cannulas

Cannulas are small, flexible tubes designed for placement into a body cavity, vessel, or duct to deliver or remove fluids, gases, or other substances. They are used across medical, veterinary, and laboratory settings for procedures such as oxygen administration, fluid and medication delivery, drainage, irrigation, and sampling. The term encompasses a range of forms, with nasal cannulas and intravenous cannulas being the most common.

Nasal cannulas are positioned at the nostrils to deliver supplemental oxygen or humidified air. They are widely used in acute and chronic care to support patients with respiratory needs. Intravenous (IV) cannulas, also called IV catheters, are inserted into a vein to provide venous access for fluids, medications, or blood draws. They are typically placed in peripheral veins and left in place for ongoing therapy or monitoring. Other cannulas include arterial cannulas for arterial access and monitoring, or specialized cannulas used during anesthesia or surgical procedures for drainage or irrigation.

Materials and sizes vary by purpose. Cannulas are commonly made from flexible polymers such as polyurethane, silicone, or PVC. Diameters and lengths are chosen to fit the application; IV cannulas are often described by gauge or French size, with typical adult ranges around 14 to 18 gauge for standard use. Nasal cannulas are sized more by fit and flow requirements rather than strict gauge.

Insertion and care emphasize aseptic technique and patient safety. IV cannulation involves puncturing a vein with a needle, advancing a catheter, and withdrawing the needle before securing the catheter. Proper fixation, monitoring for infiltration or infection, and timely removal when therapy ends are essential. Nasal cannulas require careful positioning to avoid skin irritation and displacement, with ongoing monitoring of oxygenation and comfort. Potential risks include infection, phlebitis, infiltration, and accidental dislodgement.