Changes in pulmonary artery pressure during the acute phase of respiratory distress syndrome treated with three different types of surfactant

Abstract

We studied the changes in acceleration time/right ventricular ejection time ratio (AT/RVET; indicative of changes in pulmonary artery pressure) calculated from Doppler ultrasound examinations performed before and 1, 6, and 12 h after the first and second doses of surfactant following the administration of each of three different surfactants during the acute phase of the respiratory distress syndrome. Maximum fractional inspired oxygen concentration (F(I,O2)) and peak inspiratory pressure (PIP) were recorded during each 4 h period from birth for the first 24 h and subsequently every 24 h until 72 h. Eighty-three infants were studied. Fifty patients weighing > 1 kg received Exosurf (n = 29) or ALEC (n = 21) and 33 weighing < or = 1 kg received Exosurf (n = 22) or Survanta (n = 11). The AT/RVET rose rapidly after administration of all three surfactants. There was no significant difference in the change in AT/RVET between those > 1 kg who received Exosurf and those who received ALEC (a synthetic surfactant). Similarly, there was no difference between those infants < or = 1 kg who received Exosurf and those who received Survanta. The F(I,O2) requirements, but not PIP, were lower in those infants who received Survanta at 12 and 20 h compared with those who received Exosurf. There was no significant difference in the F(I,O2) or PIP requirements between infants > 1 kg who received Exosurf compared with those who received ALEC. The rise in AT/RVET found in this study after administration of ALEC, Exosurf, or Survanta suggests that similar and rapid falls in pulmonary artery pressure occur after all three surfactant administrations, despite the difference in clinical response demonstrated between Exosurf and Survanta.