Aims
This study aimed to detect the difference in the preconditioning effect between isoflurane and sevoflurane when they are used just before aortic cross-clamp and continued throughout the bypass period by measuring cardiac troponin I (cTnI) in the postbypass period.
Settings and design
This individual closed-envelope randomization study was carried out in the Abou Ell-Resh Pediatric Hospital, Cairo University Unit of congenital heart surgery in collaboration with the anesthesia department. The study was approved by the local ethical committee and a written informed consent was obtained from the guardians of the patient. This study was carried out from March 2011 to September 2012 (18 months). Patients were allocated randomly to two equal groups of 30 patients each.
Participants and methods
Acyanotic and cyanotic patients were allocated randomly to two equal groups of 30 patients each using individual closed-envelope randomization. Patients were allocated randomly to two equal groups as follows: group I, isoflurane group ( = 30) (received isoflurane) and group S, sevoflurane group ( = 30) (received sevoflurane). cTnI, a baseline sample was obtained before cardiopulmonary bypass (T0), 8 h after bypass (T8), and 24 h after bypass (T24). Parametric data were described as mean, SD, median, and SEM. The two groups studied were compared using Student's -test. Repeated measures of the same group were compared using two-way analysis of variance, followed by post-hoc Tukey's comparison tests. For nonparametric data, nonparametric tests were used for comparison such as the Mann–Whitney -test, median, or quartiles. value less than 0.05 was considered significant (size estimation with two means is 28).
Results
Comparison of sevoflurane and isoflurane acyanotic cases showed that the cTnI ( = 0.02 and 0.01, respectively). Comparison of isoflurane and sevoflurane cyanotic cases showed that the cTnI values 8 and 24 h after bypass were higher in cyanotic cases of the isoflurane group than those of the sevoflurane group, but the difference was statistically insignificant. In terms of the difference between cyanotic and acyanotic cTnI results in the isoflurane group, cTnI values 8 h after cardiopulmonary bypass were higher in cyanotic cases compared with acyanotic cases, but this difference was insignificant, with a value of 0.42. At 24 h after CPB, cTnI values were significantly higher in cyanotic cases with a value of 0.015. In terms of the difference between cyanotic and acyanotic cTnI results in the sevoflurane group, the cTnI level 8 h after CPB was significantly higher in cyanotic cases compared with acyanotic cases with a value of 0.001; it was also significantly higher in cyanotic cases 24 h after CPB with a value of 0.005.
Conclusion
The present study showed that sevoflurane is superior to isoflurane in myocardial protection in surgical correction of congenital heart diseases only in acyanotic cases, with no difference in cyanotic cases.