Insulin is a hormone medication requiring precise measurement and careful administration to manage blood sugar levels effectively. Learning the correct technique for drawing insulin into a syringe is a fundamental skill for anyone using injectable therapy. Accurate dosing ensures the intended therapeutic effect and contributes to patient safety. Mastering the steps of syringe technique is necessary for a successful injection routine, whether preparing a single type of insulin or a combination.
Essential Preparation and Supplies
Before drawing insulin, gather all necessary supplies and perform preparatory checks to minimize contamination and medication errors. Start by washing your hands thoroughly with soap and water.
Carefully examine the insulin vials, confirming the name and concentration match the prescribed regimen. Rapid-acting and short-acting insulins should appear clear, while intermediate-acting insulins, such as NPH, will be cloudy due to stabilizing particles. Check the expiration date and inspect the liquid for abnormal changes, such as clumping or discoloration, which indicate the insulin should not be used.
If using cloudy insulin, gently roll the vial between your palms ten times to uniformly resuspend the particles. Avoid shaking the vial vigorously, as this creates air bubbles that interfere with accurate measurement. Finally, use an alcohol swab to clean the rubber stopper, allowing the alcohol to fully dry before inserting the syringe needle. Ensure you are using a U-100 syringe, calibrated for the standard concentration of 100 units per milliliter (U-100) insulin.
Step-by-Step Guide for a Single Dose
Drawing a single dose of insulin establishes the foundational technique for syringe use. Begin by pulling the plunger down to draw air into the syringe equal to the number of units you plan to inject. Injecting air into the vial equalizes the pressure, making it easier to withdraw the correct amount of liquid.
Insert the needle straight through the center of the vial’s rubber stopper, then firmly push the plunger to inject all the air above the liquid. Keep the needle inserted and invert the vial so the needle tip remains submerged in the insulin solution. This prevents drawing air instead of medication.
Pull the plunger back slowly to draw slightly more than the required dose into the syringe. Check for any large air bubbles. If bubbles are present, gently tap the side of the syringe barrel to make them rise toward the needle, then carefully push the plunger to expel only the air back into the vial.
Adjust the plunger precisely to the line representing the prescribed dose, ensuring the top edge of the rubber seal aligns with the correct unit marking. Once the dose is accurately measured and air-free, remove the syringe from the vial. The syringe is now ready for immediate administration.
Critical Steps for Mixing Two Types of Insulin
Mixing two different types of insulin, typically a short-acting (clear) and an intermediate-acting (cloudy), allows a single injection to cover both immediate and sustained blood sugar needs. This procedure requires a strict sequence known as “clear before cloudy” to prevent contamination. The most common combination involves Regular (clear) and NPH (cloudy) insulin.
The process begins by injecting air into both vials, starting with the cloudy, intermediate-acting insulin. Draw air equal to the cloudy dose and inject it into the NPH vial, ensuring the needle does not touch the liquid. Immediately withdraw the needle.
Next, draw air equal to the clear, short-acting dose and inject this air into the clear vial. Keep the needle in the clear vial and invert the bottle. This two-step air injection maintains neutral pressure in both vials without drawing any liquid yet.
While the needle remains in the clear vial, pull the plunger back slowly to draw the prescribed dose of clear insulin. Drawing the clear insulin first is important because it prevents the cloudy NPH insulin from contaminating the clear vial, which would alter its rapid action profile.
Once the clear insulin is measured, immediately insert the needle into the cloudy NPH vial. Be careful not to push any clear insulin into the cloudy vial. Invert the cloudy vial and draw the prescribed dose of NPH, pulling the plunger to the total combined unit mark on the syringe barrel.
For example, if the dose is 10 units of clear and 15 units of cloudy, the final plunger position should be at the 25-unit mark. The entire mixture must be administered promptly, usually within 5 to 10 minutes, because the short-acting insulin begins to interact with the protamine in the NPH insulin, which can change its absorption characteristics.
Safety Checks and Handling Errors
After drawing the insulin dose, ensure no air bubbles remain in the syringe barrel. Air bubbles take up volume that should be occupied by insulin, leading to an under-dosing error and potentially causing elevated blood sugar levels. If a bubble is noticed, hold the syringe upright and gently tap the barrel to encourage the air to rise to the top.
Carefully depress the plunger just enough to expel the air bubble through the needle tip. Re-verify that the top of the plunger’s rubber seal aligns precisely with the correct unit marking. Confirming the accuracy of the dose is especially important when mixing two types of insulin.
If an error occurs during the mixing process, the entire mixture must be discarded, and the procedure restarted with a fresh syringe and new vials. The most common error is accidentally drawing the cloudy NPH insulin before the clear insulin, which contaminates the clear vial with protamine. This contamination slows the action of the clear insulin, compromising blood sugar control. Used syringes and needles must be immediately placed into a designated puncture-proof sharps container to prevent accidental needle-stick injuries.