (PEEP=5 cmH2O), Group C (PEEP=10 cmH2O). The peak airway pressure values, SpO2, and rSO2 at different time points (T0: 15 minutes after anesthesia, T1: 10 minutes of one-lung ventilation, T2: 30 minutes of one-lung ventilation, T3: 60 minutes of one-lung ventilation) were compared among the three groups. The changes in the minimum cerebral oxygen saturation (rSO2 min), the maximum percentage decrease from baseline (rSO2 max%), and the average cerebral oxygen saturation (rSO2 avg) during the operation were also compared. Results: The peak airway pressure values in Groups A and C were higher than those in Group B at T1 to T3, with statistically significant differences (F=4.584, 5.773, 14.924, P<0.05). However, there was no statistically significant difference in peak airway pressure between Groups A and C at T1 to T3 (P>0.05). At T0 to T3, rSO2 in all three groups showed a gradually decreasing trend. At T2 to T3, rSO2 in Groups A and C was lower than that in Group B, and rSO2 in Group C was higher than that in Group A, with statistically significant differences (F=2.761, 10.136, 9.954, 26.564, P<0.05). The rSO2 min and rSO2 avg in Group B were higher than those in Groups A and C. The rSO2 min and rSO2 avg in Group C were higher than those in Group A. The rSO2 max% in Group B was lower than that in Groups A and C, and the rSO2 max% in Group C was lower than that in Group A, with statistically significant differences (F=9.583, 18.723, 5.674, P<0.05). Conclusion: There is an inseparable relationship between PEEP and rSO2 in elderly patients undergoing thoracoscopic surgery with one-lung ventilation. Compared with 10 cmH2O PEEP, 5 cmH2O PEEP can prevent the phenomenon of insufficient cerebral perfusion, thereby reducing the degree of decline in rSO2.