Journal article
Airway and Lung Tissue Mechanics in Asthma: Effects of Albuterol
American journal of respiratory and critical care medicine, Vol.159(1), pp.169-178
01/1999
DOI: 10.1164/ajrccm.159.1.9709109
PMID: 9872836
Abstract
We examined the partitioning of total lung resistance (RL) into airway resistance (Raw) and tissue resistance (Rti) in patients with mild to moderate asthma (baseline FEV1, 54 to 91% of predicted) before and after albuterol inhalation. An optimal ventilator waveform was used to measure RL and lung elastance (EL) in 21 asthmatics from approximately 0.1 to 8 Hz during tidal excursions. Analysis of the RL and EL provided separate estimates of airway and lung tissue properties. Eleven subjects, classified as Type A asthmatics, displayed slightly elevated RL but normal EL. Their data were well described with a model consisting of homogeneous airways leading to viscoelastic tissues before and after albuterol. The other 10 subjects, classified as Type B asthmatics, demonstrated highly elevated RL and an EL that became highly elevated at frequencies above 2 Hz. These subjects required the inclusion of an airway wall compliance in the model prealbuterol but not postalbuterol. This suggests that the Type B subjects were experiencing pronounced constriction in the periphery of the lung, resulting in shunting of flow into the airway walls. Spirometric data were consistent with higher constriction in Type B subjects. Both groups demonstrated significant (p < 0.05) decreases in Raw and tissue damping after albuterol, but tissue elastance decreased only in the Type B group. The percent contributions of Raw and Rti to RL were similar in both groups and did not change after albuterol. We conclude that in asthma, Raw comprises the majority (> 70%) of RL at breathing frequencies. The relative contributions of Raw and Rti to RL appear to be independent of the degree of smooth muscle constriction.
Details
- Title: Subtitle
- Airway and Lung Tissue Mechanics in Asthma: Effects of Albuterol
- Creators
- DAVID W KACZKAEDWARD P INGENITOELLIOT ISRAELKENNETH R LUTCHEN
- Resource Type
- Journal article
- Publication Details
- American journal of respiratory and critical care medicine, Vol.159(1), pp.169-178
- DOI
- 10.1164/ajrccm.159.1.9709109
- PMID
- 9872836
- ISSN
- 1073-449X
- eISSN
- 1535-4970
- Language
- English
- Date published
- 01/1999
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Radiology; Anesthesia
- Record Identifier
- 9984007167402771
Metrics
39 Record Views