THE DOCTOR'S BAG
KEITH SOUTER aka CLAY MORE
We all try hard to have our stories ooze with authenticity. If a reader spots an anachronism in your tale the chances are high that he or she probably won't read much further. If you have a town doctor in the old west glibly reach for a blood pressure machine and take a patients blood pressure then you are in anachronism-ville! Back then there was no such instrument in the doctor's bag. They had no awareness about th importance of blood pressure.
The history of blood pressure
Nowadays, the taking of a person’s blood pressure is regarded as one of the basic parts of a physical examination. It is interesting that the first experiments upon it were done not by a medical practitioner, but by a Church of England priest, the Reverend Stephen Hales in the eighteenth century.
The Reverend Stephen Hales (1677-1761) was intensely interested in science and he had ample time to pursue his interest. He made contributions to botany, chemistry and medicine Among other ingenious inventions he invented a a set of forceps for surgeons to use for the removal of gall stones.
Rev Stephen Hales, DD, FRS (1677-1761)
He conducted twenty-five experiments on several dogs, three horses, a sheep and a doe. He published his findings in the Statical Essays in 1733.
He deduced that the maximum pressure of the blood was reached at the end of a cardiac contraction. He further deduced that it would give an idea about cardiac output. He also deduced that the lowest pressure would be a measure of the resistance to flow and that it would be during the relaxation of the heart.
The first blood pressure machines
These were really extremely important findings, but it was not until a century later that any practical means of measuring the blood pressure could be developed. Even then the methods of measuring were invasive, involving canulating arteries, so they were of no use in clinical medicine. It then took another fifty years before a non-invasive and practical method was devised.
In 1896 Scipione Riva-Rocci invented the sphygmomanometer. This was done using an inkwell, copper piping, a bicycling wheel inner tube to form a mercury manometer.
Dr Scipione Riva-Rocci (1863-1937)
It was subsequently refined by Von Recklinghausen in 1906, which used a moving needle to measure the pressure. In neither of these was a stethoscope used. Indeed, the stethoscope was still a relatively new instrument and it did not occur to anyone that there were useful sounds that could tell one about blood pressure.
The Korotkoff sounds
A Russian doctor, Nicolai Korotkoff (1874-1920) wrote a thesis about his use of the stethoscope to measure blood pressure in 1910. It was entitled Experiments for determining the strength of the arterial collaterals. In this book he outlined the method of taking the blood pressure that has been used right up until the present day.
Dr Nicolai Korotkoff (1874-1920)
This involved applying a cuff attached to the sphygmomanometer and listening with a stethoscope over the brachial elbow at the elbow. The cuff is inflated until the radial pulse is no longer felt. The reason for doing this is to collapse the vessel, by making the pressure in the cuff greater than in the blood vessel. Then the cuff is slowly deflated. A series of different sounds will be heard. The first one is the noise of blood flowing. It is the maximum blood pressure. Then other sounds are heard, having a significance in relation to the cardiac cycle, although we need not go into the technicalities in detail here. The important sound was when the sounds disappeared, which represents the minimum blood pressure.
Sphygmomanometer used by Dr Nicolai Korotkoff
Nowadays electronic sphygomomanometers are used, since they are extremely accurate at detecting blood flow. They have by and large replaced the traditional method of listening with a stethoscope, although a lot of doctors still trust to their ears and the traditional method of listening to the Korotkoff sounds.
The risks of high blood pressure (hypertension)
This condition is quite insidious, in that it creeps up on you, often without producing symptoms. It increases the risk of many conditions, including the following:
myocardial infarction (heart attack)
peripheral artery disease
It sensible for adults to have their blood pressure checked at least every five years until the age of eighty. It should be done annually after that. If it is found to be borderline at any stage then your doctor will want to monitor it more frequently. If it is persistently raised then there are excellent treatments that will reduce the risk of the conditions mentioned above.
If this article whetted your interest in blood pressure then Dr Keith Souter's book Understanding and dealing with heart disease is available from Amazon in ebook or paperback
Clay More's novel about Dr George Goodfellow is published in the West of the Big River series by Western Fictioneers.
Available at Amazon.com:
THE DOCTOR by CLAY MORE
And his collection of short stories about Doc Marcus Quigley is published by High Noon Press
Available at Amazon.com:
And his latest western novel Dry Gulch Revenge was published by Hale on 29th August.