Study On The Lung-protective Effect Of Pressure-controlled Ventilation Volume Guaranteed In Patients Undergoing Laparoscopic Surgery In Trendelenburg Position

PART1 Comparison of ventilation effect between PCV-VG and VCV in patients with low risk of PPCs undergoing laparoscopic surgery in Trendelenburg positionObjectiveTo compare the ventilation effect of pressure-controlled ventilation volume guaranteed（PCV-VG）and volume‐controlled ventilation（VCV）in patients with low risk of postoperative pulmonary complications（PPCs）undergoing laparoscopic surgery in Trendelenburg position.MethodsSixty patients of American Society of Anesthesiologists physical status（ASA）I～Ⅲ,aged 18～64 yr,with body mass index（BMI）of 19～27 kg/m²,scheduled for laparoscopic radical prostatectomy or laparoscopic radical cystectomy,were to be scored according to ARISCAT score to identify patients with low risk.According to the different modes of mechanical ventilation,patients were randomly allocated to either VCV group（V group,n=30）or the PCV-VG group（P group,n=30）.After anesthesia induction,tracheal tube was inserted,VCV mode mechanical ventilation was used in V group,PCV-VG mode mechanical ventilation was used in P group.The peak inspiratory pressures(P_peak)and plat inspiratory pressures(P_plat),driving pressure（DP）,dynamic compliance（Cdyn）were calculated and recorded at 5 min after tracheal intubation（T₁）,at 5 min after Trendelenburg position（T₂）,and at 5,30,60 and 90 min after pneumoperitoneum(T_3-6),at 5 min after stop pneumoperitoneum and return to supine position（T₇）.Blood samples were collected from the radial artery for blood gas analysis at T₁,T₄,T₆and post-anesthesia care unit（PACU）,the p H,arterial oxygen partial pressure（P_aO₂）,arterial carbon dioxide partial pressure（P_aCO₂）,arterial oxygen saturation（S_aO₂）and alveolar-arterial oxygen gradient（A-a DO₂）were recorded.Postoperative follow-up was recorded the incidence of PPCs such as pneumonia within 7 days after the operation.ResultsCompared with V group,P_peakin P group was significantly decreased from T₁to T₇（P<0.05）,P_plat,DP were significantly decreased and Cdyn was significantly increased from T₂to T₆（P<0.05）,A-a DO₂was significantly decreased at T₁,T₄and T₆（P<0.05）.There were no significantly difference in the incidence of PPCs between the two groups within 7 days after surgery（P>0.05）.ConclusionCompared with VCV,PCV-VG can improve the respiratory mechanics of patients with low risk of PPCs in Trendelenburg position laparoscopic surgery,which may have lung protective effect.PART2 Study on the lung-protective effect of PCV-VG in elderly patients with intermediate risk of PPCs undergoing laparoscopic surgery in Trendelenburg positionObjectiveTo evaluate whether PCV-VG has the lung-protective effect on elderly patients with intermediate risk of PPCs undergoing laparoscopic surgery in Trendelenburg position.MethodsSixty patients of American Society of Anesthesiologists physical status I～Ⅲ,aged 65～80 yr,with body mass index of 19～27 kg/m²,scheduled for laparoscopic radical prostatectomy or laparoscopic radical cystectomy,were to be scored according to ARISCAT score to identify patients with intermediate risk of having PPCs.According to the different modes of mechanical ventilation,patients were randomly allocated to either VCV group（V group,n=30）or the PCV-VG group（P group,n=30）.After anesthesia induction,tracheal tube was inserted,VCV mode mechanical ventilation was used in V group,PCV-VG mode mechanical ventilation was used in P group.The P_peakand P_plat,DP,Cdyn were calculated and recorded at 5 min after tracheal intubation（T₁）,at 5 min after Trendelenburg position（T₂）,and at 5,30,60,90 and 120 min after pneumoperitoneum(T_3-7),at5 min after stop pneumoperitoneum and return to supine position（T₈）.Blood samples were collected from the radial artery for blood gas analysis at T₁,T₄,T₆and PACU,the p H,P_aO₂,P_aCO₂,S_aO₂and A-a DO₂were recorded.Blood samples were collected from the radial artery before induction of anesthesia and at the end of operation for determination of Clara cells secrete proteins-16（CC-16）,interleukin-6（IL-6）and neutrophils elastase（NE）by enzyme-linked immunosorbent assay（ELISA）.Postoperative follow-up was record the incidence of PPCs such as pneumonia within 7 days after the operation.ResultsCompared with V group,P_peakin P group was significantly decreased from T₁to T₈（P<0.05）,P_platand DP were significantly decreased at T_5-7（P<0.05）,and Cdyn was significantly increased at T_2-7（P<0.05）,A-a DO₂was significantly decreased at T_1,4,6,the plasma concentrations of CC-16,IL-6 and NE were significantly decreased（P<0.05）.There were no significantly difference in the incidence of PPCs between the two groups within 7 days after surgery（P>0.05）.ConclusionCompared with VCV,PCV-VG has a lung-protective effect on elderly patients with intermediate risk of PPCs undergoing laparoscopic surgery in Trendelenburg position,which can reduce the influence of position and laparoscopy on respiratory function,reduce the production of inflammatory factors and the degree of lung injury.