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apnea test

A test used to determine whether a comatose person receiving life support has suffered brain death.

PATIENT CARE: The patient’s ventilator is set to deliver no breaths per minute, and the carbon dioxide level of the blood is allowed to rise 20 mmg Hg to a level that is at least above 60 mm Hg. If apnea (no spontaneous breathing) occurs, brain death is confirmed. The test should not be performed if the person has recently received sedative, narcotic, or paralytic drugs; those drugs may suppress spontaneous breathing, falsely suggesting brain death.


(ap″noo-mă-tō′sĭs) [1an- + pneumatosis] Noninflation of alveoli. SYN: congenital atelectasis.


(ap-noo′mē-ă) [1an- + Gr. pneumōn, lung] Congenital absence of the lungs.


(ap-noo′sĭs) [1an- + Gr. pneusis, breathing] Abnormal respiration marked by sustained inspiratory effort. It is caused by surgical removal of the upper portion of the pons.



apo-, ap-

[Gr. apo, from] Prefixes meaning separated from or derived from.


In Ayurvedic medicine, water, one of the five essential elements. It stimulates the tongue. Its special sense is that of taste.


(ap″ŏ-krō-mat′ik) [apo- + chromatic] Free from spherical and chromatic aberrations.


(ap′ŏ-krĕn, -krīn″, -krēn″) [apo- + krinein, to separate] Pert. to secretory cells that contribute part of their protoplasm to the material secreted. SEE: eccrine; holocrine; merocrine.

apodal, apodous

(ap′ŏd-ăl, ap′ŏd-ŭs) [1an- + pod-] Lacking feet.


(ā″pō′dē-ă) [1an- + pod- + -ia] Congenital absence of one or both feet.


(ap″ŏ-dĭ-zā′shŏn) 1. Alteration of a surface by removal of its irregularities. 2. Introduction of a gradual change into a mathematical function that would otherwise be discontinuous. It is used in radiology to smooth out choppy signals, and in optics, to blend diffractive steps.


(ap″ō-en′zīm″) [apo- + enzyme] An inactive enzyme that requires a co-factor to work as a catalyst. SEE: holoenzyme; prosthetic group.


(ap″ŏ-fer′ĭt-ĭn) [apo- + ferritin] A protein that combines with iron to form ferritin. In the body, it is always bound to iron.


(ap′ŏ-jēé) [apo- + Gr. gaia, gē, earth] The climax or period of greatest severity of a disease. SYN: ...

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