Abstract
In our first report, we examined the physical strength and the electron micro-scopic images of catheters in which we had recognized abnormalities in 2 clinical cases. In the present investigation, we have examined the strength of unused catheters, then experimentally exposed them to drugs in order to comparatively evaluate physical changes in substance, 1. We conducted an examination over a period of time, based on physical strength tests-inside diameter, outside diameter, extension, solidity, strength against a pulling force-of silicone catheters from four manufacturers (Baxter, Quinton, Accurate Surgical, Create Medic). 2. The immersion test: we conducted an examination identical to that described above of catheters immersed in drugs at 60°C. Drugs used included a 70% solution of ethyl alcohol, a 10% solution of popidon-iodine gel, and a 10% solution of popidon-iodine liquid.
Result; Catheters from each manufacturer had specific strengths and durabilities. The results of the examination over a period of time did not show any remarkable difference in the inside diameter, outside diameter or extension. In the case of the horizontal pull test, a decline of strength was observed in each catheter due to lack of thickness of the silicone at the radiopaque line. In the immersion test, the Baxter catheter immersed in ethyl alcohol showed a remarkable decline in the case of the horizontal pull test. We also observed a marked decline in each catheter immersed in popidone-iodine liquid in terms of the horizontal pull test. This seems to be caused by the lack of silicone thickness at the radiopaque line. In the examination of vertical pull strength, the Quinton catheter immersed in popidone-iodine liquid showed a remarkable decline. We found that, in this case, it is important to observe the decline in strength, notwithstanding the existence of the radiopaque line on the catheter.
Catheters from each manufacturer showed differences in performance and/or durability. It seems that no certain trend could be recognized either in examinations over a period of time or in an immersion test. A decline in strength due to construction problems was confirmed, and changes in immersion examinations were enlarged. Based on the results of this study, a remarkable difference in hardness and strength caused by the differences in antiseptic solutions was observed. Accordingly, we found that the key points which should be invesigated in the future are disinfection method and the construction of catheters.
