Abstract
Although respiratory sensation such as dyspnea, or breathlessness are known to be elicited by carbon dioxide, and hypoxia, it is not well known if there is a positive interaction between both chemical stimuli, in the same manner as in ventilation. We examined both ventilation and respiratory sensation during progressive hypoxia with three different CO2 levels using 14 young subjects. Ventilatory variables such as end-tidal CO2 (PetCO2) and O2 (PetO2), tidal volume (VT), respiratory frequency (f) and minute ventilation (VE) were monitored using an aeromonitor (Minato) and the arterial oxygen saturation (SpO2) was by a pulse oxymeter (Ohmeda, Biox). All of these data were stored into a personal computer with breath by breath fashion. We built the model to extract both sensitivities and thresholds of hypercapnia and hypoxic ventilatory responses and the sensitivity of their interaction. [J Physiol Sci. 2008;58 Suppl:S118]
