Oxygen concentrations are monitored by an oxygen analyzer. A polyethylene tube 3 mm in diameter is also available to take air samples in order to measure inspired gas tensions, as a double check. Finger pulse oximetry is connected via serial port to a personal computer, for sampling every 5 seconds and averaging every 5 minutes. A one-way valve is connected by a mouthpiece to the outside, where a pneumotachograph, analogically connected to a computer records expiratory ventilation along with electrocardiogram. Douglas bags recollect the expired gas for CO2 and O2 analyses in a radiometer blood gas analyzer.
All data is registered in a central computer for future analysis.
Inside, a sitting down subject, can read, listen to a radio, watch television or talk on the phone. This multi-purpose chamber permits environmentally controlled studies and treatment of patients with acute and chronic hypoxia at high altitude in an accurate and homelike way.