Assessment of the Repeatability of Sublingual Microcirculation Function Measurements in Healthy Volunteers and Critically Ill Patients

The assessment of microcirculatory function plays a pivotal role in perioperative medicine and intensive care. One promising method for evaluating microcirculatory function is the microscopic analysis of the oral mucosal microvasculature. However, this method is not currently fully validated.

The aim of this study is to assess the repeatability of sublingual microcirculation measurements using the CytoCam-IDF device (Braedius Medical).

Study Overview

• Status: Not yet recruiting
• Conditions: Healthy; Critical Illness

• Study Type: Observational
• Enrollment (Estimated): 200

Contacts and Locations

• Study Contact: Name: Karol P. Steckiewicz, MD, PhD; Phone Number: +48 58 349 32 80; Email: karol.steckiewicz@gumed.edu.pl

Study Locations

• Poland
  • Gdansk, Poland
    • Medical University of Gdanks
    • Contact: Karol P. Steckiewicz, MD, PhD; Phone Number: +48 58 349 32 80; Email: karol.steckiewicz@gumed.edu.pl

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Probability Sample

Study Population

Patients hospitalized in the ICU at the University Clinical Center in Gdańsk, or healthy volunteers

Description

Group 1: Healthy Volunteers

Inclusion Criteria:

• ASA Physical Status I-II
• Age 18-40 years

Exclusion Criteria:

• Chronic diseases
• Chronic medication use
• Pregnancy
• Use of stimulants (caffeine, nicotine, alcohol) within 12 hours prior to the study
• Lack of consent to participate

Group 2: Patients Hospitalized in the ICU

Inclusion Criteria:

• Age > 18 years
• Hospitalization in the Intensive Care Unit (ICU)
• Requirement for vasoactive drugs (minimum norepinephrine equivalent dose >0.1μg/kg / min )
• Mechanical ventilation via an endotracheal tube

Exclusion Criteria:

• Head and craniofacial trauma
• Pregnancy
• Intensive fluid therapy (>200ml/h)
• Changes in vasoactive drug dosages within 30 minutes prior to study inclusion
• Hypothermia (body temperature <35.5 oC)
• Fever (body temperature >38.5oC)

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Healthy Volunteers
Critically ill; Patients Hospitalized in the ICU

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
FCD (Functional Capillary Density)	Sublingual Microcirculation Assessment Sublingual microcirculation will be assessed using the CytoCam-IDF camera (Braedius Medical, Huizen, The Netherlands). The measurement technique involves gently applying the microscope probe with a disposable cap to the sublingual mucosa and recording short video sequences. The device utilizes green LED light to visualize moving blood cells, allowing for subsequent computerized analysis of capillary density and flow quality within the microvessels. Two operators will perform 3 series of measurements at 5-minute intervals with Cytocam - IDF microcirculation camera. Each series will consist of measurements taken from 3 adjacent sites. All measurements will be performed by the same two individuals Unit of measurement: mm/mm^2	From enrollment every 5 minutes (3 measurements per operator) - approx. 20 min.
MFI (Microvascular Flow Index)	Sublingual Microcirculation Assessment Sublingual microcirculation will be assessed using the CytoCam-IDF camera (Braedius Medical, Huizen, The Netherlands). The measurement technique involves gently applying the microscope probe with a disposable cap to the sublingual mucosa and recording short video sequences. The device utilizes green LED light to visualize moving blood cells, allowing for subsequent computerized analysis of capillary density and flow quality within the microvessels. Two operators will perform 3 series of measurements at 5-minute intervals with Cytocam - IDF microcirculation camera. Each series will consist of measurements taken from 3 adjacent sites. All measurements will be performed by the same two individuals Unit of measurement: 0 - no flow / 1 -intermittent flow / 2 - sluggish flow / 3 - continuous flow	From enrollment every 5 minutes (3 measurements per operator) - approx. 20 min.
HI (Heterogeneity Index)	Sublingual Microcirculation Assessment Sublingual microcirculation will be assessed using the CytoCam-IDF camera (Braedius Medical, Huizen, The Netherlands). The measurement technique involves gently applying the microscope probe with a disposable cap to the sublingual mucosa and recording short video sequences. The device utilizes green LED light to visualize moving blood cells, allowing for subsequent computerized analysis of capillary density and flow quality within the microvessels. Two operators will perform 3 series of measurements at 5-minute intervals with Cytocam - IDF microcirculation camera. Each series will consist of measurements taken from 3 adjacent sites. All measurements will be performed by the same two individuals Unit of measurements none, relative measurement	From enrollment every 5 minutes (3 measurements per operator) - approx. 20 min.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
TVD (Total Vessel Density)	Sublingual Microcirculation Assessment Sublingual microcirculation will be assessed using the CytoCam-IDF camera (Braedius Medical, Huizen, The Netherlands). The measurement technique involves gently applying the microscope probe with a disposable cap to the sublingual mucosa and recording short video sequences. The device utilizes green LED light to visualize moving blood cells, allowing for subsequent computerized analysis of capillary density and flow quality within the microvessels. Two operators will perform 3 series of measurements at 5-minute intervals with Cytocam - IDF microcirculation camera. Each series will consist of measurements taken from 3 adjacent sites. All measurements will be performed by the same two individuals Unit of measurement: mm/mm^2	From enrollment every 5 minutes (3 measurements per operator) - approx. 20 min.
PVD (Perfused Vessel Density)	Sublingual Microcirculation Assessment Sublingual microcirculation will be assessed using the CytoCam-IDF camera (Braedius Medical, Huizen, The Netherlands). The measurement technique involves gently applying the microscope probe with a disposable cap to the sublingual mucosa and recording short video sequences. The device utilizes green LED light to visualize moving blood cells, allowing for subsequent computerized analysis of capillary density and flow quality within the microvessels. Two operators will perform 3 series of measurements at 5-minute intervals with Cytocam - IDF microcirculation camera. Each series will consist of measurements taken from 3 adjacent sites. All measurements will be performed Unit of measurement: mm/mm^2	From enrollment every 5 minutes (3 measurements per operator) - approx. 20 min.
PPV (Proportion of Perfused Vessels)	Sublingual Microcirculation Assessment Sublingual microcirculation will be assessed using the CytoCam-IDF camera (Braedius Medical, Huizen, The Netherlands). The measurement technique involves gently applying the microscope probe with a disposable cap to the sublingual mucosa and recording short video sequences. The device utilizes green LED light to visualize moving blood cells, allowing for subsequent computerized analysis of capillary density and flow quality within the microvessels. Two operators will perform 3 series of measurements at 5-minute intervals with Cytocam - IDF microcirculation camera. Each series will consist of measurements taken from 3 adjacent sites. All measurements will be performed by the same two individuals Unit of measurement: %	From enrollment every 5 minutes (3 measurements per operator) - approx. 20 min.
RBCv (Red Blood Cell Velocity)	Sublingual Microcirculation Assessment Sublingual microcirculation will be assessed using the CytoCam-IDF camera (Braedius Medical, Huizen, The Netherlands). The measurement technique involves gently applying the microscope probe with a disposable cap to the sublingual mucosa and recording short video sequences. The device utilizes green LED light to visualize moving blood cells, allowing for subsequent computerized analysis of capillary density and flow quality within the microvessels. Two operators will perform 3 series of measurements at 5-minute intervals with Cytocam - IDF microcirculation camera. Each series will consist of measurements taken from 3 adjacent sites. All measurements will be performed by the same two individuals Unit of measurement: mm/s	From enrollment every 5 minutes (3 measurements per operator) - approx. 20 min.
Heart rate and its variability (HRV)	Heart rate and its variability (HRV) will be recorded using a Holter ECG monitor - electrodes on the chest. Frequency domain method will be used. The number of NN (beat to beat) intervals that match high frequency band (0.15 to 0.4 Hz) or low frequency band (0.04 to 0.15 Hz) will be recorded.	From enrollment every 5 minutes (3 measurements per operator) - approx. 20 min.

Collaborators and Investigators

• Sponsor: Medical University of Gdansk
• Investigators: Principal Investigator: Karol P. Steckiewicz, MD, PhD, Medical University of Gdansk; Principal Investigator: Radosław Owczuk, MD, PhD, DSc, Prof., Medical University of Gdansk

Study record dates

Study Major Dates

• Study Start (Estimated): February 7, 2026
• Primary Completion (Estimated): February 1, 2029
• Study Completion (Estimated): February 1, 2029

Study Registration Dates

• First Submitted: February 2, 2026
• First Submitted That Met QC Criteria: February 2, 2026
• First Posted (Actual): February 9, 2026

Study Record Updates

• Last Update Posted (Actual): February 10, 2026
• Last Update Submitted That Met QC Criteria: February 7, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Disease Attributes; Pathological Conditions, Signs and Symptoms; Critical Illness
• Other Study ID Numbers: MICRO-powt

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No