Respiratory drive

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Respiratory drive is a term used in physiology . The respiratory drive serves to regulate the blood gases O 2 and CO 2 . It is controlled centrally by the respiratory center in the elongated medulla ( medulla oblongata ). With increased respiratory drive, among other things, the breathing frequency is increased, i.e. the number of breaths per minute, in order to cause an increased exhalation of CO 2 and thus its reduction in the blood.

mechanism

The respiratory drive is primarily via the CO 2 - partial pressure regulated. At a partial pressure above the normal value of 40 mmHg, the minute volume increases. In addition, a falling O 2 partial pressure (O 2 drive) and respiratory acidosis (pH drive) cause an increased breathing rate. An increase in the CO 2 partial pressure in the blood is registered via arterial receptors and leads to increased respiratory drive. The respiratory center causes increased activity of the respiratory muscles via efferent pathways . The most important muscle of the respiratory muscles is the diaphragm . The increased respiratory rate leads to a decrease in the CO 2 partial pressure and an increase in the O 2 partial pressure in the blood, as well as an increase in the pH value .

Disruptions

When breathing is disturbed, the carbon dioxide level in the blood increases faster than the oxygen level decreases. The reason for this is that oxygen passes better from the air we breathe into the blood than carbon dioxide from the blood into the air we breathe.

In patients who have lung diseases such as B. COPD have a permanently increased carbon dioxide content of the blood, it comes to habituation (adaptation), so that the shortness of breath is no longer controlled by an increase in the carbon dioxide content ( hypercapnia ), but by a decrease in the oxygen content ( hypoxemia ). In such patients, when there is shortness of breath, the uncontrolled supply of medical oxygen can lead to a decrease in respiratory drive up to and including respiratory arrest .

In the case of a swimming pool blackout , a reduced level of carbon dioxide in the blood leads to a decrease in respiratory drive, although the oxygen level is already critically low.

literature

  • Christian Hick: Physiology. 4th, revised. and updates Edition. Urban & Fischer bei Elsevier, 2002, ISBN 3-437-41891-2 .