Respiratory · Year 1 · from Respiratory
Case 2: Cheyne-Stokes Respiration in Heart Failure
Case Presentation
A 72-year-old man with severe heart failure (ejection fraction 20%) is admitted for decompensation. His wife reports that at night, his breathing stops for 15-20 seconds, then gradually becomes deeper and faster, then shallow again before stopping - a pattern that repeats throughout the night. She has observed this pattern worsening over the past several months.
Overnight polysomnography confirms Cheyne-Stokes respiration with central sleep apnea. The pattern shows regular cycles of crescendo-decrescendo breathing with central apneas lasting 15-25 seconds. The apnea-hypopnea index is 42 events per hour. Arterial blood gas shows pH 7.46, PaCO2 32 mmHg, PaO2 78 mmHg, indicating chronic respiratory alkalosis.
Cheyne-Stokes respiration results from instability in the respiratory control feedback loop, most commonly due to prolonged circulation time in severe heart failure. In normal individuals, changes in ventilation rapidly affect blood gases sensed by chemoreceptors, allowing tight feedback control. In heart failure, blood takes longer to travel from the lungs to the chemoreceptors (carotid bodies and central chemoreceptors), creating a phase delay.
When the patient hyperventilates in response to perceived hypercapnia, the resulting hypocapnia does not reach the chemoreceptors until many seconds later. By that time, excessive hypocapnia develops, and when finally sensed, triggers apnea. During apnea, CO2 rises, but this is not sensed until circulation time later, leading to overshoot hyperventilation. This oscillating pattern continues in a waxing-waning cycle.
The patient is treated with optimization of heart failure therapy. Nocturnal supplemental oxygen is provided, which blunts the hypoxic ventilatory response and reduces loop instability. Adaptive servo-ventilation (ASV), a form of positive pressure ventilation that automatically adjusts support to stabilize breathing, would have been considered but is contraindicated in patients with severely reduced ejection fraction. The patient reports improved sleep quality with nocturnal oxygen.
Key Learning Points
- Cheyne-Stokes respiration is caused by instability in the respiratory control feedback loop
- Prolonged circulation time in heart failure creates phase delay between ventilatory changes and chemoreceptor sensing
- The pattern shows regular crescendo-decrescendo breathing with periodic apneas
- Chronic respiratory alkalosis is common due to overall hyperventilation during the hyperpneic phases
- Treatment includes optimizing heart failure and providing nocturnal oxygen