Interaction between Lung Mechanics and Gas Exchange by Low Volume High Frequency Pulmonary Ventilation in Patients with Respiratory Failure.
Abstract
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 mechanism(s) 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 21, 1984
- Accession Number
- ADA193073
Entities
People
- Jeffrey M. Drazen
- Julian Solway
- Phillip Drinker
- Roger D. Kamm
- Thomas Rossing
Organizations
- Brigham and Women's Hospital