Cannula

Diagram showing a cannula CRUK 058-multilingual1

Venflon intravenous cannula 2

Cannula A

Nasal cannula

Air sensitive cannula - syringe valve 1

Cannula refers to a thin tube inserted into the body to deliver or remove fluids or for other therapeutic purposes. It is a versatile medical device used in various medical procedures, including intravenous therapy, oxygen therapy, and certain surgical interventions. Cannulas are made from different materials such as plastic, metal, and silicone, depending on their specific application.

Types of Cannulas

There are several types of cannulas, each designed for specific uses:

• Intravenous Cannula: Used for administering medications, fluids, and for blood sampling. It is inserted into a vein, usually in the arm or hand.
• Nasal Cannula: A device used to deliver supplemental oxygen or increased airflow to a patient in need of respiratory help. It consists of a lightweight tube which on one end splits into two prongs which are placed in the nostrils and from which a mixture of air and oxygen flows.
• Arterial Cannula: Used in major surgeries for arterial blood sampling and blood pressure monitoring.
• Central Venous Cannula: Inserted into a central vein, commonly the internal jugular, subclavian, or femoral veins, used for administering medication or fluids, obtaining blood tests, and directly measuring central venous pressure.
• Surgical Cannula: Used in various surgical procedures to access cavities, as in liposuction or laparoscopic surgery.

Applications

Cannulas play a crucial role in medical treatments and procedures. Their applications include:

• Delivering or removing fluids from the body.
• Administering medications, such as during chemotherapy or pain management.
• Facilitating oxygen therapy in patients with respiratory conditions.
• Assisting in surgical procedures by providing access to body cavities.
• Enabling blood transfusions and blood sampling.

Insertion and Use

The insertion of a cannula involves a sterile technique to prevent infection. The process varies depending on the type of cannula and its intended use. For example, inserting an intravenous cannula involves selecting an appropriate vein, using a needle to puncture the skin and vein, and then threading the cannula into the vein. Once in place, the needle is removed, leaving the cannula to provide ongoing access to the vein.

Risks and Complications

While cannulas are essential tools in medical care, their use is not without risks. Potential complications include:

• Infection at the insertion site.
• Phlebitis, or inflammation of the vein.
• Hematoma, or a collection of blood outside the blood vessels.
• Air embolism, if air enters the veins.
• Thrombosis, or blood clots.

Proper care and maintenance of the cannula site are crucial to minimizing these risks.

Conclusion

Cannulas are indispensable in the medical field, offering a means to administer treatments, conduct surgeries, and manage patient care more effectively. Their versatility and wide range of applications make them a cornerstone of modern medicine.