Objective: To observe the cardioprotective effects of propofol and midazolam in children with congenital heart diseases undergoing open heart surgery.
Methods: Thirty-two children with cyanotic congenital heart diseases of ASA classes I - II were randomly divided into 2 equal groups: propofol combined with low dose fentanyl group (Group PF) and midazolam combined with low dose fentanyl group (Group MF). The changes of hemodynaics, ECG, SpO2, nasopharyngeal and rectal temperatures were monitored continuously. The time of tracheal extubation and ICU staying time were recorded. Venous blood samples were collected when the venous channel was opened (T(0)), 2 h after declamping of the aorta (T(4)), and 24 h after operation (T(5)) to detect the plasma cardiac troponin I (cTnI). Myocardium samples were collected 10 - 20 min after aorta cross-clamp (T(2)), and 10 - 20 min after declamping of the aorta (T(3)) to undergo immunohistochemistry to observe the expression of heme oxygenase-1 (HO-1).
Results: The tracheal time of Group GF was 14.17 h, significantly shorter than that of Group MF (23.65 h, P < 0.05), and the ICU staying time of Group GF was 30.17 h, significantly shorter than that of Group MF (49.47 h, P < 0.05). The plasma cTnI level at T(4) of Group GF was 97 ng/ml +/- 33 ng/ml, significantly higher than those at T(0) (0.17 ng/ml +/- 0.10 ng/ml, P < 0.01) and T(5) (23 ng/ml +/- 13 ng/ml, P < 0.01). The plasma cTnI level at T(4) of Group MF was138 ng/ml +/- 56 ng/ml, significantly higher than those at T(0) (0.62 ng/ml +/- 0.96 ng/ml, P < 0.01) and T(5) (24 ng/ml +/- 6 ng/ml, P < 0.01). And the plasma cTnI levels at T(5) of these 2 groups were both significantly higher than those at T(0) (both P < 0.01), however, there was no significant difference in the plasma cTnI level at any time point between these 2 groups. The grey values of HO-1 in cardiac muscle cells at T(2) of Groups GF and MF were 182.2 +/- 0.8 and 193.5 +/- 1.4, both significantly higher than those at T(3) (125.6 +/- 2.1 and 145.5 +/- 7.4 respectively, both P < 0.01), and the grey values of HO-1 in cardiac muscle cells at T(2) and T(3) of Group MF were both significantly higher than those of Group GF (both P < 0.05).
Conclusion: Both propofol and midazolam have protective effects for the children with congenital heart diseases undergoing open heart surgery, and propofol is superior to midazolam in the cardioprotection.