Conditions Causing Change In Blood Pressure

Categories: Uncategorized
Sources: Disturbances Of The Heart

Woolley [Footnote: Woolley, P. G.: Factors Governing Vascular

Dilatation and Slowing of the Blood Stream in Inflammation, THE

JOURNAL A. M. A., Dec. 26, 1914, p. 2279.] quotes Starling as

finding that the blood vessels dilate from physical and chemical

changes in the musculature, and that this dilatation is caused by

deficient oxidation and accumulation of the products of metabolism,

including carbon dioxid. This dilat tion ordinarily is transient and

not associated with exudation, but in inflammation the dilatation is

persistent and there is exudation. The carbon dioxid increase during

exercise stimulates a greater circulation of oxygen in the tissues

which later counteracts the normal increase in acid products. In

inflammatory processes, however, the acid accumulates too rapidly to

allow of saturation. In this case the circulation becomes slowed and

the cells become affected.



Besides these charges in the blood vessels of the muscles, the

general blood pressure becomes raised on exercise, the heart more

rapid and the temperature somewhat elevated, and the breathing is

increased. This increased heart rate does not stop immediately on

cessation of the exercise, but persists for a longer or shorter

time. The better trained the individual, the sooner the speed of the

heart becomes normal.



Benedict and Cathcart [Footnote: Benedict and Cathcart: Pub. 77,

Carnegie Institute of Washington.] have found that the increased

absorption of oxygen, showing increased metabolism, persists after

exercise as long as the heart action is increased.



Newburgh and Lawrence [Footnote: Newburgh, L. H., and Lawrence C.

H.: The Effect of Heat on Blood Pressure, Arch. Int. Med., February,

1914, p. 287.] have found that increased temperature in animals,

equal to that occurring in persons suffering with infection, reduces

the blood pressure, causing a hypotension. This shows that high

temperature alone in an individual sooner or later causes

hypotension.



Although prolonged pain may cause a fall of blood pressure from

shock, the first acute pain may cause a rise in blood pressure, and

Curschmann [Footnote: Curschmann: Munchen. med. Wehnschr., Oct. 15,

1907.] found that the blood pressure was high in the gastro-

intestinal crises of tabes and in colic, and that the application of

faradic electricity to the thigh could raise the blood pressure from

8 to 10 mm. in normal individuals.



The positive effect of decomposition products in the intestine, more

especially such as come from meat proteins, is well recognized; but

the importance, in high pressure cases, of the absorption of toxins

derived from imperfectly digested food remaining in the bowels over

night is not sufficiently recognized. Patients with high blood

pressure should not eat a heavy evening meal, and especially should

they not eat meat. Willson [Footnote: Willson, R. N.: The

Decomposition Food Products as Cardiovascular Products, THE JOURNAL

A. M. A., Sept. 25, 1915, p. 1077.] well describes the condition

caused by the absorption of these toxins. If the heart muscle is

intact, he finds such absorption in high pressure cases will show

diastolic as well as systolic increase:



The vessels pulsate and throb; the skin is pale; the head aches;

the tongue is coated; the breath is foul; vertigo is often

distressing; and not infrequently the hands and feet feel distended

and swollen. A thorough house-cleaning of the gastro-intestinal

canal causes the expulsion of the offending substances and the

expulsion of gas, whereupon the blood pressure often resumes its

normal level and the symptoms disappear.



Wilson suggests that not only the meat proteins, but also the

oxyphenylethylamin in overripe cheese may often cause this

poisoning; and cheese is frequently eaten by these people at

bedtime. Of course if any particular fruit or article of food causes

intestinal upset in a given individual, they should be avoided.



When the heart is hypertrophied in disease, the cavities of the

ventricles are probably also generally enlarged, and therefore they

propel more blood at each contraction than in normal persons and

thus increase the blood pressure.



The blood pressure is raised not only by intestinal toxemia and

uremia, but also by lead poisoning and the conditions generally

present in gout.



It has been pointed out by Daland [Footnote: Daland: Pennsylvania

Med. Jour., July, 1913.] that nervous exhaustion may raise the blood

pressure in those who are neurotic, and he finds that this

hypertension may exist for months in some cases. On the other hand,

in neurasthenics the blood pressure is generally lowered. As he

points out, there is often a very great increase in the systolic

blood pressure at the menopause, while the diastolic pressure may

not be high. This makes a very large pressure pulse. This suggests

the possibility of disturbances of the glands of internal secretion.

This hypertension is generally improved under proper treatment.



Schwarzmann [Footnote: Schwarzmann: Zentralbl. f. inn. Med., Aug. 1,

1914.] studied the blood pressure in eighty cases of acute

infection, and found that a high diastolic blood pressure during

such illness indicates a tendency to paralysis of the abdominal

vessels, and hence a sluggish circulation in the vessels of the

abdomen. He found that in seriously ill patients this high diastolic

pressure is of bad prognosis. He also found that a lower systolic

pressure with a lower diastolic pressure is not a sign that the

heart is weakening, but only that the visceral tone is growing less.

On the other hand, when the diastolic pressure rises while the

systolic falls, this is a sign of failing heart.



Newburgh and Minot [Footnote: Newburgh, L. H. and Minot, G. II: The

Blood Pressure in Pneumonia, Arch. Int. Med., July, 1914, p. 48.]

find that the blood pressure course in pneumonia does not suggest

that there is a failure of the vasomotor center. They found that

"low systolic pressures are not invariably of evil omen." They also

found that the systolic pressure in fatal cases is often higher than

in those in which the patients recovered, and they found that the

rate of the pulse is more important in determining the treatment

than the blood pressure measurements.



The work which has been described under this section is of interest

as indicating the newer experimental work on the physiology of blood

pressure. Much of it is new, however, and it is difficult to draw

absolute therapeutic conclusions from the evidence offered.