An impedance-guided intra arterial catheter

Under certain circumstances, the placement of arterial catheters can be difficult. In these instances, a form of guidance is preferred to avoid repeated insertions of the arterial catheter. Ultrasonic guidance is generally used in these instances, but the equipment required is expensive and cumbersome. This study produced an arterial catheter that is guided by the impedance of biological tissue encountered between the patient´s skin and the lumen of the artery, with the aim of producing a cheaper and manageable alternative to ultrasonic guidance. Additionally, this study has inspected the impedance of human tissue in order to determine whether or not a sufficient and discernable difference between the impedance of the different tissue types could be identified and thus be used to guide an arterial catheter based on said impedance differences. The results indicate that the difference between subcutaneous tissue, fat tissue and skeletal muscle tissue are not clear enough to make accurate discrimination between tissue types. However, the study shows a clear difference between the impedance of arterial blood and the aforementioned tissue, allowing for the device to determine when accurate placement has been achieved. From the results obtained in the studies, the discrimination between blood and other intermediary tissue can be made with 99,4% confidence.