Ultrasound-guided haemodynamic profiling in haemodialysis patients: a single-centre prospective observational study protocol

Background Intradialytic hypotension (IDH) and chronic fluid overload are common and clinically important complications of maintenance haemodialysis, yet routine volume assessment remains imprecise. Multi-organ point-of-care ultrasound may provide a structured bedside assessment of cardiac reserve, pulmonary congestion and venous congestion. Methods and analysis This single-centre prospective observational cohort study will enrol approximately 60 adult patients receiving maintenance haemodialysis. Participants will undergo integrated ultrasound profiling immediately before and after dialysis at baseline and at 3, 6 and 9 months, with clinical outcomes followed for 12 months. The ultrasound protocol includes focused cardiac ultrasound, eight-zone lung ultrasound B-line quantification and a modified VEXUS assessment using inferior vena cava, hepatic vein and portal vein findings. Event-triggered intradialytic scans may also be performed for current IDH or suspected mismatch between the prescribed target weight and the best clinically tolerated weight. These examinations will not be pooled with scheduled assessments. A separate exploratory post-scan association analysis will include only scans completed while the patient is clinically stable, before the first same-session IDH and not in response to evolving current-session haemodynamic instability; the outcome is subsequent IDH before session end. Scans obtained during or after IDH or during evolving instability will be described only. The main descriptive objective is to characterise pre- and post-dialysis ultrasound-derived haemodynamic profiles and their within-session and longitudinal variability. The primary prespecified analysis for Objective 2 is an exploratory and non-confirmatory assessment of the within-patient association between pre-dialysis ultrasound parameters and same-session IDH using a scheduled-session case-crossover design. Secondary analyses include the separate event-triggered post-scan association analysis and an exploratory scheduled-session mixed-effects analysis. Event-triggered examinations will not contribute cases to the primary analysis. Exploratory objectives assess clinician-perceived usefulness and documented clinician-implemented prescription changes after delayed disclosure, without assessing clinical benefit. Ethics and dissemination The study has received ethics approval and will be conducted after written informed consent. Results will be disseminated through peer-reviewed publications and scientific meetings. Study registration https://www.isrctn.com/ISRCTN80571205 , identifier ISRCTN80571205.