Objective The study aimed to assess the association of nucleated red blood cells (NRBC), a surrogate of intrauterine hypoxia, and elevated pulmonic vascular resistance (E-PVR) and oxygen requirement after minimally invasive surfactant therapy (MIST). Study Design Retrospective study of a cohort of preterm neonates that received MIST in a single unit. Results NRBC were measured in 65 of 75 (87%) neonates administered MIST during the period. In total, 22 of 65 (34%) infants had pre-MIST echocardiography (ECHO). Neonates with elevated NRBC (predefined as >5 × 10 9 /L, n = 16) required higher post-MIST fraction of inspired oxygen (FiO 2) than neonates with normal NRBC (<1 × 10 9 /L, n = 17; FiO 2 = 0.31 ± 0.10 and 0.24 ± 0.04, respectively, p = 0.02). NRBC correlated positively with % of time in right to left ductal shunt (r = 0.51, p = 0.052) and inversely with right ventricular stroke volume (r = -0.55, p = 0.031) and time to peak velocity to right ventricular ejection time ratio (r = -0.62, p < 0.001). Conclusion Elevated NRBC are associated with elevated FiO 2 after MIST and elevated E-PVR. Intrauterine hypoxia may impact postnatal circulatory adaptations and oxygen requirement. Key Points Post-MIST FiO2 requirements are significantly higher in infants with elevated NRBC. NRBC correlates positively with elevated PVR in neonates requiring. Intrauterine hypoxia may play a role in postnatal circulatory adaptations in neonates with RDS.
- functional echocardiography
- persistent pulmonary hypertension
- pulmonary vascular resistance
- Respiratory Distress Syndrome