Effect of levosimendan on the state of blood circulation and the oxygen budgetin the perioperative period in patients with acute coronary syndrome аt coronary artery bypass graft
Background. Rapid recovery of blood flow in the myocardium often requires surgical intervention with cardiopulmonary bypass, in particular - coronary artery bypass graft. The purpose of the study: to examine the influence of levosimendan in the perioperative period on the state of blood circulation and oxygen budget in patients with acute coronary syndrome undergoing coronary artery bypass graft. Materials and methods. 85 patients with acute coronary syndrome undergoing coronary artery bypass graft were examined. The examined patients were divided into 2 groups. In patients of the 1st group (n = 40), a local protocol of anesthesia and intensive care of the State Institution “Heart Institute of the Ministry of Health of Ukraine” was used, patients of the 2nd group (n = 45) additionally received levosimendan according to the following scheme: before induction into anesthesia - 10 μg/kg for 10 min, then at a rate of 0.1 μg/kg/min - to 8 hours following the day's surgery. The research was carried out at the following stages: 1) before surgery; 2) аfter cardiopulmonary bypass; 3) transfer to the intensive care unit; 4) transfer from the intensive care unit. At these stages, the condition of blood circulation, oxygen budget in the body was assessed. Results. When there was used the local protocol, the end systolic index started to exceed the baseline level only at the end of the study, and the addition of levosimendan provided its significant excess of the baseline level аfter cardiopulmonary bypass. Ejection fraction at all stages of the study (except the first) was also significantly higher with levosimendan. Stroke index and heart index began to exceed the baseline levels in both groups also аfter cardiopulmonary bypass, but from the time of transfer to the intensive care unit, these parameters were significantly higher when levosіmendan was added than when a local protocol was used. At the same time, when levosіmendan was administered, the dose of dobutamine necessary for maintaining blood circulation was almost 3 times lower. The positive impact of levosimendan also influenced the oxygen budget. After the onset of the cardiopulmonary bypass, due to the need for hemodilution, the oxygen capacity of the blood decreased significantly, but despite this, levosimendan allowed several-fold increase in oxygen delivery due to a sufficient increase in heart index, while the use of a local protocol could not provide this, and oxygen transport decreased. The level of oxygen consumption in both groups was the same, as a result, the ratio of oxygen extraction of tissues in patients treated with levosimendan was significantly lower. It is natural that the level of lactate in the 2nd group was lower, equaling the level of the 1st group only by the end of the study. Conclusions. Levosimendan helps to accelerate the restoration of myocardial contractility, to improve the oxygen budget and may reduce the dose of dobutamine necessary to maintain blood circulation almost by 3 times.