What is a Cannula?


A cannula is a small, thin tube that can be inserted into the body to deliver or remove fluids or gases. Cannulas are usually made from plastic, latex or silicone and come in various sizes depending on their intended use. Some key facts about cannulas:

– Cannulas enter the body through skin or mucous membranes and are designed to cause minimal damage or discomfort during insertion and use.

– Common uses of cannulas include infusion of intravenous fluids, drawing blood samples, delivering anesthesia or medications, performing dialysis and cardiopulmonary support.

– Sites where cannulas are commonly inserted include veins in the arm, hand or foot for IV access, arteries for monitoring blood pressure or drawing blood gases, nasal passages and veins under the skin.

– Cannulas have multiple channels running down their length – one channel is used for inserting or removing fluids/gases while others allow the surrounding skin or tissues to remain intact.

Types of Cannulas

There are different types of cannulas used for specific purposes:

Intravenous Cannulas

Intravenous or IV cannulas are the most common type used to deliver fluids, medications, blood products and nutrients directly into a vein. IV cannulas come in small gauge sizes ranging from 24-14 and are inserted into peripheral veins in the arms or hands. Larger cannulas may be used for central line access into major veins near the heart.

Arterial Cannulas

Used to monitor blood pressure, draw arterial blood gases or deliver medications directly into an artery. As arteries are deeper and under higher pressure, arterial cannulas have refinements like side holes, steering capabilities and introducer sheaths for smooth insertion. The radial, femoral and axillary arteries are common sites.

Nasal Cannulas

Deliver supplemental oxygen via small prongs that are gently inserted just inside the nostrils. Nasal cannulas are a noninvasive oxygen delivery method commonly used for respiratory conditions, in post-surgery recovery and during anesthesia.

Dialysis Cannulas

Large gauge dual lumen cannulas are essential for hemodialysis procedures to remove waste from the blood and return purified blood back to the body. Arteriovenous fistulae or grafts in the arm are used as sites.

Chest Drainage Cannulas

Akin to nasal cannulas but much wider, chest drainage cannulas have multiple side holes and are used to drain fluid from the lung cavities or pleural space after surgery or in conditions like pneumothorax.

Epidural and Spinal Cannulas

Very thin, pencil point cannulas are carefully threaded between vertebrae to puncture the epidural or subarachnoid space and deliver anesthesia or medications directly to the spinal fluid and nerves.

Proper Cannula Selection and Insertion

When choosing a cannula, medical professionals consider several factors like:

– Patient’s condition, age, vessel/site anatomy

– Intended purpose – whether for brief or prolonged infusion, potential medication incompatibility, high or low flow rates

– Nurse or physician experience with cannula type

Proper cannula selection is important to minimize risks like inadvertent arterial puncture, nerve injury, infiltration or dislodgement. Standard insertion procedure involves:

– Sterile setup and site preparation using antiseptics

– Stabilization of vessel/site and choice of optimal entry point

– Gradual insertion at 30 degree angle, usually guided by flashback of blood into hub

– Securement of cannula with sterile dressings

– Patency checks and maintenance throughout use

Potential Complications

While cannulation is a routine procedure, some potential though unlikely complications include:

– Bleeding, hematoma or hematoma at insertion site

– Infiltration or leakage of fluids into surrounding tissue

– Air embolism if inserted into artery instead of vein

– Nerve or organ injury from improper placement

– Cannula kinking, blockage or accidental dislodgement

– Line infections like sepsis if aseptic protocols are breached

– Thrombosis or blood clots forming around cannula stem

To minimize risks, cannulas should be inserted by trained professionals, regularly monitored for securement and patency, and promptly removed as soon as their intended use is over. Following correct cannula selection, insertion technique and care guidelines is key for safe intravenous access.


In summary, cannulas are an invaluable medical device that allow administration of lifesaving interventions non-invasively. From simple IV therapy to sophisticated organ support, cannulas have revolutionized modern medicine. With proper selection, insertion technique and meticulous care, cannulas can benefit patients greatly while representing a very low complication risk. As new designs and materials are developed, cannulas will continue enabling frontline healthcare worldwide.


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

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