Effects Of Differential Lung Ventilation On Respiratory Function And Postoperative Cognitive Function In Patients Undergoing Thoracoscopic Lobectomy

Objective:To investigate the effects of differential lung ventilation（DLV）on respiratory function,cerebral oxygen metabolism,postoperative cognitive function,and postoperative recovery in patients undergoing thoracoscopic lobectomy,and to provide a reference for the clinical application of differential lung ventilation.Methods:Sixty patients undergoing elective thoracoscopic lobectomy were selected and randomly divided into two groups using the random number method:Group A,30patients with the lung on the operated side open to the atmosphere;Group D,30 patients with differential lung ventilation.For one lung ventilation（OLV）,the bronchial catheter of the operated side of the lung was opened to the air in group A and the lung on that side was allowed to atrophy naturally;in group D,the bronchial catheter of the operated side of the lung was connected to another ventilator for differential lung ventilation after the lung on that side had been atrophied naturally.Regional cerebral oxygen saturation（r Sc O₂）,mean arterial pressure（MAP）,and heart rate（HR）were recorded before induction of anesthesia（T0）;end-of-breath carbon dioxide concentration(P_ETCO₂),MAP,HR,and r Sc O₂ were recorded in the lateral recumbent position for double lung ventilation 5 min after induction of anesthesia（T1）,one-lung ventilation 30 min（T2）,one-lung ventilation 60 min（T3）,and restore ventilation to both lungs for 15min（T4）.The peak airway pressure（Ppeak）,plateau airway pressure（Pplat）,lung dynamic compliance（Cdyn）,and driving pressure（DP）were recorded at T1,T2,T3,and T4 time points.Radial artery blood and central venous blood were drawn at T1,T2,and T3 for blood gas analysis,and central venous oxygen saturation（Sv O₂）,central venous partial oxygen pressure（Pv O₂）,arterial carbon dioxide concentration（Pa CO₂）,arterial partial pressure of oxygen（Pa O₂）,and lactate（Lac）values were recorded,and calculate oxygenation index（OI）,respiratory index（RI）,intrapulmonary shunt fraction（Qs/Qt）,dead-space fraction（V_D/V_T）,arteriovenous oxygen content difference（Da-v O₂）and oxygen extraction rate（ERO₂）.Central venous blood samples were collected at T0,end of the operation（T5）,day 1 after surgery（T6）,and day 3 after surgery（T7）to measure plasma concentrations of interleukin-6（IL-6）and Clara cell secretory protein（CC16）.Patients were followed up on the day before surgery,T6,T7,and day 7 after surgery（T8）for assessment of Mini-mental state examination（MMSE）scores and delirium rating scale（CAM-CR）,and clinical pulmonary infection scores（CPIS）at day 3 after surgery,the occurrence of postoperative pulmonary complications（PPCs）within 7 days after surgery,the time of chest drain removal,and the duration of postoperative hospitalization were recorded.Results:（1）At T2 and T3,Pplat,Ppeak,and DP were significantly lower and Cdyn was significantly higher in group D than in group A（P<0.05）;at T4,Pplat,Ppeak,and DP were significantly lower in group D than in group A（P<0.05）.（2）At T2 and T3,Pa O₂,Pv O₂,and Sv O₂were significantly higher in group D than in group A（P<0.05）.At T1-T3,there was no statistically significant difference between the Pa CO₂ levels of the two groups（P>0.05）.At T2 and T3,the OI of patients in group D was significantly higher than that in group A,and Qs/Qt,RI,and V_D/V_Twere significantly lower than that in group A（P<0.05）.（3）At T2-T4,both left and right r Sc O₂ were significantly higher in patients in group D than in group A（P<0.05）.At T2 and T3,Da-v O₂was significantly lower in patients in group D than in group A（P<0.05）;at T3,ERO₂ was significantly lower in patients in group D than in group A（P<0.05）.At T1-T3,there was no statistically significant difference in Lac values between the two groups of patients（P>0.05）.（4）The differences in CC16 and IL-6 levels in patients in group D compared with group A at all corresponding time points were not statistically significant（P>0.05）.（5）There was no statistically significant difference in the MMSE scores of patients in group D compared with group A at each corresponding time point（P>0.05）.There was no statistically significant difference in the incidence of postoperative delirium between the two groups（P>0.05）.（6）Compared with group A,the postoperative chest drain extraction time and postoperative hospital stay were significantly reduced in group D,and the CPIS score was significantly lower at day 3 after surgery（P<0.05）.There was no statistically significant difference in the incidence of PPCs between the two groups within 7 days after surgery（P>0.05）.Conclusion:Compared with conventional one lung ventilation,differential lung ventilation in patients undergoing thoracoscopic lobectomy improves ventilation efficiency,reduces intrapulmonary shunts fraction,increases intraoperative oxygenation,increases cerebral oxygen saturation,and reduces the clinical lung infection scores,with no significant effect on postoperative cognitive function.