Source:http://linkedlifedata.com/resource/umls/id/C0180499
UMD: Devices designed to establish a channel for the exit of fluids (e.g., air, serum, blood, lymph, bile) or purulent material from a cavity, wound, or infected area. Drains usually consist of flexible, hollow devices (e.g., tubes) with one or more lumina. They are typically made of Silastic, polyvinyl chloride, or, less frequently, rubber; a drain may include a trocar in its lumen. Most drains are used either as components of open drainage systems (i.e., through capillary action and gravity) or in closed systems that usually apply low negative pressure through the drain lumen. Dedicated tubes, catheters, and cannulae are also used for drainage of anatomic sites such as biliary ducts (e.g., T tubes, catheters), the urethra, the stomach (i.e., nasogastric tubes), and the brain ventricle (e.g., hydrocephalus catheters, shunts).