This multicenter, prospective observational study aims to evaluate the predictive value of the Inferior Vena Cava Collapsibility Index (IVCCI), along with IVC maximum diameter (IVCmax) and IVC minimum diameter (IVCmin), for intradialytic hypotension in patients undergoing maintenance hemodialysis. The study will be conducted at The First Affiliated Hospital of Wannan Medical College, Wuhu City Second People's Hospital, Wuhu Hospital of Chinese Traditional Medicine, Wuhu Jinghu District Hospital, and Wuhu Guangji Hospital. Eligible participants are adults aged 18 years or older with diagnosed end-stage renal disease (ESRD), receiving regular hemodialysis for at least three months. Patients with acute kidney injury, severe cardiac conditions, or other factors likely to influence results will be excluded.

Ultrasound measurements of IVCCI, IVCmax, and IVCmin will be performed once, precisely at 1 hour after dialysis initiation. IVCmax will be measured during inspiration when the IVC is at its largest, and IVCmin during expiration when it is at its smallest. Blood pressure will be monitored continuously during the procedure. The primary objective is to assess the sensitivity, specificity, and optimal cutoff values of IVCCI, IVCmax, and IVCmin for predicting hypotension, aiming to provide a simple and non-invasive tool to facilitate personalized dialysis management and reduce intradialytic hypotension. A sample size of 188 participants is estimated, with data analyzed using ROC curves and multivariate regression methods. The study protocol adheres to ethical standards and regulatory requirements, demonstrating potential to improve patient safety and treatment outcomes.

Inclusion Criteria:

• Adults aged 18 years or older.
• Diagnosed with end-stage renal disease (ESRD).
• Undergoing regular hemodialysis for at least three months.

Exclusion Criteria:

• Pregnant or breastfeeding women.
• Hemodynamically unstable patients or those requiring vasopressor support.
• Patients with severe cardiac conditions, including congestive heart failure -classified as NYHA Class III-IV or severe valvular disease.
• Patients with known allergies to dialysis filters.
• Dialysis sessions terminated for reasons unrelated to hypotension (e.g., technical issues, patient request).
• Patients who withdraw informed consent during the study.
• Use of antihypertensive medications during dialysis sessions.
• Inability to undergo ultrasound assessment due to factors such as severe obesity or wounds obstructing access.

Adult patients aged 18 to 80 years with end-stage renal disease who have been receiving maintenance hemodialysis for more than three months at participating dialysis centers. Participants are required to be able to provide informed consent and cooperate with study procedures.