From Big Medical Encyclopedia

HARMFUL SPACE (synonym dead space) — the space of pneumatic ways (a nasopharynx, a trachea, bronchial tubes), air to-rogo does not participate in gas exchange with blood. Capacity of Accusative at adults is determined by Bohr's formula establishing quantitative dependence between the size of Accusative, composition of alveolar and expired air and volume of respiratory air. Existence of Accusative leads to what from 500 ml of the air inhaled at rest reaches alveoluses about 2/3 owing to what the oxygen content in an alveolar air is less, than in the atmosphere. However the name «harmful space» cannot be considered successful since Accusative plays also a positive role: in it the cold air is warmed and air is substantially purified of dust (by means of a ciliary epithelium). Reduction of air volume of pneumatic ways leads to disorder of breath, reduction of oxidizing processes, especially at physical. to loading. Artificial increase in Accusative in gas masks (see) at breath through tubes of various length deepens breath, but can lead to an anoxemia and hypoxias (see).

Bibliography: Felberbaum R. A. To a question of reflex influences from upper respiratory tracts, Fiziol, zhurn. USSR, t. 49, No. 6, page 736, 1963, bibliogr.; Physiology of breath, under the editorship of L. L. Shik, etc., L., 1973, bibliogr.

M. V. Sergiyevsky.