In the consideration of chronic diseases, especially those located within the kidneys, we do not take into consideration as we should the blood pressure, and the necessity of proper maintenance of normal pressure.
The Virginia Medical Century presents a very interesting article by Prof. Nelson, of Richmond, on this subject, in which the writer says there are three features essential to the maintenance of the normal blood pressure. These are (a) the proper force of the heart impulse, (b) the proper rate of the heart beat, and (c) a correct peripheral resistance. The effect of the variation of these influences may be stated as follows:
The blood pressure must vary with the rate of the heart if the heart's strength and peripheral resistance remain constant.
The blood pressure must vary with the peripheral resistance if the heart's strength and the heart rate remain constant.
The pressure may remain normal if one or two factors-increase while one or two decrease.
If all three factors increase, we have a corresponding increase in blood pressure.
If all three factors decrease, we must have a very great decrease in blood pressure.
All three factors are controlled by the nervous system.
The accurate measuring of the blood pressure must be done by the sphygmomanometer. The sense of touch, no matter how well trained, is not absolutely reliable.
In prolonged fevers, such as typhoid, the tension should be maintained at about normal. In this disease, pressure records are valuable because of the fact that perforations and hemorrhage cause a marked falling in tension.
A persistent low record is a point of much diagnostic importance when tuberculosis is suspected. In the later stage of pregnancy and following labor, a rise in the blood pressure indicates uremia, and if this symptom appears the condition should be anticipated by active remedies. A falling of the blood tension denotes hemorrhage.
In injury to the head or apoplexy we may be deceived, because the intercranial pressure may cause an increase of the general blood pressure.
It is difficult to determine between apoplexy and alcoholic intoxication, but with the use of the proper instruments to measure blood pressure, we find that apoplexy lowers an abnormally high pressure, while drunkenness induces low blood pressure.
In diseases of the kidneys, the blood pressure is very important. Persistent high tension may be one of the first causes of renal lesion. A persistent high tension causes heart disease, arterial sclerosis and kidney disease.
Many insurance companies, recognizing this fact, demand blood pressure records in their examinations.. Often attention to occupation, hygiene and diet are sufficient to influence the pressure without medicine. All conditions must be considered.
In surgical operations, approaching danger from shock or from the influence of anesthetics may be determined by careful observation of the tension.
In treating this condition, the abnormally high tension and the abnormally low tension are the conditions to be considered.- In lowering the abnormally high tension, there must be an avoidance of mental anxiety and worry. There must be attention to the hygiene, and food easily digested and nonstimulating in character must be given.
That group of remedies which depress the vasomotor centers are to be administered. We have very many of these vasomotor depressants but they should be selected with care. In many cases the alkaline salts and mineral remedies will be the best. Among the vegetable remedies are gelsemium, veratrum, aconite, phytolacca, quebracho, and grindelia.
When the blood pressure is low, heat should be applied, the extremities may be bandaged and certain stimulants may be given.
The author thinks that adrenalin is the most powerful of all drugs for this purpose. Digitalis is an important remedy, as is also stropanthus. Scoparius and spartein are also to be depended upon, under certain circumstances.
The author, in conclusion, raises the question whether strychnin and digitalis are proper remedies to use in surgical shock. While there are arguments in favor of the fact that their influence has been detrimental in many cases, he believes that the clinical experiences prove their benefits in most cases.