Intravenous Cannula Insertion | IV Cannulation: Common Veins Sites

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Intravenous 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 (IV) Cannula Insertion, Indications, Procedure, Common vein sites for cannula insertion, When to avoid it, Complications and some bonus tips.


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


  1. Repeated blood sampling
  2. Intravenous fluid administration
  3. Intravenous medications administration
  4. Intravenous chemotherapy administration
  5. Intravenous nutritional support
  6. Intravenous blood or blood products administration
  7. Intravenous administration of radiological contrast agents for computed tomography, magnetic resonance imaging, or nuclear imaging


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The procedure involves the following steps:

A. 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.

B. Prepare the equipment

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The equipment required for IV Cannulation should be ready. The equipment required for iv cannula insertion include:

  1. Hand sanitizer
  2. Gloves
  3. Cotton
  4. Disposable tourniquet
  5. IV cannula
  6. Suitable plaster
  7. Syringe
  8. Saline

C. Wash your hands with a hand sanitizer.

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

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E. Click Sites of Intravenous Cannula Insertion to know more about sites of choice for IV cannula insertion.

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

G. Wear the gloves and clean the patient’s skin.

H. Prepare the cannula for insertion and avoid touching it.

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

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

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

L. 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.

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M. Dispose off the needle used to ensure clinical safety.

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

O. 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 you notice any localized tissue swelling; immediately stop flushing, remove the cannula and start again.

P. Dispose off your gloves and equipment in the clinical waste bin.

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 Median vein remains the choice of vein, each vein has its own 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
  • 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.
  • 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 emergency situation.


  • 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.
  • Cannula is easily accessible in the theater environment.


  • Active patients may dislodge easily.
  • 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.
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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 emergency situations or when a 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 removal of the cannula may prevent this.
  2. Infiltration: when 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 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. Phelebitis: an inflammation of the vein resulting from mechanical or chemical irritation or from an infection. Phlebitis can be avoided by carefully choosing the site for cannulation and by checking the type of infusate used.

Bonus tips

  1. Always apply tourniquet first. This makes the vein show up easily.
  2. With patient 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.

But the best learning comes with practice, so go and try it out.

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