(kăn′ū-lă)

[L., a small reed]
A tube or sheath that encloses a trocar. After the device is inserted into a blood vessel, body cavity, duct, or hollow organ, withdrawal of the trocar lets fluid drain (so that it can be collected or sampled) or escape.

Bellocq's cannula

SEE: Bellocq's cannula

nasal cannula

Tubing used to deliver oxygen at levels from 1 to 6 L/min. The nasal prongs of the cannula extend approx. 1 cm into each naris and are connected to a common tube, which is then connected to the oxygen source. It is used to treat conditions in which a slightly enriched oxygen content is needed, such as emphysema. The exact percentage of oxygen delivered to the patient varies with respiratory rate and other factors.