Oxygen concentration and pulmonary hemodynamics in newborn lambs with pulmonary hypertension

Satyanarayana Lakshminrusimha, Daniel D. Swartz, Sylvia F. Gugino, Chang Xing Ma, Karen A. Wynn, Rita M. Ryan, James A. Russell, Robin H Steinhorn

Research output: Contribution to journalArticlepeer-review

91 Scopus citations


The effect of oxygen concentration on lowering pulmonary vascular resistance (PVR) during resuscitation in a model of persistent pulmonary hypertension of the newborn (PPHN) is not known. PPHN was induced in fetal lambs by ductal ligation 9 d before delivery. After delivery by cesarean section, resuscitation of PPHN lambs with 21%, 50%, or 100% O2 (n = 6 each) for 30 min produced similar decreases in PVR. Lambs were then ventilated with 50% O2 for 60 min and exposed to inhaled nitric oxide (iNO, 20 ppm). Initial resuscitation with 100% O2 significantly impaired the subsequent response to iNO compared with 21% O2 (42 ± 9% vs 22 ± 4% decrease from baseline PVR). Finally, each lamb was randomly and sequentially ventilated with 10%, 21%, 50%, or 100% O2. PVR decreased with increased concentrations of inhaled O2 up to 50%, there being no additional decrease in PVR with 100% O2. When PVR was correlated with Pao2, the maximal change in PVR was achieved at Pao2 values <60 mm Hg. We conclude that resuscitation with 100% O2 does not enhance pulmonary vasodilation compared with 21% and 50% O2, but impairs the subsequent response to iNO in PPHN lambs. Hypoxia increases PVR but hyperoxia does not confer significant additional pulmonary vasodilation in lambs with PPHN.

Original languageEnglish (US)
Pages (from-to)539-544
Number of pages6
JournalPediatric Research
Issue number5
StatePublished - Nov 2009
Externally publishedYes

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health


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