Effects Of Inverse Ratio Ventilation On Respiratory Mechanics In Obese Patients Undergoing Gynecologic Laparoscopy

Objective:To investigate the effects of inverse ratio ventilation?IRV?onrespiratory mechanics and oxygenation index in laparoscopic surgery for obese patients.Method:Approved by the ethics committee of the First Hospital of Jilin University,a total of 60 obese patients undergoing gynecologic laparoscopic surgery in the First Hospital of Jilin University from November 2016 to May 2017 were selected,and the BMI>30kg/m².They were randomly divided into two groups:the inverse ratio group?experimental group?and the conventional volume control ventilation group?control group?,with 30 cases in each group.Induction of anesthesia:midazolam 0.03mg-0.04mg/kg,fentanyl 3-4ug/kg,cis-atracurium 0.15mg/kg,propofol 2mg/kg were given intravenously.After endotracheal intubation,the patients are ventilated by controlled mechanical ventilation.Set tidal volume?VT?7-8ml/kg,respiratory rate?RR?12/min,I:E=1:2,the pressure control alarm value40cmH₂O,PEEP=0.Anesthesia was maintained with propofol4-8mg·kg^-1·h^-1,1.5%-2.5%sevoflurane,remifentanil 0.1-0.3ug·kg^-1·min^-1,additional muscle relaxant are required under patients'conditions and operation procedures.Intraoperative anesthesia depth monitoring was adopted by Narcotrend,and maintain the depth of anesthesia in D0-D2?37-64?.When the CO₂ pneumoperitoneum was established,the I:E of the experimental group was adjusted to 2:1,and the I:E of the control group remained unchanged at 1:2,and the RR and VT were unchanged in each group.Observe and record the airway peak pressure?Ppeak?,mean airway pressure?Pmean?,end tidal carbon dioxide partial pressure(P_ETCO₂)before pneumoperitoneum?T0?,30 minutes after pneumoperi-toneum?T1?,60 minutes after pneumoperitoneum?T2?and 3 minutes after release?T3?,and calculate dynamic pulmonary compliance?Cdyn?.Puncture arterial blood before pneumoperitoneum?T0?,30 minutes after pneumoperitoneum?T1?and 60 minutes after pneumoperitoneum?T2?,and calculate the oxygenation index?OI?.Results:There was no significant difference in age,body mass index and operation time between the two groups?P>0.05?.Arterial blood gas results showed that there was no significant difference in Ph,HCO₃-,PaCO₂ between the two groups?P>0.05?.PaCO₂ increased significantly at T1 and T2 time point in the two groups,compared with the T0 time point in the same groups,and the difference was statistically significant?P<0.05?.PaCO₂ increased significantly at T2 time point in the two groups,compared with the T1 time point in the same groups,and the difference was statistically significant?P<0.05?.Compared with the control group,the Ppeak in the experimental group decreased significantly,the difference was statistically significant?P<0.05?,Pmean increased,the difference was statistically significant?P<0.05?,and OI and Cdyn increased significantly in the experimental group,the difference was statistically significant?P<0.05?.Conclusions:Inverse ratio ventilation can effectively reduce the peak pressure of the airway in the obese patients with gynecologic laparoscopy,improve the average airway pressure and dynamic lung compliance,and improve the oxygenation.