Correcting Hypocapnia in Aneurysmal Subarachnoid Hemorrhage.

NCT07343232 | Not Yet Recruiting DMC

• 1 other identifier: CUHKShenzhen
• Study Type: observational
• Target: 80
• Locations: 1 country
• Sites: 1

Brief Summary

Based on the clinical observation that over half of the patients in the management of aneurysmal subarachnoid hemorrhage(aSAH) present with spontaneous hyperventilation, which is significantly associated with delayed cerebral ischemia and poor neurological outcomes, this prospective pilot study is designed to investigate the safety and efficacy of normobaric facemask oxygen for hypocapnia in aSAH.

Conditions

Aneurysmal Subarachnoid Hemorrhage (aSAH)

Keywords

Aneurysmal Subarachnoid Hemorrhage (aSAH); Hypocapnia

Outcome Measures

Primary Outcomes (2)

• modified Rankin Scale (mRS) >3

  The poor neurological outcome was considered to be mRs \>3, indicating severe disability or death. The modified Rankin Scale (mRS) is a commonly used scale for measuring the degree of disability or dependence in the daily activities of people who have suffered a stroke or other causes of neurological disability. (Score Description: 0---No symptoms at all. 1---No significant disability despite symptoms; able to carry out all usual duties and activities. 2---Slight disability; unable to carry out all previous activities, but able to look after own affairs without assistance. 3---Moderate disability; requiring some help, but able to walk without assistance. 4--- Moderately severe disability; unable to walk without assistance and unable to attend to own bodily needs without assistance. 5---Severe disability; bedridden, incontinent and requiring constant nursing care and attention. 6---Dead.

  90-day follow-up visit

• Incidence of delayed cerebral injury (DCI)

  The presence of new focal neurological signs or a documented decrease in the level of consciousness persisting for at least 1 hour (or a drop of at least 1 point in the total Glasgow Coma Scale score), deemed to be of ischemic origin, after ruling out other causes (such as hydrocephalus, toxic-metabolic disturbances, or seizures); or identification of a new cerebral infarction on CT or MRI imaging.

  30 days after onset

Secondary Outcomes (11)

• Montreal Cognitive Assessment (MoCA)

  90-day follow-up visit

• Cerebral Vasospasm

  Participants will be followed for the duration of the hospital stay, an expected average of 2 weeks

• Glasgow Coma Score(GCS)

  Enrollment, 30 days after onset, and 90-day follow-up visit

• The modified Rankin Scale (mRS)

  30 days after onset

• modified Rankin Scale (mRS)

  30 days after onset

Study Arms (2)

Normobaric Facemask Oxygen

Patients who received oxygen via a rebreathing facemask (ensuring no one-way valve is present), with a fractional inspired oxygen (FiO2) of 25-40% and an oxygen flow rate of ≤ 5 L/min.

Behavioral: Normobaric Facemask Oxygen

Control group

Patients who received oxygen via nasal cannula or did not receive oxygen therapy.

Behavioral: control group

Interventions

Normobaric Facemask Oxygen BEHAVIORAL

Oxygen is to be delivered via a rebreathing facemask (ensuring no one-way valve is present), with a fractional inspired oxygen (FiO2) of 25-41% and an oxygen flow rate of ≤ 5 L/min. The goals are to maintain patient SpO2 \> 95%, PaCO2 between 35-42 mmHg, and, where feasible (particularly in centers with the capability for monitoring), an intracranial pressure (ICP) of \< 15 mmHg.

Normobaric Facemask Oxygen

control group BEHAVIORAL

Using nasal cannula for oxygen inhalation or not using oxygen inhalation at all. Monitor and record the patient's SpO2, systolic blood pressure, diastolic blood pressure, PaCO2, and also monitor the intracranial pressure (ICP) at a center with monitoring capabilities.

Control group

Eligibility Criteria

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

Study Population

Aneurysmal Subarachnoid Hemorrhage Patients with Hypocapnia.

You may qualify if:

• Age \> 18 years.
• Confirmed diagnosis of aneurysmal subarachnoid hemorrhage (aSAH), with the presence of an aneurysm verified by computed tomography (CT), CT angiography (CTA), or digital subtraction angiography (DSA).
• Hunt-Hess grade II-IV.
• Presence of hypocapnia on arterial blood gas analysis, defined as PaCO2 \< 35 mmH;
• PaO2 \> 90 mmHg.

You may not qualify if:

• Presence of brain herniation or refractory intracranial hypertension, defined as a baseline intracranial pressure (ICP) \> 25 mmHg that responds poorly to conventional ICP-lowering therapy;
• Primary respiratory diseases (e.g., chronic obstructive pulmonary disease, severe asthma) known to cause chronically elevated baseline PaCO2;
• Severe acid-base disturbances other than respiratory alkalosis.
• Severe cardiac insufficiency, severe hepatic or renal dysfunction, malignant tumors, or other severe comorbidities that significantly impact prognosis;
• Before the onset of the disease, the mRS score was greater than 2, and there were other factors causing disability.
• Life expectancy \< 3 months;

Sponsors & Collaborators

• The Chinese University of Hong Kong, Shenzhen: lead

Study Sites (1)

School of Medicine Chinese University of Hong Kong-SHENZHEN

Shenzhen, Guangdong, 518000, China

Location

Related Publications (9)

• Yang L, Yuan D, Luo Z, Li Y, Zhu X. The low-flow mask oxygen could be a more effective, comfortable, and easy-to-follow treatment for psychogenic hyperventilation syndrome: A double-blind, randomized controlled trial. Int Emerg Nurs. 2025 Aug;81:101636. doi: 10.1016/j.ienj.2025.101636. Epub 2025 Jun 17.

  PMID: 40532319 RESULT

• Darkwah Oppong M, Wrede KH, Muller D, Santos AN, Rauschenbach L, Dinger TF, Ahmadipour Y, Pierscianek D, Chihi M, Li Y, Deuschl C, Sure U, Jabbarli R. PaCO2-management in the neuro-critical care of patients with subarachnoid hemorrhage. Sci Rep. 2021 Sep 28;11(1):19191. doi: 10.1038/s41598-021-98462-2.

  PMID: 34584136 RESULT

• Cai G, Zhang X, Ou Q, Zhou Y, Huang L, Chen S, Zeng H, Jiang W, Wen M. Optimal Targets of the First 24-h Partial Pressure of Carbon Dioxide in Patients with Cerebral Injury: Data from the MIMIC-III and IV Database. Neurocrit Care. 2022 Apr;36(2):412-420. doi: 10.1007/s12028-021-01312-2. Epub 2021 Jul 30.

  PMID: 34331211 RESULT

• Su R, Li HL, Wang YM, Zhang L, Zhou JX. Association of dynamic changes in arterial partial pressure of carbon dioxide with neurological outcomes in aneurysmal subarachnoid hemorrhage. Heliyon. 2024 Oct 10;10(20):e39197. doi: 10.1016/j.heliyon.2024.e39197. eCollection 2024 Oct 30.

  PMID: 39640813 RESULT

• Carrera E, Schmidt JM, Fernandez L, Kurtz P, Merkow M, Stuart M, Lee K, Claassen J, Sander Connolly E, Mayer SA, Badjatia N. Spontaneous hyperventilation and brain tissue hypoxia in patients with severe brain injury. J Neurol Neurosurg Psychiatry. 2010 Jul;81(7):793-7. doi: 10.1136/jnnp.2009.174425. Epub 2009 Dec 3.

  PMID: 19965840 RESULT

• Coles JP, Fryer TD, Coleman MR, Smielewski P, Gupta AK, Minhas PS, Aigbirhio F, Chatfield DA, Williams GB, Boniface S, Carpenter TA, Clark JC, Pickard JD, Menon DK. Hyperventilation following head injury: effect on ischemic burden and cerebral oxidative metabolism. Crit Care Med. 2007 Feb;35(2):568-78. doi: 10.1097/01.CCM.0000254066.37187.88.

  PMID: 17205016 RESULT

• Coles JP, Minhas PS, Fryer TD, Smielewski P, Aigbirihio F, Donovan T, Downey SP, Williams G, Chatfield D, Matthews JC, Gupta AK, Carpenter TA, Clark JC, Pickard JD, Menon DK. Effect of hyperventilation on cerebral blood flow in traumatic head injury: clinical relevance and monitoring correlates. Crit Care Med. 2002 Sep;30(9):1950-9. doi: 10.1097/00003246-200209000-00002.

  PMID: 12352026 RESULT

• Robba C, Battaglini D, Abbas A, Sarrio E, Cinotti R, Asehnoune K, Taccone FS, Rocco PR, Schultz MJ, Citerio G, Stevens RD, Badenes R; ENIO collaborators. Clinical practice and effect of carbon dioxide on outcomes in mechanically ventilated acute brain-injured patients: a secondary analysis of the ENIO study. Intensive Care Med. 2024 Feb;50(2):234-246. doi: 10.1007/s00134-023-07305-3. Epub 2024 Jan 31.

  PMID: 38294526 RESULT

• Williamson CA, Sheehan KM, Tipirneni R, Roark CD, Pandey AS, Thompson BG, Rajajee V. The Association Between Spontaneous Hyperventilation, Delayed Cerebral Ischemia, and Poor Neurological Outcome in Patients with Subarachnoid Hemorrhage. Neurocrit Care. 2015 Dec;23(3):330-8. doi: 10.1007/s12028-015-0138-5.

  PMID: 25846710 RESULT

MeSH Terms

Conditions

Subarachnoid Hemorrhage; Hypocapnia

Interventions

Control Groups

Condition Hierarchy (Ancestors)

Intracranial Hemorrhages; Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Vascular Diseases; Cardiovascular Diseases; Hemorrhage; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms, Respiratory; Signs and Symptoms

Intervention Hierarchy (Ancestors)

Epidemiologic Research Design; Epidemiologic Methods; Investigative Techniques; Research Design; Methods

Study Officials

• Renzhi Wang, MD

  CUHK-Shenzhen

  STUDY CHAIR

• Xinyu Yang

  CUHK-Shenzhen

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Xinyu Yang, MD

CONTACT

18622766038; cuhkshzhyang@outlook.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Target Duration: 90 Days
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: director of department

Study Record Dates

• First Submitted: December 17, 2025
• First Posted: January 15, 2026
• Study Start: January 1, 2026
• Primary Completion (Estimated): September 30, 2026
• Study Completion (Estimated): October 30, 2026
• Last Updated: January 15, 2026

Record last verified: 2026-01

Locations

CN (1)