Cortisol Response in Children After Second Cardiopulmonary Bypass

A surge in cortisol levels is seen after surgery with cardiopulmonary bypass (CPB). Based on evidence of attenuation of the cortisol response to repeated stress in other settings, we hypothesized that the magnitude of cortisol increase in children after a second exposure to CPB would be reduced. Serial cortisol levels were measured at three time points after each CPB: immediately (day 0), on the first morning (day 1), and second morning (day 2). Forty-six children underwent two surgeries with CPB during the study period. The mean age (standard deviation) at first and second surgery was 3.5 (6.3) months and 10.4 (9.9) months, respectively. Cortisol levels at the first surgery were 109 (105) µg/dl, 29 (62) µg/dl, and 17 (12) µg/dl on day 0, 1, and 2, respectively; similarly at second surgery, it was 61 (57) µg/dl on day 0 to 20 (16) µg/dl and 11 (10) µg/dl on day 1 and 2, respectively. After log-transformation and adjusting for time interval between surgeries, cortisol levels at the second surgery were lower by 42% on day 0 (p = 0.02), and 46% lower on day 2 (p = 0.02). A second exposure to CPB in children with congenital heart disease is associated with an attenuated cortisol release.