A subcutaneous injection is defined as an injection of medication into subcutaneous tissue. In nursing jargon it is often described as a sub Q injection or a sub, cut, or injection.
The medication is injected into the layer between the skin and the muscle. A syringe of an appropriate size, with medication to be administered is attached to a needle. The patient’s skin is them cleaned, usually with an alcohol based disinfectant, and the medication is injected into the subcutaneous tissue by pressing on the plunger of the syringe. The needle is then withdrawn. The disposable need and syringe are disposed into the sharps container immediately, without recapping, as this is the normal practice in most institutions.
Indications for using the subcutaneous route of administration.
The doctor decides how the particular medication is to be administered. This decision is usually based on some or all of the following reasons.
- Quantity of medication that has to be administered. Only very small doses on medications can be given via the subcutaneous route.
- Only certain types of medications can be given via this route. The speed at which the speed at which the medicine needs to act is an important consideration. Medications which need to work slowly are given via this route.
Syringe Types and sizes.
This article is for the benefit of second year student nurses. Most nurses, in second year are able to identify the parts of a syringe. These include the needle, the barrel and the plunger. The needle is the sharp part which is injected into the patient after the barrel has been filled with the prescribed medication. The nurse presses on the plunger to push the medication into the subQ area of the patient. The barrels of both plastic and glass syringes have markings on them. The markings are based on the metric system and denote millilitres of fluid. These markings are used to draw up the correct amount of medication.
In a hospital ward you will find syringes ranging from 0.5ml to 60 ml. The current trend is to use plastic disposable syringes. For the administration of a subQ injection it is normal to use an insulin syringe or a 1ml syringe. Both of these come with and without attached needles.
Insulin syringes are highly specialized to measure small doses of insulin. Insulin syringes will contain a maximum of one ml. only. The barrel of the syringe shows divisions which are marked 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100. 100 is the same as 1 mL. The marking at 50 is the same as half of a mL.
Another syringe which is usually available is the 1ml “tuberculin” or “TB syringe”. This syringe also holds up to 1 mL of medication. In this syringe the needle that comes attached is slightly longer than that of an insulin syringe.