Pharmacologic Elevation of Blood Inorganic Phosphate in Hypoxemic Patients with COPD
| Autor: | Felice Manfredi, Mark O. Farber, Edward T. Mannix, Paolo Palange, Stefano Carlone, Piero Serra |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Pulmonary and Respiratory Medicine
Cardiac function curve medicine.medical_specialty Physical exercise Etidronate Disodium Critical Care and Intensive Care Medicine Phosphates Hemoglobins chemistry.chemical_compound Internal medicine Humans Medicine Lung Diseases Obstructive Hypoxia Methemoglobin Aged 2 3-Diphosphoglycerate COPD Mean corpuscular hemoglobin concentration medicine.diagnostic_test business.industry Etidronic Acid Stroke volume Diphosphoglyceric Acids medicine.disease Oxygen Endocrinology Carboxyhemoglobin chemistry Circulatory system Exercise Test Cardiology and Cardiovascular Medicine business |
| Zdroj: | Chest. 100:147-150 |
| ISSN: | 0012-3692 |
| DOI: | 10.1378/chest.100.1.147 |
| Popis: | We have shown that in patients with COPD, myocardial efficiency during exercise is enhanced following acute elevations of plasma phosphate (Pi). A decrease in Hb-O2 affinity (increase in P50) was not responsible for the improvement. We postulated that the physiologic benefit was due to the acute reversal of a subclinical myocardial Pi depletion. To further test this hypothesis in a chronic state, we studied nine stable hypoxemic (PaO2 = 64 +/- 2 mm Hg [+/- SEM]) patients with COPD over five weeks: two weeks at normal plasma Pi; and three weeks at elevated plasma Pi, induced by etidronate disodium (Didronel; 750 mg orally daily). Administration of etidronate disodium increased (p less than 0.05) plasma level of Pi (4.4 +/- 0.2 to 5.8 +/- 0.1 mg/dl), RBC level of Pi (3.1 +/- 0.2 to 4.1 +/- 0.2 mg/dl), RBC level of 2,3-DPG (16.2 +/- 1.1 to 21.3 g+/- 1.3 mumol/g of Hb) and P50 (23.7 +/- 0.5 to 26.0 +/- 0.8 mm Hg). At the end of the treatment, the widening of the C(a-v)O2 with exercise (7.1 +/- 0.8 to 8.9 +/- 0.6 ml/dl) was less pronounced than under control conditions (6.9 +/- 0.4 to 10.1 +/- 0.6 ml/dl; p less than 0.02); concomitantly, the crossover point (COP; the PaO2 below which a rightward-shifted Hb-O2 curve causes the C(a-v)O2 to become narrower rather than wider) increased (37 +/- 2 to 49 +/- 1 mm Hg). Indicators of myocardial work efficiency were not affected by etidronate disodium at rest or during exercise. We postulate that during exercise the potential beneficial effect of the rightward shift of the Hb-O2 curve upon cardiac function was negated by the fall of PaO2 to or below the COP level, a situation which would limit increases in tissue O2 extraction. |
| Databáze: | OpenAIRE |
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