Safety and Efficacy of Normobaric Facemask Oxygen for Hypocapnia in Aneurysmal Subarachnoid Hemorrhage(FOCAL): A Prospective, Multicenter, Proof-of-concept Pilot Study
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 发起方
- 入组人数
- 80
- 试验地点
- 1
- 主要终点
- modified Rankin Scale (mRS) >3
研究概览
简要总结
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.
详细描述
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.
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Prospective
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •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.
排除标准
- •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;
- •Any other condition deemed by the investigator to pose a high risk warranting exclusion.
结局指标
主要结局
modified Rankin Scale (mRS) >3
时间窗: 90-day follow-up visit
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.
Incidence of delayed cerebral injury (DCI)
时间窗: 30 days after onset
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.
次要结局
- 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)
- Barthel Index (BI) score(90-day follow-up visit)
- All-cause mortality(90-day follow-up visit)
- Complication of severe dependent survival(90-day follow-up visit)
- Treated aneurysm rebleeding(90-day follow-up visit)
- Probable or definite bleed from another aneurysm(90-day follow-up visit)
- Incidence of adverse events(90-day follow-up visit)
研究者
Renzhi Wang
director of department
The Chinese University of Hong Kong, Shenzhen