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A time when computers, imaging devices, or laboratory equipment aren’t operational, usually because they are in need of maintenance or upgrading.


(dŏk″să′z-ă-sĭn) A peripherally acting antiadrenergic administered orally to treat hypertension and to manage the symptoms of benign prostatic hyperplasia.


Digital pathology.




reaction of degeneration; digital radiography.


drachm; dram.




(drā′kō-tŏk-sĭn) [Gr. Draco, an ancient Athenian who promulgated laws, + toxikon, poison] A 105-kilo-dalton protein isolated from the glands of the weever fish, a common bottom-dwelling poisonous fish. The protein destroys blood cells and is damaging to nerves.


(dră-kŭng″kyŭ-lī′ă-sĭs, -sēz″) pl. dracunculiases [Dracunculus + -iasis] Infestation with the nematode Dracunculus medinensis. SEE: guinea worm.


(dră-kŭng′kyŭ-lŭs) [L. dracunculus, small dragon] A genus of parasitic nematodes of the family Dracunculidae.

D. medinensis SEE: guinea worm.

draft, draught

A dose of liquid medicine intended to be taken all at once.


(drān) 1. An exit opening or a tube in a body space, used to evacuate unwanted blood, cellular debris, fluids, or pus. 2. To draw off a fluid.

Jackson-Pratt d. Jackson-Pratt drain.

Penrose d. SEE: Penrose drain.

surgical d. A drain that withdraws blood, pus, or other fluids from an operative site. It may be placed in an abscess, e.g., to speed recovery from a localized infection, or in a cyst or seroma, to remove collected fluids and cells. Drains may also be inserted into obstructed organs to relieve pressure resulting from fluid buildup within the organs. Surgical drains are composed of a variety of flexible substances, including silicone, polyvinyl chloride, or plastic polymers.


(drān′ăj) The flow or withdrawal of fluids, such as blood, infused saline, pus, and collected debris, from a cavity, organ, surgical site, or wound. SEE: autodrainage; drain.

active d. Drainage in which negative pressure is maintained in the drainage tube. It is used in treating pneumothorax and in certain types of drains or catheters in the intestinal tract, body cavity, or surgical wound. SYN: negative pressure drainage; suction.

chest d. Placement of a drainage tube in the chest cavity, usually in the pleural space. The tube is used to drain air, fluid, or blood from the pleural space so that the compressed and collapsed lung can ...

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