Non-Invasive Blood Pressure Monitoring in Trendelenburg PositionNCT07107425
How Accurate Is Non-Invasive Blood Pressure Monitoring During Trendelenburg Laparoscopic Surgery?
An observational study of Non-Invasive Blood Pressure Monitoring in Trendelenburg Position, run by Koç University at 1 site in Turkey (Türkiye).
Trial summary
This study will test how accurate a blood pressure cuff is during certain types of surgery. During some abdominal surgeries done with small tools and a camera (called laparoscopic surgery), doctors place patients in a head-down position called the Trendelenburg position. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Non-Invasive Blood Pressure Monitoring in Trendelenburg Position
- How many people
- 100 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 Sep 2025to 15 Nov 2025
- 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: Participants will be selected from adult patients scheduled for laparoscopic surgery in the Trendelenburg position at Koç University Hospital, a tertiary care academic medical center in Istanbul, Turkey.
Who may be able to join
- Age 18 years or older
- Scheduled to undergo laparoscopic surgery in the Trendelenburg position
- Will receive invasive arterial blood pressure monitoring as part of routine clinical care
Who cannot join
- Has peripheral artery disease
- Has congestive heart failure
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Accuracy of Non-Invasive Blood Pressure Monitoring During Laparoscopic Surgery in the Trendelenburg Position: A Prospective Error Grid Analysis
This study will test how accurate a blood pressure cuff is during certain types of surgery.
During some abdominal surgeries done with small tools and a camera (called laparoscopic surgery), doctors place patients in a head-down position called the Trendelenburg position. In this position, it may be harder for the blood pressure cuff on the arm to give correct readings. This study will compare the cuff's readings (non-invasive) with readings from a thin tube placed inside an artery (invasive), which is more accurate but also more risky and uncomfortable.
Read more
The researchers will use a method called error grid analysis to check how closely the cuff readings match the invasive ones. They hope to learn if the blood pressure cuff is accurate enough to be used safely in this kind of surgery. If it is, doctors may not need to use the invasive method as often.
People 18 years or older who are already going to have invasive blood pressure monitoring as part of their planned surgery can join the study. The study will collect blood pressure measurements about every 20 minutes during surgery, as well as basic information like age, weight, and what medicines are given.
Read the detailed description
This is a prospective observational study designed to evaluate the clinical accuracy and reliability of non-invasive blood pressure (NIBP) monitoring in adult patients undergoing laparoscopic surgery in the Trendelenburg position. The accuracy of NIBP will be assessed by comparing it to invasive arterial blood pressure (IABP), which is considered the reference standard. The comparison will be performed using error grid analysis, a method that not only quantifies measurement differences but also categorizes the clinical risk of those discrepancies.
The Trendelenburg position, characterized by a head-down tilt of the patient, is frequently employed during gynecological and urological laparoscopic procedures to enhance surgical exposure. However, this positioning alters hemodynamic physiology and may influence peripheral blood pressure measurements. Previous evaluations of NIBP in this context have primarily relied on Bland-Altman analysis, which measures statistical agreement but does not assess the potential clinical consequences of disagreement between methods.
Error grid analysis overcomes this limitation by mapping paired NIBP and IABP values into predefined risk zones (A-E), based on their potential to affect clinical decision-making. Zone A reflects acceptable agreement with no risk of incorrect treatment, whereas Zones B through E indicate increasing levels of clinical risk.
In this study, NIBP and IABP will be measured simultaneously every 20 minutes throughout the procedure. The proportion of measurements falling within each error grid zone will be calculated. If fewer than 90% of the paired measurements fall within Zone A, NIBP will be considered insufficiently reliable for use in this surgical context without concurrent invasive monitoring.
A pilot study of five patients was conducted to estimate the intracluster correlation coefficient and design effect, which informed the final sample size calculation. Based on these preliminary data, a total of 100 patients is estimated to provide adequate statistical power to evaluate the primary outcome with 95% confidence and a 5% margin of error.
The study will also document intraoperative variables that may affect blood pressure measurement accuracy, including the use of vasoactive infusions. These data may provide insight into subgroups where NIBP reliability is particularly limited or acceptable.
The findings of this study may inform future monitoring protocols and could reduce unnecessary use of invasive lines in appropriately selected patients, improving patient safety and comfort while maintaining clinical accuracy.
- Keywords
- Trendelenburg position, Laparoscopic surgery, Non-invasive blood pressure, Invasive arterial pressure, Error grid analysis, Hemodynamic monitoring
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 |
|---|---|---|
| Surgical Cohort | Adults (18 years and older) undergoing laparoscopic surgery in the Trendelenburg position who are already scheduled to receive invasive arterial blood pressure monitoring as part of routine clinical care. Participants will have paired invasive and non-invasive blood pressure measurements recorded during surgery for comparison using error grid analysis. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Proportion of Paired Systolic Blood Pressure Measurements Within Zone A of the Error Grid
The percentage of systolic non-invasive blood pressure (NIBP) measurements that fall within Zone A of the consensus error grid with calibrated risk zones, as described by Saugel et al.[1]. Zone A represents measurement pairs with no risk of leading to inappropriate clinical decisions, based on comparison with simultaneously recorded systolic invasive arterial blood pressure values. Systolic NIBP measurements will be considered acuurate if 90% or more of the paired values fall within Zone A.
- Saugel B, Grothe O, Nicklas JY. Error Grid Analysis for Arterial Pressure Method Comparison Studies. Anesth Analg. 2018 Apr;126(4):1177-1185
Measured: Intraoperative period (measurements taken every 20 minutes during surgery)
Proportion of Paired Mean Arterial Pressure (MAP) Measurements Within Zone A of the Error Grid
The percentage of non-invasive mean arterial pressure (MAP) measurements that fall within Zone A of the consensus error grid with calibrated risk zones, as described by Saugel et al.[1]. Zone A represents measurement pairs with no risk of leading to inappropriate clinical decisions, based on comparison with simultaneously recorded invasive MAP values. Non-invasive MAP measurements will be considered accurate if 90% or more of the paired values fall within Zone A.
- Saugel B, Grothe O, Nicklas JY. Error Grid Analysis for Arterial Pressure Method Comparison Studies. Anesth Analg. 2018 Apr;126(4):1177-1185
Measured: Intraoperative period (measurements taken every 20 minutes during surgery)
Secondary outcomes (4)
Distribution of Paired Systolic Blood Pressure Measurements Across All Error Grid Zones (A-E)
The percentage of paired systolic blood pressure measurements that fall into each zone (A, B, C, D, E) of the consensus error grid. Error grid zones reflect the clinical risk of acting on the non-invasive measurement:
Zone A: No risk Zone B: Low risk Zone C: Moderate risk Zone D: Significant risk of undertreatment Zone E: Significant risk of overtreatment The distribution will be reported as the percentage of all paired measurements falling into each zone.
Measured: Intraoperative period (measurements taken every 20 minutes during surgery)
Distribution of Paired Mean Arterial Pressure (MAP) Measurements Across All Error Grid Zones (A-E)
the percentage of paired mean arterial pressure (MAP) measurements that fall into each zone (A through E) of the consensus error grid. Error grid zones reflect the clinical risk of acting on the non-invasive measurement: Zone A: No risk Zone B: Low risk Zone C: Moderate risk Zone D: Significant risk of undertreatment Zone E: Significant risk of overtreatment The distribution will be reported as the percentage of all paired measurements falling into each zone.
Measured: Intraoperative period (measurements taken every 20 minutes during surgery)
Effect of Antihypertensive Medication Use on the Accuracy of Systolic NIBP Measurements
This outcome compares the likelihood that individual systolic non-invasive blood pressure (NIBP) measurements fall within Zone A of the consensus error grid between participants who use antihypertensive medications and those who do not. Zone A indicates values that would not lead to inappropriate clinical decisions.
To account for the fact that multiple blood pressure measurements are collected from each participant, the analysis will use mixed-effects logistic regression. This model includes a random effect for each participant to account for the correlation among repeated measurements within the same individual.
Measured: Intraoperative period (measurements taken every 20 minutes during surgery)
Effect of Antihypertensive Medication Use on the Accuracy of Mean Arterial Pressure (MAP) NIBP Measurements
This outcome compares the likelihood that individual non-invasive mean arterial pressure (MAP) measurements fall within Zone A of the consensus error grid between participants with and without antihypertensive medication use. Zone A represents measurement pairs that are clinically acceptable.
To account for the fact that multiple blood pressure measurements are collected from each participant, the analysis will use mixed-effects logistic regression. This model includes a random effect for each participant to account for the correlation among repeated measurements within the same individual.
Measured: Intraoperative period (measurements taken every 20 minutes during surgery)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Aug 2025
- Study start1 Sep 2025 (estimated)
- Primary completion1 Nov 2025 (estimated)
- Study completion15 Nov 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Non-Invasive Blood Pressure Monitoring in Trendelenburg PositionStudies 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
- Cohort
- Time perspective
- Prospective
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Koç University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Kamil Darcin, Koç University
- Investigators
- Kamil Darcin, MD, Study director, Koç University School of Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07107425
- Sponsor's protocol ID
- 2025.243.IRB2.109
- Status last verified
- Jul 2025
- First submitted
- 30 Jul 2025
- Last updated
- 6 Aug 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Anonymized individual participant data (IPD) that underlie the results of the study will be shared. These data will be made publicly available through the Zenodo repository following study completion and publication.
Publications
Saugel B, Grothe O, Nicklas JY. Error Grid Analysis for Arterial Pressure Method Comparison Studies. Anesth Analg. 2018 Apr;126(4):1177-1185. doi: 10.1213/ANE.0000000000002585.
PubMed 29239945
Study at a glance
From the registry record, last updated by the sponsor on 6 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Accuracy of Non-Invasive Blood Pressure Monitoring During Laparoscopic Surgery in the Trendelenburg Position: A Prospective Error Grid Analysis
- ClinicalTrials.gov ID
- NCT07107425
- Acronym / sponsor ID
- 2025.243.IRB2.109
- Keywords
- Trendelenburg position, Laparoscopic surgery, Non-invasive blood pressure, Invasive arterial pressure, Error grid analysis, Hemodynamic monitoring
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Koç UniversityUniversity, hospital or other
- Study start
- 1 Sep 2025 (estimated)
- Primary completion
- 1 Nov 2025 (estimated)
- Study completion
- 15 Nov 2025 (estimated)
- First posted
- 6 Aug 2025 (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 study will test how accurate a blood pressure cuff is during certain types of surgery.
During some abdominal surgeries done with small tools and a camera (called laparoscopic surgery), doctors place patients in a head-down position called the Trendelenburg position. In this position, it may be harder for the blood pressure cuff on the arm to give correct readings. This study will compare the cuff's readings (non-invasive) with readings from a thin tube placed inside an artery (invasive), which is more accurate but also more risky and uncomfortable.
The researchers will use a method called error grid analysis to check how closely the cuff readings match the invasive ones. They hope to learn if the blood pressure cuff is accurate enough to be used safely in this kind of surgery. If it is, doctors may not need to use the invasive method as often.
People 18 years or older who are already going to have invasive blood pressure monitoring as part of their planned surgery can join the study. The study will collect blood pressure measurements about every 20 minutes during surgery, as well as basic information like age, weight, and what medicines are given.
Detailed description
This is a prospective observational study designed to evaluate the clinical accuracy and reliability of non-invasive blood pressure (NIBP) monitoring in adult patients undergoing laparoscopic surgery in the Trendelenburg position. The accuracy of NIBP will be assessed by comparing it to invasive arterial blood pressure (IABP), which is considered the reference standard. The comparison will be performed using error grid analysis, a method that not only quantifies measurement differences but also categorizes the clinical risk of those discrepancies.
The Trendelenburg position, characterized by a head-down tilt of the patient, is frequently employed during gynecological and urological laparoscopic procedures to enhance surgical exposure. However, this positioning alters hemodynamic physiology and may influence peripheral blood pressure measurements. Previous evaluations of NIBP in this context have primarily relied on Bland-Altman analysis, which measures statistical agreement but does not assess the potential clinical consequences of disagreement between methods.
Error grid analysis overcomes this limitation by mapping paired NIBP and IABP values into predefined risk zones (A-E), based on their potential to affect clinical decision-making. Zone A reflects acceptable agreement with no risk of incorrect treatment, whereas Zones B through E indicate increasing levels of clinical risk.
In this study, NIBP and IABP will be measured simultaneously every 20 minutes throughout the procedure. The proportion of measurements falling within each error grid zone will be calculated. If fewer than 90% of the paired measurements fall within Zone A, NIBP will be considered insufficiently reliable for use in this surgical context without concurrent invasive monitoring.
A pilot study of five patients was conducted to estimate the intracluster correlation coefficient and design effect, which informed the final sample size calculation. Based on these preliminary data, a total of 100 patients is estimated to provide adequate statistical power to evaluate the primary outcome with 95% confidence and a 5% margin of error.
The study will also document intraoperative variables that may affect blood pressure measurement accuracy, including the use of vasoactive infusions. These data may provide insight into subgroups where NIBP reliability is particularly limited or acceptable.
The findings of this study may inform future monitoring protocols and could reduce unnecessary use of invasive lines in appropriately selected patients, improving patient safety and comfort while maintaining clinical accuracy.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Surgical Cohort | – | –Adults (18 years and older) undergoing laparoscopic surgery in the Trendelenburg position who are already scheduled to receive invasive arterial blood pressure monitoring as part of routine clinical care. Participants will have paired invasive and non-invasive blood pressure measurements recorded during surgery for comparison using error grid analysis. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Participants will be selected from adult patients scheduled for laparoscopic surgery in the Trendelenburg position at Koç University Hospital, a tertiary care academic medical center in Istanbul, Turkey.
Key inclusion criteria (3 listed)
- Age 18 years or older
- Scheduled to undergo laparoscopic surgery in the Trendelenburg position
- Will receive invasive arterial blood pressure monitoring as part of routine clinical care
Key exclusion criteria (2 listed)
- Has peripheral artery disease
- Has congestive heart failure
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
Proportion of Paired Systolic Blood Pressure Measurements Within Zone A of the Error Grid
Time frame: Intraoperative period (measurements taken every 20 minutes during surgery)
The percentage of systolic non-invasive blood pressure (NIBP) measurements that fall within Zone A of the consensus error grid with calibrated risk zones, as described by Saugel et al.[1]. Zone A represents measurement pairs with no risk of leading to inappropriate clinical decisions, based on comparison with simultaneously recorded systolic invasive arterial blood pressure values. Systolic NIBP measurements will be considered acuurate if 90% or more of the paired values fall within Zone A. 1. Saugel B, Grothe O, Nicklas JY. Error Grid Analysis for Arterial Pressure Method Comparison Studies. Anesth Analg. 2018 Apr;126(4):1177-1185
Proportion of Paired Mean Arterial Pressure (MAP) Measurements Within Zone A of the Error Grid
Time frame: Intraoperative period (measurements taken every 20 minutes during surgery)
The percentage of non-invasive mean arterial pressure (MAP) measurements that fall within Zone A of the consensus error grid with calibrated risk zones, as described by Saugel et al.[1]. Zone A represents measurement pairs with no risk of leading to inappropriate clinical decisions, based on comparison with simultaneously recorded invasive MAP values. Non-invasive MAP measurements will be considered accurate if 90% or more of the paired values fall within Zone A. 1. Saugel B, Grothe O, Nicklas JY. Error Grid Analysis for Arterial Pressure Method Comparison Studies. Anesth Analg. 2018 Apr;126(4):1177-1185
4 secondary outcomes
Distribution of Paired Systolic Blood Pressure Measurements Across All Error Grid Zones (A-E)
Time frame: Intraoperative period (measurements taken every 20 minutes during surgery)
Distribution of Paired Mean Arterial Pressure (MAP) Measurements Across All Error Grid Zones (A-E)
Time frame: Intraoperative period (measurements taken every 20 minutes during surgery)
Effect of Antihypertensive Medication Use on the Accuracy of Systolic NIBP Measurements
Time frame: Intraoperative period (measurements taken every 20 minutes during surgery)
Effect of Antihypertensive Medication Use on the Accuracy of Mean Arterial Pressure (MAP) NIBP Measurements
Time frame: Intraoperative period (measurements taken every 20 minutes during surgery)
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 6 Aug 2025.
- Background: PubMed 29239945Saugel B, Grothe O, Nicklas JY. Error Grid Analysis for Arterial Pressure Method Comparison Studies. Anesth Analg. 2018 Apr;126(4):1177-1185. doi: 10.1213/ANE.0000000000002585.
- Individual participant dataSharing planned: Yes. Anonymized individual participant data (IPD) that underlie the results of the study will be shared. These data will be made publicly available through the Zenodo repository following study completion and publication.
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.
Kamil Darcin, MD study director
Koç University School of Medicine
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Non-Invasive Blood Pressure Monitoring in Trendelenburg Position, run by Koç University at 1 site in Turkey (Türkiye).
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 3 inclusion and 2 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: opening soon, as of the sponsor's last update on 6 Aug 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). 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?
Contact Muhammet S Sogut, MD (+905056183219, ssogut@kuh.ku.edu.tr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Proportion of Paired Systolic Blood Pressure Measurements Within Zone A of the Error Grid (time frame: Intraoperative period (measurements taken every 20 minutes during surgery)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07107425, which also lists 1 linked publication.
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 6 Aug 2025.