The PaO2 response to changes in end expiratory pressure in the newborn respiratory distress syndrome.

To quantitate the effect of changes in end-expiratory pressure (EEP) upon PaO2 in infants with the respiratory distress syndrome, arterial blood gas (ABG) data was reviewed in 28 neonates. A total of 94 ABG specimen pairs were analyzed (specimen I taken before EEP adjustment; specimen II taken after EEP change). An overall change in PaO2 of 15 torr was noted per cm H2O change in EEP. Patients in whom the level of EEP was low (0-3 cm H2O) at the time of Sample I had a greater change in PaO2 (p less than 0.01) than infants whose Sample I ABG was taken at mid-range of EEP (4-6 cm H2O) or at high ranges (7-12 cm H2O). At the high ranges of EEP a minimal and variable PaO2 response was observed. The PaO2 response was not statistically different between neonates on controlled ventilation and those breathing spontaneously. Survivors had a greater PaO2 response than did nonsurvivors, but because of the variables affecting respiratory distress syndrome (RDS) patients, it could not be determined if this PaO2 response had a prognostic value. From this data, the clinician is provided with a guide to the expected PaO2 response when a change in EEP is made.