IV Cannula Insertion: Uses and Sizes Chart, Parts, Mnemonic

The IV Cannula Insertion is one important clinical procedure that requires skills and practice. But you can always get some tips and info from sources.

With the below guide, you will learn what is Intravenous or IV Cannula Insertion Procedure, its Types, Sizes, Color coding, Parts, and Uses. We will also uncover IV Cannula- Uses, Common Vein Sites, Indications, Flow Rate, Fixator, and some mnemonics for IV Cannula Sizes.


Intravenous Cannula Insertion is a procedure of inserting an IV cannula into the vein to provide easy access to the vein and hence reduce IV injection repetitions.


A list of IV Cannula uses include:

  1. IV fluid administration
  2. IV medications administration
  3. IV chemotherapy administration
  4. IV nutritional support
  5. IV blood or blood products (FFP, PCC) administration
  6. Administration of contrasts agents for radiological investigations like CT and MRI
  7. Prepare for timely administration of emergency drugs in conditions like Atrial fibrillation, DVT, and Pulmonary Embolism, etc.

IV Cannula Sizes

There are seven IV Cannula Sizes available. The color coding is done according to gauge sizes and the size according to age. Also, we have provided the respective flow rates. These are as follows:

Colour Gauge Size Water Flow Rate (mL/min) Recommended Uses
Orange 14G 240 mL/min Trauma, Rapid blood transfusion, Surgery
Grey 16G 180 mL/min Rapid fluid replacement, Trauma, Rapid blood transfusion
Green 18G 90 mL/min Rapid fluid replacement, Trauma, Rapid blood transfusion
Pink 20G 60 mL/min Most infusions, Trauma, Rapid fluid replacement, Trauma, and Routine blood transfusions
Blue 22G 36 mL/min Most infusions, Neonates, Pediatrics, Older patients, Routine blood transfusions
Yellow 24G 20 mL/min Most infusions, Neonates, Pediatrics, Older patients, Routine blood transfusions, Neonate or Pediatric blood transfusions
Purple 26G 13 mL/min Pediatric, Neonates
IV Cannula Sizes and Uses with Flow Rate and Gauge Size

IV Cannula Color Coding Mnemonic

You will love the mnemonic we have come up with:

IV Cannula Size and Color Coding Mnemonic
IV Cannula Mnemonic

Interpretation- Imagine a Child with Pink Tee and Blue jeans holding an Indian flag. He is also wearing yellow socks and purple shoes. (Oddly fashioned kid these days)

Notable points:

  • IV Cannula Size for Child (Pediatrics)- 22G, 24G, 26G
  • For Old age- 22G, 24G
  • The pink cannula is 20G with a 60 mL/min flow rate
  • The yellow cannula is 24G with a 20 mL/min flow rate


Names of Standard IV Cannula Parts are as follows:

  1. Bevel
  2. Needle
  3. Catheter
  4. Bushing
  5. Injection port cap
  6. Valve
  7. Wings
  8. Luer connector
  9. Needle grip
  10. Flashback chamber
  11. Luer lock plug
IV Cannula Parts
IV Cannula Parts

On the other hand, Three Way Cannula has different parts names. These are as follows:

  1. Three Way Stop Cock (made of medical grade PVC and 360-degree smooth tap rotation) (Arrows on the top indicate the direction of the flow)
  2. Two Female Luer Lock part
  3. Male Luer Lock part


The IV Cannula Procedure involves the following steps:

How to Insert IV Cannula IV?

Total Time: 3 minutes

Introduction with patient

Introduce yourself to the patient and ask for his consent to perform the Intravenous Cannula Insertion. Usually, this is avoided in hospitals but it is an important step.

Preparing the equipment

The equipment required for IV Cannulation should be ready. The equipment required for iv cannula insertion includes:
1. Hand sanitizer
2. Gloves
3. Cotton
4. Disposable tourniquet
5. IV cannula
6. Suitable plaster
7. Syringe
8. Normal Saline

Washing Hands

Wash your hands with hand sanitizer.

Identifying Vein Site for IV Cannula Insertion

Identify the vein in which the venous cannula is to be inserted. The preferable site includes the median vein in the arm.

Securing Vein

Apply the tourniquet above the insertion point and make sure it is tight but make sure it is comfortable for the patient.

Cleaning skin for IV Cannula Procedure

Wear gloves and clean the patient’s skin.

Preparing Cannula

Prepare the cannula for insertion and avoid touching it.

Informing the patient

Stretch the skin distally and tell the patient to expect a sharp scratch.

Inserting Needle

Insert the needle, and bevel upwards at about 30 degrees. Advance the needle until you observe blood at the back of the cannula.

Progressing IV Cannula

Once blood appears, progress the entire cannula a further 2mm, and then fix the needle, advancing the rest of the cannula into the vein.

Releasing Pressure

Release the tourniquet, apply pressure to the vein at the tip of the cannula and remove the needle fully. Remove the cap from the needle and put this on the end of the cannula.

Disposing of Needle Correctly

Dispose of the needle used to ensure clinical safety. This should be done according to the specific guidelines for the individual hospital.

Dressing over cannula

Apply the dressing to the cannula to fix it in place.


Fill the syringe with saline and flush it through the cannula to check for patency. If there is any resistance, if it causes any pain, or if you notice any localized tissue swelling; immediately stop flushing, remove the cannula and start again.

Disposing of

Dispose of your gloves and equipment in the clinical waste bin. Again, this is done according to hospital norms.

Still confused? Watch a video here:

Common Veins Sites

Sites for Intravenous cannula insertion include common veins for IV cannula- Cephalic vein, Basilica vein, Median vein, and Metacarpal veins.

Common sites of veins for Intravenous Cannulation
Common sites of veins for Intravenous Cannulation

While the Median vein remains the choice of the vein, each vein has its advantages and disadvantages.

These are as follows:

1. Cephalic vein


  • Readily receives a large cannula and is therefore a  good site for blood administration.
  • Splinted by the forearm bones
  • The cannula is easily secured


  • Can be more difficult to cannulate than the metacarpal veins.
  • May be confused with an aberrant radial artery.

2. Basilic vein


  • A large vein that is frequently overlooked while searching for other veins.


  • Requires awkward positioning of the limb to gain access to the vein.
  • The vein tends to roll away when you attempt to cannulate it.
  • Site prone to phlebitis.
  • The cannula port gets caught on sheets.

3. Median vein


  • Large veins and so they will readily accept a large cannula.
  • Do not “shut down” as quickly as the more peripheral veins.
  • First choice in an emergency.


  • Can be very positional due to elbow flexion/extension.
  • Can be very uncomfortable for the patient due to elbow flexion/extension.
  • Care must be taken not to cannulate the brachial artery.

4. Metacarpal veins


  • Easy to see and palpate veins.
  • Splinted by metacarpal bones
  • Allows use of more proximal veins in the same limb should the cannula need to be re-sited.
  • The cannula is easily accessible in the theatre environment.


  • Active patients may dislodge easily.
  • The dressing may be compromised by hand-washing.
  • May be more difficult if the skin is thin and friable.
  • Flow can be affected by wrist flexion or extension i.e. A POSITIONAL VENFLON.


There is no absolute contraindication for Intravenous cannula insertion, but some key points may always be recalled:

  1. When peripheral venous access is an injured, infected, or burned extremity, Cannulation should be avoided if possible.
  2. Some vesicant and irritant solutions (pH < 5, pH >9, or osmolarity >600m Osm/L) can cause blistering and tissue necrosis if they leak into the tissue, including sclerosing solutions, some chemotherapeutic agents, and vasopressors. These solutions are more safely infused into a central vein. They should only be given through a peripheral vein in emergencies or when central venous access is not readily available.


  1. Hematoma: a collection of blood, which can result from failure to puncture the vein when the cannula is inserted or when the cannula is removed. Selection of an appropriate vein and gently applying pressure slightly above the insertion point on the removal of the cannula may prevent this.
  2. Infiltration: when the infusate enters the subcutaneous tissue instead of the vein. To prevent this, a cannula with accurate trim distances may be used. It is essential to fix the cannula in place firmly.
  3. Embolism: this can be caused by air, a thrombus, or a fragment of a catheter breaking off and entering the venous system. It can cause a pulmonary embolism. Air emboli can be avoided by making sure that there is no air in the system. A thromboembolism can be avoided by using a smaller cannula.
  4. Phlebitis: an inflammation of the vein resulting from mechanical or chemical irritation or infection. Phlebitis can be avoided by carefully choosing the site for cannulation and by checking the type of infusate used.

IV Cannula Fixator

The IV Cannula fixator is available in two forms- Transparent and Dynaplast-like forms (such as Easyfix). These fixators hold the cannula firmly to the skin and prevent leakage or accidental removal.

IV Cannula Fixator Types
IV Cannula Fixator Types

Bonus tips

  1. Always apply the tourniquet first. This makes the vein show up easily.
  2. With patients having cold arms or arms at room temperature, veins do not tend to show up easily.
  3. Wrist sites are highly prone to infiltration, pain, and positional flowing of the IV solution. Select something mid-arm or in the hand for the best results, and always start distal and work your way proximal unless there is a clinical reason for a larger vein.
  4. If you need information on when an IV cannula is removed, you can check it out here.

But the best learning comes with practice, so go and try it out. Hope you enjoyed our post on IV Cannula Sizes and Color Guide. Please note these notes are exclusively made for PLAB 1 exam but can be used by nurses and doctors preparing for other exams also.

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