Interaction between Lung Mechanics and Gas Exchange by Low Volume High Frequency Pulmonary Ventilation in Patients with Respiratory Failure.
Annual summary rept. 1 Oct 83-30 Sep 84,
BRIGHAM AND WOMEN'S HOSPITAL BOSTON MA
Pagination or Media Count:
The factors influencing both dynamic hyperinflation and gas transport under the condition of low volume high frequency pulmonary ventilation HFV were examined. In the former area we measured gas transport and dynamic lung volumes in tracheostomized human subjects simultaneously in order to help determine the mechanisms responsible for gas trapping. We found that application of a fixed tidal volume about 50-100 ml over a range of frequencies from 0.5-20 Hz resulted in increased gas transport efficiency until a critical frequency was reached above this frequency no further increase in alveolar ventilation was achieved. In contrast, mean lung volume dynamic functional residual capacity increased only above a critical frequency. These findings were compared using a variety of electrical analog models including one which incorporated airflow limitation our findings suggest that airflow limitation mediates dynamic hyper-inflation. We also made measurements of gas transport during oscillatory flow in a hardware model which incorporated branching airways.
- Medicine and Medical Research