Overhead view of the CO2 Narcosis study set up. Photo shows the underwater joystick container, the cycle ergometer and the breathing hoses. Co-investigator, Bruce Derrick, MD testing the apparatus prior to a trial run to 200 EAD + CO2. MATB-II video game screen. The subjects must accurately control the simulator while responding to a series of warning lights a gauges during the different gas and exercise conditions. Subject performing a CO2 response curve prior to undergoing the experimental procedure. In-chamber gas switching manafold. All gases are confirmed with mass spectromtery during the study. Arterial to end tidal CO2 is compared during the different exercise and gas conditions. In-chamber setup for arterial blood gas collection.