Abstract

The effect of altering peak airway pressure, respiratory frequency, and inspiration: expiration ratio on arterial blood gas tensions, blood pressure, and calculated right-to-left shunt was investigated in 6 infants undergoing mechanical ventilation for hyaline membrane disease with a Bennet ventilator. The use of a very long inspiratory phase resulted in a large increase in P_ao₂ and fall in right-to-left shunt without affecting mean arterial blood pressure.