Physiological Reference Values of Total Arterial Impedance Derived From PRAM Monitoring (PRAM-ZTOT)

February 2, 2026 updated by: Mehmet Akif Yilmaz, Ataturk University

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.

Study Overview

Status

Completed

Conditions

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 Type

Observational

Enrollment (Actual)

437

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

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.

Description

Inclusion Criteria:

  • 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.

Exclusion Criteria:

  • 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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
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 the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
Intraoperative period

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Association between total arterial impedance and arterial load-related hemodynamic variables
Time Frame: Intraoperative period
Correlation between patient-level total arterial impedance (Ztot) and arterial load-related hemodynamic variables, including effective arterial elastance and systemic vascular resistance.
Intraoperative period
Association between total arterial impedance and cardiovascular performance indices
Time Frame: Intraoperative period
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.
Intraoperative period

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Ataturk University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 30, 2026

Primary Completion (Actual)

February 2, 2026

Study Completion (Actual)

February 2, 2026

Study Registration Dates

First Submitted

January 6, 2026

First Submitted That Met QC Criteria

January 6, 2026

First Posted (Actual)

January 14, 2026

Study Record Updates

Last Update Posted (Actual)

February 4, 2026

Last Update Submitted That Met QC Criteria

February 2, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • ATAUNI-PRAM-ZTOT-2026
  • 2026/1 (Atatürk University Clinical Research Ethics Committee)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

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.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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