Assessment of a new valveless infant ventilator.

A new valveless ventilator, which uses an air jet to provide the driving force for positive pressure ventilation, was used on 13 newborn babies (10 of very low birthweight) who had severe respiratory disease. The ventilator differs from 'true' jet ventilators in that its driving gas does not take part in gas exchange. Functionally it is a pressure pre-set, time-cycled ventilator, whose performance is characterised by the rapid and precise maintenance of both inspiratory and expiratory airway opening pressure. All the babies had progressively worsening respiratory failure (mean values of arterial pCO2 were 9.46 kPa, with a pH of 7.14, and an inspired oxygen concentration of 92.5%) on conventional mechanical ventilation. On the new ventilator, with the same settings, there was a dramatic and highly significant improvement within 20 to 30 minutes (mean values of arterial pCO2 were 6.45 kPa, pH 7.26, and inspired oxygen concentration 85.7%). This improvement was maintained. The new ventilator represents an important advance in the management of babies with severe respiratory failure.