A reappraisal of isoproterenol in goal-directed therapy of septic shock

The goal of the study was to evaluate the effect of isoproterenol prescribed in goal-directed therapy for septic shock. Out of a cohort of 89 patients with septic shock, 14 patients treated with fluid and norepinephrine had inappropriate mixed venous oxygen saturation (SvO2 < 70%) not responding to correction of hypoxemia and anemia (>8 g.dL(-1)). Isoproterenol administration was started at a dose of 0.04 mu g.kg(-1).minute(-1) with 0.025 mu g.kg(-1).minute(-1) increments every 30 minutes until SvO2 was greater than 70%. Mean arterial pressure was maintained >= 65 mm.Hg by adjusting the norepinephrine infusion. Hemodynamic, oxygen, and renal variables were collected during a 12-h period. Patients with a known prior history of coronary disease were not eligible. Isoproterenol administration increased significantly SvO2 (62% +/- 10% to 71% +/- 9%), cardiac index (3.1 +/- 0.6 to 4.4 +/- 1.4 L.min(-1).m(-2)), stroke index (27 +/- 3.4 to 38 +/- 6.1 mL.m(-2)), and left ventricular stroke work index (24 +/- 3.4 to 40 +/- 5.0 g.m(-1).m(-2)). Heart rate rise did not reach a significant level. Arterial lactate concentration decreased significantly during the study period (5.7 +/- 2.8 to 3.4 +/- 1.6 mmol.L-1). No cardiac adverse events occurred with any electrocardiographic aspects of myocardial ischemia. This study suggests that isoproterenol is efficient to improve hemodynamics and oxygen variables in septic shock patients. There is a need for future investigations in larger groups of patients to determine whether isoproterenol can be an alternative to dobutamine.