Periodic breathing or Cheyne-Stokes respiration, is a type of breathing pattern characterized by a regular cycle of deep breathing followed by shallow breathing or even a pause in breathing.
DuringCheyne-Stokes respiration, a person takes deep breaths for a certain period of time, typically lasting between 30 seconds and two minutes.
It is an oscillation of ventilation between apnea and hyperpnea with a crescendo-diminuendo pattern, and is associated with changing partial pressures of oxygen and carbon dioxide.
After this deep breathing period, the person’s breathing becomes gradually shallower until it reaches a pause, which can last for up to 30 seconds.
Then the cycle begins again with deep breathing.
Its pathophysiology is apnea leading to increased CO2 which causes excessive compensatory hyperventilation, in turn causing decreased CO2 which causes apnea, restarting the cycle.
Such a phenomena can occur during wakefulness or during sleep, where they are called the central sleep apnea syndrome.
Cyclical sighing is often associated with certain medical conditions, including heart failure, stroke, and brain damage.
C-S in heart failure, there is unstable feedback in the respiratory control system.
It can also occur during sleep and may be more noticeable during periods of stress or anxiety.
It may be caused by damage to respiratory centers or by physiological abnormalities in congestive heart failure and is also seen in newborns with immature respiratory systems and in visitors new to high altitudes.
In normal respiratory control, negative feedback allows a steady level of alveolar gas concentrations to be maintained, and therefore stable tissue levels of oxygen and carbon dioxide (CO2).
At the steady state, the rate of production of CO2 equals the net rate at which it is exhaled from the body, which (assuming no CO2 in the ambient air) is the product of the alveolar ventilation and the end-tidal CO2 concentration.
Alveolar ventilation = body CO2 production/end-tidal CO2 fraction.
In general, transient or persistent disturbances in ventilation, CO2 or oxygen levels can be counteracted by the respiratory control system in this way.
In some pathological states, the feedback is more powerful than is necessary to simply return the system towards its steady state.
Instead, ventilation overshoots and can generate an opposite disturbance to the original disturbance.
If this secondary disturbance is larger than the original, the next response will be even larger, and so on, until very large oscillations have developed.
When the cycle of enlargement of disturbances reaches a limit when successive disturbances are no longer larger, physiological responses no longer increase linearly in relation to the size of the stimulus.
Cheyne–Stokes respiration can be maintained over periods of many minutes or hours with a repetitive pattern of apneas and hyperpneas.
Risk factors are hyperventilation, prolonged circulation time, and reduced blood gas buffering capacity.
This abnormal pattern of breathing can be seen in patients with heart failure, strokes, hyponatremia, traumatic brain injuries, and brain tumors.
In some instances, it can occur in otherwise healthy people during sleep at high altitudes.
It can occur in toxic metabolic encephalopathy, a symptom of carbon monoxide poisoning, along with syncope or coma.