Discordance Between Capillary Refill Time and Oxygen Extraction Ratio in Septic Shock

NCT07774962 | Recruiting

• 1 other identifier: KAEK-11/29.07.2026.276
• Study Type: observational
• Target: 100
• Locations: 1 country
• Sites: 1

Brief Summary

In septic shock, restoring large-vessel (macrocirculatory) perfusion-reflected by a normal capillary refill time (CRT)-does not always mean that oxygen use at the tissue level has recovered. This mismatch, sometimes called loss of hemodynamic coherence, may be detectable by comparing CRT with the oxygen extraction ratio (O₂ER), a marker of how much oxygen the tissues are extracting from the blood. Patients whose CRT has normalized but whose O₂ER remains abnormal-either too high (suggesting oxygen delivery that is insufficient for demand) or too low (suggesting microcirculatory shunting)-are considered to have a "discordant" perfusion phenotype. This prospective, single-center, observational cohort study aims to determine how often this CRT-O₂ER discordance occurs at the 6th hour of resuscitation in adult patients with septic shock, and whether it is associated with 28-day mortality. Approximately 100 consecutive adult patients diagnosed with septic shock (with pre-existing central venous and arterial catheters) will be followed. Clinical and laboratory measurements-including CRT, O₂ER, lactate, mottling score, and organ dysfunction scores-will be recorded at hours 0, 6, 12, and 24, with the main phenotype grouping performed at hour 6. The study is purely observational: CRT is a painless, non-invasive bedside measurement, and O₂ER is calculated from blood gas samples already drawn as part of routine care, so no additional interventions or blood draws are performed for research purposes.

Conditions

Septic Shock; Sepsis

Keywords

Capillary Refill Time; Oxygen Extraction Ratio; Tissue Perfusion; ScvO2; Microcirculation; Hemodynamic Coherence; Lactate; Observational Cohort Study

Outcome Measures

Primary Outcomes (2)

• Prevalence of the discordant CRT-O₂ER phenotype

  Proportion of patients classified as having a discordant perfusion phenotype (normalized CRT ≤3 s with an abnormal O₂ER, i.e., \>30% or \<20%; combined Group 2a + Group 2b) at hour 6, reported with 95% confidence interval.

  At hour 6 of resuscitation (6 hours after vasopressor initiation)

• 28-day all-cause mortality

  All-cause mortality at 28 days, and its association with the hour-6 perfusion phenotype.

  28 days from Hour 0 (vasopressor initiation)

Secondary Outcomes (7)

• ICU length of stay

  Through study completion, up to 28 days

• Hospital length of stay

  Through study completion, up to 28 days

• Duration of mechanical ventilation

  Through study completion, up to 28 days

• Time to vasopressor weaning

  From Hour 0 up to 28 days

• Vasopressor-free days

  28 days

Other Outcomes (2)

• Diagnostic performance of the O₂ER threshold for mortality

  Hour 6 measurement; mortality at 28 days

• Inter-rater reliability of CRT measurement

  Hour 6, first 20-30 patients

Study Arms (1)

septic schoc cohort

Consecutive adult patients (≥18 years) admitted to the intensive care unit and diagnosed with septic shock according to the Surviving Sepsis Campaign (SSC) 2026 guideline, who have pre-existing central venous and arterial catheters. Patients are prospectively followed while receiving standard care, with serial measurements at hours 0, 6, 12, and 24 (time zero = vasopressor initiation). At hour 6, patients are classified into perfusion phenotypes based on capillary refill time (CRT) and oxygen extraction ratio (O₂ER): concordant normal, discordant with high O₂ER, discordant with low O₂ER, and concordant abnormal. The primary group of interest is the combined discordant phenotype (normalized CRT with abnormal O₂ER).

Diagnostic Test: Capillary refill time (CRT); Diagnostic Test: Oxygen extraction ratio (O₂ER) assessment

Interventions

Capillary refill time (CRT) DIAGNOSTIC_TEST

Non-invasive, standardized bedside measurement of capillary refill time on the right index finger.

septic schoc cohort

Oxygen extraction ratio (O₂ER) assessment DIAGNOSTIC_TEST

Oxygen extraction ratio calculated as (SaO₂ - ScvO₂)/SaO₂ from routinely obtained arterial and central venous blood gases.

septic schoc cohort

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Consecutive adult patients (≥18 years) admitted to a single-center intensive care unit and diagnosed with septic shock according to the Surviving Sepsis Campaign (SSC) 2026 guideline, who already have a central venous catheter and an arterial line in place as part of their clinical care. Patients are enrolled from all admission sources (emergency department, ward, operating room, or external referral) and followed prospectively while receiving standard treatment. Patients with active bleeding, ongoing ECMO, conditions that make capillary refill time measurement unreliable (e.g., Raynaud phenomenon or significant peripheral vascular disease), death within the first 6 hours, or inability to obtain hour-6 CRT or blood gas measurements are not included.

You may qualify if:

• Age ≥ 18 years
• Diagnosis of septic shock according to the Surviving Sepsis Campaign (SSC) 2026 guideline
• Presence of both a central venous catheter and an arterial line

You may not qualify if:

• Active bleeding
• Ongoing extracorporeal membrane oxygenation (ECMO)
• Raynaud phenomenon or significant peripheral vascular disease that makes capillary refill time measurement unreliable (e.g., critical ischemia, amputation, digital ulcer/necrosis, or inability to measure on the right index finger)
• Death within the first 6 hours
• Inability to obtain hour-6 CRT or blood gas (phenotyping not possible)

Sponsors & Collaborators

• Istanbul University - Cerrahpasa: lead
• Başakşehir Çam & Sakura City Hospital: collaborator

Study Sites (1)

Basaksehir Cam and Sakura City Hospital

Istanbul, Turkey (Türkiye)

RECRUITING

MeSH Terms

Conditions

Shock, Septic; Sepsis

Interventions

Physical Examination

Condition Hierarchy (Ancestors)

Infections; Systemic Inflammatory Response Syndrome; Inflammation; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Shock

Intervention Hierarchy (Ancestors)

Diagnostic Techniques and Procedures; Diagnosis

Central Study Contacts

Tugba Yesilyurt Dogu, Intensive Medicine Care Fellow

CONTACT

+9005535150847; tugbaayesilyurt@gmail.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Intensive Care Medicine Fellow

Study Record Dates

• First Submitted: August 15, 2026
• First Posted: August 19, 2026
• Study Start: August 17, 2026
• Primary Completion (Estimated): June 17, 2027
• Study Completion (Estimated): July 17, 2027
• Last Updated: August 19, 2026

Record last verified: 2026-08

Locations

TU (1)