Effect of positioning on discomfort from intramuscular injections in the dorsogluteal site.

An intramuscular injection into a relaxed muscle is believed to result in less discomfort than an injection into a contracted muscle. When the femur is internally rotated, the gluteus maximus muscle is relaxed. The hypothesis that a dorsogluteal injection with the femur internally rotated will cause less discomfort than when the femur is externally rotated was tested in 44 surgical patients who received two injections of preoperative medication. Each patient received an injection of a narcotic medication and one of diazepam. All possible combinations of the factors--position (internal and external rotation), order of injection (first or second injection), and medication (narcotic or diazepam)--were determined, and patients were randomly assigned to one of these conditions. Patients rated their perceived discomfort after each injection on a five-point scale. The hypothesis was supported by discomfort ratings from injections of both types of medications, although diazepam injections caused significantly more discomfort than injections of narcotics. Older patients tended to report less discomfort from diazepam injections than younger patients. Sex, order of injection, and nurse administering the injection did not significantly influence discomfort ratings.