Internal jugular vein ultrasound for fluid status assessment in maintenance haemodialysis: a prospective hypothesis-generating pilot study

Assessment of fluid status in patients receiving maintenance haemodialysis remains challenging. Point-of-care ultrasound (PoCUS) is increasingly used to support bedside assessment of volume overload. The internal jugular vein (IJV) has been proposed as a potential marker of central venous pressure and systemic congestion. This hypothesis-generating pilot study aimed to explore the feasibility and potential clinical utility of IJV ultrasound in patients undergoing maintenance haemodialysis and to identify candidate parameters for future validation. We conducted a prospective observational hypothesis-generating pilot study including CKD G5D patients undergoing maintenance haemodialysis. Patients with a history of jugular vein thrombosis, patients unable to complete the study procedures, and patients routinely receiving dialysis sessions without ultrafiltration were excluded. Immediately before and after a scheduled haemodialysis session, patients underwent PoCUS examination of the IJV. Thirty-six ultrasonographic parameters were collected and analysed. Exploratory associations between ultrasound parameters and fluid overload (delta from dry weight), potential clinical or technical modifiers, and pre- to post-dialysis changes were assessed. Forty-nine patients were enrolled. IJV ultrasound was feasible in all participants. No FDR-significant pre-HD IJV differences or associations were observed for the examined potential modifiers. Several pre-HD ultrasonographic parameters were associated with delta from dry weight after correction for multiple testing; AP, LL, and CSA during inspiration, JVD Ratio, and CSA Ratio represented the most robust candidate parameters. Fifteen of 18 paired ultrasound parameters remained significantly different between pre-HD and post-HD after FDR correction. In this hypothesis-generating pilot study, IJV ultrasound was feasible at the bedside and several IJV parameters showed exploratory associations with fluid status. These findings do not establish diagnostic thresholds or routine clinical applicability and require external validation in larger prospective cohorts.