Jasmin R. Kastner, United States of America

Thomas Jefferson University Anesthesiology

Presenter of 2 Presentations

NOVEL KINK-RESISTANT INSULIN INFUSION SET CAUSES SIGNIFICANTLY LESS SUBCUTANEOUS TISSUE INFLAMMATION COMPARED WITH A STRAIGHT TEFLON INSULIN INFUSION SET

Abstract

Background and Aims

Capillary Biomedical Inc. (CapBio) has developed an improved, kink-resistant, angled insulin infusion set (IIS) with a softer cannula material and 3 additional side holes for better insulin delivery. This study aimed to compare a regular 90° Teflon IIS (T90) with the CapBio improved IIS.

Methods

40 T90 and 48 CapBio IISs were inserted subcutaneously every other day for 2 weeks in 11 swine and connected to an insulin pump (basal/bolus pattern). After 2 weeks, the tissue surrounding the cannulas was excised and kinking within the tissue determined using micro-CT. The specimens were processed and stained with Masson’s Trichrome to assess the area of inflammation (AI) and thickness of inflammatory layer (LT) surrounding the cannula. Data were analyzed using Fisher’s Exact, ANOVA GLM, Kruskal Wallis, and post hoc Tukey HSD and Dwass-Steel-Chritchlow-Fligner tests.

Results

AI and LT were consistently higher using T90, with statistically significant differences after 6 days of IIS wear time. On average, the AI was reduced by 52.6% and the LT by 66.3% using the angled CapBio IIS. While 32.5% (13/40) of T90 IISs kinked (=bend in cannula >90°), only 2.1% (1/47) of the CapBio IISs kinked (p<0.001).

Conclusions

The data suggest that the new cannula design of the CapBio IIS causes less tissue trauma compared to a regular 90° Teflon IIS between 2 days and 2 weeks post insertion and is resistant to kinking. These results are supportive of the objective of extending infusion set wear through changes to the material and mechanical design of traditional IIS cannulas.

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30 VS 90: THE EFFECT OF ANGLE OF INSERTION OF INSULIN INFUSION CANNULAS ON TISSUE HISTOLOGY AND INSULIN SPREAD WITHIN THE SUBCUTANEOUS TISSUE OF SWINE

Abstract

Background and Aims

The purpose of this study was to compare tissue response and insulin bolus spread using straight and angled insulin infusion sets (IIS).

Methods

IIS with different cannula insertion angles (30° or 90°) were inserted subcutaneously every other day for 2 weeks in 11 swine and connected to an insulin pump (basal/bolus pattern). After 2 weeks, an insulin/contrast agent bolus was delivered while recording a pressure profile, evaluating maximum tubing pressure (pmax) and area under the pressure curve (AUC). The tissue-cannula specimen was excised and imaged using micro‑CT to measure bolus surface area (SA) and volume (V). Histopathological analysis of area of inflammation (AI) and thickness of inflammatory layer (LT) surrounding the cannula was carried out. Data were analyzed using ANOVA GLM, Kruskal Wallis, and post-hoc Bonferroni correction.

Results

Insulin infusion through a straight cannula caused significantly higher pmax (p=0.005) and AUC (p=0.014). Bolus SA (30°: 314.0±84.2 mm2 vs 90°: 228.7±99.7 mm2, p<0.001) and V (30°: 198.7±66.9 mm3 vs 90°: 145.0±65.9 mm3, p=0.001) were larger using an angled IIS. Bolus SA and V decreased significantly over infusion set wear time independent of insertion angle (p<0.05). Straight cannulas caused a greater mean AI (30°: 9.1±4.0 mm2 vs 90°: 14.3±8.6 mm2, p<0.001) and LT (30°: 0.7±0.4 vs 90°: 1.2±0.7 mm, p<0.001). As the LT increased, pmax increased and bolus volume decreased.

Conclusions

Although a straight IIS is clinically preferred due to easier insertion, our data suggest that angled cannulas elicit less inflammation, and deliver an insulin bolus with lower tubing pressure and greater SA and V.

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