EXPERIENCE WITH PHENYLEPHRINE AS A COMPONENT OF THE PHARMACOLOGICAL SUPPORT OF SEPTIC SHOCK

Objective: To evaluate the use of the selective alpha-1-adrenergic receptor agonist phenylephrine in the hemodynamic support of patients with septic shock. Design: Retrospective analysis of clinical use of phenylephrine. Setting: Surgical ICU in a university hospital. Patients: Thirteen patients with septic shock (diagnosed by defined criteria) requiring pharmacologic support for the treatment of hypotension. Interventions and Main Results: All patients underwent invasive hemodynamic monitoring followed by volume resuscitation and inotropic support to reverse flow-dependent oxygen consumption and lactic acidosis. Patients with persistent hypotension (mean arterial pressure [MAP] < 65 mm Hg) and vasodilation (systemic vascular resistance index [SVRI] < 1500 dyne.sec/cm5.m2 received phenylephrine at iv infusion rates of 0.5 to 9-mu-g-kg.min to maintain MAP > 70 mm Hg. MAP, SVRI, left ventricular stroke work index, and stroke volume index were significantly (p < .05) increased after phenylephrine administration and at the time of highest oxygen consumption (Vo2). Cardiac index was unchanged initially but increased at the time of highest Vo2 (p < .05). Pulmonary artery occlusion pressure and heart rate were unchanged. Average baseline Vo2 increased from 145 to 200 mL/min.m2 and oxygen delivery (Do2) increased from 447 to 597 mL/min.m2 during phenylephrine treatment (p < .05). Blood lactate concentrations decreased and urine output increased significantly (p < .05), while serum creatinine concentrations remained unchanged during phenylephrine therapy. Conclusions: Treatment with phenylephrine was associated with beneficial hemodynamic effects when used to maintain perfusion, while increasing Do2 and Vo2 in patients with septic shock.