Haemodynamics, fluids & transfusion
Physiological limits of capillary refill time: a human endotoxemia study
Authors' conclusion
Finger qCRT tracks the course of acute systemic inflammation but crosses the 3-s clinical threshold in both directions within a single episode.
Study context
- Population
- Healthy volunteerscrossover
- Participants
- 25 volunteers
- Comparison
- IV E. coli lipopolysaccharide vs saline placebo
- Primary endpoint
- Finger quantitative capillary refill time (qCRT) by polarized reflectance imaging over the inflammatory episode
- Follow-up
- Baseline and 1.5, 3.5, and 5 h
Methodological detailsdouble-blind, crossover, human endotoxemia model
- Double-blind
- Crossover
- Human endotoxemia model
Primary result
As reported in the abstract
Finger qCRT (biphasic course, crossed 3-s threshold in both directions)
Estimated marginal contrast
4.13 s
P < 0.0001
at 1.5 h
Estimated marginal contrast
- 3.10 s
P < 0.0001
at 5 h
- Baseline quantitative capillary refill time (qCRT) near
- 3.5 s
- qCRT prolonged at 1.5 h
- 8.31 s
- Reached the 10-s ceiling at 1.5 h
- 14 of 25
- qCRT shortened at 5 h during persisting systemic inflammation
- 1.27 s
Further findings
Skin temperature as qCRT covariate
- Strongest covariate; qCRT decrease per SD increase in skin temperature
- 1.62 s
- No formal mediation analysis was performed
Resting qCRT variability
- Intraclass correlation
- 0.30
- Between-subject differences explained a minority of total variance
Original publication
Physiological limits of capillary refill time: a human endotoxemia study. Crit Care. Published 31 August 2026. doi:10.
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