Effects Of Sustained Inflation On Respiratory Mechanics And Oxygenation Function In Patients Undergoing Gynecological Laparoscopic Surgery

Objective:To study the effect of sustained inflation on respiratory mechanics and the oxygenation function in patients undergoing gynecological laparoscopic surgery,and to compare the effect of different pulmonary recruitment pressure.Methods:A total of 80 patients,age 18-60 years old,ASA physical status Ⅰ-Ⅱ,BMI 18.5-25kg/m2,scheduled to undergo gynecological endoscopic surgery were randomly divided into four groups:control group(R0),experimental group 1(R1),experimental group 2(R2),experimental group 3(R3),with 20 patients in every group.Anesthesia induction was performed with propofol 1.5-2mg/kg,sufentanil 0.4 μg/kg,and rocuronium 0.6mg/kg.3 minutes before operation,Intravenous sufentanil 0.2ug/kg,rocuronium 0.2mg/kg.Sevoflurane was used to maintain the anesthesia depth during the operation,and the Bispectral index(BIS)was between 40 and 50.All the four groups received the same respiratory parameters:Tidal volume(VT)8mL/kg,Respiratory rate(RR)14 times/min,PetCO2 35-45 cmH2O by adjusting RR,Inspiration and expiration ratio(I:E)1:2,oxygen flow 2L/min,oxygen concentration 100%.Control group(R0 group):no pulmonary recruitment.Experimental group:pulmonary recruitment was performed at the end of pneumoperitoneum and 1 minute after returned to horizontal position,in which the pulmonary recruitment pressure was 30 cmH2O in R1 group,35 cmH2O in R2 group and 40 cmH2O in R3 group,respectively,lasting for 15 seconds.The observation time points:before operation(T0),5 minutes after tracheal intubation(T1),the end of pneumoperitoneum and 1 minute after returned to horizontal position(T2),during pulmonary recruitment(T3),5 minutes after the end of pneumoperitoneum and returned to horizontal position(T4)and 15 minutes after extubation(T5).The recording index:Mean arterial pressure(MAP),Heart rate(HR),Pulse oxygen saturation(SpO2),Peak airway pressure(Ppeak),Dynamic compliance(Cdyn),Arterial partial pressure of oxygen(PaO2),Arterial partial pressure of carbon dioxide(PaCO2),PH value,the pneumoperitoneum time,mechanical ventilation time and the time from the end of pneumoperitoneum to extubation were recorded.The calculation index:Oxygenation index(01)and Alveolar arterial oxygen difference(P(A-a)O2).Results:1.There was no statistically significant difference in the general conditions of patients in the four groups(P>0.05).2.Changes of related basic vital signs:Compare between groups:There was no statistically significant difference in SpO2 and HR among the four groups at each time point(P>0.05).The MAP of R1 group,R2 group,and R3 group was significantly lower than that of R0 group at T3(P<0.05),and there was no statistically significant difference among the four groups at other time points(P>0.05).Compare within groups:There was no statistically significant difference in SpO2 among the different time points in each group(P>0.05).Compared with T2,the HR of four groups decreased significantly at T3(P<0.05).Compared with T3,the HR of R1 group,R2 group,and R3 group increased significantly at T4(P<0.05),and there was no statistically significant difference in the R0 group(P>0.05).Compared with T2,the MAP of R1 group,R2 group,and R3 group decreased significantly at T3(P<0.05),and there was no statistically significant difference in the R0 group(P>0.05).Compared with T3,the MAP of R1 group,R2 group,and R3 group increased significantly at T4(P<0.05),and there was no statistically significant difference in the R0 group(P>0.05).3.Changes of respiratory mechanics:Compare between groups:The Ppeak and Cdyn of R1 group,R2 group,and R3 group were significantly lower and higher than those of R0 group at T4(P<0.05).There was no statistically significant difference in Ppeak and Cdyn among the four groups at other time points(P>0.05).Compare within groups:Compared with T1,the Ppeak of the four groups increased while the Cdyn decreased significantly at T2(P<0.05).Compared with T2,the Ppeak and Cdyn of R1 group,R2 group,and R3 group decreased and increased significantly at T4(P<0.05),respectively,and there was no statistically significant difference in the R0 group(P>0.05).Compared with T1,the Ppeak and Cdyn of R0 group increased and decreased significantly,respectively,and the Cdyn of R1 group increased significantly at T4(P<0.05),and there was no statistically significant difference in Ppeak of the R1 group and Ppeak and Cdyn of R2 group and R3 group(P>0.05).4.Changes of oxygenation function:Compare between groups:The PaO2 and OI of R1 group,R2 group,and R3 group were significantly higher than those of R0 group at T4(P<0.05),and P(A-a)O2 of R1 group,R2 group,and R3 group was significantly lower than that of R0 group at T4(P<0.05),there was no statistically significant difference among the four groups at other time points(P>0.05).Compare within groups:Compared with T0,the PaO2 and OI of R0 group decreased significantly at T5(P<0.05),and there was no statistically significant difference among R1 group,R2 group,and R3 group(P>0.05).Compared with T2,the PaO2-and OI of R1 group,R2 group,and R3 group increased significantly at T4(P<0.05),and there was no statistically significant difference in the R0 group(P>0.05).Compared with T2,the P(A-a)O2 of R1 group and R2 group decreased significantly at T4(P<0.05),and there was no statistically significant difference in the R0 group and R3 group(P>0.05).5.Changes of PH and PaCO2:Compare between groups:there was no statistically significant difference in PH and PaCO2 among the four groups at each time point(P>0.05).Compare within groups:Compared with T0,the PH of the four groups decreased significantly at T2,T4,and T5,while the PaCO2 of the four groups increased significantly at T2 and T5(P<0.05),and there was no statistically significant difference in PaCO2 among the four groups at T4(P>0.05).Compared with T2,the PH of R1 group,R2 group,and R3 group increased significantly at T4,and the PaCO2 of the four groups decreased significantly at T4(P<0.05),and there was no statistically significant difference in the PH of the R0 group(P>0.05).6.There was no statistically significant difference in the time of pneumoperitoneum,mechanical ventilation,and the time from the end of pneumoperitoneum to extubation(P>0.05).Conclusion:Pulmonary recruitment can improve the respiratory mechanics and the oxygenation function of patients undergoing gynecological laparoscopic surgery.The respiratory mechanics and the oxygenation function of patients do not change in the pulmonary recruitment pressure range of 30cmH2O to 40cmH2O.Therefore,it is recommended choosing the pulmonary recruitment pressure of the 30 cmH2O for patients undergoing gynecological laparoscopic surgery.