Technic


Categories: Uncategorized
Sources: Disturbances Of The Heart

It is essential that the patient on whom the examination is to be

made should be at rest, either comfortably seated, or lying down.

All clothing should be removed from the arm, and there should be no

constriction by sleeves, either of the upper arm or the axilla. When

the blood pressure is taken over the sleeve of a garment, the

instrument will register from 10 to 30 mm. higher than on the bare

arm. [Footnote: Rowan, J. J.: The Practical Application of Blood

Pressure Findings, The JOURNAL A. M. A., March 18, 1916, p. 873.]



While it may be better, for insurance examinations, to take the

blood pressure of the left arm in right handed persons as a truer

indicator of the general condition, the difference is generally not

great. The right arm of right handed persons usually registers a

full 5 mm. higher systolic pressure than the left arm.



The patient, being at rest and removed as far as possible from all

excitement, may be conversed with to take his mind away from the

fact that his blood pressure is being taken. He also should not

watch the dial, as any tensity on his part more or less raises the

systolic pressure, the diastolic not being much affected by such

nervous tension. The armlet having been carefully applied, it is

better to inflate gradually 10 mm. higher than the point at which

the pulsation ceases in the radial. The stethoscope is then firmly

applied, but with not too great pressure, to the forearm just below

the flexure of the elbow. The exact point at which the sound is

heard in the individual patient, and the exact amount of pressure

that must be applied, will be determined by the first reading, and

then thus applied to the second reading. One reading is never

sufficient for obtaining the correct blood pressure. The blood

pressure may be read by means of the stethoscope during the gradual

raising of pressure in the cuff, note being taken of the first sound

that is heard (the diastolic pressure), and the point at which all

sound disappears, as the pressure is increased (the systolic

pressure). The former method is the one most frequently used.



By taking the systolic and diastolic pressures, the difference

between the two being the pressure pulse, we learn to interpret the

pressure pulse reading. While the average pressure pulse has

frequently been stated as 30 mm., it is probable that 35 at least,

and often 40 mm. represents more nearly the normal pressure pulse,

and from 25 mm. on the one hand to 50 on the other may not be

abnormal.



Faught [Footnote: Faught: New York Med Jour., Feb. 27, 1915, p.

396.] states his belief that the relation of the pressure pulse to

the diastolic pressure and the systolic pressure are as 1, 2 and 3.

In other words, a normal young adult with a systolic pressure of 120

should have a diastolic pressure of 80, and therefore a pulse

pressure of 40. If these relationships become much abnormal, disease

is developing and imperfect circulation is in evidence, with the

danger of broken compensation occurring at some time in the future.



It should be remembered that the diastolic pressure represents the

pressure which the left ventricle must overcome before the blood

will begin to circulate, that is, before the aortic valve opens,

while the pressure pulse represents the power of the left ventricle

in excess of the diastolic pressure. Therefore it is easy to

understand that a high diastolic pressure is of serious import to

the heart; a diastolic pressure over 100 is significant of trouble,

and over 110 is a menace.





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