Objectives: The aim of this study was to construct an experimental model replicating blood flow within human superior vena cava and to determine the degree of the immediate aspiration of the drug introduced via central venous catheter through the distally positioned dialysis catheter. Methods: A model replicating superior vena cava was built, catheters were inserted into the model, placing the orifice of the central venous catheter in positions regarding the orifice of the arterial lumen in central venous dialysis catheter (from +2 to −8 cm). Methylene blue was used as a tracer, and the concentration was determined by ultraviolet-visible spectroscopy. Four different sets of samples were generated according to infusion and aspiration speeds: continuous–slow, continuous–fast, bolus–slow, and bolus–fast. Results: The concentration of the tracer was related to the distance between the catheter tips, representing a bimodal dependence. When the central venous catheter was placed distally to the central venous dialysis catheter, the aspiration of the tracer was minimal. When withdrawing the central venous catheter proximally, the aspiration of the tracer increased, reaching its peak at −4 cm with aspiration rates form 4.2% to 140.7%. Furthermore, the infusion speed of the tracer had more effect on the aspirated concentrations than the aspiration speed. Conclusion: Findings of our experimental model suggest that concentration of aspired drug is effected by the distance between the central venous catheter and central venous dialysis catheter, being lowest when the drug is infused distally to central venous dialysis catheter. Furthermore, the concentration of the tracer is directly proportional to the infusion speed and far less effected by the aspiration rate of the drug.
Objective:
High blood pressure (BP) and consequential cardiovascular complications remain the leading cause of death in hemodialysis (HD) patients. Aim of this study is to link BP variations during HD with a 1 year mortality.
Design and method:
We conducted a cohort study in tertiary reference dialysis center. Patients undergoing HD were enrolled. Systolic, diastolic and mean arterial BP were measured before, every hour during and after HD procedure. These patients were observed for 12 months and mortality rate was evaluated. Mean values of measurements were compared across the groups. Furthermore, these measurements were included in univariate and multivariate regression analysis, determining their potency to predict 1 year mortality.
Results:
Study enrolled 99 patients. Mean age of patients was 58.7 ± 14.4 years, more than a half of them were men 51 (51.5%) with median time on HD for 4,5 [2,0–8,5] years. Mortality rate was 15.2 % (n = 15). All of the BP measurements were significantly lower in deceased group, except of BP before HD. (Table 1). Univariate regression analysis revealed that all of these pressures were linked to 1 year mortality, however, after application of stepwise forward selection model in multivariate analysis the most potent predictor was eluded to be MAP of the 1st HD hour (OR CI95% p), tripling the risk of mortality per every decrease of 10mmHg. However, the difference in precipitated risk of mortality for 2nd h, 3rd h and post HD MAP was minimal.
Conclusions:
One year mortality in HD patients is substantial. Blood pressure during and post HD is a more potent predictor of mortality than a blood pressure measured before the procedure. Further studies should investigate the application of intradialytic BP for the timely intervention.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.