Real-time dynamic carbon dioxide administration: A novel treatment strategy for stabilization of periodic breathing with potential application to central sleep apnea

Objectives This study targeted carbon dioxide (CO2) oscillations seen in oscillatory ventilation with dynamic pre-emptive CO2 administration. Background Oscillations in end-tidal CO2 (et-CO 2) drive the ventilatory oscillations of periodic breathing (PB) and central sleep apnea in heart failure (HF). Methods Seven healthy volunteers simulated PB, while undergoing dynamic CO2 administration delivered by an automated algorithm at different concentrations and phases within the PB cycle. The algorithm was then tested in 7 patients with HF and PB. Results In voluntary PB, the greatest reduction (74%, p < 0.0001) in et-CO2 oscillations was achieved when dynamic CO2 was delivered at hyperventilation; when delivered at the opposite phase, the amplitude of et-CO2 oscillations increased (35%, p = 0.001). In HF patients, oscillations in et-CO2 were reduced by 43% and ventilatory oscillations by 68% (both p < 0.05). During dynamic CO2 administration, mean et-CO2 and ventilation levels remained unchanged. Static CO2 (2%, constant flow) administration also attenuated spontaneous PB in HF patients (p = 0.02) but increased mean et-CO2 (p = 0.03) and ventilation (by 45%, p = 0.03). Conclusions Dynamic CO2 administration, delivered at an appropriate time during PB, can almost eliminate oscillations in et-CO2 and ventilation. This dynamic approach might be developed to treat central sleep apnea, as well as minimizing undesirable increases in et-CO2 and ventilation. © 2010 American College of Cardiology Foundation.