Hemodynamic Effects of Norepinephrine Reduction on Critical Closing Pressure in Distributive Shock

NCT07653659 | Recruiting

• 1 other identifier: pumch-micu202606
• Study Type: observational
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

This study prospectively observes changes in critical closing pressure (Pcc) and derived hemodynamic parameters in mechanically ventilated distributive shock patients when clinically indicated norepinephrine dose reduction is performed by the attending physician. Pcc is measured before and 30 minutes after dose reduction using a stepwise inspiratory hold maneuver via PiCCO monitoring.

Conditions

Distributive Shock; Hemodynamic Assessment; Critical Illness

Keywords

Critical closing pressure; Tissue perfusion pressure; Vascular waterfall; Norepinephrine dose; Distributive shock

Outcome Measures

Primary Outcomes (2)

• Change in critical closing pressure (Pcc, Unit: mmHg) before and after norepinephrine dose reduction

  Pcc is derived from linear regression of simultaneously measured cardiac output against mean arterial pressure during stepwise inspiratory hold maneuvers via PiCCO monitoring. The x-intercept of the regression line (at zero flow) represents Pcc. Measurement is performed at baseline and 30 minutes after norepinephrine dose reduction.

  Baseline and 30 minutes after norepinephrine dose reduction

• Change in tissue perfusion pressure (TPP, unit: mmHg) before and after norepinephrine dose reduction

  TPP is calculated as the difference between mean arterial pressure (MAP) and critical closing pressure (Pcc): TPP = MAP minus Pcc, unit: mmHg

  Baseline and 30 minutes after norepinephrine dose reduction

Secondary Outcomes (3)

• Change in mean systemic filling pressure analogue (Pmsf, unit: mmHg) before and after norepinephrine dose reduction

  Baseline and 30 minutes after norepinephrine dose reduction

• Change in Vascular waterfall (VW, unit: mmHg) before and after norepinephrine dose reduction

  Baseline and 30 minutes after norepinephrine dose reduction

• Change in capillary refill time (CRT, unit: seconds）

  Baseline and 30 minutes after norepinephrine dose reduction

Study Arms (1)

Distributive shock patients undergoing norepinephrine dose reduction

Mechanically ventilated distributive shock patients in whom the attending physician clinically indicated norepinephrine dose reduction, with MAP transitioning from the 75-85 mmHg range to the 65-75 mmHg range.

Other: Not applicable- observational study

Interventions

Not applicable- observational study OTHER

Observation of hemodynamic parameters before and after clinically indicated norepinephrine dose reduction. No investigator-initiated intervention was performed.

Distributive shock patients undergoing norepinephrine dose reduction

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

Adult distributive shock patients receiving invasive mechanical ventilation and norepinephrine treatment

You may qualify if:

• Adult distributive shock patients aged ≥18 years;
• Receiving norepinephrine infusion with MAP in the 75-85 mmHg range;
• PiCCO catheter in situ;
• Under mechanical ventilation;
• Clinically indicated norepinephrine dose reduction per attending physician judgment.

You may not qualify if:

• Significant cardiac arrhythmia affecting CO measurement reliability;
• Contraindication to airway plateau pressure maneuver;
• Active titration of other vasoactive agents within 30 minutes prior to measurement;
• Hemodynamic instability making it impossible to reduce norepinephrine dose.

Sponsors & Collaborators

• Peking Union Medical College Hospital: lead

Study Sites (1)

Peking Union Medical College Hospital

Beijing, Beijing Municipality, 100730, China

RECRUITING

MeSH Terms

Conditions

Critical Illness

Condition Hierarchy (Ancestors)

Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Bin Du, Dr

CONTACT

86+15136289398; sunyaliii@163.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: June 8, 2026
• First Posted: June 17, 2026
• Study Start: September 1, 2025
• Primary Completion (Estimated): July 1, 2027
• Study Completion (Estimated): September 1, 2027
• Last Updated: June 17, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)