Chapter 4, Problem 4.35P

Interpretation Introduction

Interpretation:

The total blood volume of the patient is to be calculated.

Concept introduction:

In some channels, devices like rotameters and orifice meters cannot be used to determine the flowrates of the fluids. In such cases, Indicator-dilution method is used to determine the flowrates of the fluids.

A variation of this method is used to measure the total blood volume in the human body. Tracer of known amount is injected into the bloodstream and allowed to disperse uniformly in the circulatory system. The measured tracer concentration is then used to calculate the total blood volume in the human body as:

$C=\frac{m_{\text{T}}}{V}$ …… (1)

Here, $C$ is the measured tracer concentration in the blood in $\mu \text{g}/\text{L}$, $m_{\text{T}}$ is the total amount of tracer injected in the bloodstream in $\mu \text{g}$ and $V$ is the total blood volume in $\text{L}$.

Spectrophotometer is the device which is used to measure the amount of light absorbed by a chemical substance by measuring the intensity of light as its beam passes over a sample solution.

Equation of a straight line which passes through origin and a given point, $\left(x,y\right)$ with slope $\text{'m'}$ is:

$x=\text{m}y$ …… (2)

Conversion factor to convert ${\text{cm}}^3$ to $\text{L}$ is:

$1{\text{ cm}}^3=1{\text{ cm}}^3\times \frac{1\text{ L}}{{10}^3{\text{ cm}}^3}$ …… (3)

Conversion factor to convert $\text{mg}$ to $\mu \text{g}$ is:

$\text{1 mg}=1\text{ mg}\times \frac{{\text{10}}^3\mu \text{g}}{\text{1 mg}}$ …… (4)

Amount of any substance $\left(m_{\text{T}}\right)$ from its given concentration $\left(C_{\text{T}}\right)$ and solution volume $\left(V_{\text{T}}\right)$ is given by:

$m_{\text{T}}=C_{\text{T}}\times V_{\text{T}}$ …… (5)