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What is Cannulation? Types, Techniques, and Importance

Phlebotomy Training Institute
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Cannulation is an important procedure used in different areas of medicine, including surgery, anaesthesia, emergency medicine, and critical care. It involves the insertion of a hollow tube or cannula into a blood vessel or duct to administer medication and fluids or to facilitate monitoring.

In medicine, there are many tools that might seem scary if you don’t know about them. One of these tools is the cannula, which looks simple but is really important.

This blog will explain cannulation in detail, including its types, how it’s done, when it’s used, possible problems, and why it’s important in healthcare today.

Experienced cosmetologist holding medical intravenous cannula for anti-ageing procedure

What is Cannulation?

Cannulation comes from the Latin word “cannula,” which means “little reed.” It’s a medical procedure involving the insertion of a thin, flexible tube or cannula into a blood vessel, duct, or cavity. The main reason for cannulation is to establish access to various medical interventions, including administering medications, fluids, blood products, and contrast agents, as well as for monitoring purposes such as blood sampling and measuring blood pressure.

So, what is a Cannula?

A cannula, in essence, is a thin, flexible tube made of plastic. It’s designed to be inserted into a body cavity or vein to deliver fluids, medication, or even withdraw fluids or blood for analysis. Cannulas come in various sizes, with the appropriate size depending on the purpose and the patient’s anatomy.

Delighted adult female lying on couch and talking over mobile phone while getting skin nutrition via venous cannulation

Benefits of Cannulation

Cannulation offers a multitude of advantages in healthcare:

  • Provides direct access: It allows for a reliable and efficient way to deliver fluids, medications, and oxygen.
  • Minimises discomfort: Compared to repeated injections, cannulas offer a less invasive approach for long-term treatment.
  • Fast and effective: Cannulas enable swift delivery of medication or fluids, which is crucial in emergency situations.
  • Blood sampling: Certain cannulas can be used for drawing blood samples, which ultimately eliminates the need for multiple needle pricks.

Visit our insightful blog to learn the differences between Venipuncture and Cannulation.

The Two Main Types of Cannulation

There are two primary types of cannulation procedures:

  • Intravenous (IV) Cannulation: This is the most common type, where the cannula is inserted into a vein, typically in the arm. This provides a direct route for delivering fluids, medications, and nutrition directly into the bloodstream.
  • Nasal Cannulation: In this procedure, a shorter and softer cannula is inserted into the nostrils to deliver supplemental oxygen. This is often used for patients with respiratory difficulties.

There are some other types of cannulation, too. Let’s check out the following.

  • Central Venous Cannulation: This involves putting a tube into a big vein in the centre of the body, like the internal jugular, subclavian, or femoral vein. It’s used for giving strong medicines, nutrition, or checking the heart’s health.
  • Arterial Cannulation: This is when a tube is placed into an artery, usually in the wrist, upper arm, or groin. It’s mainly used for keeping an eye on blood pressure or taking blood samples for testing.

Visit our informative blog to learn about the importance of the order of draw blood bottles.

Close-up of sick female patient with a nasal cannula

The Process of Cannulation

Inserting a cannula, particularly an IV cannula, is a sterile procedure performed by trained medical professionals. Here’s a simplified breakdown of the process:

  • Preparation: The healthcare provider will explain the procedure and obtain your consent. They will then clean the insertion site and gather the necessary equipment.
  • Insertion: With the aid of a small needle, the cannula is carefully inserted into a vein. Once placement is confirmed, the needle is removed, leaving the cannula in place.
  • Securing the Cannula: The cannula is then secured with a dressing to prevent dislodgement and maintain sterility.

Besides, check out our latest blog post on the 8 sites of Venipuncture.

Indications for Cannulation

Cannulation is indicated in various clinical scenarios, including:

  • Administration of medications, fluids, and blood products.
  • Intravenous access for patients who require frequent blood sampling or continuous medication infusion.
  • Hemodynamic monitoring in critically ill patients.
  • Parenteral nutrition administration.
  • Contrast-enhanced imaging studies.

In addition, visit our latest blog post to get a detailed understanding of the best practices and procedures in Phlebotomy.

Close-up of intravenous drip in the ward at hospital

Complications of Cannulation

Despite its utility, cannulation is associated with potential complications, including:

  • Infection at the cannulation site.
  • Bleeding or hematoma formation.
  • Nerve or vascular injury.
  • Thrombosis or embolism.
  • Catheter-related bloodstream infections.
  • Air embolism.
  • Catheter misplacement.

What Should be Done to Avoid the Above Complications of Cannulation?

To lower the chance of problems with cannulation, healthcare providers should follow these steps:

  • Keep everything clean: Wash hands well and wear clean gloves and equipment to avoid infections.
  • Choose the right spot: Look carefully at the patient’s body to pick the best place for the cannula. Avoid areas that look infected, have lots of scars, or where blood flow might be bad.
  • Be gentle: Handle everything carefully during cannulation to avoid hurting tissues or causing bleeding, bruises, or injury to nerves or blood vessels.
  • Use ultrasound: Consider using ultrasound, especially for central venous or arterial cannulation, to help put the cannula in the right place and lower the risk of accidentally poking an artery or causing bruises.
  • Secure the catheter: Make sure the cannula is firmly in place to prevent it from moving around, which could cause infections or air bubbles in the blood.
  • Keep an eye on things: Check the cannulation spot regularly for any signs of trouble like swelling, redness, or pain. Also, check how well the cannula is working.
  • Prevent blood clots: Take steps to stop blood clots from forming, like rinsing the catheters with special liquids, making sure patients drink enough, and encouraging movement, especially in patients who can’t move much.
  • Train and educate: Make sure everyone who does cannulation is well-trained and knows what they’re doing. Keep teaching them new things and updates to make cannulation safer for patients.

Wrapping Up

In wrapping up, what is cannulation? It’s a crucial medical procedure to insert a tube into a blood vessel. Knowing its types, techniques, and importance is key. With proper care, complications can be minimised, ensuring better patient outcomes. If you’re feeling overwhelmed by learning about cannulation, don’t worry. You should consider getting trained at a recognised institute that teaches all about it. Further, learning how to put a tube into someone’s vein is really important for someone wishing to excel in the healthcare field.

Getting certified from a recognised program, like the CPD-accredited and NHS-accepted one at the Phlebotomy Training Institute, ensures you learn theory and practical skills. This training improves your abilities and confidence in cannulation. It blends hands-on practice with online learning for a complete education.

Before starting cannulation training, ensure you enrol in phlebotomy training first.


1) What are the different types of cannula sizes?

Cannulas come in various sizes (gauges) to accommodate different vein sizes and purposes. Smaller gauges are used for delicate veins or for administering medications, while larger gauges are used for delivering fluids or blood transfusions.

2) Does cannulation hurt?

You might feel a slight prick during insertion, but most discomfort comes from finding the vein. A topical anaesthetic cream can be applied to numb the area beforehand.

3) How long can a cannula stay in place?

The duration depends on the type and purpose of the cannula. IV cannulas typically last 2-3 days, while subcutaneous ones can remain for weeks. A healthcare professional will determine the appropriate placement time.

4) What are the signs of a cannulation infection?

Look for redness, swelling, or pus around the insertion site. Pain, fever, or chills can also indicate infection. If you experience any of these, consult a doctor immediately.

5) Can I shower or bathe with a cannula?

Generally, yes, but it’s crucial to keep the insertion site dry. Cover the area with a waterproof dressing while showering and remove it afterwards to allow the skin to breathe.


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