The December 1996 issue of Pediatrics carries a quotation from an article by J R Platt:

[the crucial question] ... consists of asking in your own mind, on hearing a scientific experiment described: “What hypothesis does your experiment disprove?”.1

In an issue which also carries three papers relating to high frequency ventilation this would seem a useful standpoint from which to assess these three important contributions. The areas addressed by these papers are important—areas where technology has advanced dramatically and sales of machines seem to be high—yet good evidence of efficacy is perhaps still awaited, or is it provided by these submissions?

High frequency ventilation may be achieved using either: a rapid firing jet which is positioned at the end of an endotracheal tube; an oscillator in which rapid alternation of positive and negative pressure are applied to the lungs; or by a high frequency flow interrupter which works like a conventional ventilator but at high speed. There are no randomised data to support the use of the latter technique, although at least one trial is under way. Of the three oscillators available in the UK at present, only the Sensormedics 3100/3100A has been used in randomised trials. High frequency jet ventilation (HFJV) has not found wide acceptance in the UK.

The three papers are related by their investigation of the effects of prospective management of respiratory distress syndrome using high frequency ventilation delivered either by jet or oscillator. Most authorities agree that from their own personal experience high frequency ventilation is a valuable addition to “rescue” treatments for children in respiratory failure that is unresponsive to conventional treatments, and that its effect may be additive with nitric oxide. Its use in rescue mode may be dramatic for some patients but it is not a modality to be used …