Control of Respiration
Rahul's Noteblog Notes on Pulmonology Control of Respiration
Respiratory Drive:
Why are chronically hypercapnic patients not maintained at 100% ventilator oxygen?
In healthy individuals, pCO2 is the major stimulatory drive for respiration. Thus, if pCO2 increases, (i.e., patients with acute hypercapnia), the medullary respiratory center gets stimulated and increases the respiratory rate.
However, in patients with chronic hypercapnia, the increased pCO2 has no effect on the medullary respiratory center. Nevertheless, there is another parameter which simulates the medullary respiratory center: decreased pO2 which is detected through aortic and carotid bodies in peripheral chemoreceptors. This means that if we maintain chronically hypercapnic patients on ventilators at 100% oxygen, we are shutting off the peripheral chemoreceptor drive and the medullary respiratory center is plugged out. However, if we maintain these patients at 92% oxygen, we're stimulating the peripheral chemoreceptors, which in turn stimulate the medullary respiratory center, thus, maintaining the respiratory rate.
Note that signal through the aortic receptors travels through the vagus nerve, and signal through the carotid bodies travels through the glossopharyngeal nerve.
Additional Reading:
Basic Pulmonology
1. Lung Mechanics
2. Alveolar-Blood Gas Exchange
3. Gas Transport and Regulation of Respiration
4. Four Causes of Hypoxemia
5. Control of Respiration
6. Systemic vs Pulmonary Circulation FAQ
7. Principles of Gas Exchange in Lungs
8. Hypoxia, Hypoxemia & Hemoglobin-Oxygen Saturation Curve
9. FAQ on Mechanics of Breathing
10. FAQ on Control of Breathing
11. Criteria for Transudate Pleural Effusion
12. Light's Criteria for Exudate Pleural Effusion
13. Notes on Lung Sounds
14. Patient with Acute Respiratory Distress Syndrome (ARDS)
15. Management of Acute Deep Venous Thrombosis
16. Notes on Asthma Treatment
Pulmonology Videos
1. Video of Pulmonology Examination in a Clinical Setting
Related Topics
1. Histology of the Respiratory System
2. Upper and Lower Respiratory Disorders
3. Pulmonary Examination for Internal Medicine
Medical Images
Useful Medical Images & Diagrams (link opens in a new window)
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