Relationship Between Sedation, Patients' Left Ventricular Ejection Fraction and Frequency of Need for Sympathomimetic and Inotropic Support in Patients After Cardiac Surgery in the Early Postoperative Period

Abstract

Introduction: Most patients who are indicated for cardiac surgery are patients with reduced left ventricular ejection fraction (LVEF). Also, most patients after cardiac surgery receive sedation, which, in combination with reduced LVEF, can lead to severe hemodynamic disturbances. Whether there is a relationship between the drug for sedation in the early postoperative period in patients after cardiac surgery and the initial left ventricular ejection fraction until the end, there is still no consensus.
 Purpose: To monitor the relationship between the drug for sedation, the patients' initial left ventricular ejection fraction and the frequency of the need for sympathomimetic support and inotropic support in the early postoperative period.
 Materials and methods: A randomized controlled parallel study was conducted. The study included 194 patients over 18 years of age who underwent cardiac surgical treatment using artificial blood circulation. The control point for evaluating the effect of sedation on hemodynamics was the use of inotropic and sympathomimetic therapy and the analysis of the frequency of use in groups with different ejection fractions of the left ventricle. An assessment of the frequency of vasopressor/inotropic therapy without taking into account the sedation strategy was also carried out. Statistical data processing was carried out on the basis of GraphPad Prism 9.0 software.
 Results: In the group receiving propofol sedation (n=95), 83.16 % (n=79) of patients received inotropic/vasopressor therapy, which is 40.72 % of the total number of patients in all 3 groups (n=194). In the group receiving received sedation with dexmedetomidine (n=16), 81.25 % (n=13) received supportive inotropic/vasopressor therapy, which is 6.7 % of the total number of patients in all 3 groups (n=194). Patients who were sedated with a combination of these drugs (n =83) received supportive inotropic/vasopressor therapy in 91.57 % (n=76) of cases, which is 39.18 % of the total number of patients in all 3 groups (n=194). (p = 0.2093). When analyzing the frequency of use of inotropic therapy in each LVEF group, regardless of the type of sedation, it was found that the frequency of use depended on the fraction of LVEF emission below 55 % (p=0.0484). When comparing the groups of patients with LVEF ≥ 55 % and LVEF 40 – 30 %, more patients with PV 40 – 30 % received inotropic support (p=0.0299 RR 0.7878 95 % CI 0.6542-0.9528). No difference was found in the frequency of use of inotropic support when comparing LVEF ≥ 55 % and LVEF≤ 30% (p=0.7474 RR 0.9103 95% CI 0.7255-1.275), PV 55 – 40% and PV 40 – 30 % (p=0.4527 RR – 1.592)
 Conclusions: According to the conducted study, in patients in the early postoperative period after cardiac surgery, no influence was found between the strategy of sedation, the output fraction of the left ventricle and the frequency of use of norepinephrine, dobutamine, dopamine or their combination (p=0.2093). But it was found that inotropic/vasopressor therapy was more often needed in patients with LVEF less than 55 % regardless of the sedation strategy. The doses of dobutamine and dopamine were the same in all 3 sedation groups, which can speak in favor of the absence of a difference in the frequency of the syndrome of decreased cardiac output. During the analysis, it was also found that the doses and frequency of norepinephrine use were higher in the group where sedation was carried out with propofol (p=0.0011), which may indicate that sedation with propofol leads to a higher frequency of hypotension, the correction of which requires higher doses of norepinephrine.