Document Detail


Automated system for detailed measurement of respiratory mechanics.
MedLine Citation:
PMID:  8732817     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: The mechanical properties of the respiratory system (i.e., elastance and resistance) depend on the frequency, tidal volume, and shape of the flow waveform used for forcing. We developed a system to facilitate accurate measurements of elastance and resistance in laboratory and clinical settings at the frequencies and tidal volumes in the physiologic range of breathing. METHODS: A personal computer (PC) is used to drive a common clinically used ventilator while simultaneously collecting measurements of airway flow, airway pressure, and esophageal pressure from the experimental subject or animal at different frequencies and tidal volumes. Analysis analogous to discrete Fourier transform at the fundamental frequency (i.e., ventilator setting) is used to calculate elastances and resistances of the total respiratory system and its components, the lungs and the chest wall. We have shown that this analysis is independent of the high-frequency harmonics that are present in the waveform from clinical ventilators. RESULTS: The system has been used successfully to make measurements in anesthetized/paralyzed dogs and awake or anesthetized human volunteers in the laboratory, and in anesthetized human volunteers in the laboratory, and in anesthetized humans in the operating room and intensive care unit. Elastances and resistances obtained with this approach are the same as those obtained during more controlled conditions, e.g., sinusoidal forcing. CONCLUSIONS: Accurate, standardized measurements of lung and chest wall properties can be obtained in many settings with relative ease with the system described. These properties, and their frequency and tidal volume dependences in the physiologic range, provide important information to aid in the understanding of changes in respiratory function caused by day-to-day conditions, clinical intervention and pathologies.
Authors:
M D Green; G Ho; H Polu; Z Ma; M Agarwal; P Hu; G M Barnas
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of clinical monitoring     Volume:  12     ISSN:  0748-1977     ISO Abbreviation:  J Clin Monit     Publication Date:  1996 Jan 
Date Detail:
Created Date:  1996-11-07     Completed Date:  1996-11-07     Revised Date:  2010-03-24    
Medline Journal Info:
Nlm Unique ID:  8506707     Medline TA:  J Clin Monit     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  61-7     Citation Subset:  IM    
Affiliation:
Department of Anesthesiology, University of Maryland, Baltimore 21201, USA.
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MeSH Terms
Descriptor/Qualifier:
Airway Resistance / physiology
Anesthesia, General
Animals
Automatic Data Processing*
Dogs
Esophagus / physiology
Fourier Analysis
Humans
Lung / physiology
Lung Compliance / physiology
Microcomputers
Neuromuscular Blockade
Pressure
Pulmonary Ventilation / physiology
Respiration / physiology
Respiratory Mechanics / physiology*
Thorax / physiology
Tidal Volume / physiology
Ventilators, Mechanical
Wakefulness
Grant Support
ID/Acronym/Agency:
HL-33009/HL/NHLBI NIH HHS; HL-44128/HL/NHLBI NIH HHS

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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