Plasma glucagon concentration did not change significantly throughout the study period in either group (Fig 1). However, a slight increase during CPB in group 2 and a slight decrease during hypothermic CPB in group 1 led to significantly greater values in group 2. In group 1, rewarming was accompanied by an increase in plasma glucagon so that glucagon was similar in the two groups at the completion of CPB. Subsequently, in group 1 glucagon decreased to less than group 2 levels (p<0.02) at the first postoperative hour.
Plasma cortisol concentration decreased not significantly after induction (Fig 2). In group 1, cortisol further decreased 15 min after starting CPB, then increased continuously throughout the study period. In group 2, a similar evolution was observed but with higher values than in group 1 (p<0.05) at 15 and 30 min of CPB.
Plasma GH concentration slightly decreased after induction (Fig 2). In group 1, plasma GH further decreased at the beginning of CPB and remained under control levels throughout surgery. In group 2, no significant change occurred with CPB. No intergroup difference was observed.
Figure 2. Plasma cortisol, GH, epinephrine and norepinephrine concentrations. Same legends as in Figure 1.