Capillary Refill TimeCRTAppNCT07473869
Smartphone Application for Automated Measurement of Capillary Refill Time (CRT)
An observational study of Capillary Refill Time and Peripheral Tissue Perfusion, run by Assistance Publique - Hôpitaux de Paris at 1 site in France.
Trial summary
This prospective, monocenter observational study aims to validate a smartphone application (CRTApp) that automatically measures capillary refill time (CRT) from a short video of a standardized finger compression. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Capillary Refill Time, Peripheral Tissue Perfusion
- How many people
- 60 participants
- Where
- 1 siteFrance
- Study dates
- 1 Jun 2026to 1 Jun 2027
- 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: Adults (≥18 years) admitted to the medical intensive care unit at Hôpital de Bicêtre (AP-HP) for whom a standardized capillary refill time measurement can be performed.
Who may be able to join
- Age ≥ 18 years
- Adult patients hospitalized in an intensive care unit
- Clinical indication for capillary refill time assessment (hemodynamic monitoring, suspected peripheral hypoperfusion, or therapeutic evaluation)
- No objection from the patient or legal representative
Who cannot join
- Skin lesions at the measurement site
- Known severe peripheral vascular disease
- Finger amputation
- Presence of distinctive skin marks on fingers (tattoos, significant scars, or prominent moles) that may interfere with measurement or increase the risk of patient re-identification
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Gwénolé ABGRALL contact
France1 site
CHU Bicêtre
Le Kremlin-Bicêtre
Xavier MONNET, 45213547 ext. 0033, xavier.monnet@aphp.fr
Gwénolé ABGRALL, gwenoleabgrall@gmail.com
About this study
This prospective, monocenter observational study aims to validate a smartphone application (CRTApp) that automatically measures capillary refill time (CRT) from a short video of a standardized finger compression. Sixty adult intensive care unit (ICU) patients will undergo a CRT measurement recorded with a professional Android smartphone. Clinical CRT will be determined from the video by three blinded observers (reference = median of the three measurements). The application will analyze the same video locally to provide an automated CRT measurement. Agreement between automated and clinical reference CRT will be assessed, and predefined subgroup analyses will explore performance across skin tone, ambient lighting, smartphone characteristics, and severity of peripheral hypoperfusion.
Read the detailed description
Capillary refill time (CRT) is a bedside indicator of peripheral perfusion, but visual assessment is prone to inter-observer variability. In this study, CRT is measured using a standardized method (10-second finger compression with a glass slide). A video of the fingertip is captured without audio; framing is strictly limited to the fingers. Files are pseudonymized at acquisition. Videos are transferred via USB to an AP-HP workstation and stored on an AP-HP server; no cloud or messaging is used, and videos are deleted from the smartphone after import. Automated CRT is computed locally from the video by CRTApp without network transmission and without retaining the video. Statistical analyses will include intraclass correlation coefficient and Bland-Altman analysis for agreement. Secondary analyses will evaluate agreement stratified by skin tone (Monk scale / ITA), ambient lighting (lux), smartphone characteristics, and severity of peripheral hypoperfusion.
- Conditions
- Capillary Refill Time, Peripheral Tissue Perfusion
- Keywords
- Observer Variation, Reproducibility of Results, Capillary Refill Time, Peripheral Tissue Perfusion, Hemodynamic Monitoring, Shock, Critical Illness, Intensive Care Units, Smartphone Application, Automated Measurement, Digital Health, Clinical Assessment
- Medical subject headings
- Shock, Critical Illness
What is being measured
The primary outcome is the main question the study is designed to answer.
Agreement Between Automated and Clinical Capillary Refill Time Measurement
Agreement between capillary refill time measured by the smartphone application and the clinical reference measurement performed by expert clinicians using the standardized method (10-second glass slide compression). Agreement is assessed using the intraclass correlation coefficient between the automated measurement and the median of three blinded observers.
Measured: At inclusion (single assessment)
Secondary outcomes (5)
Inter-Observer Variability of Clinical Capillary Refill Time Measurement
At inclusion (single assessment)
Measured: Inter-observer variability of clinically measured capillary refill time assessed by three independent observers, expressed as the coefficient of variation.
Agreement Stratified by Skin Tone
Intraclass correlation coefficient between automated and clinical capillary refill time measurements stratified according to skin tone using the Monk Skin Tone Scale.
Measured: At inclusion (single assessment)
Agreement Stratified by Ambient Lighting Conditions
At inclusion (single assessment)
Measured: Intraclass correlation coefficient between automated and clinical capillary refill time measurements stratified according to ambient light intensity measured in lux.
Agreement Stratified by Smartphone Model Characteristics
At inclusion (single assessment)
Measured: Intraclass correlation coefficient between automated and clinical capillary refill time measurements stratified by smartphone type (iOS or Android) and camera resolution.
Agreement Stratified by Severity of Peripheral Hypoperfusion
At inclusion (single assessment)
Measured: Intraclass correlation coefficient between automated and clinical capillary refill time measurements stratified by clinical capillary refill time (< 3 seconds versus ≥ 3 seconds).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Mar 2026
- Study start1 Jun 2026 (estimated)
- Primary completion1 Jun 2026 (estimated)
- Study completion1 Jun 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Capillary Refill TimeStudies of the same condition, open and under way.
- More trials run by Assistance Publique - Hôpitaux de ParisThe sponsor's other registered studies.
- 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
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Assistance Publique - Hôpitaux de Paris
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07473869
- Sponsor's protocol ID
- APHP251601
- Acronym
- CRTApp
- Status last verified
- Mar 2026
- First submitted
- 11 Mar 2026
- Last updated
- 16 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 16 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Smartphone Application for Automated Measurement of Capillary Refill Time (CRT)
- ClinicalTrials.gov ID
- NCT07473869
- Acronym / sponsor ID
- CRTApp / APHP251601
- Conditions
- Capillary Refill Time, Peripheral Tissue Perfusion
- Keywords
- Observer Variation, Reproducibility of Results, Capillary Refill Time, Peripheral Tissue Perfusion, Hemodynamic Monitoring, Shock, Critical Illness, Intensive Care Units
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Assistance Publique - Hôpitaux de ParisUniversity, hospital or other
- Study start
- 1 Jun 2026 (estimated)
- Primary completion
- 1 Jun 2026 (estimated)
- Study completion
- 1 Jun 2027 (estimated)
- First posted
- 16 Mar 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 prospective, monocenter observational study aims to validate a smartphone application (CRTApp) that automatically measures capillary refill time (CRT) from a short video of a standardized finger compression. Sixty adult intensive care unit (ICU) patients will undergo a CRT measurement recorded with a professional Android smartphone. Clinical CRT will be determined from the video by three blinded observers (reference = median of the three measurements). The application will analyze the same video locally to provide an automated CRT measurement. Agreement between automated and clinical reference CRT will be assessed, and predefined subgroup analyses will explore performance across skin tone, ambient lighting, smartphone characteristics, and severity of peripheral hypoperfusion.
Detailed description
Capillary refill time (CRT) is a bedside indicator of peripheral perfusion, but visual assessment is prone to inter-observer variability. In this study, CRT is measured using a standardized method (10-second finger compression with a glass slide). A video of the fingertip is captured without audio; framing is strictly limited to the fingers. Files are pseudonymized at acquisition. Videos are transferred via USB to an AP-HP workstation and stored on an AP-HP server; no cloud or messaging is used, and videos are deleted from the smartphone after import. Automated CRT is computed locally from the video by CRTApp without network transmission and without retaining the video. Statistical analyses will include intraclass correlation coefficient and Bland-Altman analysis for agreement. Secondary analyses will evaluate agreement stratified by skin tone (Monk scale / ITA), ambient lighting (lux), smartphone characteristics, and severity of peripheral hypoperfusion.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Adults (≥18 years) admitted to the medical intensive care unit at Hôpital de Bicêtre (AP-HP) for whom a standardized capillary refill time measurement can be performed.
Key inclusion criteria (4 listed)
- Age ≥ 18 years
- Adult patients hospitalized in an intensive care unit
- Clinical indication for capillary refill time assessment (hemodynamic monitoring, suspected peripheral hypoperfusion, or therapeutic evaluation)
- No objection from the patient or legal representative
Key exclusion criteria (4 listed)
- Skin lesions at the measurement site
- Known severe peripheral vascular disease
- Finger amputation
- Presence of distinctive skin marks on fingers (tattoos, significant scars, or prominent moles) that may interfere with measurement or increase the risk of patient re-identification
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
Agreement Between Automated and Clinical Capillary Refill Time Measurement
Time frame: At inclusion (single assessment)
Agreement between capillary refill time measured by the smartphone application and the clinical reference measurement performed by expert clinicians using the standardized method (10-second glass slide compression). Agreement is assessed using the intraclass correlation coefficient between the automated measurement and the median of three blinded observers.
5 secondary outcomes
Inter-Observer Variability of Clinical Capillary Refill Time Measurement
Time frame: Inter-observer variability of clinically measured capillary refill time assessed by three independent observers, expressed as the coefficient of variation.
Agreement Stratified by Skin Tone
Time frame: At inclusion (single assessment)
Agreement Stratified by Ambient Lighting Conditions
Time frame: Intraclass correlation coefficient between automated and clinical capillary refill time measurements stratified according to ambient light intensity measured in lux.
Agreement Stratified by Smartphone Model Characteristics
Time frame: Intraclass correlation coefficient between automated and clinical capillary refill time measurements stratified by smartphone type (iOS or Android) and camera resolution.
Agreement Stratified by Severity of Peripheral Hypoperfusion
Time frame: Intraclass correlation coefficient between automated and clinical capillary refill time measurements stratified by clinical capillary refill time (< 3 seconds versus ≥ 3 seconds).
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 16 Mar 2026.
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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.
Gwénolé ABGRALL contact
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 Capillary Refill Time and Peripheral Tissue Perfusion, run by Assistance Publique - Hôpitaux de Paris at 1 site in France.
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: opening soon, as of the sponsor's last update on 16 Mar 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 France. 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 Xavier MONNET, PhD (45213547 ext. +33, xavier.monnet@aphp.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Agreement Between Automated and Clinical Capillary Refill Time Measurement (time frame: At inclusion (single assessment)). 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 16 Mar 2026.