Capillary Refill Time, Peripheral Tissue Perfusion
Conditions
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
Brief 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. 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.
Interventions
None listed
Sponsors
Assistance Publique - Hôpitaux de Paris
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* 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
Exclusion criteria
* 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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Agreement Between Automated and Clinical Capillary Refill Time Measurement | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Agreement Stratified by Skin Tone | At inclusion (single assessment) | Intraclass correlation coefficient between automated and clinical capillary refill time measurements stratified according to skin tone using the Monk Skin Tone Scale. |
| Inter-Observer Variability of Clinical Capillary Refill Time Measurement | Inter-observer variability of clinically measured capillary refill time assessed by three independent observers, expressed as the coefficient of variation. | At inclusion (single assessment) |
| Agreement Stratified by Ambient Lighting Conditions | Intraclass correlation coefficient between automated and clinical capillary refill time measurements stratified according to ambient light intensity measured in lux. | At inclusion (single assessment) |
| Agreement Stratified by Smartphone Model Characteristics | Intraclass correlation coefficient between automated and clinical capillary refill time measurements stratified by smartphone type (iOS or Android) and camera resolution. | At inclusion (single assessment) |
| Agreement Stratified by Severity of Peripheral Hypoperfusion | Intraclass correlation coefficient between automated and clinical capillary refill time measurements stratified by clinical capillary refill time (< 3 seconds versus ≥ 3 seconds). | At inclusion (single assessment) |
Countries
France
Contacts
CONTACTXavier MONNET, PhD
CONTACTGwénolé ABGRALL
Outcome results
None listed