There is increasing concern that the dramatic improvement in the survival of immature infants has been accompanied by an increase in incidence of pulmonary complications, some seriously crippling and eventually fatal.1 Both barotrauma and oxygen toxicity have been considered in the pathogenesis of these disorders; circulatory disorders as a result of failure of closure of the ductus arteriosus or fluid overload have also been proposed as contributory factors. Reports of successful application of the principles of high frequency ventilation (HFV) in the treatment of infants with respiratory distress syndrome (RDS)2-4 and particularly those with severe interstitial emphysema5 have raised hopes that this technique might prevent barotrauma to the lungs and have stimulated physicians and engineers to develop new equipment that might be useful in ventilating small infants. HFV, however has not been evaluated in infants with regard to efficacy or safety; and gas exchange is not well understood under those circumstances. Because of the rapidly growing interest in this type of ventilatory support, a workshop was convened to examine the state-of-the-art of this technique in the developing respiratory system and to identify areas requiring further investigation. It was also considered important to discuss the necessity and feasibility of conducting a controlled clinical trial of this new modality of care, prior to its widespread application.
THEORETICAL CONSIDERATIONS
HFV involves the use of small tidal volumes, delivered at respiratory frequencies ranging from 60 to 2,400 breaths per minute (1 to 40 Hz).6-11 There are several systems for delivering HFV, each of which has different characteristics and therefore may have different effects.
Submitted on August 27, 1982