The Carbon County news. [volume] (Red Lodge, Mont.) 1924-1931, 1927-07-28
BASAL METABOLISM
Part 2

The heat value of oxygen varies
with the respiratory quotient but ever
at its widest possible variation it is
still within less than three per cent
of this figure 4.025. For all practical
purposes this small percentage varia-
ton is inconsequential.
In all present day tests the respira-
tory quotient need, therefore, not be
determined since to do this it would
be necessary, as above shown, to esti-
mate the patients output of carbon
dioxide--a procedure that is expensive
and time consuming. Moreover, the
respiratory quotient seldom varies
enough to cause even the small three
per cent variation noted above. To de-
termine the amount of oxygen the sub
ject consumes in a given period of
time is accordingly sufficient to de-
termine his basal metabolic rate.
How Test Is Made
By the oxygen consumption method
the amount of oxygen the subject con-
sumes is measured while he is
breathing under basal conditions.
This amount is compared with that
which a person of the same age,
height and weight normally consumes.
Comparison of the actual with the
normal consumption gives the Basal
Metabolic Rate, and this may be plus
40 or minus 25 or any other figure
within certain limits above or below
normal. The carbon dioXide which the
patient actually exhales goes into a
chamber of the mechanism contain
ing Sansolime.
The apparatus used in making the
test consists of tank containing the
oxygen to be inhaled and the chamber
for receiving the carbon dioXide. Con
nected with these chambers are two
tubes which pass into the subjects
mouth. Through one he inhales the
oxygen, trough the other he exhales
the carbon dioxide. Placed alongside
the oxygen tank is a revolving drum
about which is wound sheet OF paper
showing a chart. A stem on the pls.
ton within the oxygen tank carries a
pen which is in contact with the chart.
When the tank is supplied with oxy-
gen from a storage tank the piston
rises to a certain level and the pen
marks this point on the chart. The
apparatus is now set into motion, the
patient inhaling and exhaling through
the mouth. AS the oxygen in the tank
is consumed the pen records the rate
on the chart. The difference between
the figure to which the pen first.
pointed and the figure at the conclu-
sion of the test denotes the number
of cubic centimeters of oxygen con-
sumed by the subject during the time
it took the drum to usually
eight minutes.
How Rate Is Computed
Numerous tests were made In
healthy individuals to determine what.
is the normal oxygen consumption per
minute under basal conditions, for.
persons of a certain sex, age, height,
and weight. Thus the normal rate for.
a man SO inches tall, weighing l52
pounds, aged so years, is 227 c. c. Ii
a man corresponding in all respects
with those figures consumes 257 C. c.
under the etst his metabolic rate IS
computed as follows: The actual con-
sumption (257 minus the normal
(227) divided by the normal (22D.
For example: 257 minus 227 equals
80 (above normaD divided by 227
equals plus Is per cent.
Clinical Significance of MetabolIc
Rate
Inasmuch as the metabolic rate is a
measure of the breaking down and
building up processes in the living
body, it indicates if one is suffering
from a disorder due to disturbed me-
tabolism. As stated, the rate may be
too high or too low. Most authorities
have accepted 10 per cent variation
in either direction from the normal as
being within normal physiological
limits. Therefore a variation from
normal in either direction, must ex-