Background: Regular monitoring of vascular access in patients on maintenance hemodialysis is important to detect early vascular access complications. We compared vascular access blood flow determined by blood temperature monitor and Doppler ultrasonography to evaluate the usefulness of blood temperature monitor.
Methods: In total, 70 patients on maintenance hemodialysis were enrolled from three dialysis centers. Vascular access blood flow was measured thrice at 6-month intervals using Doppler ultrasonography to determine arterial inflow (Q-DUa), venous outflow (Q-DUv), and flow between punctures (Q-DUb) using BTM® (Q-BTM). Twister® was placed between the hemodialysis needle and blood lines, allowing simple reversal of flow without stopping the hemodialysis pump.
Results: In total, 203 measurements were recorded, with median values (interquartile range) for Q-BTM, Q-DUa, Q-DUv, and Q-DUb of 1139.0 (868.0-1588.0) mL/min, 960.3 (658.7-1380.4) mL/min, 946.0 (552.0-1515.0) mL/min, and 1067.7 (544.8-1635.0) mL/min, respectively. For all measurements, the mean intraclass correlation coefficients were 0.52 (95% confidence interval, 0.36-0.64) for Q-DUa; 0.37 (95% confidence interval, 0.15-0.53) for Q-DUv; and 0.45 (95% confidence interval, 0.26-0.59) for Q-DUb. Analysis of a receiver operating characteristics curve yielded a cut-off of 627 mL/min for Q-BTM to predict stenosis.
Conclusion: In patients on maintenance hemodialysis, blood flow measured by blood temperature monitor moderately correlated with Doppler blood flow. It was more related to arterial inflow than venous outflow or flow between punctures. The blood temperature monitor method was not inferior to Doppler ultrasonography. Therefore, blood temperature monitor could be recommended for routine vascular access monitoring because it can be done quickly without interrupting dialysis.
Keywords: Blood flow; blood temperature monitoring; vascular access.