North Trent Critical Care Network

Written by Critical Care Introduction:
To examine the cardiac consequences of early administration of norepinephrine in severely hypotensive septic patients hospitalised in a medical intensive care unit of a university hospital

Methods:
We included 105 septic shock patients who already received volume resuscitation. All received norepinephrine early because of life-threatening hypotension and the need to rapidly achieve a sufficient perfusion pressure and maintain adequate flow. We analysed the changes in transpulmonary thermodilution variables associated with the increase in mean arterial pressure (MAP) induced by norepinephrine when the achieved MAP was [greater than or equal to]65mmHg.

Results:
Norepinephrine significantly increased MAP from 54+/-8 to 76+/-9 mmHg, cardiac index (CI) from 3.2+/-1.0 to 3.6+/-1.1 L/min/m2, stroke volume index (SVI) from 34+/-12 to 39+/-13 mL/m2, global end-diastolic volume index (GEDVI) from 694+/-148 to 742+/-168 mL/m2 and cardiac function index (CFI) from 4.7+/-1.5 to 5.0+/-1.6 min-1. Beneficial haemodynamic 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 [less than or equal to]45%. No change in CI, SVI, GEDVI or CFI was observed in the 17 patients with baseline LVEF [less than or equal to]45% for whom values of MAP [greater than or equal to]75 mmHg 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 [greater than or equal to]75 mmHg were achieved.

Authors: Olfa Hamzaoui

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