Vasopressor Use Improves Macrocirculation, But What Are Its Effects on Microcirculation?

To manage the treatment in the intensive care unit for patients with septic shock, central venous oxygen saturation (scvO2) is used as a macrocirculatory indicator, with a target value of 70% or higher being recommended. Tissue oxygenation (stO2) measurement can be implemented to assess the microcirculation in these patients, but a specific target value has not been established yet. The investigators believe that guiding the treatment of septic shock patients based on the measurement of microcirculation using stO2 and evaluating its correlation with scvO2 can reduce mortality.

This study aims to investigate the independent impact of high-dose norepinephrine on microvascular reactivity assessed by NIRS-VOT in patients with septic shock, while also examining how these microcirculatory indices relate to the macrocirculatory marker ScvO₂.

Study Overview

• Status: Completed
• Conditions: Sepsis; Septic Shock; Hemodynamic Instability; Tissue Ischemia
• Intervention / Treatment: Diagnostic test: Vascular Occlusion Test

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Istanbul, Turkey (Türkiye), 34255
    • Gaziosmanpasa Training Research Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 18 years or older
• Diagnosis of septic shock
• Receiving vasopressor and mechanical ventilation therapy
• Presence of a central venous catheter that allows ScvO₂ sampling
• Ability to obtain tissue oxygenation (stO₂) measurements using a NIRS probe placed on the thenar eminence
• Written informed consent obtained from patient or legal representative

Exclusion Criteria:

• Local infection, wound, or skin lesion at the planned NIRS probe application site
• Mean arterial pressure (MAP) < 60 mmHg despite vasopressor therapy
• Pregnancy
• Inability to safely perform the vascular occlusion test (as judged by treating clinician)
• Any condition preventing safe blood sampling or reliable stO₂ measurement

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Study group; The study will include adult patients aged 18 and above who are receiving vasopressor therapy due to septic shock in the intensive care unit.	Diagnostic test: Vascular Occlusion Test; The vascular occlusion test is a procedure performed to assess the vascular status and perfusion of a limb. It involves temporarily stopping blood flow to the limb by applying a blood pressure cuff.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Central Venous Oxygen Saturation (ScvO₂) Level	Central venous oxygen saturation will be measured from a central venous blood gas sample. The ScvO₂ value obtained at baseline will be recorded.	Baseline (first 1 hour)
Norepinephrine Equivalent Vasopressor Dose	The vasopressor requirement will be expressed as the norepinephrine equivalent dose (NEq), calculated in µg/kg/min.	Baseline (first 1 hour)
Baseline Tissue Oxygen Saturation (stO₂_baseline)	Tissue oxygen saturation will be measured non-invasively from the thenar eminence using Near-Infrared Spectroscopy (NIRS). The baseline stO₂ value will be recorded immediately before the vascular occlusion test.	Within 1 hour of enrollment
Minimum Tissue Oxygen Saturation During Vascular Occlusion (stO₂_min)	During the vascular occlusion test (inflation of a cuff to stop arterial inflow), the lowest tissue oxygen saturation (stO₂_min) recorded from the NIRS probe on the thenar eminence will be measured and recorded.	Within 1 hour of enrollment
Maximum Tissue Oxygen Saturation After Reperfusion (stO₂_max)	After release of the vascular occlusion, the highest tissue oxygen saturation (stO₂_max) value recorded during reactive hyperemia will be measured and recorded.	Within 1 hour of enrollment
Recovery Time (From stO₂_min to stO₂_max)	Recovery time will be defined as the time interval between the minimum tissue oxygen saturation (stO₂_min) during vascular occlusion and the maximum tissue oxygen saturation (stO₂_max) after cuff release, as measured by NIRS on the thenar eminence.	Within 1 hour of enrollment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
28-Day All-Cause Mortality	Vital status (alive or deceased) will be assessed 28 days after enrollment to determine all-cause mortality.	28 days

Collaborators and Investigators

• Sponsor: Gaziosmanpasa Research and Education Hospital

Study record dates

Study Major Dates

• Study Start (Actual): April 1, 2023
• Primary Completion (Actual): August 31, 2023
• Study Completion (Actual): September 30, 2023

Study Registration Dates

• First Submitted: July 7, 2023
• First Submitted That Met QC Criteria: December 16, 2025
• First Posted (Actual): December 31, 2025

Study Record Updates

• Last Update Posted (Actual): December 31, 2025
• Last Update Submitted That Met QC Criteria: December 16, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: microcirculation; Septic Shock; Sepsis; Tissue oxygenation; Vazopressor
• Additional Relevant MeSH Terms: Pathologic Processes; Infections; Systemic Inflammatory Response Syndrome; Inflammation; Shock; Pathological Conditions, Signs and Symptoms; Sepsis; Shock, Septic
• Other Study ID Numbers: 1234 (Department of Defense)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No