Abstract
When CO2 is inhaled as a constant fraction (CF) in inspired air, the CO2 load is linearly related to ventilation, but when CO2 is added to the inspired airstream at a constant flow, the CO2 load is fixed and independent of ventilation,1. In the latter case, both the deadspace of the inspiratory limb of the equipment and ventilation have a significant effect on the timecourse of CO2 within each breath — i.e. a small deadspace causes a large amplitude early-inspired pulse (EIP) of CO2 in each inspiration because of CO2 build up during expiration, whilst a large deadspace distributes CO2 more evenly throughout each inspiration. We compared the normoxic ventilatory response to step changes in the fraction of CO2 in the inspired air with step changes in the flow of CO2 delivered into the inspired air when a small deadspace is used. The results of each experiment are discussed in terms of their effect on the time-course of alveolar CO2 oscillations which occur during a respiratory cycle.
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© 1989 Plenum Press, New York
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Mussell, M.J., Miyamoto, Y., Nakazono, Y. (1989). Inhaled CO2 as a Constant Fraction in Inspired Air and as Early-Inspired Pulses. In: Swanson, G.D., Grodins, F.S., Hughson, R.L. (eds) Respiratory Control. Springer, Boston, MA. https://doi.org/10.1007/978-1-4613-0529-3_32
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DOI: https://doi.org/10.1007/978-1-4613-0529-3_32
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