[Patterns in the change in the body state of dogs during a breakdown of the atmosphere regeneration system in a pressurized space].

Experiments were carried out on dogs kept in a sealed chamber. Changes in the O2 and CO2 concentrations as well as variations of physiological functions, the so-called survival curves, were studied under the conditions of terminated O2 supply and CO2 utilization. The criteria of investigation, mathematical and physiological analysis were chosen from the point of view of predicting hazardous states during failures of the environmental control system. Tolerance limits during slow and rapid changes of the environment, phases of changes of the body state and mechanisms of a combined effect of increasing hypercapnia and hypoxia were considered.