IntroductionIntradialytic hypotension (IDH) is a frequent and serious complication of maintaining haemodialysis (HD) patients and associated with subsequent cardiovascular events and higher mortality. Furosemide is commonly used in non-dialysis chronic kidney disease patients and can effectively manage the volume and blood pressure. However, these agents are often discontinued on initiation of dialysis. Two large observational studies have demonstrated that furosemide can lower the rate of IDH episodes. However, there is still no randomised controlled trial (RCT) to investigate the efficacy and safety of furosemide for prevention of IDH in HD patients. The purpose of this study was to assess the efficacy of furosemide in reducing IDH in HD patients with residual renal function.Methods and analysisA two-arm, parallel, multicente RCT will be conducted at 12 hospitals in China. An estimated sample of 560 HD patients will be recruited. Eligible patients will be randomly assigned to treatment group (patients receive oral furosemide 80 mg/day; after a 2-week treatment, if their urine volume is less than 400 mL/day, the dose of furosemide is adjusted to 160 mg/day) and blank control group via a central randomisation system using 1:1 ratio. The primary outcome is the occurrence of IDH. Outcome assessors and data analysts will be blinded and participants will be asked not to reveal their allocation to assessors. The outcome analyses will be performed both on the intention-to-treat, which includes all patients randomised, and per-protocol population, which includes eligible patients who adhere to the planned treatment and follow-ups.Ethics and disseminationThe trial protocol has been approved by the Biomedical Research Ethics Committee of West China Hospital of Sichuan University (2019.385)Results will be presented at national and international conferences and published in peer-reviewed journals.Trial registration numberChiCTR2000039724.

Background: The current practice involves blood sampling from the circuit line to measure acid-base and electrolyte parameters during continuous renal replacement therapy (CRRT). However, there is limited evidence supporting its reliability due to the effects of anticoagulant mechanism and access recirculation associated with regional citrate anticoagulation (RCA).Aim: To evaluate the reliability of monitoring acid-base and electrolyte parameters through circuit lines in regular and reversed connections during RCA-CRRT. Study design:In this prospective cohort study, we included critically ill patients receiving RCA-CRRT via a double-lumen catheter. During the second hour after CRRT initiation, we collected blood samples to monitor acid-base and electrolyte parameters and their levels were compared between samples from the circuit lines (at 0, 3, and 5 minutes) and those from the central venous catheter (CVC) line (at 0 minute). During this time, CRRT switched to the replacement state as controls. Results:We observed 128 CRRT circuits in 60 adult patients receiving RCA-CRRT.Ninety-eight (76.6%) circuits had regular connections, while 30 (23.4%) had reversed connections. Among regular connections, no differences were observed in any acidbase or electrolyte parameters between samples from the CVC line and those from the circuit line at all time points (P > .05). Among reversed connections, ionized calcium levels were dramatically decreased at all three time points in samples from the circuit line compared with those from the CVC line (0.65 ± 0.12, 0.72 ± 0.11, and 0.78 ± 0.99 vs 0.98 ± 0.07 mmol/L, P < .001), with comparable levels of other acidbase or electrolyte parameters between the sampling patterns (P > .05).Conclusions: Acid-base and electrolyte parameters could be reliably monitored through the circuit line during RCA-CRRT in regular connections. However, in reversed connections, pre-filter ionized calcium concentrations determined through the circuit line were lower than those determined through the CVC line.