Victoria Ophelia Chan MBBCH, Presenter: Nothing to Disclose

Jane Anna Clare Colville MBBCh, Abstract Co-Author: Nothing to Disclose

Thara Persaud, Abstract Co-Author: Nothing to Disclose

Orla Buckley MD, Abstract Co-Author: Nothing to Disclose

Samuel Hamilton MBBCh, Abstract Co-Author: Nothing to Disclose

William Carmelo Torreggiani MB, Abstract Co-Author: Nothing to Disclose

To determine the percentage of patients who actually receive an intramuscular dose into the gluteal muscle.

This was a prospective study carried out from October 2004 to March 2005 in which patients who were scheduled for a CT abdomen and pelvis and were receiving intramuscular medication were asked to participate. Approval was obtained from the Medical Ethics Committee. In total 50 patients were recruited, ranging in age from 21 to 87 years (mean 53.6 years), with equal numbers of males and females. Prior to the CT scan, an intramuscular injection was given with the addition of 1mL of air into the upper outer quadrant of the buttocks using a standard 23 gauge needle. The CT scans were analyzed by 2 independent radiologists to establish the location of the air bubble. Body mass index (BMI), distance to injection site, and thickness of subcutaneous fat and muscle were also measured and compared to the CT scan results.

Only 25% (n = 12/50) of the cohort received an intramuscular injection. The majority of patients who received a subcutaneous injection were female, had an average fat thickness of more than 2cm (2.5 – 8.7cm) and an average muscle thickness of less than 3cm (0 – 5.2cm). In contrast, those who received an intramuscular injection were all male, had an average fat thickness of less than 2cm (0.89 – 1.8cm) and an average muscle thickness of more than 3cm (1.83 – 5.7cm).

75% (n = 38/50) of patients did not receive an intramuscular dose in the gluteal muscle. The efficacy of intramuscular injections is related to gender as well as subcutaneous fat and muscle thickness. The results of this study may have an impact on the administration of intramuscular injections.

To determine the percentage of patients who actually receive an intramuscular dose into the gluteal muscle.

This was a prospective study carried out from October 2004 to March 2005 in which patients who were scheduled for a CT abdomen and pelvis and were receiving intramuscular medication were asked to participate. Approval was obtained from the Medical Ethics Committee. In total 50 patients were recruited, ranging in age from 21 to 87 years (mean 53.6 years), with equal numbers of males and females. Prior to the CT scan, an intramuscular injection was given with the addition of 1mL of air into the upper outer quadrant of the buttocks using a standard 23 gauge needle. The CT scans were analyzed by 2 independent radiologists to establish the location of the air bubble. Body mass index (BMI), distance to injection site, and thickness of subcutaneous fat and muscle were also measured and compared to the CT scan results.

Only 25% (n = 12/50) of the cohort received an intramuscular injection. The majority of patients who received a subcutaneous injection were female, had an average fat thickness of more than 2cm (2.5 – 8.7cm) and an average muscle thickness of less than 3cm (0 – 5.2cm). In contrast, those who received an intramuscular injection were all male, had an average fat thickness of less than 2cm (0.89 – 1.8cm) and an average muscle thickness of more than 3cm (1.83 – 5.7cm).

75% (n = 38/50) of patients did not receive an intramuscular dose in the gluteal muscle. The efficacy of intramuscular injections is related to gender as well as subcutaneous fat and muscle thickness. The results of this study may have an impact on the administration of intramuscular injections.

Chan, V, Colville, J, Persaud, T, Buckley, O, Hamilton, S, Torreggiani, W, Intramuscular Injections into the Buttocks: Are They Truly Intramuscular?.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4407560.html