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What Is A Cannula: Different Types, Placement & More

What Is A Cannula: Different Types, Placement & More

Apria Editorial |

Cannulas are one of the most commonly used pieces of medical equipment used today.

In celebration of this incredible innovation, we've composed this helpful guide. Learn everything there is to know about the cannula, from different cannula types to placement & more, with ApriaHome.

Although IV treatment as we know it has only been around for about a century, the technique of injecting fluids into a vein dates back to the 1600s.

However, early efforts to provide medications and fluids via intravenous lines were often ineffective because they lacked comprehensive scientific knowledge and understanding of the human body.

There was a major shift in how doctors and nurses administered intravenous treatment to treat their patients and save lives as a direct result of the devastation of both world wars. Despite the fact that the fundamentals have been used for quite some time, the most major advancements in IV treatment equipment, medications, and implementations have just taken place within the past quarter of a century.

Cannulas are one of the most commonly used pieces of medical equipment used today. This technology also paved the way for non-invasive at home oxygen therapy as well as IV treatments. In celebration of this incredible innovation, we've composed this helpful guide. Learn everything there is to know about the cannula, from different cannula types to placement and more, with ApriaHome.

What Is A Cannula?

Cannulas (Latin for "small reed") are tubes that are inserted into the body to distribute or remove fluids, collect samples, or perform other medical procedures.

A cannula is placed around a trocar needle's inner or outer surfaces to increase the functional needle length. Cannulas are typically 14-24 gauge in size, and tubes of varying sizes are generally color-coded for identification.

Once a physician considers that a cannula is no longer necessary for breathing, the cannula is removed permanently (extubation) in a process known as decannulation.

How Cannulation Works

Cannulas are inserted into a body cavity using a needle that punctures a vein or blood artery. After the needle is removed, the cannula is kept in place for easy access to extract or inject something into the vessel.

What Is A Cannula Used For?

A cannula is a small tube inserted into a vein or other body cavity (such as the nose) either to withdraw or provide medication or fluids. Cannulas are used by medical professionals for a variety of procedures, including fluid drainage, medicine administration, collecting blood samples, and oxygen delivery.

What Are The Two Main Types Of Cannula?

The choice of cannula depends on the procedure and the patient's tolerance for pain. There are two main types of cannula:

IV Cannula

During IV cannulation, medical practitioners insert IV cannulas, which are tiny, flexible tubes, into veins to provide medication and other forms of therapy and preventive care. Once the cannula has been inserted into a vein, medical practitioners can administer infusions of medication, fluids, or even blood.

The three varieties of standard IV cannulas include:

  • Peripheral IV Cannula: The peripheral intravenous (IV) cannula is the most common kind of IV cannula and is adhered to the skin using adhesive tape after being connected to an IV catheter. This treatment is mostly used for those undergoing surgery, those in need of urgent care, and those undergoing radiological imaging procedures. The maximum length of time that these intravenous lines are in use is four days before replacement.
  • Central Line IV Cannula: The central line IV cannula is used to provide fluids and medications over the course of weeks or months to patients receiving long-term therapy. They facilitate the quick distribution of medicines for immediate reactions. They are also useful for administering large volumes of fluid to a patient, e.g. blood, emergency rehydration, or plasma.
  • Midline catheters: Midline catheters are the best choice for patients whose treatment will take more than five days but less than a month. This is considered a less invasive technique and is used most frequently in hospital settings.

    IV Cannula Sizes And Flow Rates

    Different styles of cannulas are available in a variety of colors and sizes for a wide range of applications.

    NB: The cannula number drops as the cannula diameter grows. A lower gauge will allow for faster flow than one with a higher gauge.

    The "G" in cannula size denotes the term "Birmingham gauge".

    The diameter of different IV cannulas varies, and the color they are allocated indicates their function. IV cannula diameters typically vary from 14 to 24 gauge. The size is determined by the patient's health, the anticipated usage of the IV cannula, and the urgency of the fluid or oxygen supply.

    The following are descriptions of various cannula diameters, flow rates, colors, and applications:

    14G Cannula Size

    • Color: Orange
    • Flow rates for blood 10.3l/hr
    • Flow rates for plasma are 16.2l/hr
    • Flow rates for crystalloid fluids are 10.3l/hr
    • Application: Fluid replenishment, operations, blood transfusion, and trauma situations.

      16G Cannula Size

      • Color: Grey
      • Flow rates for blood 7.1l/hr
      • Flow rates for plasma are 10.8l/hr
      • Flow rates for crystalloid fluids are 7.1l/hr
      • Applications: IV fluid replenishment, surgery (when immediate results are necessary), and blood transfusion.

        18G Cannula Size

        • Color: Green
        • Flow rates for blood 2.7l/hr
        • Flow rates for plasma are 4.8l/hr
        • Flow rates for crystalloid fluids are 2.7l/hr
        • Applications: Trauma situations, blood transfusions, large fluid volumes, major operations, stem cell harvesting, fluid replenishment, and parenteral nourishment.

          20G Cannula Size

          • Color: Pink
          • Flow rates for blood 1.9l/hr
          • Flow rates for plasma are 3.2l/hr
          • Flow rates for crystalloid fluids2.9l/hr
          • Applications: Blood and IV fluids transfusions.

            22G Cannula Size

            • Color: Blue
            • Flow rates for blood 1.1l/hr
            • Flow rates for plasma are 1.9l/hr
            • Flow rates for crystalloid fluids 1.1l/hr
            • Applications: Fluids and blood infusions through smaller veins. Safe for use for use in elderly, pediatric & cancer patients.

              24G Cannula Size

              • Color: Yellow
              • Flow rates for blood 20ml / minute
              • Applications: Treatment for newborns and young children.

                Nasal Cannula

                If your oxygen levels are low, a medical professional may recommend using a nasal cannula to provide oxygen treatment. Nasal cannulas are available in either low flow or high flow.

                Flexible tubing is used to create nasal cannulas, which are inserted into the nostrils to provide oxygen. The two-pronged apparatus is worn on a cushion just below the nostrils.

                Nasal Cannula Sizes And Flow Rates

                Nasal cannulas may be found in various nasal cannulas sizes and nasal cannulas types, each with its unique airflow capacity. Unlike intravenous cannulas, which only exist in a certain number of sizes, nasal cannulas come in sizes designated for use on adults, children, and infants.

                A standard nasal cannula can deliver 4-6 l/min of oxygen. High-flow nasal cannula treatment, on the other hand, may provide as much as 60 l/min of oxygen.

                Cannula Insertion

                The insertion of IV cannulae will only be performed by registered nurses with experience and appropriate training. Nasal cannulas provide the potential for safe at-home use with proper guidance.

                How To Insert On A IV Cannula?

                Ensure that all equipment is in order before proceeding Equipment list:

                • Alcohol wipe
                • Antiseptic gel/rub
                • Blood sample tubes
                • Cannula
                • Connectors/adapters
                • Couch or chair for the patient
                • Disposable gloves
                • Gauze swabs
                • Giving set
                • IV stand
                • Intravenous solution
                • Medical waste bin
                • Orange plastic disposable bag
                • Semi-occlusive or transparent dressing
                • Sterile sodium chloride for flush
                • Syringe for saline flush
                • Tape to secure the cannula
                • Tourniquet
                • Trolley/tray
                • Vacutainer shield


                  • The designated staff member must verify the correct participant is identified. Names, birthdates, last names, research study names and numbers, and, if applicable, hospital identification numbers must all be verified (CHI - Community Health Index).
                  • Explain the method to the patient and obtain verbal/informed consent to initiate the procedure.
                  • Before placing the intravenous cannula, ensure you have all the necessary tools and paperwork. Local infection control protocols should be followed while sanitizing the work trolley.
                  • Be sure to double-check the dates on all of your supplies and machinery.
                  • Make sure the patient is lying down, and keep an eye on them during the treatment to look for signs of fainting, such as pale complexion ness excessive perspiration.
                  • Locate an IV access point, preferably in a vein of a non-dominant upper limb, away from any joints. NB: Vein health is important; the vein should be visible and in good condition whenever possible.
                  • Choose a cannula that is suitable for the intended procedure, expected period of usage, and patient's age.
                  • If the patient's arm needs assistance, ensure they have it and are comfortable.
                  • Observe the principles of antisepsis during the whole operation.
                  • Use an alcohol rub or gel to clean your hands according to your facility's hand hygiene policy before beginning the procedure.
                  • Use an alcohol swab or other skin preparation to clean the area, then let it air dry before continuing.
                  • Place the tourniquet above where you want to insert the needle. Do not apply the tourniquet for more than 1 minute. Tourniquets should be used only on one patient at a time to prevent the spread of infection.
                  • Warn the patient that they can expect to feel a sharp pinching feeling.
                  • Stabilizing the vein requires anchoring it by exerting physical tension on the skin a few centimeters below the planned cannulation location. Insert the needle attached to the cannula into the vein. Ensure the angle of the cannula is pointing upwards.
                  • NB: The presence of swelling, hematoma, discomfort, or resistance may indicate a rupture of the vein wall. As soon as the cannula and needle are withdrawn, the tourniquet may be loosened, and cotton wool can be used to provide pressure.
                  • The cannula should be advanced over the needle and into the vein as soon as the blood is seen in the flashback chamber.
                  • Withdraw the needle slightly, and you will observe a second flashback of blood down the shaft of the cannula.
                  • Maintain skin traction while slowly moving the cannula of the needle into the vein with the dominant hand.

                    How To Put On A Nasal Cannula?

                    First, check that the cannula is the right size. Then, pick a cannula that rests comfortably in your nose and doesn't extend too deep.

                    • Connect the tip connection to your oxygen supply. A connection on one end of the nasal cannula connects to your oxygen concentrator. Ensure to insert it securely so that there is no oxygen leaking.
                    • Modify the quantity of oxygen. Your doctor will recommend the best flow for you. Adjust the quantity of oxygen according to the flow rate.
                    • Insert the cannula into your nasal passage. The curved tip makes them suitable for use in the nasal passages. Insert the tips upwards into your nostrils. Place the tubes over your ear and secure the cannula as far as it will comfortably go.

                      Frequently Asked Questions Regarding Cannulation

                      Are IV cannulas painful?

                      You can expect to feel some discomfort or a slight pinch when an IV cannula is inserted. However, the cannula should not cause any discomfort thereafter. If you are experiencing pain, alert your medical team at once.

                      How to clean a nasal cannula?

                      Rinse the cannula/mask in a mix of 10 parts water to 1 part vinegar after washing it in warm, soapy water. Vinegar will eliminate the bacteria while leaving the plastic tubing unaffected. Finally, rinse thoroughly in hot water and hang it up to dry.

                      How to keep a nasal cannula in place while sleeping?

                      Raise the slider to fit the tubes higher and tighter on your cheeks. This reduces movement and excess friction on the tubing. You can also make sure the tubes don't slide around too much by taping them firmly behind your ears using fabric medical tape.

                      Bridging Gaps Between Hospital & Home Treatment Solutions

                      More than two million patients rely on ApriaHome each year for home medical equipment and clinical care. Offering a wide variety of IV and nasal cannulation products and related services, ApriaHome has become a top supplier of home healthcare in the United States over its 275 branches.

                      Our mission is to be the best supplier of home healthcare treatments requiring high-touch service while also bridging the gap between hospital-grade and at-home treatment solutions. This gives patients and carers access to care and services while lowering overall treatment costs.

                      ApriaHome presents a compelling value proposition to patients, service providers, and carers alike.

                      Looking for cannulation solutions for your treatment facility or at-home oxygen therapy? You've come to the right place! We source and supply the best nasal cannula therapy treatment solutions from around the world, all from the convenience of our online portal.

                      Here are our top recommendations in terms of quality, affordability, and ease of use.

                        Looking for advice? Our helpful agents are on call at (800) 780-1508 between 8:00 am - 10:00 pm EST Daily. Get in touch today.


                        LEGAL DISCLAIMER: Material in this newsletter is only: (1) provided for general health education and informational purposes, and to provide references to other resources; it may not apply to you as an individual. While Apria believes that the information provided through this communication is accurate and reliable, Apria cannot and does not make any such guarantee. It is not intended to be a replacement for professional medical advice, evaluation, diagnosis, services or treatment (collectively, "medical treatment"). Please see your healthcare provider for medical treatment related to you and your specific health condition(s). Never disregard medical advice or delay seeking medical care because of something you have read on or accessed through this website. Reading this newsletter should not be construed to mean that you have a healthcare provider/patient relationship with Apria.