Insulin Injection Technique
o Check the Insulin Vial
Type, species, strength, specific brand, date of expiry and appearance of insulin must be checked.
o Bring vial to room temperature
If insulin has been refrigerated, it should be kept outside for about 30 minutes to bring it to room temperature. Injecting chilled insulin can be painful. Alternatively, the cold insulin vial may be warmed between the palms.
A cloudy insulin is a suspension of insulin particles. In order to have an uniform suspension of insulin, turn the vial upside down and gently roll it in your palms. Do not shake the insulin vial vigorously, as that gives rise to bubbles.
o Wash your hands and injection site
Wash your hands with soap and water. Soap and water should be used to clean the injection site. Wipe your hands and the injection site with a clean cloth. Spirit is not necessary to clean the injection site. However, if it is used, inject only after the spirit has evaporated.
o Wipe the rubber cap of the insulin vial
Wipe the rubber cap of the insulin vial with apiece of cotton moistened with an antiseptic (Savlon or Dettol) or spirit.
o Draw air into syringe
An amount of air equal to the dose of insulin required should first be drawn up and injected into the vial to avoid creating a vacuum.
o Withdraw insulin
Insert the needle into the rubber cap of the insulin vial. Turn over the insulin vial, support it in one palm and slowly pull down the plunger upto the desired mark, keeping the mark at the level of the eye to eliminate parallax error. o Remove air bubbles in the syringe After the insulin is drawn into the syringe, it should be inspected for air bubbles. One or two quick flicks of the forefinger against the upright syringe should allow the bubbles to escape. Air bubbles themselves are not dangerous but can reduce the amount of insulin actually injected.
o Injecting insulin
If you are right-handed, hold the insulin syringe like a pen (not like a knife) in the right hand. With the other hand, lightly grasp a fold of skin and underlying fat, between the thumb and the forefinger. Insert the needle at 45xxx for not more than 3-5 mm. Thin individuals and children should exercise this care, because a needle inserted vertically would go into the muscle, if fat under the skin is scanty. The needle should not be inserted parallel to the skin nor should a weal be raised above the skin, as this amounts to an injection in the skin. Routine aspiration (drawing back the piston to check for blood) is not necessary. Inject insulin. Pull out the needle and apply a cotton swab. Press for 5-8 seconds without rubbing as this hastens insulin absorption.
o Inspect injection site
If an injection seems especially painful or if blood or clear fluid is seen after withdrawing the needle, the patient should apply pressure for a longer time. Blood glucose monitoring should be done more frequently on a day when this occurs. If the patient suspects that a significant portion of the insulin dose was not administered, blood glucose should be checked within a few hours of the injection. The patient's insulin injection technique should be reviewed by a physician or diabetes educator, if bruising, soreness, welts, redness or pain occur at the injection site.
Mixture of Insulins
- Patients who are well controlled on a particular mixed-insulin regimen should continue their standard procedure for preparing their insulin doses.
- No other medication or diluent should be mixed with any insulin product unless approved by the prescribing physician.
- Use of commercially available pre-mixed insulins is preferred to extemporaneous mixing by the patient, if the insulin ratio is appropriate to the patient requirements.
- Mixing insulins of different manufacturers, species and types should be avoided.
- Currently available regular and NPH formulations may be used immediately or stored for future use.
- Mixing of regular and lente insulins is not recommended except for patients already controlled on such a combination. On mixing, zinc present in lente insulin binds with the regular insulin and delays the onset of action.
- Phosphate buffered insulins, for example, NPH, PZI should not be mixed with lente insulin.
- Plain and protamine zinc insulin should not be mixed in the same syringe, because when mixed, part of the plain insulin is converted into PZ insulin.
- Actual mixing of insulins
- If 8 units of short-acting insulin is to be mixed with 14 units of intermediate-acting insulin
- First draw 14 units of air into the syringe.
- Push this air into the vial of intermediate-acting insulin but do not withdraw the insulin. Keep the vial aside.
- Draw 8 units of air into the syringe.
- Push the air into the vial containing short-acting insulin and this time withdraw the short-acting insulin upto the 8 units mark.
- Withdraw the needle and push it into the vial of intermediate-acting insulin.
- Since 14 units of air have already been injected into the vial the plunger should be withdrawn upto the 22 units mark (8+14=22).
- Withdraw the needle and inject.