Patent ductus arteriosus during high-frequency ventilation for hyaline membrane disease.

The cardiovascular effects of a patent ductus arteriosus (PDA) in a premature baboon model of hyaline membrane disease treated with conventional positive-pressure ventilation (CPPV) or high-frequency ventilation (HFV) were studied. Twenty-seven (84%) of 32 infant baboons delivered at 75% gestation had positive retrograde aortograms at one hour of life. Eleven (34%) of these infant baboons had persisting evidence for retrograde flow over the first 24 h by Doppler examination. Significantly higher fluid requirements and bicarbonate requirements were present in the animals with a persisting PDA. Mean aortic BP values were significantly lower in these same animals. No significant differences were found between groups when mean airway pressure, heart rate, urine output, or form of ventilation were compared. The only significant differences found between the conventional and high-frequency ventilated animals with PDA were higher peak airway pressures and lower PEEP levels in the conventionally ventilated infants. The premature baboons can be a useful primate model to study the PDA. There appears to be no significant difference regarding the clinical effects of HFV and CPPV on PDA.