Reversible conversion of moderate obstructive sleep apnea to severe behavioral hyperventilation–induced central sleep apnea under pandemic-related psychological stress: a case report

Behavioral hyperventilation–induced central sleep apnea (BH-CSA) is a recently recognized subtype of central sleep apnea (CSA). Although several cases have been reported recently, its long-term clinical course and reversibility remain unclear. Here, we report a case of BH-CSA that demonstrated reversibility over the long-term course. We report a previously healthy woman in her 50s with moderate obstructive sleep apnea (OSA; apnea–hypopnea index [AHI] 25.6 events/h) who developed severe BH-CSA during the COVID-19 pandemic. Pandemic-related psychological stress provoked repeated arousals with hyperventilation, during which CO₂ levels fluctuated and arterial PaCO₂ fell to a nadir of 31.7 mmHg, converting OSA to central sleep apnea (AHI 95 events/h, 93% central events). Volume-assured non-invasive positive-pressure ventilation stabilized her breathing and restored slow-wave and REM sleep. With anxiolytic therapy and the easing of restrictions, stress declined, and polysomnography two months later showed reversion to severe OSA (AHI 30.6 events/h). This case indicates that acute psychophysiological stress can transiently replace OSA with BH-CSA via hyperventilation-induced hypocapnia and heightened loop gain. This highlights the need to address reversible stressors before escalating ventilatory support in susceptible patients, particularly those with obesity. This case further illustrates that psychophysiological stress and behavioral hyperventilation can transiently destabilize ventilatory control, especially in individuals with obesity who may be predisposed to higher loop gain and reduced CO₂ reserve.