Cutis/subcutis thickness at insulin injection sites and localization of simulated insulin boluses in children with type 1 diabetes mellitus: need for individualization of injection technique?

The study aimed to describe the variations of cutis/subcutis thickness at insulin injection sites in children with Type 1 diabetes mellitus and to localize the tissue position of a simulated insulin bolus in order to evaluate the need for individualization of injection technique in children. Cutis/subcutis thickness was measured by ultrasound in 47 children (25 girls and 22 boys) without compression (CSCUT) and with compression (CSCT) of the skin at 11 insulin injection sites. Tissue deposition of insulin was measured by ultrasound of a simulated insulin bolus of 200 microl of sterile air injected by the patients using their usual technique and site. On the thigh, 44% of girls and 95% of boys had a CSCT of less than 8 mm at one of the measured sites, while 16% of girls and 50% of boys had a CSCT of less than 6 mm at one injection site on the thigh and buttock. Significant differences in cutis/subcutis thickness in the same anatomical region were shown. CSCT was up to 35% less than CSCUT. The air bolus injection was placed inappropriately by 19% of children (using 8 mm needles). Unawareness of the skin thickness at the injection sites may contribute to inappropriate deposition. We propose that regular ultrasound measurements of subcutis depth at insulin injection sites be taken. This will allow the injection technique to be individualized (vertical or at an angle of 45 degrees). More children would be able to use the simpler vertical technique if 6 mm needles were used where available, or if even shorter (4 mm) needles were produced.