Hypercapnic

During room-air breathing, the ventilatory pattern was evaluated by a Fleisch type 3 pneumotachograph with subjects sitting comfortably in an armchair. The flow signal was integrated into volume. From the spirogram, we derived inspiratory time (Ti), expiratory time, total respiratory cycle breathing time, and Vt, Respiratory frequency (1/total respiratory cycle breathing time X 60) and minute ventilation (Ve) [Vt X respiratory frequency] were also calculated.
Expired CO2 (Pco2) was sampled continuously at the mouth by an infrared CO2 meter (Normocap 200 Datex; Helsinki, Finland), The output of the CO2 meter, flow signal, integrated flow signal, and mouth pressure were recorded on a personal computer hard-disk using an eight-channel analog/digital board at 50-Hz sampling rate. After a 10-min adaptation period, evaluation began. Signals were recorded over a 10-min time period. Average values for each subject are presented.   http://treatment-with-cnp.nl/#promoted Hypercapnic-Hyperoxic Rebreathing Test
A hypercapnic-hyperoxic rebreathing test (RT) was performed following the procedure recommended by Read, a clinical method for assessing the ventilatory response to CO2. Rebreathing was terminated when the Pco2 reached 72 to 74 mm Hg, Changes in arterial oxygen saturation, volume and time compo nents of breathing pattern, and Pessw were recorded continuously. Details of the procedures have been described elsewhere.