Moderate CO2 increase during anesthesia to boost collateral flow in clot removal for acute anterior stroke

Evaluation of the Effect of Moderate and Controlled Hypercapnia on Ischemic Penumbra Vascular Collaterality During General Anesthesia for Anterior Circulation Acute Ischemic Stroke Mechanical Thrombectomy

PHASE2 · University Hospital, Clermont-Ferrand · NCT05051397

This study will test whether slightly higher blood carbon dioxide during anesthesia improves collateral blood flow and protects the brain in people having mechanical thrombectomy for anterior large-vessel ischemic stroke.

Quick facts

PhasePHASE2
Study typeInterventional
Enrollment50 (estimated)
Ages18 Years and up
SexAll
SponsorUniversity Hospital, Clermont-Ferrand (other)
Locations1 site (Clermont-Ferrand)
Trial IDNCT05051397 on ClinicalTrials.gov

What this trial studies

This randomized Phase 2 trial enrolls patients with anterior-circulation large-vessel occlusion ischemic stroke who undergo mechanical thrombectomy under general anesthesia. After induction and intubation, patients are randomized to moderate hypercapnia (target PaCO2 50 mmHg) or normocapnia (target PaCO2 40 mmHg) achieved by adjusting ventilator settings with arterial blood gas confirmation. Baseline and pre-reperfusion collateral circulation will be graded using the ASITN scale on angiography while systolic blood pressure and anesthetic depth are standardized. The study compares the effect of controlled CO2 modulation on collateral blood flow and periprocedural cerebral protection prior to intra-arterial revascularization.

Who should consider this trial

Good fit: Adults with anterior-circulation large-vessel occlusion ischemic stroke who are eligible for mechanical thrombectomy under general anesthesia and meet the trial's inclusion/exclusion criteria.

Not a fit: Patients with active smoking, chronic respiratory failure, BMI over 40, prior intubation, suspected elevated intracranial pressure, pregnancy, or posterior-circulation strokes are excluded and likely would not benefit from this approach.

Why it matters

Potential benefit: If successful, moderate hypercapnia during anesthesia could increase collateral cerebral blood flow before reperfusion and reduce ischemic injury, potentially improving recovery after thrombectomy.

How similar studies have performed: Physiologic and observational studies show hypercapnia increases cerebral blood flow, but randomized evidence testing CO2 modulation specifically during thrombectomy is limited.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

• Large vessel occlusion anterior circulation stroke (terminal carotid artery and/or middle cerebral artery M1-M2 segment) eligible to mechanical thrombectomy under general anesthesia

Exclusion Criteria :

* Active smoker
* Chronic respiratory failure with ambulatory oxygen supplementation
* Obesity with BMI\>40Kg/ m2
* Intubation before the procedure
* Heart failure with intolerance to decubitus
* Severe renal failure
* Suspected elevated intracranial pressure
* Pregnant or breastfeeding women

Where this trial is running

Clermont-Ferrand

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Ischemic Stroke, Acute, Thrombectomy, Anesthesia, General, Cerebrovascular Circulation, Carbon Dioxide, mechanical thrombectomy, large vessel occlusion stroke, carbon dioxide tension

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.