Abnormal breathing patterns and sleep apnea !
- Regulation
- Exam priority: medium
How someone breathes says a lot: cycles that swell and fade, deep breaths from acid, or pauses in sleep each have different causes.
Updated 2026-11-01
Also called: Cheyne-Stokes, Kussmaul, Biot breathing, Obstructive sleep apnea
See it in 3D: Medulla oblongata · Carotid bifurcation · Nasal cavity · Epiglottis
What it is
Abnormal breathing patterns show where control of breathing is failing: in the chemical feedback loop, in the brainstem or in the upper airway. Cheyne-Stokes is an oscillation from delay and excess gain in the chemical loop; Kussmaul is the compensatory response to metabolic acidosis; Biot and ataxic patterns mean brainstem damage. In obstructive sleep apnea control is normal, but the pharynx collapses during sleep.
How it works, step by step
- Breathing is set by a loop: PaCO₂ rises → chemoreceptors → more ventilation → PaCO₂ falls.
- In heart failure blood takes longer to travel from lung to chemoreceptor; the correction arrives late and overshoots.
- Hyperventilation drives PaCO₂ below the apnea threshold; breathing stops until CO₂ builds up again.
- That delay, plus highly sensitive chemoreceptors, sustains the Cheyne-Stokes oscillation.
- In metabolic acidosis H⁺ stimulates the chemoreceptors and deep ventilation lowers PaCO₂ (Kussmaul).
- In sleep the tone of the pharyngeal dilator muscles falls; a narrow airway (obesity, large tonsils) collapses.
- Obstructive apnea causes hypoxemia, hypercapnia and micro-arousals; repeated sympathetic surges raise blood pressure.
Patterns and what they mean
| Pattern | What it looks like | Where the problem is | Example |
|---|---|---|---|
| Cheyne-Stokes | Crescendo–decrescendo with apneas | Slow or unstable chemical loop | Heart failure |
| Kussmaul | Deep, regular, fast or normal rate | Response to metabolic acidosis | Diabetic ketoacidosis |
| Biot / ataxic | Irregular, with random pauses | Medulla and pons | Brainstem hemorrhage, raised intracranial pressure |
| Obstructive apnea | Snoring, pauses with chest effort | Pharynx collapsing in sleep | Obesity, tonsillar hypertrophy |
| Opioid hypoventilation | Slow and shallow | Depressed respiratory center | Opioid overdose |
Clinical notes
- Patient in ketoacidosis: deep breathing with a fruity odor; the low PaCO₂ is compensation, not a lung problem.
- Cheyne-Stokes in heart failure carries a worse prognosis and can improve as cardiac function is optimized.
- At altitude (Bogotá and higher) mild periodic breathing at night is common in newcomers.
- Nursing: watch the pattern for a full minute; record pauses, depth and regularity.
Test yourself
Think of the answer, then tap the question to see it.
Why does heart failure favor Cheyne-Stokes breathing?
Low output lengthens lung-to-chemoreceptor circulation time; the PaCO₂ correction arrives late, overshoots and the cycle oscillates.
What does a patient in ketoacidosis gain from Kussmaul breathing?
Lowering PaCO₂ limits the fall in pH: it is the respiratory compensation for metabolic acidosis.
How is obstructive apnea told apart from central apnea on polysomnography?
In obstructive apnea chest and abdomen keep moving against a closed pharynx; in central apnea there is no respiratory effort.
Why is obstructive sleep apnea linked to high blood pressure?
Each apnea causes hypoxemia, hypercapnia and an arousal with a sympathetic surge; repeated all night, they raise sympathetic tone by day as well.
See it in 3D
The structures of Durgical's 3D anatomy where it happens.
Related topics
- Control of breathing, chemoreceptors and lung reflexes
- Metabolic acidosis, the anion gap and compensation
- Respiratory acidosis and alkalosis
- High altitude and acclimatization
- Wakefulness, sleep, the EEG and seizures
- Heart failure physiology
Related conditions
In Pharmacology
Educational physiology content; not a diagnostic or treatment guide and no substitute for a health professional's advice. Values are approximate references. No doses are given.
Sources: 22.3 The Process of Breathing (OpenStax (Rice University), 2022); Obstructive Sleep Apnea (StatPearls (NCBI Bookshelf), 2026); Diabetic ketoacidosis: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026); Heart Failure (Congestive Heart Failure) (StatPearls (NCBI Bookshelf), 2026); Hall JE. Guyton and Hall Textbook of Medical Physiology, 13th ed. (ch. 42). Reference book used to check facts; its text and figures are not reproduced (Elsevier, 2016).
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Representative model, for educational purposes only.