dead-air space

• Terme utilisé en radiodiffusion et télécommunications pour désigner une période de silence involontaire ou une absence de signal pendant une transmission, ou en radiocommunication, une zone où les signaux ne sont pas reçus. Peut aussi désigner métaphoriquement un silence gênant dans une conversation.

A term used in broadcasting and telecommunications to describe an unintended period of silence or lack of signal during a transmission, or in radio communication, a zone where signals cannot be received. It can also refer metaphorically to an awkward pause in conversation.

1. Respiratory anatomyC1formal

   The portion of the respiratory system where air does not participate in gas exchange, such as the trachea and bronchi.

   Espace mort anatomique

   • The anatomical dead-air space includes the nasal passages and bronchial tubes.
   • During shallow breathing, the dead-air space volume remains constant.
   • An increase in dead-air space can reduce the efficiency of oxygen exchange.

2. Ventilation measurementC1formal

   In respiratory physiology, the volume of inhaled air that does not reach the alveoli for gas exchange.

   Espace mort

   • The dead-air space is measured using the Bohr equation.
   • Mechanical ventilation settings must account for dead-air space to ensure proper oxygenation.
   • A high dead-air space fraction indicates poor ventilation efficiency.