A chamber system for maintaining a hyperbaric environment for long-term animal studies

An experimental hyperbaric chamber system is described whereby animals, including nonhuman primates, can be cared for under altered environmental conditions for periods in excess of 1 wk. The chamber itself is capable of a working pressure of 200 atm abs, used with various mixtures of gases which can be varied independently. The novel approach of vertical mounting enables cages to be lowered into position, and food and water can be supplied from above while excreta can be removed from below, irrespective of the internal pressure. The chamber has an integrated life support system such that temperature, both of the chamber and of the mass of gas inside, humidity, oxygen, carbon dioxide, and noise levels can be accurately and finely controlled, all within a pathogen-free environment.