Best practice for deltoid intramuscular injections in older adults: Study in cadavers

Most injectable vaccines are administered via deltoid intramuscular injection (IMI). Nursing students are taught to perform deltoid IMI in their entry-to-practice education program. However, best practice evidence is lacking regarding specific techniques of deltoid IMI, and students are often taught what their instructor was taught in his/her own entry-to-practice (ETP) program. Nursing textbooks provide instructions and diagrams for how to perform deltoid IMI, but rarely cite underpinning empirical evidence. This study tested the injection techniques of bunching (squeezing) or flattening (stretching) the deltoid muscle before administering IMI using medical school donated cadavers. Flattening technique resulted in over-penetration of deltoid injections more than 85% of the time in these older adults, whereas nearly 80% of deltoid IMI are successful using bunching technique. Body mass index (BMI) and needle length are also crucial considerations when administering deltoid IMI. Nurses, and other health professionals who use deltoid IMI to administer vaccines to older adults, should determine the client’s body mass index to select the appropriate needle length. Based on these results, bunching technique is recommended. Flattening technique is not recommended for older adults with a BMI < 30.