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NCT Number: NCT07617428

Clinical Validation of a Blood Loss Monitoring System

This observational study aims to evaluate the practicality of a novel multifunctional intraoperative blood loss monitoring system in real-world surgical settings. The primary questions it seeks to address are:

Using the direct measurement method as the reference standard, what is the magnitude of measurement error of the monitoring system, and does it tend to overestimate or underestimate blood loss? Does the monitoring system demonstrate superior accuracy compared with visual estimation, the gravimetric method, and the hemoglobin concentration-based method? During surgery, intraoperative blood loss will be measured simultaneously using five approaches: the novel multifunctional monitoring system, the direct measurement method, visual estimation, the gravimetric method, and the hemoglobin concentration method. These measurements will be conducted without interfering with the surgical procedure.

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Key information

Conditions

Intraoperative Blood Loss Hemorrhage Pathologic Processes Pathological Conditions, Signs and Symptoms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Gansu Provincial People's Hospital, Lanzhou, Gansu, China

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients undergoing elective urological or general surgical procedures
  • Age 18 years or older
  • Preoperative hemoglobin concentration available
  • Intraoperative blood loss assessment required during surgery

Exclusion criteria

  • Patients with incomplete intraoperative blood loss measurement data,
  • Severe hemolysis or other conditions that may affect hemoglobin measurement
  • Emergency surgery
  • Intraoperative blood loss assessment required during surgery 24 hours after surgery
  • Refusal to participate, when applicable

Treatment and study plan

Primary outcomes

  1. Absolute error of the automatic intraoperative blood loss monitor compared with the direct measurement method

    Time frame: At the end of surgery

    Absolute error is defined as the numerical difference between intraoperative blood loss measured by the automatic intraoperative blood loss monitor and intraoperative blood loss measured by the direct measurement method. A positive value indicates that the monitor overestimates blood loss compared with the direct measurement method, whereas a negative value indicates underestimation.

    Unit of Measure: Milliliters (mL)

Secondary outcomes

  1. Percentage error of the automatic intraoperative blood loss monitor compared with the direct measurement method

    Time frame: At the end of surgery

    Percentage error is defined as the relative difference between intraoperative blood loss measured by the automatic intraoperative blood loss monitor and intraoperative blood loss measured by the direct measurement method, expressed as a percentage of the average value obtained by the two methods. A positive value indicates overestimation by the monitor, whereas a negative value indicates underestimation.

    Unit of Measure: Percentage

  2. Absolute error of visual estimation compared with the direct measurement method

    Time frame: At the end of surgery

    Absolute error is defined as the numerical difference between intraoperative blood loss estimated by visual estimation and intraoperative blood loss measured by the direct measurement method. A positive value indicates overestimation by visual estimation, whereas a negative value indicates underestimation.

    Unit of Measure: Milliliters

  3. Absolute error of the gravimetric method compared with the direct measurement method

    Time frame: At the end of surgery

    The accuracy of five methods (monitoring system, direct measurement, visual Absolute error is defined as the numerical difference between intraoperative blood loss estimated by the gravimetric method and intraoperative blood loss measured by the direct measurement method. A positive value indicates overestimation by the gravimetric method, whereas a negative value indicates underestimation.

    Unit of Measure: Milliliters

  4. Absolute error of the hemoglobin concentration-based method compared with the direct measurement method

    Time frame: 24 hours after surgery

    Absolute error is defined as the numerical difference between blood loss estimated by the hemoglobin concentration-based method and intraoperative blood loss measured by the direct measurement method. The hemoglobin concentration-based estimate is calculated using preoperative hemoglobin concentration, hemoglobin concentration measured 24 hours after surgery, and estimated blood volume. A positive value indicates overestimation by the hemoglobin concentration-based method, whereas a negative value indicates underestimation.

    Unit of Measure: Milliliters

  5. Intraclass correlation coefficient between the automatic intraoperative blood loss monitor and the direct measurement method

    Time frame: At the end of surgery

    The intraclass correlation coefficient is used to quantify agreement between intraoperative blood loss measured by the automatic intraoperative blood loss monitor and intraoperative blood loss measured by the direct measurement method. Higher values indicate stronger agreement between the two methods.

    Unit of Measure: Unitless coefficient

  6. Bland-Altman mean bias between the automatic intraoperative blood loss monitor and the direct measurement method

    Time frame: Unit of Measure: Milliliters

    Bland-Altman mean bias is defined as the mean difference between intraoperative blood loss measured by the automatic intraoperative blood loss monitor and intraoperative blood loss measured by the direct measurement method. A positive mean bias indicates systematic overestimation by the monitor, whereas a negative mean bias indicates systematic underestimation.

  7. Bland-Altman limits of agreement between the automatic intraoperative blood loss monitor and the direct measurement method

    Time frame: At the end of surgery

    Bland-Altman limits of agreement describe the range within which most differences between intraoperative blood loss measured by the automatic intraoperative blood loss monitor and intraoperative blood loss measured by the direct measurement method are expected to fall.

    Unit of Measure: Milliliters

Sponsors and collaborators

Lead sponsor

Lanzhou University Second Hospital

Other

Collaborators

  • Lanzhou University First Hospital

Registry information

Official study title

Prospective Multicenter Clinical Validation of a Novel Multifunctional Intraoperative Blood Loss Monitoring System

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Jun 1, 2026
Registry last updated
Jun 23, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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