A Prediction Model of Basic Blood Volume Based on Hemodynamics and Ultrasound

Shanghai Jiao Tong University

Status: Begins enrollment this month

Conditions: Blood Volume Analysis; Ultrasound; Hemodynamic

Study type: Observational

Funder types: Other

Identifiers

NCT06957587

2025-135

Details and patient eligibility

About

1. Research Background

   Effective blood volume management is critical in perioperative and critical care settings, as both hypovolemia and hypervolemia can lead to severe complications, including organ dysfunction, hemodynamic instability, and increased mortality. Traditional methods of assessing blood volume, such as central venous pressure (CVP) monitoring, have significant limitations, including poor sensitivity and delayed responsiveness to dynamic changes in intravascular volume status.

   In recent years, continuous hemodynamic monitoring (e.g., LiDCO) and point-of-care ultrasound (POCUS) have emerged as promising tools for real-time blood volume assessment. The LiDCO system provides dynamic parameters such as stroke volume variation (SVV), pulse pressure variation (PPV), cardiac output (CO), and systemic vascular resistance (SVR), which are highly sensitive to fluid responsiveness. Meanwhile, inferior vena cava (IVC) ultrasound offers non-invasive measurements of IVC diameter, cross-sectional area (CSA), and collapsibility index (IVC-CI), which correlate with intravascular volume status.

   Despite these advances, no integrated model currently combines continuous hemodynamic and IVC ultrasound parameters to predict blood volume quantitatively. Most existing approaches rely on either static measurements (e.g., CVP) or single-modality dynamic indices (e.g., SVV alone), which may not fully capture the complex interplay between vascular tone, cardiac function, and circulating blood volume.

2. Current Research Status 2.1 Hemodynamic Monitoring in Blood Volume Assessment

   The LiDCO system, based on pulse contour analysis, provides real-time hemodynamic data that are strongly associated with fluid responsiveness. Studies have demonstrated that SVV >10-13% and PPV >12% reliably predict fluid responsiveness in mechanically ventilated patients. However, these parameters are influenced by factors such as cardiac arrhythmias, spontaneous breathing, and vasopressor use, limiting their standalone predictive accuracy.

   2.2 IVC Ultrasound in Volume Status Evaluation

   IVC ultrasound has gained traction as a rapid, non-invasive method for assessing volume status. Key parameters include:

   IVC maximum diameter (IVCmax): A distended IVC (>2 cm) suggests volume overload, while a collapsed IVC (<1.5 cm) indicates hypovolemia.

   IVC collapsibility index (IVC-CI): Calculated as (IVCmax - IVCmin)/IVCmax × 100%, an IVC-CI >50% is highly predictive of fluid responsiveness.

   IVC cross-sectional area (IVC-CSA): Emerging evidence suggests that IVC-CSA changes may better reflect intravascular volume than diameter alone.

   2.3 Limitations of Existing Models

   Current blood volume assessment methods suffer from:

   Lack of integration: Most studies analyze hemodynamic and ultrasound parameters separately rather than combining them into a unified predictive model.

   Qualitative rather than quantitative assessment: While SVV and IVC-CI can indicate fluid responsiveness, they do not provide an absolute blood volume estimation.

3. Research Objectives

This study aims to develop and validate a machine learning-based predictive model integrating LiDCO hemodynamic and IVC ultrasound parameters for quantitative assessment of preoperative basic blood volume.

Enrollment: 300 estimated patients

Sex: All

Ages: 18 to 75 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Agree to join this study and sign the informed consent form; Age between 18 and 75 years old (inclusive); BMI (body mass index) is between 18 and 30 kg/m2; American Society of Anesthesiologists (ASA) grades I-II;

Exclusion criteria

• Coagulation dysfunction (INR>1.5, PLT<50 × 10 ⁹/L); Severe heart failure (LVEF<40%), liver and kidney dysfunction, respiratory dysfunction; Hemoglobin (Hb)<8 g/dL; Those who have no indications for invasive arterial monitoring, refuse to undergo invasive arterial monitoring, or have contraindications for arterial puncture; Pregnant woman; Combined chest and abdominal multiple injuries or cervical spine injuries; Frequent arrhythmias, including atrial flutter, atrial fibrillation, frequent premature ventricular contractions, atrioventricular block, or implantation of pacemakers.

Trial design

300 participants in 1 patient group

patients undergoing general anesthesia

Description:

The patients aged 18-75 years old undergoing general anesthesia will be assigned into the cohort.