Pharm Basics, part 6: Routes of Administration: Intradermal, Subcutaneous, Intramuscular

by Cathy Parkes August 13, 2021 Updated: August 21, 2021

Full Transcript

Hi, I'm Cathy with Level Up RN. In this video, we will be talking about preparation of injections, and I'll also be covering intradermal, subcutaneous, and intramuscular routes of administration. At the end of the video, I'll provide you guys with a quick quiz to test your understanding of the information I'll be covering. My focus during this video are on the best practices and key points about these routes of administration. So you may get questions about these on the NCLEX or your nursing exams. This video isn't intended to give you step-by-step instructions on how to perform these injections. You can find that information in our nursing skills playlist.

All right. So let's first talk about how to prepare an injection. If you need to remove medication from an ampule, you want to take a small gauze pad and kind of wrap it around the neck of the ampule. And then you want to break the ampule away from the body. So you're going to pull the top of the ampule towards you. Then you want to draw up the medication using a filter needle, and you do not put air into the ampule, as opposed to a vial, which we do want to put air into a vial when we're drawing up medication. So removing medication from a vial is much more common than from an ampule, but you still need to know how to do both, obviously. So with the vial, we're going to want to scrub the top of the vial for 15 seconds with an alcohol swab or other antimicrobial swab. Then we want to inject the amount of air that is equal to the medication dose into the vial. So if we have to draw up 1 milliliter of the medication, we want to inject 1 milliliter of air. And then without removing the needle, we're going to turn that vial upside down, make sure our needle is in the liquid, and then draw up that 1 milliliter of medication.

When we are doing an intradermal injection, we're going to use a 26- to 29- gauge needle that may vary in size between 3/8 and 1/2 inch. We're only going to inject a very small amount of volume through this route, so a max of 0.1 milliliters. In terms of best practices, we're going to hold the skin taut with our nondominant hand, and we're going to inject the needle at a 10- to 15-degree angle, just until the bevel is under the skin. And then we're going to slowly inject the medication to form a small bubble or wheal under the skin. And then we're going to remove the needle quickly and not massage the site. So the most common scenario where we would do an intradermal injection is with a TB skin test.

For subcutaneous injections, we want to use a 25- to 27-gauge needle that may vary in length between 3/8 and 5/8 of an inch. We can definitely inject a lot more volume subcutaneously as compared to an intradermal injection. So volume amounts may range between 0.5 and 2 milliliters. We want to perform our injection in a fatty area of the body, so this can include the abdomen or the upper lateral arm. We want to make sure we rotate injection sites, and we will inject at a 45- to 90-degree angle. If your patient is on the heavier side of things, then a 90-degree angle would be most appropriate. If you are having to do an insulin injection, you want to use a special insulin syringe, as these syringes are marked with units.

And then there are some special teaching and some key points that I want to convey here about insulin administration. So, first of all, if you are administering a short-acting insulin for your patient, that short-acting insulin should be clear in color. If it looks cloudy or discolored, you do not want to administer it. If you are administering an insulin suspension, you want to gently rotate the vial prior to drawing it up. You never want to shake that insulin suspension. And then, in terms of injection, just like with our other subcutaneous injections, we want to rotate sites in order to prevent lipohypertrophy, which is a buildup of scar tissue that would occur if you keep doing an injection in the same site over and over again.

All right. Next, let's talk about mixing insulins. And I have to be honest with you here that the chance of you needing to mix insulins when you become a nurse is pretty low. So I share an office with the diabetic educator from my hospital, and I asked her about mixing insulin. She's like, "Where is this happening?" And I'm like, "It's a big thing in nursing school. You have to know this for the NCLEX and nursing exams." And she was like, "No. They kind of come premixed these days. We don't really have people mix insulin." So, like I said, you have to know it for nursing school. It's important. But following nursing school, you will likely not have to mix insulins.

But in the meantime, here are the important steps for knowing how to mix insulin. I want you to remember clear before cloudy. So remember, clear is going to be our shorter-acting insulin, and our cloudy insulin is going to be our longer-acting insulin, such as NPH. Of note, we are not mixing long-acting insulin. So insulin glargine is a long-acting insulin. We're not mixing long-acting insulins with any other insulin. So our little cool chicken hint here on the card is long-acting is lonely. They both start with L. So when I say longer-acting, I'm referring to NPH insulin. So here are the steps. First of all, you want to inject air into the longer-acting insulin, so the NPH. And then you want to remove the needle, and you want to inject air in the shorter-acting insulin, such as regular insulin. And then, without removing the needle from that regular insulin, you want to invert the vial and remove the regular insulin, put down the vial, and then go over to the longer-acting insulin, the NPH insulin, and remove that insulin. Okay? And those are the steps on how to mix insulin that you have to know for nursing school, but at some point, after you graduate, you can likely purge from your mind.

For intramuscular injections, we want to use a 20- to 23-gauge needle, and the needle length will be much longer than what we've seen with the previous routes of administration. So the needle size will be between 1 and 1 1/2 inches. And it makes sense that it's longer because, if you think about it, we have the epidermis, the dermis, the fat tissue, so the subcutaneous tissue, and then the muscle. So we've got to get through all of those layers to get to the muscle, which is why the needle length is going to be longer. In terms of the injection site, if we are administering an IM injection to an infant, we want to use the vastus lateralis muscle. We don't want to use the deltoid muscle or the ventrogluteal muscle. The vastus lateralis muscle is going to be the right one to use for infants. Now, as children get older and for adults, we can use that ventrogluteal site or the deltoid site. We don't often use the dorsogluteal site due to the risk for sciatic nerve damage with those injections. In terms of the injection angle, we want to use a 90-degree angle. And if we are injecting a medication that can stain the tissue, such as iron dextran, which is an iron supplement, we want to use a Z-track method. So with the Z-track method, we would take our nondominant hand and kind of push the skin and underlying tissue to the side, put the needle in, perform the injection, pull the needle out, and then let the skin go back in place.

All right. It's time for a quiz. I have three questions for you. First question, what type of needle do you use to draw up medicine from an ampule? The answer is a filter needle. Question number two, what angle do you insert the needle for an intradermal injection? If you said 10 to 15 degrees, you are correct. Number three, what is the best site to use when giving an IM injection to an infant? If you said the vastus lateralis muscle, you're right. I hope you did great with that quiz. If not, just go back and watch the video, review our cards again. You got this. Thanks so much for watching.

[BLOOPERS]

For subcutaneous injections, we want to use a 20-- sorry. For intradermal-- nope, I'm on intramuscular.


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