Abstract

Our lab over the past several years has been developing a research project that examines the relationship between a respiratory stress response to 7% CO₂ and behavioral inhibition. However, we were encountering issues with the methods of the delivery of room air and CO₂ and the accuracy of the data. The problems that were being encountered by the lab were unphysiologic respiration data during eupnea (resting breathing), and the inability for the CO₂ delivery system to elicit a doubling and tripling of breathing as has been demonstrated time and time again in the physiologic literature. It was hypothesized that the breathing mask worn by the subjects, created an additional stressor and caused an increase in the subject’s eupneic breathing, and that the CO₂ delivery system was leaking. To address the aforementioned problems, the respiratory rate, minute ventilation, and tidal volume of four subjects were measured over a period of 15 minutes using an airflow transducer connected to a Bio Pac data collection system. Two methods of CO₂ delivery were compared: a facial mask, and a mouthpiece plus a nose clip setup. Our data suggest that the mask delivered a more controlled and steadily decreasing breathing response during eupnea over a 15 minute experiment. In addition we recalibrated and tested the CO₂ delivery system and were successful at eliciting a three-fold increase in breathing.