Abstract
BackgroundHemodialysis catheters are commonly used for vascular access in patients undergoing blood purification therapies. However, the sudden dysfunction of catheters represents a serious problem, and while we know that the major causative factor is suction between the catheter and the vessel wall, it is very difficult to evaluate this in vivo. Therefore, we created a new experimental system to investigate this phenomenon ex vivo, using pig veins, which allowed us to quantitatively analyze the effect of suction.MethodsWe attempted to create a model system for quantitative evaluation using azygos veins from a pig. Four types of catheters were inserted into an extracted pig vein: true circle type 1, true circle type 2, semi-circle type 1, and semi-circle type 2. We then circulated 50% glycerol solution through the vein at a flow rate (Qv) from 100 to 1000 mL/min. Glycerol solution was also circulated within the catheters at a flow rate (Qb) from 100 to 200 mL/min. We measured the frequency of suction towards the vessel wall ten times, under each experimental schedule, at a Qb of both 100 and 200 mL/min. We then measured the pressure between the pre-Qb pump and the blood circuit, when the arterial side opening was positioned approximately in the center of the blood vessel to prevent catheter suction towards the vessel wall.ResultsSuction towards the vessel wall occurred 8/10 times with the true circle type 1 catheter and 10/10 times with the semi-circle type 2 catheter in the arterial pore of the catheter is only one, when Qb and Qv were 100 and 100 mL/min, respectively. Suction towards the vessel wall occurred 3/10 times with the semi-circle type 2 catheter, when Qb and Qv were 100 and 1000 mL/min, respectively. The true circle type 1 catheter showed a minimum pressure of − 58.6 ± 0.516 mmHg when Qb and Qv were 100 and 300 mL/min, respectively, while the true circle type 2 catheter showed a minimum pressure of − 137 ± 5.96 mmHg when Qb and Qv were 200 and 300 mL/min, respectively.ConclusionsWe successfully established a novel ex vivo evaluation system for catheters using a pig vein which allowed us to recreate the effect of suction from catheters towards a vessel wall in vivo.
Highlights
Hemodialysis catheters are commonly used for vascular access in patients undergoing blood purification therapies
Catheters often fail during blood purification therapy, most commonly due to catheter suction towards the vessel wall [2], thrombotic occlusion [3], and the development of a fibrin sheath [4]
The circulating blood cannot be sent to a blood purification machine, making it very difficult to continue with blood purification therapy
Summary
Hemodialysis catheters are commonly used for vascular access in patients undergoing blood purification therapies. The sudden dysfunction of catheters represents a serious problem, and while we know that the major causative factor is suction between the catheter and the vessel wall, it is very difficult to evaluate this in vivo. Catheters often fail during blood purification therapy, most commonly due to catheter suction towards the vessel wall [2], thrombotic occlusion [3], and the development of a fibrin sheath [4]. These issues represent serious problems because there is no suitable method available at present with which to detect and evaluate these phenomena.
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