Effect Of Dexmedetomidine On Inflammatory Response And Respiatory Functions In Cardiac Valve Replacement Surgery

The purpose of the paper is to observe the effect of dexmedetomidine on lung injury caused by cardiopulmonary bypass (CPB) in cardiac valve replacement surgery, and evaluate the lung protective effects of dexmedetomidine during cardiac valve replacement surgery45patients scheduled for cardiacvalve replacement were randomly divided into three groups:high-dose dexmedetomidine group (n=15), low-dose dexmedetomidine group (n=15) and control group (n=15).For the high-dose dexmedetomidine group was infused intravenously with the dose of0.5μg·kg-1·h-1and low-dose dexmedetomidine group with the dose of0.25μg·kg-1·h-1after induction of anesthesia. In control group, normal saline was given instead of dexmedetomidine.Seven time points:after induction of anesthesia (T1), the ending of CPB(T2), after the termination of CPB2h (T3),6h(T4),12h(T5),24h (T6) and before tracheal extubation(T7). Blood samples were taken from radial artery in each time points of T1-T7for detemrination of TNF-a, IL-8, IL-10, sICAM-1and MDA. For each group, blood samples were taken from radial artery in each time of T1、T2、T3、 T4、T7for gas analysis.Oxygen partial pressure (PO2), carbon dioxide partial pressure (PaCO2), tidal volume (TV), plateau airway pressure (PAP), positive end-expiratory press (PEEP) were also recorded from anesthesia machine and respiratory machine to calculated the alveolar-artery oxygen difference(PA-aO2), oxygenation index(OI), and lung compliance(Cst).The results show that:The age, weight, sex ratio, preoperative cardiac function grading, left ventricular ejection fraction, intraoperative aortic clamping time, bypass time, ICU treatment time, and the number of hospital days are not statistically significant (P>0.05). The patients drainage after operating24hours and post-operating duration of mechanical ventilation in group of D1and D2were significantly lower than that in group C, the difference was statistically significant (P<0.05).②serum inflammatory mediators:The level of TNF-a were significantly increased after CPB shutdown in both three groups (P<0.05). The increased degree of TNF-a were significantly lower in group of D1and D2than that in group C (P<0.05), and that in group D2were also significantly lower than D1group (P<0.05). The level of IL-8were significantly increased after CPB shutdown in both three groups (P<0.05). The increased degree of IL-8were significantly lower in group of D1and D2than that in group C (P<0.05), and that in group D2were also significantly lower than D1group (P<0.05). The level of IL-10were significantly increased after CPB shutdown in both three groups (P<0.05), and it restored to pre-operating level in both groups at the time of T6. The increased degree of IL-10were significantly higher in group of D1and D2than that in group C (P<0.05), and that in group D2were also significantly higher than D1group (P<0.05).③respiatory functions:The level of PA-aO2were significantly increased after CPB shutdown in both three groups (P<0.05). The increased degree of PA-aO2were significantly lower in group of D1and D2than that in group C (P<0.05), and that in group D2were also significantly lower than D1group (P<0.05). The level of OI and Cst were significantly decreased after CPB shutdown in both three groups (P<0.05). The decreased degree of those were significantly lower in group of D1and D2than that in group C (P<0.05), and those in group D2were also significantly lower than D1group (P<0.05).④MDA and sICAM-1:three groups of serum MDA level increased significantly (P<0.05) after the CPB shutdown. The increased degree of MDA were significantly lower in group of D1and D2 than that in group C (P<0.05), and that in group D2were also significantly lower than D1group (P<0.05). The level of sICAM-1were significantly increased after CPB shutdown in both three groups (P<0.05). The increased degree of sICAM-1were significantly lower in group of D1and D2than that in group C (P<0.05), and that in group D2were also significantly lower than D, group (P<0.05).From results, the following conclusions can be drawn:①Valve replacement surgery can induce the inflammatory response;②Valve replacement surgery can affected the respiatory functions;③Infusion dexmedetomidine have protect effect on inflammatory response lung injury caused by cardiac valve replacement surgery, and objectively in high-dose group.