| The flow-time waveform predicts respiratory system resistance and compliance. | |
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MedLine Citation:
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PMID: 22226421 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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PURPOSE: Knowledge of patients' lung compliance and resistance aids clinical management. We investigated whether these values, readily measured during volume assist-control ventilation (VACV), could also be estimated during pressure assist-control ventilation (PACV). METHODS: Data were collected in 12 mechanically ventilated human subjects. During VACV, peak pressure, plateau pressure, end-expiratory pressure, tidal volume, and inspiratory flow rate were measured. During PACV, inspiratory pressure, end-expiratory pressure, and tidal volume were recorded. The linear component of the pressure-time waveform was extrapolated to time and flow axes. Using the equation of motion for the respiratory system, assuming a nonlinear resistance, we calculated inspiratory resistance and compliance. During VACV, compliance and inspiratory resistance were calculated in the conventional manner. RESULTS: In ventilated subjects, mean compliance during PACV was 37.06 ± 15.65 mL/cm H(2)O, and during VACV, 36.93 ± 12.18 mL/cm H(2)O. Mean inspiratory resistance during PACV was 15.17 ± 5.14 cm H(2)O/L per second, whereas during VACV, it was 12.50 ± 2.99 cm H(2)O/L per second. A strong correlation is evident between compliance and inspiratory resistance calculated during PACV vs VACV (r(2) of 0.73 and 0.51, respectively). CONCLUSIONS: During PACV, the inspiratory flow waveform is linear, and its slope contains information regarding inspiratory resistance and compliance. Calculated values correlate with those during VACV. |
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Authors:
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Boulos S Nassar; Nicole D Collett; Gregory A Schmidt |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-1-4 |
Journal Detail:
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Title: Journal of critical care Volume: - ISSN: 1557-8615 ISO Abbreviation: - Publication Date: 2012 Jan |
Date Detail:
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Created Date: 2012-1-9 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8610642 Medline TA: J Crit Care Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
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Copyright © 2011 Elsevier Inc. All rights reserved. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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