Hypotension

Arterial hypotension (from the Greek arteria ἀρτηρία, impact, artery ', ὑπό hypo, under' and τείνειν teinein, span ') describes a blood pressure below a defined limit of normal. In Germany, one usually refers to a systolic blood pressure less than 110 mmHg, the National Heart, Lung, and Blood Institute (USA) is 90/60 mmHg as the threshold to.

Pathophysiology and Classification

The cause of arterial hypotension is a mismatch of vascular volume and circulating blood volume. This mismatch can be caused by a decreased vascular resistance to low absolute blood volume, low blood return to the heart, or through reduced pumping function of the heart. Depending on the cause, there are three forms of arterial hypotension.

Symptomatic hypotension

When symptomatic hypotension is called low blood pressure on a clearly definable cause, eg a disease or medication due, (see table).

Orthostatic hypotension

Orthostatic hypotension (synonyms: orthostatic hypotension, orthostatic dysregulation ) is a change in the upright body position ( orthostatic hypotension ) occurring impaired regulation of blood pressure.

Physiology

Normally, the organism controls the resulting by the orthostatic hypotension contrary to the orthostatic reaction. Orthostatic hypotension occurs when counter-regulation of the body does not run properly.

Molding

Three forms of regulation disorder can be distinguished:

• Sympatheticotonic orthostatic hypotension: The sympathetic counter-regulation is excessive. There is an increase in diastolic blood pressure and heart rate ( at least 16/min more) at the same time mirror image of a strong drop in systolic blood pressure.
• Asympathikotone orthostatic hypotension: The sympathetic counter-regulation fails too weak. It comes with the same or even falling heart rate to a relatively large decrease in systolic and diastolic blood pressure.
• Postural orthostatic tachy syndrome (synonym orthostatic intolerance ): Hypotension remains off, but there is a relatively large increase in heart rate ( > 130 / min).

Essential hypotension

The most common form is the essential hypotension (idiopathic hypotension). Its cause is unclear. One assumes that their is a setpoint adjustment is based. It is increased in young, slender women and often has no clinical significance.

Symptoms

• Pallor, cold hands and feet
• Rapid fatigability, lack of concentration
• Dizziness
• Headache
• Tachycardia
• Tendency to collapse, syncope

Of greatest relevance is the occurrence of brief fainting ( syncope ). Through the - compared to the ideal value ( 120/80 mmHg) - low blood pressure, there is a reduced supply the brain with oxygen-rich blood and thereby to unconsciousness. This often leads to falls and associated injuries.

Arterial hypotension occurs frequently in lean or obese people in their teens.

Diagnostics

A longer existing hypotension should be investigated medically. The main aim of diagnosis is to identify symptomatic hypotension or exclude, as it can be an expression of a life-threatening disease may. These are in addition to medical history and clinical examination apparatus procedures such as echocardiography or a long-term blood pressure measurement and a blood test of significance. In the diagnosis of orthostatic hypotension Schellong test and tilt table testing play a crucial role.

Therapy

In the long term arterial hypotension opposite of hypertension with respect to cardiovascular risk is considered to be favorable. If there is no identifiable underlying disease, therapy is therefore indicated and carried out by physical means such as sports, gymnastics and cold showers and a change of diet ( salt- rich meals with increased fluid intake ) only in case of complaints. Only rarely a medical therapy with sympathomimetics, dihydroergotamine or mineralocorticoid is displayed.

Controlled hypotension

The controlled hypotension is a method in which it lowers deliberately during the operation the blood pressure of a patient in order to reduce blood loss. It is used particularly effectively in orthopedic procedures, but can also be applied in other types of operations.