dead space

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dead space2016-11-15T17:02:28+00:00

dead space 


A general term for all non-air exchanging spaces of the upper respiratory tract; there is about 2.0 ml of “dead space”/kg body weight, i.e., a 70 kg person has 140-150 ml of dead space in the oronasopharynx, bronchi, bronchioles. 

Respiratory dead space–DS is divided into:

(1) Anatomic DS–respiratory system volume exclusive of alveoli, and

(2) Physiologic DS–”wasted ventilation” or volume of gas not equilibrating with blood are the same in healthy subjects, clinically measured by single breath nitrogen curve; the relation of ventilation–V to blood flow–Q, V/Q ratio may be substantially altered in disease states 


A term of art referring to that part of a syringe’s tip and needle that contains medication which can’t be administered.

DS is important in insulin therapy, and for drugs where the syringe has < 0.5 mL capacity 

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