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Intramuscular injections into the buttocks: are they truly intramuscular?
V O Chan1, J Colville, T Persaud
1Department of Radiology, The Adelaide and Meath Hospital, Tallaght, Dublin 24, Ireland.
Insights
Most buttock intramuscular (IM) injections are actually subcutaneous, with significantly lower efficacy in females. This highlights a critical issue in medication administration and patient care.
Area of Science:
- Medical Imaging
- Radiology
- Anatomy
Background:
- Intramuscular (IM) injections into the gluteal region are common for medication delivery.
- Accurate IM injection placement is crucial for proper drug absorption and efficacy.
- Previous studies have questioned the accuracy of IM injection techniques in the buttocks.
Purpose of the Study:
- To radiologically verify the true anatomical location of IM injections administered into the buttock.
- To assess the accuracy of IM injections in the upper outer quadrant of the gluteal region.
Main Methods:
- Prospective study involving 50 inpatients receiving an IM buttock injection with air contrast.
- Computerized tomography (CT) scans were used to visualize the injected air bubble's position.
- Radiologists analyzed CT images to differentiate between intramuscular and subcutaneous placement, measuring relevant anatomical factors.
Main Results:
- Only 32% of all injections were confirmed as truly intramuscular.
- A significant majority (68%) of injections were found to be subcutaneous.
- Intramuscular injection success rates differed markedly by gender: 56% in males versus only 8% in females.
Conclusions:
- The study demonstrates that most presumed IM gluteal injections are incorrectly administered subcutaneously.
- Gender significantly impacts the accuracy of IM buttock injections, with females experiencing much lower success rates.
- Findings indicate a need to review and improve IM injection techniques in clinical practice.
Aim:
To radiologically determine if intramuscular (IM) injections into the buttocks are truly intramuscular.
Materials And Methods:
This was a prospective study conducted during a 6 month period beginning in October 2004. Fifty inpatients were recruited from a single tertiary referral hospital. Approval was obtained from the hospital research ethics committee and informed written consent was acquired from all participants. Prior to computerised tomography (CT), each patient received an IM injection of their prescribed medication along with 1 mL of air into the upper outer quadrant of the buttocks. CT images were subsequently analyzed by two radiologists to determine the position of the injected air bubble and to assess whether it was intramuscular or subcutaneous in position. Body mass index (BMI), distance to injection site, subcutaneous fat and muscle thickness were also measured.
Results:
Overall, only 32% (n=16/50) of patients had intramuscular injections, with the majority of injections (68%, n=34/50) being subcutaneous. When analysed by gender, 56% (n=14/25) of males had intramuscular injections while in females, the efficacy rate was significantly lower at 8% (n=2/25).
Conclusion:
The majority of assumed intramuscular injections are actually subcutaneous.
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