What is Cheyne-Stokes respiration?
In this first aid blog post we discuss a pattern of breathing known as ‘Cheyne-Stokes breathing’.
Cheyne-Stokes respiration is characterised by a few seconds of apnoea (not breathing) followed by respirations that gradually increase in frequency and volume to a peak intensity and then gradually subside to a period of apnoea. This pattern is cyclical.
Cheyne-Stokes respiration is often a poor prognostic sign.
Causes of this breathing pattern include:
- Brainstem lesions and stroke
- Raised intracranial pressure
- Heart failure
- Chronic pulmonary oedema
While usually seen in some comatose patients (usually pre-terminal), it can sometimes also be seen in patients with congestive heart failure. Hyperventilation is associated with pulmonary congestion, and Cheyne-Stokes respiration is more prone to occur during sleep, when the respiratory system is mainly dependent on chemical control.
The brain continuously monitors the body’s status and continuously decides the proper rate and depth of breathing to command. In particular, the brain continuously monitors how much carbon dioxide is contained in the bloodstream.
Breathing is normally controlled by a simple cycle of events:
- When the level of carbon dioxide gets too high, the brain sends a “breathe now” command to the breathing muscles.
- The act of breathing lowers the level of carbon dioxide in the blood.
- There is no stimulus to breathe until the level of carbon dioxide rises again to the “too high” level.
- Since the body continuously produces carbon dioxide, the “too high” level is reached again in a few seconds. The cycle starts again.
Heart failure disrupts this cycle, and Cheyne-Stokes breathing is the result. Heart failure is disruptive because the blood circulates more slowly through the body in heart failure. As a result, the carbon dioxide levels seen by the brain are not current information, they represent carbon dioxide information from several seconds earlier.
Cheyne-Stokes breathing may occur in normal persons at altitude or after forced hyperventilation.