Cardiology in the young
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Cardiology in the young · Jan 1998
Effects of positive pressure ventilation and inspired oxygen on pulmonary vascular resistance and tissue oxygen delivery in neonatal pigs.
Management of pulmonary vascular resistance in neonates with congenital heart disease is important for stabilization before and after surgical interventions. Thus, we determined which combination of positive end-expiratory pressure ventilation and fraction of oxygen in the inspired air increases pulmonary vascular resistance without compromising delivery of oxygen to the tissue. Eight piglets were anesthetized, intubated and ventilated. ⋯ The combination of a ventilatory pressure of 15 cm of water and inspired oxygen of 1.00, or ventilatory pressure at 5 cm of water and oxygen delivery of 0.15, produced similar changes in pulmonary vascular resistance (19.1 +/- 2.8 vs. 20.0 +/- 3.8 mmHg/(L/min)) and cardiac output (0.78 +/- 0.07 vs. 0.93 +/- 0.10 L/min) but, the higher level of positive pressure plus 1.00 inspired oxygen gave a significantly higher arterial oxygen saturation (0.99 +/- 0.03 vs. 0.72 +/- 0.19%) and delivery of oxygen to the tissues (13.7 +/- 2.9 vs. 7.4 +/- 1.5 ml O2/min, p < 0.05). Thus, both high positive pressure ventilation and hypoxia increase pulmonary vascular resistance. Only high pressure ventilation plus high concentrations of inspired oxygen, however, increased pulmonary vascular resistance without compromising delivery of oxygen, suggesting that this combination is a superior means of increasing pulmonary vascular resistance.