Objective:Anesthesia

surgery and cardiopulmonary bypass (CPB) are conventionally considered the major stress factors in the hormonal and metabolic responses to cardiac surgery.This study was to determine the influence of CPB on hormones

carbohydrate metabolism and insulin resistance.Methods:Blood samples were obtained from 19 patients at the following intervals:(1)before anesthesia(2)before CPB(3) 15 min after begining of CPB(4)5min after declamping of aorta(5)20min after CPB.Insulin

C-peptide

cortisol

growth hormone and blood glucose were measured.The ratio of insulin to glucose in blood(I/G) and insulin-sensitivity index [1/(I×G)] were obtained.Results:Insulin

growth hormone and cortisol were higher during and after CPB than that before CPB.Similar changes in levels of blood glucose

I/G and C-peptide were also observed

even though there was a significant decrease of insulin-sensitivity index.Conclusion:There are an obvious increase of concentrations in stress hormones and blood glucose and an aggravation of insulin resistance.All changes above do reflect the degree of surgical stress.The secretion of pancreatic beta cells is not suppressed during and after CPB.It is suggested that insulin supplement therapy may be beneficial to improve insulin resistance in the period of CPB.