Transonic, thermodilution, or ionic dialysance to manage vascular access: which method is best?

Area of Science:

• Nephrology
• Vascular Surgery
• Biomedical Engineering

Background:

• Regular monitoring of vascular access blood flow (Qa) is crucial for predicting dysfunction and preventing thromboses.
• Integrated access flow devices offer potential for easier and more cost-effective monitoring.

Purpose of the Study:

• To compare the accuracy and reproducibility of two integrated access flow devices: thermodilution (Qa-BTM) and ionic dialysance (Qa-ID).
• To evaluate these devices against the gold standard saline dilution method (Qa-T) for measuring Qa in hemodialysis patients.

Main Methods:

• Sequential measurements of access flow using Qa-T, Qa-BTM, and Qa-ID were performed in 24 long-term hemodialysis patients.
• Statistical analyses included Bland-Altman, linear regression (r²), and intraclass correlation coefficients (ICC) to assess reproducibility, correlations, and concordance.
• Recirculation was measured using both saline dilution and thermodilution methods.

Main Results:

• Average access flow measurements were comparable across all three methods (Qa-T: 1549 mL/min, Qa-BTM: 1530 mL/min, Qa-ID: 1619 mL/min).
• Thermodilution (Qa-BTM) demonstrated superior precision and concordance with saline dilution (ICC=0.99, r²=0.98, bias=-19 mL/min) compared to ionic dialysance (ICC=0.75, r²=0.65, bias=+69 mL/min).
• Reproducibility of thermodilution and ionic dialysance was not significantly different from saline dilution; recirculation measurements were identical (0%).

Conclusions:

• Integrated access flow measurement devices, specifically thermodilution, are reliable alternatives to saline dilution for monitoring vascular access.
• Thermodilution offers enhanced precision and correlation, simplifying vascular access monitoring without additional costs or consumables.
• These integrated devices facilitate easier monitoring, potentially reducing thrombotic events in hemodialysis patients.