Edema causes death
Acute pulmonary edema. Vicious circle of pulmonary edema
A common cause of death with heart failure is acutepulmonary edema, which develops in patients suffering from chronic heart failure for a long time. The cause of this may be a temporary heart overload or during exercise, or with emotional stress, or even under hypothermia. It is believed that in these cases, pulmonary edema is the result of the formation of a vicious circle.
1. Load increase on the weakened left ventricle starts the mechanism of the vicious circle. As the pump function of the left ventricle is reduced, the blood begins to accumulate in the lungs.
2. An increase in the volume of blood in the lungs leads to an increase in pressure in the pulmonary capillaries. The transudation of fluid from the capillaries into the lung tissue and the alveoli begins.
3. The accumulation of fluid in the lungs reduces the degree of oxygenation of the blood.
4. Reduction of the oxygen content in the blood leads to further weakening of the heart muscle, as well as to a decrease in the contractility of the smooth muscle wall of the arterioles. There is an expansion of peripheral vessels.
5. Expansion of peripheral vessels increases the venous return of blood to the heart.
6. Increased venous return contributes to an even greater accumulation of blood in the lungs, strengthening the transudation of the fluid, reducing the saturation of arterial blood with oxygen, increasing venous return, etc.
So, vicious circle was formed. Once formed and overcome a certain critical point, the vicious circle continues to develop until the patient's death, unless in a few minutes he will not receive the necessary medical care. Urgent measures that can break the vicious circle and save the patient's life are as follows.
1. The application of harnesses to all four limbs in order to stop the flow of blood from the veins and reduce the burden on the left heart.
3. Introduction of fast-acting diuretics, such as furosemide, in order to quickly remove fluid from the body.
4. Breathing with pure oxygen for complete saturation of the arterial blood, supplying the myocardium with oxygen, preventing the expansion of peripheral vessels.
5. Introduction of high-speed cardiotonic drugs, such as digitalis or other cardiac glycosides, enhancing cardiac contractions.
Vicious circle at the heart of acute pulmonary edema develops so quickly that the patient's death can occur within a period of 20 minutes to 1 hour. Consequently, all medical measures must be carried out immediately.
The maximum degree of excess normal value of cardiac output is calledreserve of the heart. Thus, in young healthy people the heart reserve is 300 to 400%, and in well-trained athletes it reaches 500-600%. To show what the normal heart reserve means, let us give the following example. In a healthy young man, when performing severe physical exertion, the cardiac output increased approximately 5-fold compared to the resting level. This means that the excess of the resting level is 400% and the heart reserve of the young man is 400%. However, with heart failure, the reserve of the heart is completely exhausted.
Any factors that reduce the pumping function of the heart. lead to a decrease in the reserve of the heart. Such factors may be coronary heart disease, primary myocarditis, vitamin deficiency, myocardial damage, heart valve defects, etc.