Abstract | OBJECTIVE: DESIGN: A randomized prospective trial of biologically variable ventilation vs. control mode ventilation in swine. SETTING: University research laboratory. SUBJECTS: Eighteen farm-raised pigs. INTERVENTIONS:
Methacholine was administered as a nebulized aerosol to initiate bronchospasm, defined as doubling of peak inspiratory pressure and respiratory system resistance, and then randomized (n = 9 each group) to either continue control mode ventilation or switch to biologically variable ventilation at the same minute ventilation. Over the next 4 hrs, hemodynamics, blood gases, respiratory mechanics, and carbon dioxide expirograms were recorded hourly. At end-experiment, tracheobronchial lavage was undertaken to determine interleukin-6 and -10 concentrations. MEASUREMENTS AND MAIN RESULTS: Measurements of physiologic variables and inflammatory cytokines showed that biologically variable ventilation significantly improved gas exchange, with greater arterial oxygen tensions (p = .006; group x time interaction), lower arterial carbon dioxide tensions (p = .0003; group effect), lower peak inspiratory pressures (p = .0001; group x time), greater static compliance (p = .0001; group x time), greater dynamic compliance (p = .0001; group x time), and lower total respiratory system resistance (p = .028; group x time), compared with conventional ventilation. The appearance of inflammatory cytokines in bronchoalveolar lavage fluid (interleukin-6 and -10) was not affected by mode of ventilation. CONCLUSIONS: In this experimental model, biologically variable ventilation was superior to control mode ventilation in terms of gas exchange and respiratory mechanics during severe bronchospasm.
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Authors | W Alan C Mutch, Timothy G Buchman, Linda G Girling, Elizabeth K-Y Walker, Bruce M McManus, M Ruth Graham |
Journal | Critical care medicine
(Crit Care Med)
Vol. 35
Issue 7
Pg. 1749-55
(Jul 2007)
ISSN: 0090-3493 [Print] United States |
PMID | 17522581
(Publication Type: Comparative Study, Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Cytokines
- Methacholine Chloride
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Topics |
- Animals
- Bronchial Spasm
(therapy)
- Cytokines
(metabolism)
- Least-Squares Analysis
- Methacholine Chloride
- Pulmonary Gas Exchange
- Random Allocation
- Respiration, Artificial
(methods)
- Respiratory Mechanics
- Status Asthmaticus
(therapy)
- Swine
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