The canine spleen in oxygen transport: gas exchange and hemodynamic responses to splenectomy
| Autor: | Connie C.W. Hsia, D. Merrill Dane, Harrieth Wagner, Eugene Y. Wu, Robert L. Johnson, Peter D. Wagner, Aaron S. Estrera |
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| Rok vydání: | 2007 |
| Předmět: |
Male
medicine.medical_specialty Physiology medicine.medical_treatment Physical Exertion Splenectomy Hemodynamics Blood Pressure Spleen Diffusion Hemoglobins Dogs Oxygen Consumption Physiology (medical) Internal medicine Diffusing capacity Respiration medicine Animals Cardiac Output Respiratory system Lung Erythrocyte Volume Carbon Monoxide Blood Volume biology Pulmonary Gas Exchange Chemistry Fissipedia Oxygen transport Carbon Dioxide Hydrogen-Ion Concentration biology.organism_classification Oxygen Endocrinology medicine.anatomical_structure Hematocrit Anesthesia Pulmonary Diffusing Capacity Vascular Resistance |
| Zdroj: | Journal of Applied Physiology. 103:1496-1505 |
| ISSN: | 1522-1601 8750-7587 |
| Popis: | In athletic animals the spleen induces acute polycythemia by dynamic contraction that releases red blood cells into the circulation in response to increased O2 demand and metabolic stress; when energy demand is relieved, the polycythemia is rapidly reversed by splenic relaxation. We have shown in adult foxhounds that splenectomy eliminates exercise-induced polycythemia, thereby reducing peak O2 uptake and lung diffusing capacity for carbon monoxide (DLCO) as well as exaggerating preexisting DLCO impairment imposed by pneumonectomy (Dane DM, Hsia CC, Wu EY, Hogg RT, Hogg DC, Estrera AS, Johnson RL Jr. J Appl Physiol 101: 289–297, 2006). To examine whether the postsplenectomy reduction in DLCO leads to abnormalities in O2 diffusion, ventilation-perfusion inequality, or hemodynamic function, we studied these animals via the multiple inert gas elimination technique at rest and during exercise at a constant workload equivalent to 50% or 80% of peak O2 uptake while breathing 21% and 14% O2 in balanced order. From rest to exercise after splenectomy, minute ventilation was significantly elevated with respect to O2 uptake compared with exercise before splenectomy; cardiac output, O2 delivery, and mean pulmonary and systemic arterial blood pressures were 10–20% lower, while O2 extraction was elevated with respect to O2 uptake. Ventilation-perfusion inequality was unchanged, but O2 diffusing capacities of lung (DLO2) and peripheral tissue during exercise were lower with respect to cardiac output postsplenectomy by 32% and 25%, respectively. The relationship between DLO2 and DLCO was unchanged by splenectomy. We conclude that the canine spleen regulates both convective and diffusive O2 transport during exercise to increase maximal O2 uptake. |
| Databáze: | OpenAIRE |
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