Changes In Regional Cerebral Oxygen Saturation And Related Influencing Factors In Patients Undergoing Single-lung Ventilation

Objective:To study the change of regional cerebral oxygen saturation?rScO₂?and its influencing factors during single-lung ventilation?SLV?in patients undergoing thoracic surgery,in order to maintain the stability of cerebral oxygen saturation by controlling its related factors,reduce the occurrence of postoperative complications and improve the prognosis of patients.Methods:A total of 175 patients scheduled for elective thoracic surgery with single-lung ventilation were randomly enrolled in the Fourth Hospital of Hebei Medical University and the First Hospital of Peking University from August 2017 to September 2018,including 105 patients in the Fourth Hospital of Hebei Medical University and 70 patients in the First Hospital of Peking University.Inclusion criteria:1)age?55 years old;2)Preparing for elective thoracic surgery and requiring intraoperative single-lung ventilation;3)expected operation time?2 hours.Exclusion criteria:1)Refusal to participate in this study;2)Emergency surgery;3)Severe visual,hearing and language impairment affecting delirium assessment;4)Schizophrenia history;5)Severe cognitive impairment,such as coma and dementia;6)ASA grade?and above;7)Researchers consider it unsuitable to participate in this study.After intravenous induction,SLV was managed by double lumen tracheal tube.Continuous inhalation of 1-3%sevoflurane was used to maintain anesthesia.Remifentanil was continuously pumped 0.1-0.3?g/kg/min or sufentanil was intermittently injected 0.1-0.2?g/kg to maintain analgesia.Cisatracurium or rocuronium were intermittently injected to maintain muscle relaxation.Bipectral index?BIS?was maintained between 40 and 60 to ensure proper anesthesia depth.End-expiratory partial pressure of carbon dioxide(P_ETCO₂)ranged from 35 to 45 mmHg by adjusting respiratory parameters.During anesthesia,if SBP was less than 90 mmHg or 30%lower than the baseline value,ephedrine 6 mg or norepinephrine 4 mg was injected;atropine 0.5 mg was injected if HR was less than 50 times per minute;If SpO₂ was lower than92%,the position of double-lumen endotracheal tube was repositioned and the positive end-expiratory pressure?PEEP?of 5-8 mmHg was added.rScO₂ from patients entering the room to extubation after anesthesia was continuously collected by FORE-SIGHT Brain Oxygen Monitor.In order to avoid bias in anesthesia management caused by monitoring cerebral oxygen saturation,the screen of brain oxygen saturation monitor was covered during the study period.Anesthesiologists need to manage anesthesia according to the routine indicators of clinical anesthesia.The basic data of patients,past history,baseline values of cerebral oxygen saturation and intraoperative monitoring data,anesthesia-related information,surgery-related information,intraoperative adverse events,fluid intake,blood loss and urine volume were collected.The patients were divided into low rScO₂ group?L group?and normal rScO₂ group?N group?according to whether the minimum value of rScO₂ during one lung ventilation was less than 65%or decreased more than 20%of the baseline value.The change of rScO₂ and its influencing factors were analyzed.Results:The baseline value of rScO₂ was 69%?67,73?and decreased to63%?58,67?during single lung ventilation.During single lung ventilation during thoracic surgery,about 61%?n=107?of the patients showed a decrease in regional cerebral oxygen saturation.Univariate analysis showed that hypoxemia and hypoxia were positively correlated with the decrease of rScO₂,while general anesthesia combined with epidural block was negatively correlated with the decrease of rScO₂ compared with general anesthesia.Multivariate logistic regression analysis showed that hypoxemia,general anesthesia combined with epidural block were independent correlative factors of rScO₂ reduction during one-lung ventilation.Conclusion:During SLV of thoracic surgery,rScO₂ may decrease;hypotension,hypoxemia,general anesthesia combined with epidural block is the related factor of rScO₂ decrease;hypoxemia is the independent risk factor of rScO₂ decrease;compared with general anesthesia,general anesthesia combined with epidural block is the protective factor of rScO₂.