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Needle design related to pain, penetration force in type 2 diabetes
Needle diameters and designs were related to skin trauma, skin penetration force and pain in patients with type 2 diabetes, researchers in Denmark reported.
“Needle performance is usually measured by pain perception of test subjects in a clinical trial or by mechanical tests with measurement of penetration force through polyurethane rubber,” Kezia A. Praestmark, PhD, MSc, of the department of biomedical sciences at the University of Copenhagen, and colleagues wrote. “However, pain is a subjective measure with many individual frames of reference causing high data variance, and clinical trials are costly and time-consuming. Furthermore, it is unknown if and how [penetration force] through [polyurethane] relates to ease of insertion through skin, pain or other biological factors.”
Praestmark and colleagues conducted a single-center, single blind study on 30 patients with type 2 diabetes and a BMI of 25 kg/m2 to 35 kg/m2. Each patient underwent abdominal insertions from 18 distinct types of needles, undergoing two tests with each type. No substances were injected. The researchers evaluated penetration force, perceived pain on a 100-mm visual analogue scale and changes in skin blood perfusion. All patients were white and aged 18 to 70 years.
Needle diameter was positively correlated with penetration force and skin blood perfusion (P < .05), Praestmark and colleagues reported, and although pain intensity also seemed to increase with needle diameter, the difference was not significant. Small needle hooks and a lack of lubrication were also linked to increased skin blood perfusion and penetration (P < .05), but again, this did not increase perceived pain. Needles with a short tip and obtuse grinds also raised skin blood perfusion and penetration force, but increased pain only in “extreme cases,” the researchers wrote. Praestmark and colleagues identified a linear relationship between penetration force in skin and polyurethane rubber. All effects were positively related to one another, the researchers reported. Skin blood perfusion was predictive of pain (P = .0002), followed by penetration force (P = .0154).
“Needle design in terms of needle diameter and obtuse tip designs were positively related to skin [penetration force], pain and skin trauma. Thus, smaller needle diameter and more robust alternative tip designs should be used in combination when developing new needles in order to provide better user experiences,” the researchers wrote. – by Andy Polhamus
Disclosure: All researchers report employment and stock holdings with Novo Nordisk A/S.