Introduction Previous studies of infants on ventilatory support suggest that right ventricular output (RVO) decreases with increasing mean airway pressure. This may be due to increased pressure in the thoracic cavity. We investigated changes in cardiac output (CO) at different levels of nasal continuous positive airway pressure (nCPAP) in preterm infants with evolving chronic lung disease.
Methods We studied infants between 28 and 34 weeks corrected gestational age, a minimum of two weeks old, treated with nCPAP of 5 to 7 cm H2O, with an O2 requirement of 25–40%, in whom written parental consent was obtained. Infants with significant cardiac shunts were excluded. Infants were randomly assigned to nCPAP levels of 4, 6, and 8 cm H2O for 15 min each. Right and left ventricular output, left pulmonary artery flow, superior vena cava flow, heart rate and blood pressure were measured after each change with a Vivid-I ultrasound machine by a single examiner (FB) blinded to nCPAP levels.
Results Thirty infants with a median (IQR) gestational age of 25.9 (25.6–26.8) weeks and a birth weight of 0.78 (0.66–0.94) kg were studied at a median age of 43 (24–53) days. There were no significant differences in any cardiovascular parameters at different levels of nCPAP.
Discussion We conclude that nCPAP levels between 4 and 8 cm H2O did not have an effect on CO in our study population of stable preterm infants with evolving chronic lung disease.