Ventral medullary extracellular fluid pH and PCO2 during hypoxemia
| Autor: | L. J. Teppema, S. Javaheri |
|---|---|
| Rok vydání: | 1987 |
| Předmět: |
Acid-Base Equilibrium
Male Medulla Oblongata Pathology medicine.medical_specialty Medullary cavity Physiology Chemistry Carbon Dioxide respiratory system pCO2 respiratory tract diseases Hypoxemia Physiology (medical) Extracellular fluid Cats medicine Animals Female medicine.symptom Extracellular Space Hypoxia circulatory and respiratory physiology |
| Zdroj: | Journal of Applied Physiology. 63:1567-1571 |
| ISSN: | 1522-1601 8750-7587 |
| DOI: | 10.1152/jappl.1987.63.4.1567 |
| Popis: | We designed experiments to study changes in ventral medullary extracellular fluid (ECF) PCO2 and pH during hypoxemia. Measurements were made in chloralose-urethan-anesthetized spontaneously breathing cats (n = 12) with peripherial chemodenervation. Steady-state measurements were made during normoxemia [arterial PO2 (PaO2) = 106 Torr], hypoxemia (PaO2 = 46 Torr), and recovery (PaO2 = 105 Torr), with relatively constant arterial PCO2 (approximately 44 Torr). Mean values of ventilation were 945, 683, and 1,037 ml/min during normoxemia, hypoxemia, and recovery from hypoxemia, respectively. Ventilatory depression occurred in each cat during hypoxemia. Mean values of medullary ECF PCO2 were 57.7 +/- 7.2 (SD), 59.4 +/- 9.7, and 57.4 +/- 7.2 Torr during normoxemia, hypoxemia, and recovery to normoxemia, respectively; respective values for ECF [H+] were 60.9 +/- 8.0, 64.4 +/- 11.6, and 62.9 +/- 9.2 neq/l. Mean values of calculated ECF [HCO3-] were 22.8 +/- 3.0, 21.7 +/- 3.3, and 21.4 +/- 3.1 meq/l during normoxemia, hypoxemia, and recovery, respectively. Changes in medullary ECF PCO2 and [H+] were not statistically significant. Therefore hypoxemia caused ventilatory depression independent of changes in ECF acid-base variables. Furthermore, on return to normoxemia, ventilation rose considerably, still independent of changes in ECF PCO2, [H+], and [HCO3-]. |
| Databáze: | OpenAIRE |
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