Direct effect of PaCO2 on respiratory sinus arrhythmia in conscious humans
| Autor: | Hirotada Katsuya, Joseph A. Fisher, Nobuko Sasano, Hiroshi Sasano, Alex Vesely, David Preiss, Ron B. Somogyi, Kiyoyuki Miyasaka, Steve Iscoe, Junichiro Hayano |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Adult
Male Pulmonary Circulation Consciousness Heart disease Physiology Partial Pressure Respiratory physiology Electrocardiography Reference Values Physiology (medical) Tidal Volume Humans Medicine Arrhythmia Sinus Lung volumes Respiratory system Tidal volume Lung medicine.diagnostic_test business.industry Carbon Dioxide medicine.disease Respiratory Function Tests medicine.anatomical_structure Anesthesia Respiratory Mechanics medicine.symptom Cardiology and Cardiovascular Medicine business Hypercapnia |
| Zdroj: | American Journal of Physiology-Heart and Circulatory Physiology. 282:H973-H976 |
| ISSN: | 1522-1539 0363-6135 |
| Popis: | Respiratory sinus arrhythmia (RSA) may improve the efficiency of pulmonary gas exchange by matching the pulmonary blood flow to lung volume during each respiratory cycle. If so, an increased demand for pulmonary gas exchange may enhance RSA magnitude. We therefore tested the hypothesis that CO2directly affects RSA in conscious humans even when changes in tidal volume (VT) and breathing frequency ( F B), which indirectly affect RSA, are prevented. In seven healthy subjects, we adjusted end-tidal Pco 2 (Pet CO2 ) to 30, 40, or 50 mmHg in random order at constant VT and F B. The mean amplitude of the high-frequency component of R-R interval variation was used as a quantitative assessment of RSA magnitude. RSA magnitude increased progressively with Pet CO2 ( P < 0.001). Mean R-R interval did not differ at Pet CO2 of 40 and 50 mmHg but was less at 30 mmHg ( P < 0.05). Because VT and F B were constant, these results support our hypothesis that increased CO2directly increases RSA magnitude, probably via a direct effect on medullary mechanisms generating RSA. |
| Databáze: | OpenAIRE |
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