Equations for predicting changes in hemodynamic parameters by various inotropes in patients of cardiogenic shock with acute coronary syndrome: EQUINOX study

Context: Inotropes are the medications that enhance cardiac contractility or induce vasoconstriction in patients with cardiogenic shock (CS), a life-threatening complication of acute coronary syndrome (ACS) associated with significant morbidity and mortality. Optimization of hemodynamics with inotropic support is essential; however, the hemodynamic response to different agents varies considerably. Aim: This study was conducted to predict the effect of various inotropes, administrated singly or in combination, on hemodynamic parameters in patients of CS with ACS. Settings and Design: Sixty consecutive patients of ACS presenting with CS were evaluated in a prospective, open label, and single center study. Methods: Patients were analyzed into four groups according to the combinations of inotropes used in them. Appropriate blood samples were taken and hemodynamic parameters measured at baseline and at 6 h to calculate the cardiac output (CO), mean arterial pressure (MAP), systemic vascular resistance (SVR), and cardiac power (CP). Intra-aortic balloon pump (IABP) was the only mechanical assist device used in the study in 30 (50%) of the patients as per the discretion of treating intensivist. Results: Formulae derived to predict the expected mean change in CO, SVR, CP, and MAP at 6 h of these different combinations is proposed here. There was no significant difference between four groups for the mean change in these parameters ( P > 0.05). Hemodynamic impact of IABP resulted in 49% lower usage of dobutamine in the cohort. Conclusions: Formulae to predict the expected change in hemodynamic parameters while using inotropes can be used to achieve the desired hemodynamic changes instead of arbitrary usage of currently used hemodynamic parameters.