Objective:To explore the effect of cardiopulmonary bypass on the concentration of neuropeptide Y(NPY)

Substance P(SP)

angiotensin Ⅱ(AngⅡ)and calcitonin gene relative peptide(CGRP)during cardiopulmonary bypass in child heart surgery

and to determine their clinical significance.Methods:20 children with congenital heart disease were chosen in hospital.Blood samples were taken from central vein to determine the concentration of NPY

SP

CGRP

and AngⅡin plasma by radioimmunoassay before CPB

during CPB at 7min

at the termination of CPB

and 12 hours after-opertation.Results:The concentration of NPY

SP

Ang Ⅱ and CGRP increased significantly during CPB and at the termination of CPB(P<0.05)

and restored to baseline at 12h after operation with no significant difference form pre-cardioplumonary bypass(P>0.05).The duration of CPB had positive correlation with the concentration of peptides(P<0.05).Conclusions:Cardiopulmonary bypass is a non-physiological perfusion

The change of peptides is a compensational reaction to cardiopulmonary bypass.Reducing the time of cardiopulmonary bypass and keeping relative balance of peptides may have important significance for recovering from illness.