Blood Volume Measurement
Blood Volume Measurement - Related Videos
01:21
Measuring Cerebral Blood Volume in the Auditory Cortex Using Vascular Space Occupancy
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2025
Position a human participant’s head within the head coil of a functional magnetic resonance imaging, or fMRI, system.Employ vascular space occupancy or VASO, a technique to measure changes in cerebral blood volume, or CBV, the blood volume within the brain.Begin by applying an inversion recovery pulse to suppress signals from blood, allowing only signals from the surrounding tissue within the region to be detected.Next, use MRI-compatible earbuds to deliver auditory stimuli.The stimuli reach...
08:54
Measuring Blood Pressure in Mice using Volume Pressure Recording, a Tail-cuff Method
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Cited by 175 •
2009
The CODA 8-Channel High Throughput Non-Invasive Blood Pressure system measures the blood pressure in up to 8 mice or rats simultaneously. This tail-cuff system uses Volume Pressure Recording (VPR) to measure the blood pressure by determining the tail blood volume.
08:51
Understanding Concentration and Measuring Volumes
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2023
Solutions are utilized to some degree in almost all biological research applications. Therefore understanding how to measure and manipulate them is imperative to any experiment. In this video, concepts in preparing solutions are introduced. Solutions consist of a solute dissolved in solvent to yield a homogeneous mixture of molecular substances. Solutions are generally identified by their components and corresponding concentrations. Concentrated solutions are diluted through various...
09:15
Measuring Pressure Volume Loops in the Mouse
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Cited by 16 •
2016
This manuscript describes a detailed protocol for the collection of pressure-volume data from the mouse.
09:49
Measurement of the Pressure-volume Curve in Mouse Lungs
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Cited by 47 •
2015
Here we present a protocol to simply and reliably measure the lung pressure-volume curve in mice, showing that it is sufficiently sensitive to detect phenotypic parenchymal changes in two common lung pathologies, pulmonary fibrosis and emphysema. This metric provides a means to quantify the lung’s structural changes with developing pathology.
FAQs
A plasma tracer and a red blood cell tracer can be evaluated separately after each reaches the bloodstream. The measured concentration of each label indicates the distribution volume of its corresponding compartment. This distinction allows clinicians to assess whether an abnormal total blood volume reflects altered plasma, altered cellular volume, or changes affecting both components.
The method relates a known tracer amount to the concentration measured after mixing in the circulation. When the tracer distributes through a larger volume, its concentration is lower; when it occupies a smaller volume, its concentration is higher. This dilution relationship converts a blood sample measurement into an estimate of the relevant circulating compartment.
Hematocrit describes the proportion of blood occupied by red blood cells, but it does not by itself establish the absolute amount of circulating blood or plasma. Blood volume measurement adds compartment-specific quantitative information. Consequently, it can help distinguish changes in fluid balance from changes in cellular concentration when routine vital signs or hematocrit do not provide enough information.
The findings are interpreted by considering measured plasma and cellular volumes rather than relying on a single blood concentration. Reduced circulating volume supports assessment of hypovolemia, while an increased red blood cell compartment can support evaluation of polycythemia. Conversely, a reduced cellular compartment may contribute to assessment of anemia, particularly when concentration-based measures are difficult to interpret.
The procedure begins with introduction of a known quantity of a labeled tracer into the bloodstream. The tracer is allowed to mix within the circulation, after which a blood sample is obtained and its concentration is measured. The resulting dilution is used to estimate the distribution volume, with separate measurements possible for plasma and red blood cells.
Assessment requires the amount of tracer introduced, adequate circulation for the label to mix, and a blood sample for concentration measurement. When plasma and red blood cell compartments must be distinguished, separate tracers can be used. These measurements support calculation of compartment-specific distribution volumes rather than relying only on a general blood concentration.
Clinicians may use the measurement when they need quantitative information about circulatory status or fluid balance. It can support evaluation of suspected hypovolemia, polycythemia, anemia, and abnormal fluid shifts. The results may also assist treatment planning and the assessment of physiological changes when routine vital signs provide an incomplete picture.
By quantifying circulating plasma and cellular components, the results provide more specific information about the nature of a volume abnormality. That information can help clinicians evaluate fluid shifts, support diagnostic decisions, and assess physiological changes over time. In medicine, this makes the measurement relevant when management depends on distinguishing altered fluid volume from altered red blood cell volume.