Journal article
Analysis of the critical determinants of renal medullary oxygenation
American Journal of Physiology-Renal Physiology, Vol.317(6), pp.F1483-F1502
2019
Abstract
We have previously developed a three-dimensional computational model of oxygen transport in the renal medulla. In the present study, we used this model to quantify the sensitivity of renal medullary oxygenation to four of its major known determinants: medullary blood flow (MBF), medullary oxygen consumption rate (V̇o2,M), hemoglobin (Hb) concentration in the blood, and renal perfusion pressure. We also examined medullary oxygenation under special conditions of hydropenia, extracellular fluid volume expansion by infusion of isotonic saline, and hemodilution during cardiopulmonary bypass. Under baseline (normal) conditions, the average medullary tissue Po2 predicted for the whole renal medulla was ~30 mmHg. The periphery of the interbundle region in the outer medulla was identified as the most hypoxic region in the renal medulla, which demonstrates that the model prediction is qualitatively accurate. Medullary oxygenation was most sensitive to changes in renal perfusion pressure followed by Hb, MBF, and V̇o2,M, in that order. The medullary oxygenation also became sensitized by prohypoxic changes in other parameters, leading to a greater fall in medullary tissue Po2 when multiple parameters changed simultaneously. Hydropenia did not induce a significant change in medullary oxygenation compared with the baseline state, while volume expansion resulted in a large increase in inner medulla tissue Po2 (by ~15 mmHg). Under conditions of cardiopulmonary bypass, the renal medulla became severely hypoxic, due to hemodilution, with one-third of the outer stripe of outer medulla tissue having a Po2 of <5 mmHg.
Details
- Title
- Analysis of the critical determinants of renal medullary oxygenation
- Authors/Creators
- C-J Lee (Author/Creator)B.S. Gardiner (Author/Creator)R.G. Evans (Author/Creator)D.W. Smith (Author/Creator)
- Publication Details
- American Journal of Physiology-Renal Physiology, Vol.317(6), pp.F1483-F1502
- Publisher
- American Physiological Society
- Identifiers
- 991005541474007891
- Copyright
- © 2019 the American Physiological Society
- Murdoch Affiliation
- College of Science, Health, Engineering and Education
- Language
- English
- Resource Type
- Journal article
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- Collaboration types
- Domestic collaboration
- Citation topics
- 1 Clinical & Life Sciences
- 1.55 Urology & Nephrology - General
- 1.55.830 Acute Kidney Injury
- Web Of Science research areas
- Physiology
- Urology & Nephrology
- ESI research areas
- Clinical Medicine