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Pulmonary vascular resistance and viscosity: the forgotten factor
1Department of Pediatrics and Cardiovascular Research Institute, University of California, 505 Parnassus Avenue, San Francisco, CA 94143, USA. julien.hoffman@ucsf.edu
Pulmonary vascular resistance calculations require adjustments for hematocrit levels. This review explains how to account for blood viscosity, using hindrance or relative viscosity, to improve accuracy in medical research.
Area of Science:
- Cardiovascular Physiology
- Medical Research
Background:
- Pulmonary vascular resistance (PVR) is a critical metric in clinical medicine.
- The impact of hematocrit on PVR calculations is well-documented but often overlooked in published studies.
Purpose of the Study:
- To review the relationship between blood viscosity and pulmonary vascular resistance.
- To highlight the importance of correcting PVR calculations for hematocrit-induced viscosity changes.
Main Methods:
- Discussion of established physiological principles relating blood viscosity and resistance.
- Explanation of methods for calculating hindrance and relative viscosity.
Main Results:
- Hematocrit significantly influences blood viscosity, thereby affecting calculated PVR.
- Incorporating viscosity corrections, via hindrance or relative viscosity, enhances the accuracy of PVR measurements.
Conclusions:
- Accurate PVR calculation necessitates accounting for blood viscosity variations.
- The methods discussed provide a framework for improving the reliability of PVR data in medical literature.
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