Researchers at AAAAI Annual Meeting Believe Needles May Be Too Long for Standard Care
Los Angeles, CA – What is the optimal needle length for infants and toddlers who need epinephrine? Researchers from Western University Schulich School of Medicine and Dentistry in London, Ontario, asked this question at the 2016 AAAAI Annual Meeting in Los Angeles.
“Epinephrine auto-injectors are the first line of treatment for anaphylaxis. It’s most effective when delivered intramuscularly but too much force or imprecise needle length can cause intraosseous injection, causing the needle to come into the bone marrow. This can be harmful,” primary author Harold L. Kim, MD, said.
“The standard needle length for pediatric patients is 12.7 mm, however, the ideal needle length for infants and toddlers weighing 7.5 to 15 kg is unknown,” he said.
For the study, 53 children weighing 7.5 kg (16.5 pounds) to 15 kg (33.1 pounds) underwent baseline and compression ultrasounds of the anterolateral thigh. They used a modified ultrasound transducer that mimicked the footprint and maximum activation force of an epinephrine autoinjector.
“Ultrasound images were analyzed offline, blinded to clinical data, and we were looking at skin-to-bone distance and skin-to-muscle distance in short axis approaches,” Kim explained.
Average baseline distance from skin-to-bone was 22.8 mm and average baseline distance from skin-to-muscle was 8.2 mm. With 10 pounds of pressure to mimic the force of an epinephrine autoinjector, however, the ultrasound images told a different story.
“With ten pounds of compression, the mean skin-to-bone distance was 13.3 mm and the mean skin-to-muscle distance was 6.3 mm. That means a standard needle length of 12.7 mm would strike the bone in 43.1% of our patients,” Kim concluded.
Kim stressed that epinephrine, of course, remains the first line treatment for anaphylaxis, a serious and life-threatening allergic reaction that is most commonly caused by foods, insect stings, medications and latex.
“Even with our findings, the epinephrine autoinjectors should be used when required. I often educate parents with some simple instructions on how to avoid needle penetration that is too deep. For example, squeezing the thigh muscle to prevent muscle compression while injecting the autoinjector would likely work for most children,” Kim pointed out.
People with severe allergy or a history of anaphylaxis should carry autoinjectable epinephrine with them at all times. Families with epinephrine autoinjectors, especially those with infants and toddlers, should discuss their prescriptions with their allergist/immunologist and pharmacist so they know exactly which kind of epinephrine autoinjector they are receiving and ensure they have been properly trained in how to use it.
The AAAAI represents allergists, asthma specialists, clinical immunologists, allied health professionals and others with a special interest in the research and treatment of allergic and immunologic diseases. Established in 1943, the AAAAI has more than 6,800 members in the United States, Canada and 72 other countries. The AAAAI’s Find an Allergist/Immunologist service is a trusted resource to help you find a specialist close to home.