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.

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Definition

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.

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Uses

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.

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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

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IV Cannula Color Coding Mnemonic

You will love the mnemonic we have come up with:

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

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Parts

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

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

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Procedure

The IV Cannula Procedure involves the following steps:

Still confused? Watch a video here:

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Common Veins Sites

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

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

These are as follows:

1. Cephalic vein

Advantages:

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

Disadvantages:

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

2. Basilic vein

Advantages:

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

Disadvantages:

• 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

Advantages”

• 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.

Disadvantages:

• 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

Advantages:

• 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.

Disadvantages:

• 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.

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Contraindications

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.

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Complications

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.

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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.

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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.

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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.