Gas exchange during simulated airway secretion in the anaesthetized rabbit
| Autor: | L Lagerstrand, M Dahlback, G Hedenstierna |
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| Rok vydání: | 1992 |
| Předmět: | |
| Zdroj: | European Respiratory Journal. 5:1215-1222 |
| ISSN: | 1399-3003 0903-1936 |
| DOI: | 10.1183/09031936.93.05101215 |
| Popis: | We wished to study the effect of airways secretion on gas exchange. Peripheral airway secretion was simulated in 9 rabbits by the continuous inhalation of nebulized isotonic saline, at a droplet size of about 3 microns. Intrapulmonary deposition of saline in the peripheral airways (83% in airways smaller than 0.5 mm) did not alter total inspiratory resistance (mean 5.4 kPa.l-1.s), but led to a decrease in compliance of the total respiratory system from 45.9 to 21.8 ml.kPa-1 after one hour of nebulization. Arterial oxygen tension decreased from 17.8 kPa to 12.1 and 6.9 kPa after 5 and 60 min of nebulization, respectively. PaCO2 was unaffected after 5 min (4.5 kPa) but increased to 7.0 kPa after 60 min of nebulization. Ventilation-perfusion relationships (VA/Q) showed a significant increase in perfusion of areas with low VA/Q ratios (from 0.7 to 6.3% of cardiac output) and in shunt (from 1.4 to 4.3%) after 5 min of nebulization. At the end of the experiment shunt was increased markedly to 29.7% of cardiac output whereas perfusion of low VA/Q regions remained at the same level (7.3%). The results from this animal model indicate that all gas exchange abnormalities known to occur in asthma can be reproduced without measurably increasing the resistance of the respiratory system. |
| Databáze: | OpenAIRE |
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