Effect of norepinephrine on ventricular systolic function during septic shock: the ENESySS study

To determine whether norepinephrine improves the left ventricle systolic function in early septic shock patients.

Single-center, prospective, observational study in critically ill patients over a 2-year period in Italy. Hypotensive patients were included within 24 hours from the diagnosis of septic shock; preload responsiveness was excluded by a passive leg raising test. The main objective was the augmentation of the left ventricular outflow tract velocity time integral (LVOT-VTI) induced by the increase of norepinephrine infusion dosage.

Thirty patients were included in the final analysis, with a median age and SAPS II score of 67 (51-77) years and 49 (41-65), respectively. All patients were mechanically ventilated, 25 (83%) invasively and 5 (17%) non-invasively. The time elapsed between septic shock diagnosis and inclusion was 8 (3-17) hours. The norepinephrine infusion dose was increased from 0.3 (0.2-0.6) to 0.6 (0.4-0.9) µg kg^-1 min^-1, p < 0.01. The LVOT-VTI improved from 14 (11-17) to 17 (13-20) cm, p < 0.01. Conversely, the left ventricle ejection fraction (LVEF) did not change (p = 0.54). The end-systolic left ventricle elastance and the arterial elastance augmented from 1.02 (0.64-1.78) to 1.64 (0.98-2.22) mmHg ml^-1-p < 0.01-and from 1.71 (1.28-2.03) to 2.01 (1.71-2.82) mmHg ml^-1-p < 0.01, respectively; hence, the ventriculoarterial coupling decreased from 1.75 (1.15-2.29) to 1.29 (0.99-1.78), p < 0.01. An improvement of the left ventricle systolic indices was recorded also in the 15 (50%) patients with baseline depressed LVEF.

Norepinephrine improved the left ventricle systolic function and the ventriculoarterial coupling in septic shock patients.