IV milrinone for cardiac output increase and maintenance: comparison in nonhyperdynamic SIRS/sepsis and congestive heart failure

Abstract

Objective: To characterize the effect of the phosphodiesterase inhibitor (PDEI) milrinone in adult patients with a non-hyperdynamic condition during the course of the systemic inflammatory response syndrome (SIRS) or sepsis when compared with patients with congestive heart failure (CHF). PDEIs are potent inhibitors of cytokine production and expression. We hypothesized that there might be an outstanding beneficial effect of PDEIs in the setting of SIRS/sepsis. Design: Prospective, open labeled, protocol-driven pilot study. Patients: Nine patients with a non-hyperdynamic hemodynamic condition during SIRS/sepsis (group 1) and seven patients with CHF (group 2) requiring inotropic support. All patients were having heart disease. All patients had a combination of various catecholamines at the time of inclusion in the study and had received fluid resuscitation to an extent that left ventricular stroke work index (LVSWI) did not increase further. Intervention: Milrinone infusion at a rate of 0.5 μg/kg per min in addition to preexisting catecholamine therapy. Measurements and results: Measurements of cardiac index (CI; thermodilution) and calculation of vascular resistance and LVSWI was done every 8 h for at least 40 h during milrinone infusion. CI and LVSWI significantly increased in both groups (p < 0.001 and p = 0.006, respectively). There were no significant differences between groups in these parameters (p > 0.11 and p > 0.13, respectively). The LVSWI increase occurred while there was a decrease in pulmonary capillary wedge pressure, suggesting a true and comparable improvement in cardiac function relatively independent of loading conditions. Preexisting catecholamines had to be increased in both groups (NS). Milrinone had to be discontinued in one patient due to hypotension. Conclusion: Milrinone administration is feasible in selected patients with a non-hyperdynamic condition during SIRS/sepsis and with preexisting heart disease. Under the conditions of this study, milrinone was no better in terms of CI and LVSWI maintenance in septic cardiac dysfunction when compared with CHF. These results do not necessarily extend to other cohorts with no preexisting heart disease.