Subcutaneous Po 2 as an index of the physiological limits for hemodilution in the rat
| Autor: | William R. Drucker, David Burris, Christine Waasdorp, Joseph DeFeo, Howard Hufnagel, Peter W. Soballe, Frederick J. Pearce |
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| Rok vydání: | 2005 |
| Předmět: | |
| Zdroj: | Journal of Applied Physiology. 99:814-821 |
| ISSN: | 1522-1601 8750-7587 |
| Popis: | This study was designed to test the hypothesis that changes in subcutaneous Po2 (PscO2) during progressive hemodilution will reliably predict a “critical point” at which tissue O2 consumption (V̇o2) becomes dependent on O2 delivery (Q̇o2). Twelve pentobarbital-anesthetized male Sprague-Dawley rats (315–375 g) underwent stepwise exchange of plasma for blood (1.5 ml of plasma for each 1 ml of blood lost). The initial exchange was equal to 25% of the estimated circulatory blood volume, and each subsequent exchange was equal to 10% of the estimated circulatory blood volume. After nine exchanges, the hematocrit (Hct) fell from 42 ± 1 to 6 ± 1%. Cardiac output and O2 extraction rose significantly. PscO2 became significantly reduced ( P < 0.05) after exchange of 45% of the blood volume (Hct = 16 ± 1%). V̇o2 became delivery dependent when Q̇o2 fell below 21 ml·min−1·kg body wt−1 (mean Hct = 13 ± 1%). Eight control rats undergoing 1:1 blood-blood exchange showed no change in PscO2, pH, HCO3−, or hemodynamics. Measurement of PscO2 may be a useful guide to monitor the adequacy of Q̇o2 during hemodilution. |
| Databáze: | OpenAIRE |
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