Hemodynamic Effects of Norepinephrine Reduction on Critical Closing Pressure in Distributive Shock
Trial statusRecruiting
Trial phaseNot listed
Trial typeObservational
Biological sexAll
Age18+
SponsorPeking Union Medical College Hospital
About this trial
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.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
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;
Disqualifiers
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.
Trial population
Adult distributive shock patients receiving invasive mechanical ventilation and norepinephrine treatment
Trial design
Design model
Cohort
Time perspective
Prospective
Treatments tested in this trial
Not applicable- observational study
Other interventionObservation of hemodynamic parameters before and after clinically indicated norepinephrine dose reduction. No investigator-initiated intervention was performed.
Treatment groups
30 Participants
are divided into 1 treatment groupGroup A: Distributive shock patients undergoing norepinephrine dose reduction1 intervention
Trial outcomes
Primary outcomes
1
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.
Time frame
Baseline and 30 minutes after norepinephrine dose reduction2
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
Time frame
Baseline and 30 minutes after norepinephrine dose reductionSecondary outcomes
1
Change in mean systemic filling pressure analogue (Pmsf, unit: mmHg) before and after norepinephrine dose reduction
Pmsf is estimated as the x-intercept of the linear regression of cardiac output against central venous pressure (CVP), representing the venous pressure at zero flow.
Time frame
Baseline and 30 minutes after norepinephrine dose reduction2
Change in Vascular waterfall (VW, unit: mmHg) before and after norepinephrine dose reduction
Vascular waterfall (VW) is calculated as Pcc minus Pmsf.
Time frame
Baseline and 30 minutes after norepinephrine dose reduction3
Change in capillary refill time (CRT, unit: seconds）
Capillary refill time is assessed by applying pressure to the fingertip for 5 seconds and measuring the time for color to return after release.
Time frame
Baseline and 30 minutes after norepinephrine dose reductionSponsors and contacts
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Source ClinicalTrials.gov