It’s every child’s nightmare. Flu shots and immunizations are necessary evils, but children still have nightmares of needles, ranging from the small sharp needles to the monstrous needles that could only be used as swords. But really, why do needles have to be so big? For the worst needle-phobic people, any needle is “huge.” The system indicating needle size doesn’t help. One of the smallest needles has the “gauge” size of 31, while one of the largest needles is gauge 18. The smaller the number is, the larger the needle. Here’s a piece of advice; don’t ask for a lower gauge if you want a smaller needle.
Why Needle Size Matters
The size of the needle depends on the task it needs to perform. For example, a shot in the buttocks is going to require one of those atrociously long needles to penetrate through the muscle tissue. This is called an intramuscular injection. Most needles used for IM injections are gauge 20 or 22 needles. As for an insulin injection or any subcutaneous injection for that matter, needles used are generally gauge 25 or 30. Shorter needles are required for such injections because, as opposed to IM shots, subcutaneous injections only need to go as far as the fatty tissue underneath the skin. The reason why needles only need to access a certain area is because certain medicines work faster when distributed via the muscle tissues, while others work more efficiently when dispersed by fatty cells or the blood.
In addition, the size of the needle depends on what procedure is going to be performed. Naturally, the amount of pain also increases when larger needles are used. It is simple logic: the larger the needle, the more it’s going to hurt. For instance, an IM shot in the buttocks is typically more painful than an insulin shot in the arm. So thankfully, needles can also be incredibly small depending on their use. For the poor needle-phobic diabetics, injecting insulin requires a smaller needle. Also, diabetics now have a less painful option. There is a little needle called a “pen needle,” which is a gauge 31 needle that causes very little pain.
Needle size is also determined by what sort of fluid is going to be injected into a person. If the fluid that’s going to be introduced is thin and watery, then a needle with a smaller hole, maybe a gauge 23, will suffice. But for more viscous fluids, such as corticosteroids and certain antibiotics, gauge 21 needles are required.
Why Bigger Needles are Used for Surgical Patients
When you go into surgery, an IV drip using a gauge 18 needle will most likely be used. There are several reasons why the biggest needles are used for surgical patients. Firstly, bigger needles have larger holes. So, in case you might require a blood transfusion or other emergency treatment, it’ll be much easier to inject you with fluids. Furthermore, blood is thick and cells cannot pass through or will have difficulty going through needles with smaller holes. Gauge 18 needles are also used for patients that need parenteral nutrition or IV feeding.
So don’t worry. If you get a regular shot in the arm, it’s unlikely that you’ll see that 6-inch needle anywhere near you. But if you need to be subjected to the long needles, just know that it’s needed and surely for your own good.
Claire Hunt is a freelance blogger and a registered nurse. She writes articles for CIA Medical, which is a company that distributes branded medical supplies. The company carries brands like BD, Kendall, and Terumo.