Early administration of norepinephrine increases cardiac preload and cardiac output in septic patients with life-threatening hypotension

INTRODUCTION: We sought to examine the cardiac consequences of early administration of norepinephrine in severely hypotensive sepsis patients hospitalized in a medical intensive care unit of a university hospital. METHODS: We included 105 septic-shock patients who already had received volume resuscitation. All received norepinephrine early because of life-threatening hypotension and the need to achieve a sufficient perfusion pressure rapidly and to maintain adequate flow. We analyzed the changes in transpulmonary thermodilution variables associated with the increase in mean arterial pressure (MAP) induced by norepinephrine when the achieved MAP was ≥65 mm Hg. RESULTS: Norepinephrine significantly increased MAP from 54 ± 8 to 76 ± 9 mm Hg, cardiac index (CI) from 3.2 ± 1.0 to 3.6 ± 1.1 L/min/m(2), stroke volume index (SVI) from 34 ± 12 to 39 ± 13 ml/m(2), global end-diastolic volume index (GEDVI) from 694 ± 148 to 742 ± 168 ml/m(2), and cardiac function index (CFI) from 4.7 ± 1.5 to 5.0 ± 1.6 per min. Beneficial hemodynamic effects on CI, SVI, GEDVI, and CFI were observed in the group of 71 patients with a baseline echocardiographic left ventricular ejection fraction (LVEF) >45%, as well as in the group of 34 patients with a baseline LVEF ≤45%. No change in CI, SVI, GEDVI, or CFI was observed in the 17 patients with baseline LVEF ≤45% for whom values of MAP ≥75 mm Hg were achieved with norepinephrine. CONCLUSIONS: Early administration of norepinephrine aimed at rapidly achieving a sufficient perfusion pressure in severely hypotensive septic-shock patients is able to increase cardiac output through an increase in cardiac preload and cardiac contractility. This effect remained in patients with poor cardiac contractility except when values of MAP ≥75 mm Hg were achieved.