The Effect Of Insulin Infusion On Pulmonary Preservation During CPB And The Underlying Mechanism

Objective:To investigate the role of insulin infusion in pulmonary protection induced by cardiopulmonary bypass in combined mitral and aortic valves replacement, and to explore the underlying mechanisms by measuring the endothelium activation and proinflammatory cytokines in the different timepoint perioperatively.Methods:90patients with selected combined mitral and aortic valves replacement under cardiopulmonary bypass were randomly divided into3groups:the saline control group (n=30), the low-and high-dose insulin groops (both n=30). Patients of the two insulin groups were administrated with0.005or0.01u/kg/min insulin infusion respectively from5min before to the ceasing of CPB, meanwhile patients of the saline group were pumped intravenously with the same amount of saline. At after anesthesia induction (TO), immediately before CPB (T1), immediately after CPB (T2), and2h (T3),4h (T4),6h (T5) after CPB, every4ml arterial blood was acquired from each patient,1ml for the blood gas analysis and blood sugar measurement, and the other3ml for ICAM-1, E-selectin, IL-8、TNF-a and IL-10measurement by ELISA method, and concentration of NO by Nitrate reductase method. Also the extubation time, ICU stay time, rate of pulmonary compliance, length of post-operational hospital stay and mortality postoperatively were detected. Results:Concentration of ICAM-1, E-selectin, IL-8and TNF-a of the two insulin groups at T2and T3were significantly lower than that of saline control group (p<0.05), and the high-dose insulin group has the lowest level (p<0.05); the concentration of NO in the two insulin groups was also lower than that in the saline group significantly at T2、T3、T4timepoint (p<0.05), and the high-dose insulin group has the lower concentration than the low-dose insulin group at T2、T3(p<0.05); blood sugar was expectedly lower in the two insulin groups than in the saline group (p<0.05); however, the concentration of IL-10, extubation time, ICU stay time, rate of pulmonary compliance, length of post-operational hospital stay and mortality postoperatively were unexpectedly similar in all the three groups (all p>0.05)Conclusions:The insulin infusion during the CPB maybe dose dependently improve the pulmonary function by reducing the endothelium activation and the production of related pro inflammatory cytokines, as well as prevention of excessive NO syntheses. Howerer, the short duration of insulin infusion has no effect on comprehensive prognosis.