The Effect Of Mechanical Ventilation Modes On Morbidly Obese Patients During Pneumoperitoneum In Respiratory And Circulatory Function

Objective:To investigate the effect of two types of mechanical ventilation modes on morbidly obese patients undergoing laparoscopic gastric bypass surgery during pneumoperitoneum on patients respiratory and circulatory function.Methods:40 morbidly obese patients undergoing laparoscopic gastric bypass surgery were randomly divided into volume-controlled ventilation group(VCV) and pressure-controlled ventilation group(PCV),20 cases in each group.Two groups of patients were implemented endotracheal intubation general anesthesia,and ventilationed respectively with different programs. End-tidal carbon dioxide partial pressure Pet CO2 should maintained at between35-45 mm Hg.Before pneumoperitoneum(T1), 30 min after pneumoperitoneum(T2),60 min after pneumoperitoneum(T3), 90 min after pneumoperitoneum(T4),30 min after pneumoperitoneum lifting(T5),arterial blood was respectively collected to analysis blood gas.Aa DO2,xygenation index(OI) and respiratory index(RI) were calculated.Different point of patients’ variables were recorded such as airway pressure max(Pmax),tidal volume(Vte).While Clt was calculated.Before anesthesia(T0),T1,T2,postoperation 2h(T6),By cardiac ultrasound monitoring records left entricular ejection fraction(LVEF) and stroke volume(SV).The data of the arterial blood were colleeted at T1 and T2 for determination of malondialdehyde(MDA),superoxide dismutase(SOD),interleukin-6(IL-6)and lactic acid(LD).Results:1.There were no significant differences in patient characteristics in the two groups(p>0.05).2.Compared with the other point,at T1 in both groups, p H value increased significantly and Pa CO2 decreased significantly(p<0.05).3. Compared with the other point,at T1 and T5 in both groups,Pmax decreasedsignificantly and Vte increased significantly(p<0.05);Compared with the VCV group,Pmax in PCV group were lower(p<0.05);Vte in PCV group were significantly higher than VCV group(p<0.05).4. In two groups,differences of OI,RI and Aa DO2 were not statisticaly significant(p>0.05).5. Compared with the other point,at T1 and T5 in both groups, Clt increased significantly(p<0.05);Compared with the VCV group,Clt in PCV group were higher(p<0.05).6.At T1 and T2,SV in PCV group were significantly higher than VCV group(p<0.05);In two groups,differences of LVEF were not statisticaly significant(p>0.05).7.In VCV group,SOD of T2 was significantly lower than of T1,and LD of T2 was significantly higher than of T1(p<0.05);In two groups,MDA of T2 was significantly higher than of T1(p<0.05);In two group,MDA,SOD,LD and IL-6 were no significant differences between T1 and T2(p>0.05).Conclusion:Laparoscopic gastric bypass surgery during pneumoperitoneum, compared with the volume control ventilation, pressure control of ventilation modes for morbidly obese patients can improve lung compliance and the ventilation effect,reduce lung injury and the impact on cardiac function.Key Words:...