alveolar dead space


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dead space

 
1. a space remaining in the tissues as a result of failure of proper closure of surgical or other wounds, permitting the accumulation of blood or serum.
2. the portions of the respiratory tract that are ventilated but not perfused by pulmonary circulation.
alveolar dead space the difference between anatomical dead space and physiologic dead space, representing the space in alveoli occupied by air that does not participate in oxygen–carbon dioxide exchange (alveolar ventilation). It varies in different parts of the lungs and under different conditions.
anatomical dead space the airways of the mouth, nose, pharynx, larynx, trachea, bronchi, and bronchioles.
equipment dead space the volume of equipment that results in rebreathing of gases.
physiologic dead space the sum of the anatomic and alveolar dead spaces; its volume (VD) is determined by measuring the partial pressure of carbon dioxide in a sample of exhaled gas (PECO2) and in the arterial blood (PaCO2) and (with tidal volume of VT) using the formula VD/VT = (PaCO2−PECO2)/PaCO2.

al·ve·o·lar dead space

the difference between physiologic dead space and anatomic dead space; it represents that part of the physiologic dead space resulting from ventilation of relatively underperfused or nonperfused alveoli; it differs specifically in being placed so as to fill and empty in parallel with functional alveoli, rather than being interposed in the conducting tubes between functional alveoli and the external environment.

alveolar dead space

al·ve·o·lar dead space

(al-vē'ŏ-lăr ded spās)
The difference between physiologic dead space and anatomic dead space; it represents that part of the physiologic dead space resulting from ventilation of relatively underperfused or nonperfused alveoli; it differs specifically in being placed so as to fill and empty in parallel with functional alveoli, rather than being interposed in the conducting tubes between functional alveoli and the external environment.

alveolar dead space

The volume of inspired air that fills the tubes leading to the air sacs (alveoli) of the lungs, but which is unable to undergo gas exchange with the blood.
References in periodicals archive ?
2]-free gas expired from the large airway and tracheal tube dead space, Phase H represents a mixture of gas from both the large airway dead space and alveolar dead space and Phase III (or alveolar plateau) represents alveolar ventilation (13,14).
Along the second axis, increased alveolar dead space, commonly due to acute lung injury, volume overload, obstructive lung disease, hypovolemia, excess PEEP or pulmonary arterial occlusion, impairs the lung's CO2-exchanging efficiency.
Q] ratio of [infinity], and are alveolar dead space units.