Intraoperative Blood LossNCT07617428
Clinical Validation of a Blood Loss Monitoring System
An observational study of Intraoperative Blood Loss, run by Lanzhou University Second Hospital at 3 sites in China.
Trial summary
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… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Intraoperative Blood Loss
- How many people
- 170 participants
- Where
- 3 sitesChina
- Study dates
- 10 Sep 2025to 30 Dec 2026
- How long will I take part?
- 1 Day
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The study population will be recruited from adult patients undergoing elective urological and general surgical procedures at two tertiary hospitals in China, including Lanzhou University Second Hospital and Lanzhou University First Hospital. Participants will be selected from routine clinical practice settings where intraoperative blood loss monitoring is required. This population represents adult surgical patients managed under standard perioperative care, providing a real-world clinical context for evaluating intraoperative blood loss measurement methods.
Who may be able to join
- Patients undergoing elective urological or general surgical procedures
- Age 18 years or older
- Preoperative hemoglobin concentration available
- Intraoperative blood loss assessment required during surgery
Who cannot join
- 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
Trial locations and contacts
3 sites in 1 country. Contact the study team or a site near you to ask about taking part.
China3 sites
Gansu Provincial People's Hospital
Lanzhou, Gansu, 730030
Lanzhou University Frist Hospital
Lanzhou, Gansu, 730030
Lanzhou University Second Hospital
Lanzhou, Gansu, 730030
About this study
Official title: Prospective Multicenter Clinical Validation of a Novel Multifunctional Intraoperative 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.
- Conditions
- Intraoperative Blood Loss
- Keywords
- blood loss, Clinical Validation, Monitoring Equipment
- Medical subject headings
- Hemorrhage
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Self-controlled | This study includes a single self-controlled cohort of patients undergoing urological surgical procedures. All participants will undergo simultaneous intraoperative blood loss assessment using five different methods within the same surgical procedure: a novel multifunctional intraoperative blood loss monitoring system, the direct measurement method (reference standard), visual estimation, the gravimetric method, and the hemoglobin concentration-based method. No intervention is applied in this observational study. All measurements are performed according to a predefined protocol and do not interfere with the standard surgical workflow. The purpose of this design is to enable within-subject comparison of measurement accuracy across different methods under identical clinical conditions. | |
| Workflow feasibility and real-time responsiveness cohort | A separate workflow feasibility cohort assessed clinical implementation during routine surgery; these cases were excluded from accuracy and agreement analyses. Used sponges were inserted when no longer needed in the operative field, and suctioned fluid entered intermittently via the suction pathway. A sponge-processing event was each sponge insertion; a suction-response event was each visible episode of blood-containing fluid entering the pathway followed by an updated screen value. Response times were measured by two trained investigators independently reviewing de-identified intraoperative videos showing only the input port, suction pathway and display; disagreements were resolved by consensus or a third reviewer. Sponge response time was the interval from complete sponge insertion to stabilisation of the updated cumulative value; suction response time, from fluid entry to stabilisation; time to final result, from completion of final sample processing to availability of the final es | |
| Blood Recovery Subgroup: Independent Reference Assessment of Device Recovery Fraction | A consecutive subgroup of 40 participants undergoing elective urological surgery, enrolled to quantify completeness of blood recovery by the automatic monitor and to establish a device-independent reference standard. The automated elution step generates the mixed fluid used for the primary comparison, so both readings are multiplied by the same recovery fraction, which cancels; that comparison quantifies analytical agreement, not completeness of recovery. After the monitor reading is recorded, sponges are retrieved, weighed and manually re-eluted in measured saline, and the chamber, drainage tubing, suction canister and tubing are flushed with measured saline. Hemoglobin is measured in duplicate by the cyanmethemoglobin method. Outcomes: residual blood loss; EBL_ref = EBL_monitor + EBL_residual; recovery fraction f = EBL_monitor / EBL_ref. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Absolute error of the automatic intraoperative blood loss monitor compared with the direct measurement method
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)
Measured: At the end of surgery
Secondary outcomes (10)
Percentage error of the automatic intraoperative blood loss monitor compared with the direct measurement method
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
Measured: At the end of surgery
Absolute error of visual estimation compared with the direct measurement method
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
Measured: At the end of surgery
Absolute error of the gravimetric method compared with the direct measurement method
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
Measured: At the end of surgery
Absolute error of the hemoglobin concentration-based method compared with the direct measurement method
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
Measured: 24 hours after surgery
Intraclass correlation coefficient between the automatic intraoperative blood loss monitor and the direct measurement method
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
Measured: At the end of surgery
Bland-Altman mean bias between the automatic intraoperative blood loss monitor and the direct measurement method
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.
Measured: Unit of Measure: Milliliters
Bland-Altman limits of agreement between the automatic intraoperative blood loss monitor and the direct measurement method
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
Measured: At the end of surgery
workflow feasibility cohort
Because each patient could contribute multiple sponge-processing and suction-response events, response times were first summarised within each patient and patient-level medians were then summarised across the cohort. Case-level feasibility outcomes were reported as counts and percentages.
Measured: At the end of surgery
Device blood recovery fraction (f)
Proportion of shed hemoglobin recovered by the automated elution process of the monitor, calculated as f = EBL_monitor / EBL_ref, where EBL_monitor is the monitor reading and EBL_ref = EBL_monitor + EBL_residual. EBL_residual is derived from the residual hemoglobin mass recovered by manual re-elution of sponges and by flushing of the collection chamber, drainage tubing and suction circuit, divided by the preoperative hemoglobin concentration, after subtraction of mixed fluid carried over by wet sponges, the chamber dead-space contribution where applicable, and the batch blank. f = 1 indicates complete recovery. Reported as the mean with 95% confidence interval (t distribution), overall and within prespecified strata of reference blood loss (<=200, 201-500 and >500 mL).
Measured: Intraoperative; assessed within 30 minutes after completion of the surgical procedure and final sample processing.
Agreement between monitor-derived and independent reference blood loss
Ratio of monitor-derived to independent reference blood loss (EBL_monitor / EBL_ref), with 95% limits of agreement. Because incomplete recovery produces an error proportional to blood loss, agreement is assessed on the logarithmic scale and back-transformed; results are expressed as percentage differences. The prespecified clinically acceptable margin is +/-20% of the reference value, anchored to the hemoglobin content of half a unit of allogeneic whole blood. The proportion of measurements falling within this margin is reported. Values below the limit of quantification are assigned LOQ/sqrt(2) in the primary analysis; sensitivity analyses assign zero or exclude such measurements.
Measured: Intraoperative; assessed within 30 minutes after completion of the surgical procedure and final sample processing.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Jun 2026
- Study start10 Sep 2025
- Primary completion30 Dec 2026 (estimated)
- Study completion30 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Intraoperative Blood LossStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case only
- Time perspective
- Prospective
- Enrolment
- 170 participants (estimated)
- Target duration
- 1 Day
Sponsor and investigators
- Lead sponsor
- Lanzhou University Second Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- LanZhou University
- Responsible party
- Principal investigator, Zhiping Wang, Lanzhou University Second Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07617428
- Sponsor's protocol ID
- 2025A-987
- Status last verified
- Apr 2026
- First submitted
- 5 May 2026
- Last updated
- 15 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: The clinical data involves sensitive patient privacy. We are currently undecided on sharing the IPD, as it requires specific informed consent from the patients and authorization from the hospital's ethics committee.
Study at a glance
From the registry record, last updated by the sponsor on 15 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Prospective Multicenter Clinical Validation of a Novel Multifunctional Intraoperative Blood Loss Monitoring System
- ClinicalTrials.gov ID
- NCT07617428
- Acronym / sponsor ID
- 2025A-987
- Conditions
- Intraoperative Blood Loss
- Keywords
- blood loss, Clinical Validation, Monitoring Equipment
- Study type
- Observational
- Recruitment status
- Enrolling by invitation
- Enrolment
- 170 participants (estimated)
- Lead sponsor
- Lanzhou University Second HospitalUniversity, hospital or other
- Collaborators
- LanZhou University
- Study start
- 10 Sep 2025 (actual)
- Primary completion
- 30 Dec 2026 (estimated)
- Study completion
- 30 Dec 2026 (estimated)
- First posted
- 1 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Observational model
- Case only
- Time perspective
- Prospective
- Target follow-up
- 1 Day
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Self-controlled | – | –This study includes a single self-controlled cohort of patients undergoing urological surgical procedures. All participants will undergo simultaneous intraoperative blood loss assessment using five different methods within the same surgical procedure: a novel multifunctional intraoperative blood loss monitoring system, the direct measurement method (reference standard), visual estimation, the gravimetric method, and the hemoglobin concentration-based method. No intervention is applied in this observational study. All measurements are performed according to a predefined protocol and do not interfere with the standard surgical workflow. The purpose of this design is to enable within-subject comparison of measurement accuracy across different methods under identical clinical conditions. |
| Workflow feasibility and real-time responsiveness cohort | – | –A separate workflow feasibility cohort assessed clinical implementation during routine surgery; these cases were excluded from accuracy and agreement analyses. Used sponges were inserted when no longer needed in the operative field, and suctioned fluid entered intermittently via the suction pathway. A sponge-processing event was each sponge insertion; a suction-response event was each visible episode of blood-containing fluid entering the pathway followed by an updated screen value. Response times were measured by two trained investigators independently reviewing de-identified intraoperative videos showing only the input port, suction pathway and display; disagreements were resolved by consensus or a third reviewer. Sponge response time was the interval from complete sponge insertion to stabilisation of the updated cumulative value; suction response time, from fluid entry to stabilisation; time to final result, from completion of final sample processing to availability of the final es |
| Blood Recovery Subgroup: Independent Reference Assessment of Device Recovery Fraction | – | –A consecutive subgroup of 40 participants undergoing elective urological surgery, enrolled to quantify completeness of blood recovery by the automatic monitor and to establish a device-independent reference standard. The automated elution step generates the mixed fluid used for the primary comparison, so both readings are multiplied by the same recovery fraction, which cancels; that comparison quantifies analytical agreement, not completeness of recovery. After the monitor reading is recorded, sponges are retrieved, weighed and manually re-eluted in measured saline, and the chamber, drainage tubing, suction canister and tubing are flushed with measured saline. Hemoglobin is measured in duplicate by the cyanmethemoglobin method. Outcomes: residual blood loss; EBL_ref = EBL_monitor + EBL_residual; recovery fraction f = EBL_monitor / EBL_ref. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The study population will be recruited from adult patients undergoing elective urological and general surgical procedures at two tertiary hospitals in China, including Lanzhou University Second Hospital and Lanzhou University First Hospital. Participants will be selected from routine clinical practice settings where intraoperative blood loss monitoring is required. This population represents adult surgical patients managed under standard perioperative care, providing a real-world clinical context for evaluating intraoperative blood loss measurement methods.
Key inclusion criteria (4 listed)
- Patients undergoing elective urological or general surgical procedures
- Age 18 years or older
- Preoperative hemoglobin concentration available
- Intraoperative blood loss assessment required during surgery
Key exclusion criteria (5 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
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)
10 secondary outcomes
Percentage error of the automatic intraoperative blood loss monitor compared with the direct measurement method
Time frame: At the end of surgery
Absolute error of visual estimation compared with the direct measurement method
Time frame: At the end of surgery
Absolute error of the gravimetric method compared with the direct measurement method
Time frame: At the end of surgery
Absolute error of the hemoglobin concentration-based method compared with the direct measurement method
Time frame: 24 hours after surgery
Intraclass correlation coefficient between the automatic intraoperative blood loss monitor and the direct measurement method
Time frame: At the end of surgery
Bland-Altman mean bias between the automatic intraoperative blood loss monitor and the direct measurement method
Time frame: Unit of Measure: Milliliters
Bland-Altman limits of agreement between the automatic intraoperative blood loss monitor and the direct measurement method
Time frame: At the end of surgery
workflow feasibility cohort
Time frame: At the end of surgery
Device blood recovery fraction (f)
Time frame: Intraoperative; assessed within 30 minutes after completion of the surgical procedure and final sample processing.
Agreement between monitor-derived and independent reference blood loss
Time frame: Intraoperative; assessed within 30 minutes after completion of the surgical procedure and final sample processing.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Oct 2026.
- Individual participant dataSharing planned: Undecided. The clinical data involves sensitive patient privacy. We are currently undecided on sharing the IPD, as it requires specific informed consent from the patients and authorization from the hospital's ethics committee.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Intraoperative Blood Loss, run by Lanzhou University Second Hospital at 3 sites in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 15 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Absolute error of the automatic intraoperative blood loss monitor compared with the direct measurement method (time frame: At the end of surgery). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 Oct 2026.