Experience with phenylephrine as a component of the pharmacologic support of septic shock

Abstract

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] less than 65 mm Hg) and vasodilation (systemic vascular resistance index [SVRI] less than 1500 dyne.sec/cm5.m2 received phenylephrine at iv infusion rates of 0.5 to 9 micrograms/kg.min to maintain MAP greater than 70 mm Hg. MAP, SVRI, left ventricular stroke work index, and stroke volume index were significantly (p less than .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 less than .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 less than .05). Blood lactate concentrations decreased and urine output increased significantly (p less than .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.