VOLUME DELIVERY DURING HIGH-FREQUENCY OSCILLATION

Aim-To examine the delivered volume during ''high volume strategy'' hi gh frequency oscillation, used as rescue treatment in preterm infants; and to identify factors, other than frequency and oscillatory amplitu de, influencing the magnitude of volume delivery. Method-Twenty infant s (median gestational age 29 weeks) were studied on 45 occasions. Two oscillator types were used (SensorMedics and SLE). Delivered volume wa s measured under clinical conditions with the arterial blood gases wit hin a predetermined range. A specially calibrated pneumotachograph sys tem was used. Results-Overall, the median delivered volume was 2.4 ml/ kg (range 1.0 to 3.6 ml/kg); on 32 occasions the delivered volume was greater than 2.0 ml/kg and on seven greater than 3.0 ml/kg. The delive red volume related significantly to disease severity; there was an inv erse correlation between delivered volume and both the oxygenation ind ex (OI) (r=-0.51) and AaDO(2) (r=-0.54). Conclusion-Delivered volume d uring HFO may, in certain infants, exceed the anatomical dead space, p ermitting some direct alveolar ventilation.