Nine infants (47 percent) required supplemental oxygen for part or all of the first six months of life because their Pa02 values were less than 70 mm Hg on FIo2 0.21 percent. At 6 months of age only one patient still required supplemental oxygen and this was the only infant that required rehospitalization during the first six months for respiratory failure. Three other infants had upper respiratory tract infections and otitis media during these six months but they were managed on an outpatient basis. Arterial blood gas levels by radial artery puncture were obtained in 12 infants at 6 months of age. Transcutaneous oxygen tension was monitored continuously during arterial puncture for correlation. The mean Pa02 was 80 ±5 mm Hg. Five of 12 infants (42 percent) still had Pa02 <80 mm Hg while they were breathing room air (Fig 1). The mean pH was 7.44 ±0.01 and PaC02 was 31 ±2 mm Hg, representing acute hyperventilation secondary to crying during arterial puncture.
Since an arterial blood gas level may not represent oxygenation at rest or during feeding and wakefulness, continuous noninvasive oxygen monitoring was obtained in 18 ECMO patients while they were breathing room air. The infants were observed for an average duration of 34.9 ±3.2 min during sleep.
Figure 1. Dynamic pulmonary compliance, Raw, TGV at FRC and Pa02 while patients were breathing room air are plotted for the ECMO survivors. Individual data points are shown. The shaded area represents the normal range; 35 percent had abnormal Cdyn, 84 percent had abnormal Raw, 40 percent were hypoxic and TGV was normal in all.