Hypoxic and Hypercapnic Drive Response Make an Appointment Ask a Question Refer Patient Reviewed by Amy Olson and George Zeman (October 01, 2014) Hypoxic response is a measure of the change in breathing patterns associated with decreases in inspired O2 concentration while end-tidal CO2 is stabilized. Hypercapnic response is a measure of the change in breathing patterns associated with increases in inspired CO2 concentration. This information has been approved by George Zeman BS, RRT, CPFT and Amy L. Olson, MD, MSPH (October 2014).