Commonly written in medical notes as SOB (one of the few medical acronyms with reasonably large worldwide acceptance within the English speaking world), this is one of the most common problems patients have upon presentation to hospital.
Getting oxygen to the body tissues is what the game is all about. It requires the A, the B and the C of the ABCs of resuscitation. It requires that all of the following for it to work:
- air to breathe
- airway patency
- airway protection
- functioning respiratory movements
- sufficient uncompromised lung tissue
- functional gas exchange
- good lung perfusion
- good systemic circulation
Shortness of breath can be triggered by pathology in any of the steps involved. Chemoreceptors and baroreceptors measure the amount of oxygen and carbon dioxide in the circulation. When the carbon dioxide level is too high or the oxygen level is too low, the feedback mechanisms make the person breathe harder. When breathing harder cannot cope with the demand for oxygen, the patient feels short of breath.
Feeling short of breath is normal for a healthy person who exercises hard. Feeling short of breath at rest is never normal.