Low cardiac output measured by bioreactance and adverse outcome in preterm infants with birth weight less than 1250 g

Abstract

Background: Recently a new continuous non-invasive cardiac output measurement, bioreactance, has become available. Bioreactance measurement of cardiac output has been shown to correlate with left ventricular output detected by echocardiography in healthy term and preterm neonates.

Aims: Our aim was to correlate cardiac output measurements by bioreactance in the first 48 h of life with adverse outcomes attributable to hypoperfusion (peri/intraventricular haemorrhage (PIVH) and/or necrotising enterocolitis (NEC)) in the cohort of extremely preterm infants.

Study design: A prospective observational cohort study.

Subjects: Preterm infants with birth weight less than 1250 g.

Outcome measures: Cardiac output was measured between six and 48 h of age by bioreactance. Our primary outcome was a difference in cardiac output between infants with an adverse outcome attributable to hypoperfusion (Group 1), and infants without the predefined adverse outcome (Group 2).

Results: There were 39 infants enrolled in the study. There were six infants in Group 1. These infants had a significantly lower minimal cardiac output measurement compared to Group 2 (mean 36.7 ml/kg/min vs 64.5 ml/kg/min, p = .0006). The mean cardiac output in Group 1 was significantly lower on day one of life, followed by a significant increase in cardiac output on day two of life compared to Group 2.

Conclusions: Infants with birth weight less than 1250 g and PIVH and/or NEC had significantly lower cardiac output compared to infants without these complications on day one of life. This low cardiac output was then followed by a significant increase on day two of life.

Keywords: Adverse outcome; Bioreactance; Cardiac output; Extreme prematurity.