Feeding was recorded in 15 infants (11.3 ± 1.8 min) and awake time recording was obtained in 16 infants (16.5 ±2.4 min). The mean observed Sa02 during wakefulness (98.7 ±0.3) and feeding (99 ±0.2) was comparable to the same value during sleep (98.7 ±0.3 percent) (NS). No significant desaturation (Sa02 <90 percent) was observed during sleep. Only two infants (11 percent) experienced brief episodes of desaturation for 5 s during feeding and wakefulness. Twelve infants (67 percent) experienced short periods of apnea of 4- 10s duration during sleep. These apneic episodes were not associated with bradycardia or oxygen desaturation. There was no significant difference in the average number of apneic episodes observed during active sleep or quiet sleep.
Assessment of pulmonary mechanics revealed abnormalities of Cdyn and Raw (Table 2 and Fig 1). The mean Cdyn was 1.68 ±0.2 ml/cm H20/kg, and 35 percent of infants had abnormally low Cdyn (<1.5 ml/ cm H20) at 6 months of age. The mean Raw was 50.9 ±3.4 cm H20/L/s, and 84 percent of the infants had abnormally high Raw (>40 cm H20/L/s). The SGaw was decreased (<0.231/cm H20/L/s) in 89 percent of infants. Thoracic gas volume was normal.
Table 2—Pulmonary Mechanics in ECMO Survivors
|No. of infants||19|
|Respiratory rate (breaths per minute)||35±2|
|Raw (cm H20/IVs)||50.7±3.4|
|Sgaw (1/cm H20/IVs)||0.17±0.01|
|Cdyn/kg (ml/cm H20/kg)||1.7±0.2|