title: Skin blood perfusion and cellular response to insertion of insulin pen needles with different diameters.
abstract: Today most research on pen needle design revolves around pain perception statements through clinical trials, but these are both costly, timely, and require high sample sizes. The purpose of this study was to test if tissue damage, caused by different types of needles, can be assessed by evaluating skin blood perfusion response around needle insertion sites. Three common sized pen needles of 28G, 30G, and 32G as well as hooked 32G needles, were inserted into the neck skin of pigs and then removed. Laser Speckle Contrast Analysis was used to measure skin blood perfusion for 20 minutes after the insertions. Seven pigs were included in the study and a total of 118 randomized needle insertions were conducted. Histology was made of tissue samples inserted with 18G, 28G, and 32G needles, and stained to quantify red and white blood cell response. Based on area under curve, calculated for each individual blood perfusion recording and grouped according to needle type, skin blood perfusion response relates to needle diameter. The response was significantly higher after insertions with 28G and hooked 32G needles than with 30G (P < .05) and 32G (P < .01) needles. Histology results were not significant, but there was a trend of an increased response with increasing needle diameter. Skin blood perfusion response to pen needle insertions rank according to needle diameter, and the tissue response caused by hooked 32G needles corresponds to that of 28G needles. The relation between needle diameter and trauma when analyzing histology was also suggested.
authors.affiliation: University of Copenhagen, Department of Biomedical Sciences, Copenhagen, Denmark Novo Nordisk A/S, Device R&D, Hillerød, Denmark kezj@novonordisk.com.
authors.forename: Kezia Ann
authors.initials: KA
authors.lastname: Præstmark
authors.affiliation: Novo Nordisk A/S, Device R&D, Hillerød, Denmark.
authors.forename: Casper Bo
authors.initials: CB
authors.lastname: Jensen
authors.affiliation: University of Copenhagen, Department of Biomedical Sciences, Copenhagen, Denmark.
authors.forename: Bente
authors.initials: B
authors.lastname: Stallknecht
authors.affiliation: Novo Nordisk A/S, Device R&D, Hillerød, Denmark.
authors.forename: Nils Berg
authors.initials: NB
authors.lastname: Madsen
authors.affiliation: Novo Nordisk A/S, Diabetes Research Unit, Måløv, Denmark.
authors.forename: Jonas
authors.initials: J
authors.lastname: Kildegaard
mesh_terms: D000818:Animals; D004867:Equipment Design; D004906:Erythrocyte Count; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D007279:Injections, Subcutaneous / Q000009:adverse effects / Q000295:instrumentation*; D007328:Insulin / Q000008:administration & dosage*; D007958:Leukocyte Count; D009333:Neck; D009339:Needles; D010146:Pain / Q000209:etiology; D012039:Regional Blood Flow; D012867:Skin / Q000098:blood supply*; D013552:Swine
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin
keywords: diabetes; injections; laser speckle contrast analysis; needle size; pen needles; tissue damage