April 13, 2024

Cannula: Essential Medical Device for Delivering and Draining Body Fluids

What is a Cannula?
A cannula is a small, thin tube made from plastic, metal or silicone that is inserted into the body to deliver or drain fluids. The term “cannula” comes from Latin meaning “little reed”. Cannulas are widely used in medical procedures for a variety of purposes.

Uses of Cannulas
Cannulas have numerous uses in different medical procedures and treatments. Some of the main uses of cannulas include:

Intravenous Cannulation
One of the most common uses of cannulas is for intravenous (IV) therapy. IV cannulas are inserted into veins to deliver fluids, medications and blood products directly into the circulatory system. IV cannulas allow for quick delivery of substances that can treat conditions or save lives in emergency situations.

Arterial Cannulation
Arterial cannulas are used to monitor blood pressure and collect blood samples from arteries. They help doctors closely observe a patient’s blood pressure, oxygen levels and other indicators of their condition. Arterial lines using cannulas are commonly placed in surgery or intensive care settings.

Dialysis Cannulation
For patients with kidney failure, cannulas are used to access blood vessels for hemodialysis. Two cannulas are inserted, one for removing blood to be cleansed and another for returning now-filtered blood back to the body. This allows for an artificial filtering process external to the body.

Drainage and Decompression
Drainage cannulas help remove fluids that have accumulated in body cavities. Common places drainage cannulas are inserted include the chest, abdomen and joints. They decompress pressure and drain out blood, pus, urine or other liquids.

Central Venous Cannulation
Larger cannulas are placed into major central veins for long-term IV access, administration of concentrated substances or parenteral nutrition. Central lines using cannulas remain in for weeks or months at a time for patients with serious conditions.

Types of Cannulas
Cannulas come in different shapes, sizes and materials depending on the specific medical application and site of insertion:

Intravenous Cannulas: Narrow and flexible tubes that are usually less than 1 mm in diameter. IV cannulas are designed for easy insertion into veins.

Arterial Cannulas: Slightly stiffer tubes often used with an integrated pressure monitoring system. Sizes range around 20-24 gauge.

Drainage Cannulas: Have side holes or slits for drainage and wider lumens to allow fluid outflow. Drainage cannulas come in varying diameters.

Central Venous Cannulas: Larger tubes up to 14 or 16 gauge for long-term central access and administration of medications like chemotherapy.

Dialysis Cannulas: Come with two parallel cannulas fused into one assembly for hemodialysis. Tend to be thicker at around 12-14 gauge.

insertion is Performed
Correct insertion of cannulas is crucial for intended function and patient safety. Some general steps involved:

1. Preparation includes selecting the right size cannula, cleaning the insertion site, applying local anesthesia if needed.

2. Stabilizing the vein by applying tourniquet or manual pressure above insertion area.

3. Making a small puncture wound with needle into vein through which the cannula is slid.

4. Advancement of cannula into vessel while holding needle steady.

5. Removal of needle, leaving cannula successfully placed in vessel.

6. Securing cannula with sterile dressings and sometimes stabilization device.

7. Connecting cannula to intended medical tubing/equipment as needed.

8. Monitoring insertion site for complications and proper cannula function.

Precautions with Cannula Use
While cannulas provide important clinical access, certain precautions must be followed with their use:

– Sterile technique is vital to prevent infection risks from insertion or during use.

– Securing dressings properly limits motion that could lead to dislodgment or damage.

– Monitoring for signs of infiltration where fluid leaks into surrounding tissue.

– Being aware of possibilities like air embolism if improperly placed into artery rather than vein.

– Care in handling and dressing changes to avoid accidental removal of securely positioned cannula.

– Limiting duration of indwelling cannulas to avoid complications of long-term foreign body presence.

In summary, cannulas are indispensable yet minimally invasive medical devices that allow vital fluid administration, drainage and monitoring when properly inserted and cared for. With suitable precautions, they provide clinical benefits for numerous applications across healthcare settings.


  1. Source: Coherent Market Insights, Public sources, Desk research

2. We have leveraged AI tools to mine information and compile it