Clinical Research
Heart Failure
Real-Time Dynamic Carbon Dioxide Administration: A Novel Treatment Strategy for Stabilization of Periodic Breathing With Potential Application to Central Sleep Apnea

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Objectives

This study targeted carbon dioxide (CO2) oscillations seen in oscillatory ventilation with dynamic pre-emptive CO2administration.

Background

Oscillations in end-tidal CO2(et-CO2) 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 CO2administration 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-CO2oscillations was achieved when dynamic CO2was delivered at hyperventilation; when delivered at the opposite phase, the amplitude of et-CO2oscillations increased (35%, p = 0.001). In HF patients, oscillations in et-CO2were reduced by 43% and ventilatory oscillations by 68% (both p < 0.05). During dynamic CO2administration, mean et-CO2and 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 CO2administration, delivered at an appropriate time during PB, can almost eliminate oscillations in et-CO2and ventilation. This dynamic approach might be developed to treat central sleep apnea, as well as minimizing undesirable increases in et-CO2and ventilation.

Key Words

carbon dioxide
periodic breathing
treatment

Abbreviations and Acronyms

CSA
central sleep apnea
et-CO2
end-tidal carbon dioxide
HF
heart failure
PB
periodic breathing
VPB
voluntary periodic breathing

Cited by (0)

Supported by National Institute for Health Research Biomedical Research Centrefunding scheme. Dr. Giannoni was supported by a European Society of Cardiologyresearch grant. Dr. Baruah (PG/07/065) and Dr. Francis (FS/04/079) were supported by the British Heart Foundation. K. Willson and Dr. Mebrate received support from the Foundation for Circulatory Health(ICCH/05/5004). C. Manisty received support from the Wellcome Trust(077049/Z/05/Z). All other authors have reported that they have no relationships to disclose. Drs. Giannoni and Baruah contributed equally to this work; the studies of voluntary periodic breathing were predominantly conducted by Dr. Giannoni and the studies of the heart failure patients were predominantly conducted by Dr. Baruah.