Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
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.
Spontaneous hyperventilation (SH) is highly prevalent following aneurysmal subarachnoid hemorrhage (aSAH) and is significantly associated with poor neurological outcomes.The core pathophysiological mechanism involves hypocapnia induced by hyperventilation, which triggers cerebral vasoconstriction and consequently leads to a decrease in cerebral blood flow (CBF).Although this response may transiently reduce intracranial pressure, persistent cerebral vasoconstriction markedly increases the risk of delayed cerebral ischemia (DCI) and secondary brain injury. Therefore, maintaining the arterial partial pressure of carbon dioxide (PaCO2) within the physiological range of mmHg is recommended to minimize the detrimental effects of hypocapnia.
Currently, there is a lack of standardized management strategies for hypocapnia resulting from SH after aSAH. Based on physiological principles, low-flow (<5 L/min) oxygen delivery via a facemask may effectively correct hypocapnia by promoting the rebreathing of carbon dioxide within the dead space of the facemask.10 A randomized controlled trial investigating psychogenic hyperventilation syndrome provides preliminary evidence for this approach, demonstrating that low-flow (3 L/min) facemask oxygen therapy can relieve symptoms more rapidly and improve patient comfort compared to traditional breathing training.11
However, high-level evidence regarding the safety, efficacy, and impact on neurological outcomes of using low-flow facemask oxygen therapy (functioning as a rebreathing mask) as a targeted intervention for correcting hypocapnia in aSAH patients remains scarce. Consequently, this proof-of-concept prospective study aims to systematically evaluate the operational safety and clinical effectiveness of rebreathing facemask oxygen therapy for correcting hypocapnia in patients with aSAH.
Not provided
Not provided
Not provided
Not provided
| Label | Type | Description | Intervention Names |
|---|---|---|---|
| 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. |
| |
| Control group | Patients who received oxygen via nasal cannula or did not receive oxygen therapy. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| 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. |
| Measure | Description | Time Frame |
|---|---|---|
| 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 |
| Measure | Description | Time Frame |
|---|---|---|
| Montreal Cognitive Assessment (MoCA) | Cognitive function was evaluated using the Montreal Cognitive Assessment (MoCA), a standardized screening tool with scores ranging from 0 to 30, where higher scores indicate better cognitive performance and lower scores reflect greater cognitive impairment. Measure mean score or median compared between groups. And the rate of MoCA score of 20 or less between groups. |
Not provided
Inclusion Criteria:
Exclusion Criteria:
Not provided
Not provided
Not provided
Aneurysmal Subarachnoid Hemorrhage Patients with Hypocapnia.
| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Xinyu Yang, MD | Contact | 18622766038 | cuhkshzhyang@outlook.com |
| Name | Affiliation | Role |
|---|---|---|
| Renzhi Wang, MD | CUHK-Shenzhen | Study Chair |
| Xinyu Yang | CUHK-Shenzhen | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| School of Medicine Chinese University of Hong Kong-SHENZHEN | Shenzhen | Guangdong | 518000 | China |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 40532319 | Result | 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. | |
| 34584136 | Result |
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
| ID | Term |
|---|---|
| D013345 | Subarachnoid Hemorrhage |
| D016857 | Hypocapnia |
| ID | Term |
|---|---|
| D020300 | Intracranial Hemorrhages |
| D002561 | Cerebrovascular Disorders |
| D001927 | Brain Diseases |
| D002493 | Central Nervous System Diseases |
Not provided
Not provided
| ID | Term |
|---|---|
| D035061 | Control Groups |
| ID | Term |
|---|---|
| D015340 | Epidemiologic Research Design |
| D004812 | Epidemiologic Methods |
| D008919 | Investigative Techniques |
| D012107 | Research Design |
Not provided
Not provided
Not provided
Not provided
Not provided
|
| 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. |
|
| 90-day follow-up visit |
| Cerebral Vasospasm | Incidence of moderate and severe radiographic cerebral vasospasm (catheter angiogram, CTA, MRA) or incidence OR moderate and severe vasospasm by transcranial doppler (TCD) criteria. | Participants will be followed for the duration of the hospital stay, an expected average of 2 weeks |
| Glasgow Coma Score(GCS) | The Glasgow Outcome Scale was used as secondary outcomes. The level of consciousness was assessed using the Glasgow Coma Scale (GCS), a standardized scale ranging from 3 to 15, where higher scores indicate a better neurological status (i.e., a higher level of consciousness), and lower scores reflect more severe impairment. | Enrollment, 30 days after onset, and 90-day follow-up visit |
| The modified Rankin Scale (mRS) | Shift analysis of mRS scores at 30 days after onset. 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. The higher scores indicate worse functional disability and lower scores reflect better functional independence. | 30 days after onset |
| modified Rankin Scale (mRS) | The rate of modified Rankin Scale (mRS) score > 3. 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. The higher scores indicate worse functional disability and lower scores reflect better functional independence. | 30 days after onset |
| Barthel Index (BI) score | Activities of daily living were evaluated using the Barthel Index (BI), a functional assessment scale ranging from 0 to 100, where higher scores indicate greater independence in daily activities and lower scores reflect more severe functional dependence. | 90-day follow-up visit |
| All-cause mortality | Death caused by any reason. | 90-day follow-up visit |
| Complication of severe dependent survival | eg, chest or other infections | 90-day follow-up visit |
| Treated aneurysm rebleeding | Treated aneurysm rebleeding | 90-day follow-up visit |
| Probable or definite bleed from another aneurysm | Probable or definite bleed from another aneurysm | 90-day follow-up visit |
| Incidence of adverse events | Ischaemic stroke, Other intracranial haemorrhage, Cardiac, Cancer, Suicide, Renal failure, Infections not related to dependent survival, Other causes (eg, trauma, perforated ulcer, pulmonary embolus, neurodegenerative) | 90-day follow-up visit |
| 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. |
| 34331211 | 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. |
| 39640813 | 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. |
| 19965840 | 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. |
| 17205016 | 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. |
| 12352026 | 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. |
| 38294526 | 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. |
| 25846710 | 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. |
| D009422 | Nervous System Diseases |
| D014652 | Vascular Diseases |
| D002318 | Cardiovascular Diseases |
| D006470 | Hemorrhage |
| D010335 | Pathologic Processes |
| D013568 | Pathological Conditions, Signs and Symptoms |
| D012818 | Signs and Symptoms, Respiratory |
| D012816 | Signs and Symptoms |
| D008722 | Methods |