High frequency ventilation and afferent vagal activity.
Recordings were made from pulmonary afferent fibres in the vagus nerves of anaesthetised dogs during conventional and high frequency ventilation. In single and multiple fibre preparations, the mean spike counts per minute at 14 breaths/minute were in the ranges 36.9-155.3 and 755-1921, respectively. These counts decreased by up to 61 and 44% respectively at 100 breaths/minute, and by 27-89% and 22-51% at 200 breaths/minute. At this frequency there was a further decrease of between 19 and 65% when the positive end expiratory pressure was removed. The findings of this study are intuitively acceptable, since pulmonary stretch receptor activity is proportional to tidal volume, and are in keeping with the clinical impression that high frequency ventilation per se does not eliminate respiratory drive.
Royal Postgraduate Medical School, Hammersmith Hospital, London.
A W
AW
Harrop-Griffiths
M K
MK
Chakrabarti
J G
JG
Whitwam
D000818:Animals; D001794:Blood Pressure; D004285:Dogs; D006612:High-Frequency Ventilation; D009412:Nerve Fibers / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology*; D012119:Respiration; D014630:Vagus Nerve / Q000502:physiology*