Shock Definition Health And Treatment....
This word in its medical sense is difficult to define; it should probably never be used without a modifying adjective such as haemorrhagic, hypovolaemic (low circulatory volume), septicaemic, cardiogenic, and so on.
The concept of shock arose from the observation of wounded men and animals. Even though the nature of the wound might vary widely from one individual to another, a clinical picture developed which in many respects was similar in all.
Nowadays, we understand this common reaction with increasing clarity. The concept of shock is becoming identified with the effects of a diminished circulation to the tissues: these effects are partly the impair-ment of functions of sensitive organs, and partly reactionary responses of the subject which are aimed at minimizing the consequences of the injury. In particular it must be emphasized that shock in a medical context has no relation to the emotional disturbance referred to as shock in everyday speech.
The earliest features of shock are due to the sensitivity of the brain to a reduction in blood supply: agitation, inability to concentrate, nausea, giddiness, dimness of vision, prostration, unconsciousness. As the cardiac output diminishes, the arterial blood pressure falls; as the renal blood flow drops, the urine output ceases.
The compensatory measures are that the heart-rate increases and the blood vessels in areas that are insensitive to the blood-lack, particularly the skin, constrict. The narrowing of the skin blood vessels produces the pallor and coldness typical of inadequate cardiac output. These effects are partly produced by an increased liberation of the hormone adrenaline from the adrenal gland, and because this agent also has an effect upon sweat glands the subject breaks out into a (cold) sweat. The compensatory changes of vasoconstriction and an increase in the heart-rate bolster up the arterial blood pressure for a time. Ultimately, this phase of compensation can no longer be maintained and there is a precipitate fall in blood pressure and a marked deterioration in the patient's condition.
The key to management is the state of the veins. If the central venous pressure is high the heart is failing and drugs to increase the efficiency of the heart are indicated. If the central venous pressure is low (in which case peripheral veins such as those in the back of the hand look collapsed) then the circulatory failure is due to a diminished blood volume or to a dilatation of the capillary circulation.
The surgeon may place a fine catheter via the veins of the neck or the arm into the large veins entering the heart within the thorax, and order a slow infusion of normal saline solution to be maintained to keep the catheter patent. From time to time this infusion can be stopped and the central venous pressure incasunx1 by noting the height above the sternum to which the column of saline in the tubing ffills. In cases of reduction in the venous return, the surgeon will set up a second intravenous infusion through which the circulation can be restored with blood or other fluids.
This word in its medical sense is difficult to define; it should probably never be used without a modifying adjective such as haemorrhagic, hypovolaemic (low circulatory volume), septicaemic, cardiogenic, and so on.
The concept of shock arose from the observation of wounded men and animals. Even though the nature of the wound might vary widely from one individual to another, a clinical picture developed which in many respects was similar in all.
Nowadays, we understand this common reaction with increasing clarity. The concept of shock is becoming identified with the effects of a diminished circulation to the tissues: these effects are partly the impair-ment of functions of sensitive organs, and partly reactionary responses of the subject which are aimed at minimizing the consequences of the injury. In particular it must be emphasized that shock in a medical context has no relation to the emotional disturbance referred to as shock in everyday speech.
The earliest features of shock are due to the sensitivity of the brain to a reduction in blood supply: agitation, inability to concentrate, nausea, giddiness, dimness of vision, prostration, unconsciousness. As the cardiac output diminishes, the arterial blood pressure falls; as the renal blood flow drops, the urine output ceases.
The compensatory measures are that the heart-rate increases and the blood vessels in areas that are insensitive to the blood-lack, particularly the skin, constrict. The narrowing of the skin blood vessels produces the pallor and coldness typical of inadequate cardiac output. These effects are partly produced by an increased liberation of the hormone adrenaline from the adrenal gland, and because this agent also has an effect upon sweat glands the subject breaks out into a (cold) sweat. The compensatory changes of vasoconstriction and an increase in the heart-rate bolster up the arterial blood pressure for a time. Ultimately, this phase of compensation can no longer be maintained and there is a precipitate fall in blood pressure and a marked deterioration in the patient's condition.
The key to management is the state of the veins. If the central venous pressure is high the heart is failing and drugs to increase the efficiency of the heart are indicated. If the central venous pressure is low (in which case peripheral veins such as those in the back of the hand look collapsed) then the circulatory failure is due to a diminished blood volume or to a dilatation of the capillary circulation.
The surgeon may place a fine catheter via the veins of the neck or the arm into the large veins entering the heart within the thorax, and order a slow infusion of normal saline solution to be maintained to keep the catheter patent. From time to time this infusion can be stopped and the central venous pressure incasunx1 by noting the height above the sternum to which the column of saline in the tubing ffills. In cases of reduction in the venous return, the surgeon will set up a second intravenous infusion through which the circulation can be restored with blood or other fluids.
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