Sepsis-associated microvascular dysfunction measured by peripheral arterial tonometry: an observational study.

Area of Science:

• Critical Care Medicine
• Vascular Biology
• Biomarkers

Background:

• Sepsis management is challenged by high mortality, often linked to microcirculatory and endothelial dysfunction.
• Effective tools are needed to assess microvascular responses to therapies in sepsis.
• Peripheral arterial tonometry (PAT) offers a user-independent measure of endothelium-dependent microvascular reactivity.

Purpose of the Study:

• To investigate if PAT-measured microvascular reactivity is impaired in sepsis.
• To determine if this impairment correlates with sepsis severity.
• To explore the relationship between microvascular reactivity, endothelial activation, and L-arginine concentrations.

Main Methods:

• An observational cohort study involving 85 adults with sepsis and 45 controls.
• Bedside measurement of microvascular reactivity using peripheral arterial tonometry (PAT) at baseline and 2-4 days later.
• Correlation analysis with disease severity scores (APACHE II, SOFA), plasma L-arginine, and endothelial activation markers.

Main Results:

• The reactive hyperaemia index (RH-PAT index), a measure of microvascular reactivity, was significantly lower in severe sepsis (1.57) compared to sepsis without organ failure (1.85) and controls (2.05).
• APACHE II score and mean arterial pressure independently predicted baseline RH-PAT index in sepsis.
• A lower baseline RH-PAT index correlated with increased SOFA scores over time, indicating worsening sepsis severity.

Conclusions:

• Endothelium-dependent microvascular reactivity is impaired in sepsis, decreasing with disease severity.
• This suggests reduced endothelial nitric oxide bioavailability in sepsis.
• PAT shows potential as a user-independent tool for monitoring therapeutic responses in sepsis-related endothelial dysfunction.