Acute hemorrhagic shock decreases airway resistance in anesthetized rat
| Autor: | Walid Habre, Marc Fathi, Sam Bayat, Flore Portier, Gergely Albu, Ferenc Peták, Skander Layachi |
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| Rok vydání: | 2011 |
| Předmět: |
Pulmonary Circulation
Physiology Dead space Blood volume Respiratory physiology Shock Hemorrhagic 030204 cardiovascular system & hematology Catecholamines/blood Rats Sprague-Dawley 03 medical and health sciences Catecholamines 0302 clinical medicine Airway resistance Physiology (medical) Animals Medicine Plethysmograph Anesthesia Respiratory system Airway Resistance/physiology Blood Volume ddc:617 business.industry Airway Resistance Shock Hemorrhagic/physiopathology Respiratory Mechanics/physiology Blood flow Rats Blood Volume/physiology Pulmonary Circulation/physiology Acute Disease Respiratory Mechanics Lung Volume Measurements business Airway 030217 neurology & neurosurgery |
| Zdroj: | Journal of Applied Physiology, Vol. 111, No 2 (2011) pp. 458-64 |
| ISSN: | 1522-1601 8750-7587 |
| DOI: | 10.1152/japplphysiol.00024.2011 |
| Popis: | We studied the relation between changes in pulmonary and systemic hemodynamics to those in the airway resistance, respiratory tissue mechanics, and thoracic gas volume (TGV) following acute hemorrhage and blood reinfusion in rats. Forced oscillation technique was used to measure airway resistance (Raw), respiratory tissue damping, and elastance at baseline and after stepwise 1-ml blood withdrawals up to 5 ml total, followed by stepwise reinfusion up to full restoration. Mean systemic (Pam) and pulmonary arterial pressures and suprarenal aortic blood flow were measured at each step. In supplemental animals, plethysmographic TGV, Pam, and respiratory mechanics measurements were performed. Blood volume loss (BVL) led to proportional decreases in Raw (66.5 ± 8.8 vs. 44.8 ± 9.0 cmH2O·s·l−1 with 5 ml, P < 0.001), Pam, and aortic blood flow. In contrast, tissue damping increased significantly (1,070 ± 91 vs. 1,235 ± 105 cmH2O/l, P = 0.009 with 5 ml BVL), whereas tissue elastance did not change significantly. TGV significantly increased with acute BVL (3.7 ± 0.2 vs. 4.2 ± 0.2 ml, P = 0.01). Stepwise reinfusions produced opposite changes in the above parameters, with Raw reaching a higher value than baseline ( P = 0.001) upon full volume restoration. Both adrenalin ( P = 0.015) and noradrenalin levels were elevated ( P = 0.010) after 5-ml blood withdrawal. Our data suggest that the decreases in Raw following BVL may be attributed to the following: 1) an increased TGV enhancing airway parenchymal tethering forces; and 2) an increase in circulating catecholamines. The apparent beneficial effect of a reduction in Raw in acute hemorrhagic shock is counteracted by an increase in dead space and the appearance of peripheral mechanical heterogeneities due to de-recruitment of the pulmonary vasculature. |
| Databáze: | OpenAIRE |
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