Effect Of Lung Protective Ventilation Strategy On Postoperative Cognitive Function In Elderly Patients After Laparoscopic Colorectal Cancer Surgery

Objective:To investigate the effect of lung protective ventilation strategy on pulmonary oxygenation and inflammatory mediators and cognitive status in elderly patients undergoing laparoscopic colorectal cancer surgery.Methods:50 elderly patients undergoing elective laparoscopic colorectal cancer radical operation in our hospital from April 2018 to October 2018 were chosed,They were classified by ASA ?-? and aged over 60 years.Fifty subjects were divided into two groups by random number table:VCV group and PCV group.During mechanical ventilation under general anesthesia,the VCV group adopted the traditional volume-controlled ventilation mode,and the tidal volume was set to 8 mL/kg PCV group adopted the lung protective ventilation strategy.Tidal volume was set to 6mL/kg and 5 cmH₂O positive end expiration pressure,and manual pulmonary resuscitation was given every 30 minutes after pneumoperitoneum?airway pressure was no more than 30cmH₂O,lasting 30seconds every time?.Hemodynamic parameters?heart rate?systolic blood pressure?diastolic blood pressure?mean arterial pressure?oxygen saturation??cerebral oxygen saturation and respiratory mechanics indexes(tidal volume?respiratory frequency?peak airway pressure?airway platform pressure?end-expiratory CO_2?lung compliance)were recorded 5 minutes before pneumoperitoneum?T0?,5 minutes after pneumoperitoneum?T1?,30 minutes after pneumoperitoneum?T2?,60 minutes after pneumoperitoneum?T3?and 120 minutes after pneumoperitoneum?T4?,pneumoperitoneum stopped 10minutes later.Blood gas was extracted at T0?T4 and the time of leaving PACU,and oxygenation index was calculated.Intravenous blood was taken one day before operation,T4 and one day after operation to detect the levels of CRP and IL-6 in plasma.Mini-mental State Examination was used to assess the cognitive status of patients one day before operation and one day after operation and three days after operation.Results:There were no significant differences in general conditions such as sex?age?weight?anesthesia time?operation time?pneumoperitoneum time?fluid intake?blood loss and urine volume between the two groups?Table1?.Compared with VCV group,There were lower airway pressure at T4?T5 and higher lung compliance at T4?T5?P<0.05??Table2?in group PCV.There was no significant difference in hemodynamic parameters between the two groups.The value of cerebral oxygen saturation at T4 and T5 in PCV group was higher than that in VCV group?P<0.05??Table4?.Compared with VCV group,PCV group had a higher oxygenation index at T4 and after leaving PACU?P<0.05??Table5?.IL-6 and CRP in PCV group was lower at one day after operation?P<0.05??Table6?.Compared with VCV group,the MMSE score of PCV group was higher on one day and three days after operation.There was significant difference between PCV group and VCV group?P<0.05??Table7?.Conclusion:Pulmonary protective ventilation strategy can improve pulmonary oxygenation,reduce the release of inflammatory mediators,improve brain oxygen saturation,and reduce the occurrence of cognitive dysfunction in elderly patients.