Myocyte stretch is the main stimulus of brain natriuretic peptide (BNP) synthesis and release. During septic shock, important variations of volemia can occur and a correlation has been described between the cardiac index and the BNP level 1. However, the relation between the echocardiographic left ventricule area and the BNP level has never been described. The aim of our study was to evaluate BNP and left ventricule area variations after an acute fluid loading in septic shock.

Mechanical ventilated patients with septic shock, and without anterior cardiac disease, were included in our study. A fluid challenge was performed with colloid (500 ml) in 30 minutes. A BNP blood sample was drawn before and 1 hour after fluid loading. The primary endpoint was BNP variation after fluid challenge. Median values (25–75th percentiles) were compared with the Wilcoxon test (P < 0.05). The end-diastolic left ventricule area was recorded before and 1 hour after fluid challenge. Linear regression of BNP variation and left ventricular area variation was determined and r² was calculated.

Eight patients (median age 68 years; six males/two females; SOFA score = 12) were enrolled in our study. The initial BNP level median increased from 695 (417–2,738) to 715 (478–2,596) μg/ml after a fluid loading (P = 0.7) (Figure 1).We did not find a statistically significant relationship between BNP variation and left ventricule area variation after fluid challenge (P = 0.13) (Figure 2).