Ventilation at high respiratory frequencies

Abstract

This paper reviews the development of different methods of ventilation at respiratory rates higher than 60 per minute (1 Hz) along with data on experimental and clinical uses of the techniques. The definitions and terms that have been used for these high rates at the present time are confusing. An attempt to clarify the terms has been made. Whereas high frequency positive pressure ventilation (HFPPV) refers to respiratory rates between 60-110 per minute (1-1.8 Hz), high frequency jet ventilation (HFJV) usually refers to rates between 110-400 per minute (1.8-6.7 Hz) and high frequency oscillation (HFO) refers to rates above 400 and up to 2400 per minute (40 Hz). It should be recognised that this differentiation in terminology is rather arbitrary and does not necessarily represent a sudden switch to different physiological methods of ventilation. In view of the various techniques which are involved in ventilation methods utilising rates greater than 60 per minute (1 Hz), it is the purpose of the present work to review the literature. In so doing, the contrasting rates, mechanical equipment, and experimental and clinical uses of these different methods will be discussed in order to clarify their potential contribution to clinical medicine.