Intraoperative HemodynamicsPRAM-ZTOTNCT07340333
Physiological Reference Values of Total Arterial Impedance Derived From PRAM Monitoring
An observational study of Intraoperative Hemodynamics, run by Ataturk University at 1 site in Turkey (Türkiye).
Trial summary
Total arterial impedance (Ztot) is an advanced hemodynamic parameter that reflects the global arterial load opposing ventricular ejection by integrating both steady and pulsatile components of the arterial system. Read more about this study
- Who is it for?
- Ages 18 to 75 years
- Conditions the study is for
- Intraoperative Hemodynamics
- How many people
- 437 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 30 Jan 2026to 2 Feb 2026
- Phase
- Observational
- Are there results?
- None posted in the registry
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 to 75 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The study population consists of adult surgical patients who underwent routine intraoperative invasive arterial monitoring, from whom PRAM-based hemodynamic data were retrospectively analyzed during predefined hemodynamically stable intraoperative periods.
Who may be able to join
- Adult patients (≥18 years) who underwent surgery with invasive arterial catheterization.
- Availability of intraoperative hemodynamic data recorded using PRAM-based arterial waveform monitoring.
- Presence of predefined hemodynamically stable intraoperative periods meeting physiological stability criteria.
- Adequate arterial waveform signal quality for PRAM-derived parameter analysis.
Who cannot join
- Age <18 years.
- Inadequate arterial waveform signal quality or missing PRAM-derived data.
- Absence of intraoperative periods fulfilling predefined hemodynamic stability criteria.
- Incomplete or corrupted intraoperative monitoring records.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Reference Values and Hemodynamic Associations of Total Arterial Impedance Derived From PRAM Monitoring During Hemodynamically Stable Intraoperative Periods
Total arterial impedance (Ztot) is an advanced hemodynamic parameter that reflects the global arterial load opposing ventricular ejection by integrating both steady and pulsatile components of the arterial system. Although Ztot can be continuously derived from Pressure Recording Analytical Method (PRAM)-based monitoring, physiological reference values under stable clinical conditions are not well established.
This observational study aims to define patient-level physiological reference values for Ztot using intraoperative hemodynamic data obtained from PRAM-based arterial waveform analysis during hemodynamically stable periods. In addition, the study evaluates the associations between Ztot and key hemodynamic variables reflecting arterial load and cardiovascular performance.
High-resolution intraoperative data routinely recorded during standard clinical care are retrospectively analyzed. The findings of this study are intended to improve the interpretability of Ztot in advanced hemodynamic monitoring and to support future clinical and research applications.
Read the detailed description
Total arterial impedance (Ztot) is a comprehensive descriptor of arterial load that integrates resistive, compliant, and pulsatile components of the arterial system. Unlike conventional pressure-based parameters, Ztot provides a more physiologically meaningful representation of the opposition encountered by ventricular ejection. Although Ztot can be continuously estimated using Pressure Recording Analytical Method (PRAM)-based arterial waveform analysis, standardized physiological reference values applicable to routine clinical practice are lacking.
This single-center, observational study is designed to establish patient-level reference values for PRAM-derived Ztot during hemodynamically stable intraoperative periods. The study retrospectively analyzes high-resolution intraoperative hemodynamic data obtained during routine clinical care. Adult surgical patients monitored with an invasive arterial catheter and PRAM-based hemodynamic monitoring are included in the analysis.
Hemodynamic stability is defined according to predefined physiological criteria, including ranges of mean arterial pressure, cardiac index, heart rate, stroke volume variation, cardiac cycle efficiency, and arterial waveform quality indicators. Only measurements meeting all stability criteria are considered eligible for analysis.
To account for repeated measurements within individuals, patient-level median values are used for all primary analyses. The physiological reference interval for Ztot is estimated using a non-parametric percentile-based approach. In addition, associations between Ztot and key hemodynamic variables related to arterial load and cardiovascular performance are explored using correlation analyses.
This study does not involve any interventions, treatment assignments, or changes to standard clinical management. The primary objective is descriptive and physiological, aiming to provide a reference framework that may enhance the clinical interpretability of Ztot in advanced hemodynamic monitoring. The results are expected to support future prospective and outcome-oriented research evaluating the role of Ztot in perioperative and critical care settings.
- Conditions
- Intraoperative Hemodynamics
- Keywords
- Total arterial impedance, PRAM monitoring, Arterial load, Advanced hemodynamic monitoring, Pressure waveform analysis, Physiological reference values, Intraoperative hemodynamics
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 |
|---|---|---|
| Intraoperative PRAM Monitoring Cohort | Adult surgical patients with invasive arterial monitoring whose intraoperative hemodynamic data were retrospectively analyzed during predefined hemodynamically stable periods using PRAM-based waveform analysis. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Physiological reference interval of total arterial impedance (Ztot)
Patient-level physiological reference interval (2.5th-97.5th percentiles) of PRAM-derived total arterial impedance (Ztot) calculated from intraoperative hemodynamic measurements obtained during predefined hemodynamically stable periods.
Measured: Intraoperative period
Secondary outcomes (2)
Association between total arterial impedance and arterial load-related hemodynamic variables
Correlation between patient-level total arterial impedance (Ztot) and arterial load-related hemodynamic variables, including effective arterial elastance and systemic vascular resistance.
Measured: Intraoperative period
Association between total arterial impedance and cardiovascular performance indices
Association between patient-level total arterial impedance (Ztot) and indices of cardiovascular performance, including cardiac output, stroke volume, cardiac power output, and cardiac cycle efficiency.
Measured: Intraoperative period
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Jan 2026
- Study start30 Jan 2026
- Primary completion2 Feb 2026
- Study completion2 Feb 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (8)Papers the sponsor has linked to this study.
- Other trials for Intraoperative HemodynamicsStudies 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
- Retrospective
- Enrolment
- 437 participants (actual)
Sponsor and investigators
- Lead sponsor
- Ataturk University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Mehmet Akif Yilmaz, Ataturk University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07340333
- Sponsor's protocol ID
- ATAUNI-PRAM-ZTOT-2026
- Other IDs
- 2026/1
- Acronym
- PRAM-ZTOT
- Status last verified
- Feb 2026
- First submitted
- 6 Jan 2026
- Last updated
- 4 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared due to institutional and ethical restrictions related to patient privacy and the retrospective nature of the study. The analyzed data consist of anonymized intraoperative monitoring records collected during routine clinical care. Aggregated and summary-level results are reported in publications, and additional information may be made available upon reasonable request and with appropriate institutional approval.
Publications
Vlachopoulos C, O'Rourke M, Nichols WW. McDonald's Blood Flow in Arteries: Theoretical, Experimental and Clinical Principles. 6 ed. Boca Raton, FL: CRC Press; 2011.
Kelly RP, Ting CT, Yang TM, Liu CP, Maughan WL, Chang MS, Kass DA. Effective arterial elastance as index of arterial vascular load in humans. Circulation. 1992 Aug;86(2):513-21. doi: 10.1161/01.cir.86.2.513.
PubMed 1638719Kass DA. Ventricular arterial stiffening: integrating the pathophysiology. Hypertension. 2005 Jul;46(1):185-93. doi: 10.1161/01.HYP.0000168053.34306.d4. Epub 2005 May 23.
PubMed 15911741Sunagawa K, Sagawa K, Maughan WL. Ventricular interaction with the loading system. Ann Biomed Eng. 1984;12(2):163-89. doi: 10.1007/BF02584229.
PubMed 6507965Westerhof N, Lankhaar JW, Westerhof BE. The arterial Windkessel. Med Biol Eng Comput. 2009 Feb;47(2):131-41. doi: 10.1007/s11517-008-0359-2. Epub 2008 Jun 10.
PubMed 18543011O'Rourke M, Adji A, Nichols WW, Vlachopoulos C, Edelman ER. Application of Arterial Hemodynamics to Clinical Practice: A Testament to Medical Science in London. Artery Res. 2017 Jun;18:81-86. doi: 10.1016/j.artres.2017.03.003. No abstract available.
PubMed 29861794de Keijzer IN, Scheeren TWL. Perioperative Hemodynamic Monitoring: An Overview of Current Methods. Anesthesiol Clin. 2021 Sep;39(3):441-456. doi: 10.1016/j.anclin.2021.03.007. Epub 2021 Jul 12.
PubMed 34392878Pinsky MR. Functional hemodynamic monitoring. Crit Care Clin. 2015 Jan;31(1):89-111. doi: 10.1016/j.ccc.2014.08.005.
PubMed 25435480
Study at a glance
From the registry record, last updated by the sponsor on 4 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Reference Values and Hemodynamic Associations of Total Arterial Impedance Derived From PRAM Monitoring During Hemodynamically Stable Intraoperative Periods
- ClinicalTrials.gov ID
- NCT07340333
- Acronym / sponsor ID
- PRAM-ZTOT / ATAUNI-PRAM-ZTOT-2026
- Conditions
- Intraoperative Hemodynamics
- Keywords
- Total arterial impedance, PRAM monitoring, Arterial load, Advanced hemodynamic monitoring, Pressure waveform analysis, Physiological reference values, Intraoperative hemodynamics
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 437 participants (actual)
- Lead sponsor
- Ataturk UniversityUniversity, hospital or other
- Study start
- 30 Jan 2026 (actual)
- Primary completion
- 2 Feb 2026 (actual)
- Study completion
- 2 Feb 2026 (actual)
- First posted
- 14 Jan 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.
Total arterial impedance (Ztot) is an advanced hemodynamic parameter that reflects the global arterial load opposing ventricular ejection by integrating both steady and pulsatile components of the arterial system. Although Ztot can be continuously derived from Pressure Recording Analytical Method (PRAM)-based monitoring, physiological reference values under stable clinical conditions are not well established.
This observational study aims to define patient-level physiological reference values for Ztot using intraoperative hemodynamic data obtained from PRAM-based arterial waveform analysis during hemodynamically stable periods. In addition, the study evaluates the associations between Ztot and key hemodynamic variables reflecting arterial load and cardiovascular performance.
High-resolution intraoperative data routinely recorded during standard clinical care are retrospectively analyzed. The findings of this study are intended to improve the interpretability of Ztot in advanced hemodynamic monitoring and to support future clinical and research applications.
Detailed description
Total arterial impedance (Ztot) is a comprehensive descriptor of arterial load that integrates resistive, compliant, and pulsatile components of the arterial system. Unlike conventional pressure-based parameters, Ztot provides a more physiologically meaningful representation of the opposition encountered by ventricular ejection. Although Ztot can be continuously estimated using Pressure Recording Analytical Method (PRAM)-based arterial waveform analysis, standardized physiological reference values applicable to routine clinical practice are lacking.
This single-center, observational study is designed to establish patient-level reference values for PRAM-derived Ztot during hemodynamically stable intraoperative periods. The study retrospectively analyzes high-resolution intraoperative hemodynamic data obtained during routine clinical care. Adult surgical patients monitored with an invasive arterial catheter and PRAM-based hemodynamic monitoring are included in the analysis.
Hemodynamic stability is defined according to predefined physiological criteria, including ranges of mean arterial pressure, cardiac index, heart rate, stroke volume variation, cardiac cycle efficiency, and arterial waveform quality indicators. Only measurements meeting all stability criteria are considered eligible for analysis.
To account for repeated measurements within individuals, patient-level median values are used for all primary analyses. The physiological reference interval for Ztot is estimated using a non-parametric percentile-based approach. In addition, associations between Ztot and key hemodynamic variables related to arterial load and cardiovascular performance are explored using correlation analyses.
This study does not involve any interventions, treatment assignments, or changes to standard clinical management. The primary objective is descriptive and physiological, aiming to provide a reference framework that may enhance the clinical interpretability of Ztot in advanced hemodynamic monitoring. The results are expected to support future prospective and outcome-oriented research evaluating the role of Ztot in perioperative and critical care settings.
Study design
- Observational model
- Cohort
- Time perspective
- Retrospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Intraoperative PRAM Monitoring Cohort | – | –Adult surgical patients with invasive arterial monitoring whose intraoperative hemodynamic data were retrospectively analyzed during predefined hemodynamically stable periods using PRAM-based waveform analysis. |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The study population consists of adult surgical patients who underwent routine intraoperative invasive arterial monitoring, from whom PRAM-based hemodynamic data were retrospectively analyzed during predefined hemodynamically stable intraoperative periods.
Key inclusion criteria (4 listed)
- Adult patients (≥18 years) who underwent surgery with invasive arterial catheterization.
- Availability of intraoperative hemodynamic data recorded using PRAM-based arterial waveform monitoring.
- Presence of predefined hemodynamically stable intraoperative periods meeting physiological stability criteria.
- Adequate arterial waveform signal quality for PRAM-derived parameter analysis.
Key exclusion criteria (4 listed)
- Age <18 years.
- Inadequate arterial waveform signal quality or missing PRAM-derived data.
- Absence of intraoperative periods fulfilling predefined hemodynamic stability criteria.
- Incomplete or corrupted intraoperative monitoring records.
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
Physiological reference interval of total arterial impedance (Ztot)
Time frame: Intraoperative period
Patient-level physiological reference interval (2.5th-97.5th percentiles) of PRAM-derived total arterial impedance (Ztot) calculated from intraoperative hemodynamic measurements obtained during predefined hemodynamically stable periods.
2 secondary outcomes
Association between total arterial impedance and arterial load-related hemodynamic variables
Time frame: Intraoperative period
Association between total arterial impedance and cardiovascular performance indices
Time frame: Intraoperative period
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Feb 2026.
- BackgroundVlachopoulos C, O'Rourke M, Nichols WW. McDonald's Blood Flow in Arteries: Theoretical, Experimental and Clinical Principles. 6 ed. Boca Raton, FL: CRC Press; 2011.
- Background: PubMed 1638719Kelly RP, Ting CT, Yang TM, Liu CP, Maughan WL, Chang MS, Kass DA. Effective arterial elastance as index of arterial vascular load in humans. Circulation. 1992 Aug;86(2):513-21. doi: 10.1161/01.cir.86.2.513.
- Background: PubMed 15911741Kass DA. Ventricular arterial stiffening: integrating the pathophysiology. Hypertension. 2005 Jul;46(1):185-93. doi: 10.1161/01.HYP.0000168053.34306.d4. Epub 2005 May 23.
- Background: PubMed 6507965Sunagawa K, Sagawa K, Maughan WL. Ventricular interaction with the loading system. Ann Biomed Eng. 1984;12(2):163-89. doi: 10.1007/BF02584229.
- Background: PubMed 18543011Westerhof N, Lankhaar JW, Westerhof BE. The arterial Windkessel. Med Biol Eng Comput. 2009 Feb;47(2):131-41. doi: 10.1007/s11517-008-0359-2. Epub 2008 Jun 10.
- Background: PubMed 29861794O'Rourke M, Adji A, Nichols WW, Vlachopoulos C, Edelman ER. Application of Arterial Hemodynamics to Clinical Practice: A Testament to Medical Science in London. Artery Res. 2017 Jun;18:81-86. doi: 10.1016/j.artres.2017.03.003. No abstract available.
- Background: PubMed 34392878de Keijzer IN, Scheeren TWL. Perioperative Hemodynamic Monitoring: An Overview of Current Methods. Anesthesiol Clin. 2021 Sep;39(3):441-456. doi: 10.1016/j.anclin.2021.03.007. Epub 2021 Jul 12.
- Background: PubMed 25435480Pinsky MR. Functional hemodynamic monitoring. Crit Care Clin. 2015 Jan;31(1):89-111. doi: 10.1016/j.ccc.2014.08.005.
- Individual participant dataSharing planned: No. Individual participant data will not be shared due to institutional and ethical restrictions related to patient privacy and the retrospective nature of the study. The analyzed data consist of anonymized intraoperative monitoring records collected during routine clinical care. Aggregated and summary-level results are reported in publications, and additional information may be made available upon reasonable request and with appropriate institutional approval.
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
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 Intraoperative Hemodynamics, run by Ataturk 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 4 inclusion and 4 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: finished, as of the sponsor's last update on 4 Feb 2026. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Physiological reference interval of total arterial impedance (Ztot) (time frame: Intraoperative period). 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 NCT07340333, which also lists 8 linked publications.
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 4 Feb 2026.