Technologies of diagnosis and treatment

Switching to warm blood cardioplegia supplemented with magnesium sulfate: what do we gain?

Iu.S. Guzgan, V.D. Moscalu, G.G. Manolache, V.I. Morozan, A.A. Batrinac

Cardiac Surgery Department, Republican Hospital, Chisinau, Republic of Moldova

The aim – to evaluate the efficacy of intermittent warm blood cardioplegia using magnesium sulfate in patients undergoing on-pump cardiac surgery.

Materials and methods. The study was performed in two groups of patients without significant differences of preoperative clinical conditions, who underwent surgery with CPB. In the 1st group (control) intermittent cold crystalloid-blood cardioplegia (8–10 °C) was delivered every 20 minutes, rectal temperature decreased to 30.0 ± 1.5 °C. In the 2nd group of patients temperature was maintained at 35.5 ± 1.1 C applying warm blood cardioplegia according to A. Calafiore (1995) and S. Casalino et al. (2008) protocol subsequently modified by adding magnesium sulfate to all portion of cardioplegia and extending the period of ischemia up to 25 minutes. The frequency of spontaneous cardiac rhythm restoration; emergence of the ECG changes; the frequency of cardioversion after reperfusion; the requirements in inotropes during first two days after the intervention; release of CPK MB, Tn I and transaminases, length of staying in ICU were studied.

Results. Apart from convenience of cardioplegia management, several features showing superiority of warm blood cardioplegia were noted in the 2nd group. This group included fewer patients with cardioversions after reperfusion; number of patients requiring inotropic support in the early days after surgery was more in the control group; average length of stay in ICU was 2.5 ± 0.3 for the study group and 2.9 ± 0.4 days in the control group. There was less myocardial damage in the study group confirmed by significant differences of CK MB and AST release (P < 0.05).

Conclusions. Intermittent warm blood cardioplegia supplemented with magnesium sulfate makes possible to safely extend the period of ischemia between reperfusions to 25 minutes and has a positive impact on some clinical and biochemical parameters in the immediate post surgery period.

Key words: myocardium, protection, crystalloid-blood cardioplegia, blood cardioplegia, magnesium sulfate.