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Mechanical dead space or external dead space is volume in the passages of a breathing apparatus in which the breathing gas flows in both directions as the user breathes in and out, causing the last exhaled gas to be immediately inhaled on the next breath, increasing the necessary tidal volume and respiratory effort to get the same amount of ...
dead space Physiological dead space is the volume of ventilated gas that does not reach parts of the lung in which gas exchange occurs. [19] Breathing apparatus usually add some mechanical dead space to increase the total dead space of the system of breathing apparatus and user. demand valve
Breathing hoses are usually long enough to connect the apparatus to the user's head in all attitudes of their head, but should not be unnecessarily long, which will cause additional weight, hydrodynamic drag, risk snagging on things, or contain excess dead space in a pendulum rebreather. Breathing hoses can be tethered down to a diver's ...
Breathing apparatus of several types may affect the physical work capacity of the wearer if they cause additional breathing resistance or dead space ad by the weight that must be carried. The effects are changes to breathing patterns, hypoventilation, and the associated carbon dioxide retention due to increases in the work of breathing.
The breathing apparatus will generally increase dead space by a small but significant amount, and cracking pressure and flow resistance in the demand valve will cause a net work of breathing increase, which will reduce the diver's capacity for other work. Work of breathing and the effect of dead space can be minimised by breathing relatively ...
The process by which oxygen is taken in by the bloodstream is called oxygenation. Lung compliance is the capacity of the lungs to contract and expand. The obstruction of airflow via the respiratory tract is known as airway resistance. The amount of ventilated air that is not involved in gas exchange is known as dead-space ventilation. [5] [tone]
The normal relaxed state of the lung and chest is partially empty. Further exhalation requires muscular work. Inhalation is an active process requiring work. [4] Some of this work is to overcome frictional resistance to flow, and part is used to deform elastic tissues, and is stored as potential energy, which is recovered during the passive process of exhalation, Tidal breathing is breathing ...
Like any other breathing apparatus, the dead space must be limited to minimise carbon dioxide buildup in the mask. In some cases the outlet suction must be limited and a back-pressure regulator may be required. This would usually be the case for use in a saturation system.