Cannula – Low-flow Oxygen Delivery (Nursing)

by Rhonda Lawes, PhD, RN

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    00:00 Hi, welcome to our video series on Respiratory. Now, we're going to look at this one on low-flow oxygen delivery. So we're going to walk through what every nurse should know about nasal cannula, simple face masks and reservoir masks. These are all examples of low-flow oxygen delivery. Now, we're going to talk about nasal cannula because that 's normally where a patient start when they first need oxygen. So it's low-flow, meaning it's not being delivered at a rate that's any higher than the patient's inspiratory needs. So, you've got oxygen concentration of approximately 24%-40%. Now, take a look at the graphic. We've got 4 examples there for you of nasal cannula. You can see other different sizes. That's because there are different-sized noses. So make sure you get one that's not too big or too small for your patient. Now the flow rates will be 1-6 liters a minute. That's really important. These aren't just numbers that need to fly by, make sure you help reinforce those in your mind.

    01:05 1-6 liters a minute is about what we'll use for nasal cannula. Now, how do you know how many liters a minute a patient is on? Or how do you adjust the liters per minute? There's a flow meter that we either be attached to a portable oxygen tank or more often in a hospital setting right into the wall. Remember there's a knob that you turn and there's a little black ball that floats. Now that little black ball floats up and down, you're looking for the middle of the ball to be lined up with one of the numbers on the gauge. That will tell you how many liters per minute your patient is receiving of oxygen. Now with every liter that you go up or you increase delivered to the patient, the FiO₂ will increase about 4%. Remember, room air starts at approximately 21%. You can't take that specifically or precisely but is a good rule of thumb.

    01:59 Now we have specialty cannulas. These are pretty cool. They are not that expensive than what a regular nasal cannula is, but they can measure end-tidal CO₂ and that gives us some really specific information about patients. Most cannulas, just regular nasal cannulas that deliver oxygen, but we do have specialty cannulas that measure end-tidal CO₂. Okay, so with the low-flow, we've put this chart in here just to kind of make it easier for you to remember.

    02:30 Remember it's approximate FiO₂. Every increase 1 liter equates to about 4% increase in FiO₂.

    02:38 So starting from about 24%, this gives you a safe estimate if you are kind of approximate.

    02:43 Hey, what percentage of FiO₂ is this patient on if they're on 4 liters? Right, about 36%. What about 6 liters? About 44-ish percent. The actual FiO₂ with nasal delivered oxygen really depends on some other variables. Mostly the patient's breathing rate, they're tidal volume.

    03:05 So when we say tidal volume that's how big a breath or small a breath they're taking. The amount of room air they're inhaling through their mouth, through their nose and mixing with it, that's why it's a rule of thumb not an exact science but this is a good estimate. So this chart or table is a good one to keep in mind or in the back of your mind when you're working with patients on nasal cannula. Now, it does matter how you place the cannula. So let's walk through 3 to 4 quick steps on how you do that. You want to turn the nasal cannula so the prongs are turned or curved downward in the patient's nose where the air would naturally flow. So see those green arrows that go in there? At first I thought "Wow, that patient's like drippin' snot but those are arrows so that will help you remember. Turn the cannula to the prongs or turn it or curve downward in the patient's nose the way air would naturally flow.

    03:59 So you want to gently put the cannula in the nostrils, make sure it's not too big or too small because you want it to be appropriate for the patient's size. Now, gently lift the tubes and place them over the patient's ears. Now if a patient has to be on oxygen for very long, these can, believe it or not, become very uncomfortable where that tubing puts pressure on the ear.

    04:22 So if that becomes irritating for the patient or I just like to do it even before it comes irritated, you want to wrap that tubing with some fabric or foam tape to help decrease that friction. Now some fancy cannulas already come with some special holders so you can put over the tubing where it touches the patient's ears. But if not, roll a foam tape always works great but I really would encourage you don't wait until the patient is uncomfortable. Start before the skin breakdown starts to show up. That will keep your patient much happier.

    About the Lecture

    The lecture Cannula – Low-flow Oxygen Delivery (Nursing) by Rhonda Lawes, PhD, RN is from the course Supplemental Oxygen (Nursing).

    Included Quiz Questions

    1. 4%
    2. 10%
    3. 1%
    4. 7.5%
    1. Turn the cannula so the prongs are curved downward into the client's nose.
    2. Check that the cannula size is not too big or too small for the client's nose.
    3. Wrap the tubing with fabric or foam tape to help alleviate uncomfortable friction behind the ears.
    4. Apply lubrication on the end of the prongs before inserting the cannula in the client's nose.
    5. Allow the prongs to rest loosely on the client's face to avoid irritation of the nose.
    1. 1–6 LPM
    2. 1–2 LPM
    3. 6–15 LPM
    4. 1–10 LPM

    Author of lecture Cannula – Low-flow Oxygen Delivery (Nursing)

     Rhonda Lawes, PhD, RN

    Rhonda Lawes, PhD, RN

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    humb rule with the 4%
    By Emanuel Y. on 08. March 2021 for Cannula – Low-flow Oxygen Delivery (Nursing)

    the thumb rule with the 4% each level, now I got that and even I have a math formula for that- 21%+(L/min* 4%)