An experimental chamber for long-term studies of chronic hypoxia in small animals

¹ Departments of Anatomy and Engineering, Bowman Gray School of Medicine, Winston-Salem, North Carolina

An experimental chamber was designed in which chronic hypoxia, as well as adaptation to hypoxia, could be studied over prolonged periods of time in 36 or more small laboratory animals. Rats have been kept in this chamber for periods up to 90 days with oxygen levels from 21% down to 3%, the percentage of oxygen being controllable to 0.25%. The chamber is temperature controlled and maintains a constant relative humidity which may be predetermined. Oxygen levels are maintained by adjusting input of air and nitrogen. The nitrogen tanks are attached to an automatic manifold control which maintains a constant flow of nitrogen even while nitrogen tanks are being changed. It is practical to have a bank of six to eight nitrogen tanks attached to the manifold. Such a bank of nitrogen tanks may last from 4 to 12 days depending on the percentage of oxygen desired. The percentage of oxygen in the chamber is measured directly by means of an oxygen analyzer.

Submitted on June 29, 1964