Editing Nursing Skills and Procedures (section)

=== Subcutaneous ===
Angle is chosen by tissue depth: 90 degrees when at least 2.5 cm, or one inch, of tissue can be grasped, and 45 degrees when only about 1.25 cm can be grasped. Aspiration is not performed for subcutaneous injections.
* '''Heparin''': give in the abdomen at least 5 cm, about two inches, away from the umbilicus, at 90 degrees, do not aspirate, and do not massage, because both increase hematoma risk. Rotate sites. Low molecular weight heparin such as enoxaparin comes in a prefilled syringe with an air bubble that is not expelled, and the skin fold is held throughout injection.
* '''Insulin''': use an insulin syringe with units marked, inject at 90 degrees, do not aspirate, and do not massage. Absorption is fastest from the abdomen, then arm, then thigh, then buttock. Rotate within one anatomic region rather than across regions to keep absorption consistent, and space sites about 2.5 cm apart to prevent lipohypertrophy. When mixing, draw air into the intermediate-acting cloudy insulin first, then air into the clear regular insulin, then withdraw the clear regular insulin, then the cloudy: clear before cloudy. Insulin glargine, detemir, and degludec are never mixed with other insulins.