[High frequency "bubble" oscillation ventilation in the neonatal period]

The authors tested their own high frequency, oscillation, "bubble" ventilator on a model of neonatal lungs in vitro and in vivo. They used the effect of oscillations which develop when through fluid (in vivo water) a mixture of air is bubbled and which can be, if the expiration tube is sufficiently rigid, transmitted back into the lungs. If the CPAP circuit is suitably arranged, it can ensure an adequate exchange of blood gases. The authors found marked changes in the amplitude of pressure oscillations as well as of the frequency in relation to the shape of the ending beneath the fluid surface (greatest when a funnel with a 30 mm diameter and 90 degree angle in relation to a normal line projected on the water surface is used). They found that the compliance (C) has no substantial effect on the amplitude nor on the frequency of oscillations. The mentioned bubble system approached as to its efficiency the commercial oscillation ventilator Stephen 3000 SFH and was used in the therapy of respiratory failure in three neonates with body weights of 1250-2700 g. The authors conclude that high frequency oscillation "bubble" ventilation is a cheap, safe and highly effective therapy which can be used in any department providing care of neonates even during transport.