Longer needles are required to inject fat people with intra-muscular injections due to the fatty tissues which prevent people from deriving the full benefits of the dosage. This has been revealed by Victoria Chan, a scientist at the Adelaide and Meath Hospital in Dublin. This conclusion was arrived at after studying 50 patients who came for a CT scan. The patients were administered an intra-muscular injection with a 23 gauge needle, which included a small air bubble.
Two independent radiologists analyzed the CT scans to fix the position of the bubble, Dr. Chan said. The analysis found that among the women, 23 of 25 injections, or 92% failed to reach muscle. Among men, 11 of 25 injections, or 44% missed the mark. Overall, the failure rate of the injections was 68%.
The message for clinicians is that a longer needle may be needed, Dr. Chan said, especially for women, who typically have more fat and less muscle in their buttocks than men. Many medications are administered through injections into the muscles of the buttocks, including painkillers, vaccines, contraceptives and anti-nausea drugs.
'The more fat tissue there is in the buttock, the less likely the needle will reach the muscles underneath that fat,' Dr. Chan said. The details of the study were presented at a conference of the Radiological Society of North America.