B-type natriuretic peptide: Usefulness in the management of critically-ill neonates

B-type natriuretic peptide (BNP) is responsible for changes in the heart organogenesis and is associated with transition to extrauterine life. In the first week of life, BNP levels are high and return to normal with the physiological loss in weight. High BNP levels are associated with different conditions.

To establish the relationship between BNP levels and criticality and the short-term clinical course among patients hospitalized in the neonatal intensive care unit.

Observational and analytical study conducted in a prospective cohort. Criticality was defined as a requirement for assisted mechanical ventilation with a fraction of inspired oxygen of more than 50% and/or inotropes. Two blood samples were collected 72 hours apart.

Seventy-three patients were included in the study. Depending on their clinical course on day 7, they were divided into 2 groups: patients with a good clinical course or a persistent, severe clinical course. The median baseline BNP level was similar in both groups (p: 0.15). The median BNP level at 72 hours was higher among patients with a persistent, severe clinical course (p: 0.005). The difference between both BNP values was calculated (ΔBNP: BNP level at 72 hours - BNP level at 0 hours). The ΔBNP was positive among patients with a persistent, severe clinical course (X= 1260 pg/mL; range: 426-2094) and negative in the group with a good clinical course (X= -967 pg/mL; range: -1656/-278) (p: 0.0002); sensitivity: 87%; specificity: 86%; positive predictive value: 74%; and negative predictive value: 93%.

In this group of patients, the delta-BNP value reflected the short-term clinical course.