Monitoring Respiratory Muscle Function in Acute Respiratory Failure Patients Requiring Non-invasive Respiratory Support (MONITOR-NIV): A Prospective Observational Study
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 50
- 试验地点
- 2
- 主要终点
- Usability
研究概览
简要总结
Acute respiratory failure is a common, life-threatening condition where the lungs cannot provide enough oxygen to the body. Many patients are treated with non-invasive respiratory support (NRS) such as high-flow nasal oxygen (HFNO), continuous positive airway pressure (CPAP), or bilevel positive airway pressure (BiPAP). However, up to half of patients receiving NRS still deteriorate and require intubation and invasive ventilation, which is linked to longer hospital stays, more complications, and slower recovery.
A major challenge in caring for these patients is that clinicians currently cannot directly see how well the breathing muscles (especially the diaphragm and parasternal intercostal muscles) and the lungs are working while the patient is using NRS. Existing bedside measures, such as respiratory rate or oxygen levels, only show part of the picture. They do not indicate how hard the patient is working to breathe or whether their respiratory muscles are becoming fatigued. This lack of information may delay important decisions about adjusting NRS settings or switching to other treatments.
This study aims to find out whether two advanced but non-invasive, radiation-free bedside monitoring tools can be used effectively in routine care:
- Ultrasound, which can measure breathing muscle thickness, movement, and lung aeration
- Electrical impedance tomography (EIT), which uses a soft belt of small electrodes around the chest to measure changes in air and blood flow within different regions of the lungs in real time
These tools have shown promise in earlier research, and interviews with patients and clinicians suggest they are comfortable, well-tolerated, and potentially useful. However, they have not yet been evaluated together in a real-world hospital environment where many acute respiratory failure patients are cared for outside the ICU.
What the study will involve:
Up to 100 adults with acute respiratory failure requiring any type of non invasive respiratory support will be recruited with the goal of obtaining complete data from at least 50 patients. Each participant will undergo ultrasound and EIT assessments up to seven times during the first 72 hours after starting NRS, plus an additional measurement if they improve enough to stop NRS or if they deteriorate and require intubation. These assessments take place at the bedside, require brief exposure of the upper chest, and last approximately 15-45 minutes. Routine clinical data-such as heart rate, oxygen levels, and breathing measures-will also be recorded.
In parallel, clinical staff caring for these patients will complete a short Healthcare System Usability Scale questionnaire to rate how useful, understandable, and practical they find the information generated by ultrasound and EIT. Some staff may also take part in optional interviews to explore usability in more depth.
What the study is trying to learn:
The primary aim is to determine the usability of these monitoring methods meaning understanding if they are practical, easy to use, and helpful for clinicians making decisions about NRS treatment.
Secondary aims include understanding:
- how the respiratory muscles and lungs change over time during NRS
- whether these changes are linked to treatment settings (e.g., flow rate, pressure support)
- whether certain patterns are associated with treatment success or failure (intubation or death)
- whether these tools could help identify patients at risk of deterioration earlier
Risks and benefits:
Both ultrasound and EIT are widely used, safe, and non-invasive. They involve no radiation, needles, or harmful exposure. Minor temporary discomfort from the gel or belt placement is possible. Participation will not change any clinical treatments. Although patients may not directly benefit, the study may help future patients by improving understanding of breathing muscle function and supporting more personalised respiratory care.
By contributing to this research, patients and clinicians will help determine whether advanced monitoring can be realistically implemented in busy hospital settings and whether it could lay the groundwork for future trials aimed at improving outcomes for people with acute respiratory failure.
详细描述
Background and Rationale Acute respiratory failure (ARF) is a common and life-threatening syndrome characterised by inadequate gas exchange, resulting in hypoxaemia with or without hypercapnia, and frequently necessitating hospital admission and escalation of respiratory support. ARF is associated with substantial short-term mortality and long-term morbidity, including prolonged hospitalisation, reduced functional capacity, impaired quality of life, and increased healthcare utilisation. Despite advances in supportive respiratory therapies, outcomes remain poor for a significant proportion of patients, particularly when clinical deterioration is not recognised early.
Non-invasive respiratory support (NRS), including high-flow nasal oxygen (HFNO), continuous positive airway pressure (CPAP), and bilevel positive airway pressure (BiPAP), has become first-line therapy for many forms of ARF. These modalities aim to improve oxygenation, reduce work of breathing, and prevent the need for endotracheal intubation and invasive mechanical ventilation. Avoiding invasive ventilation is associated with reduced risk of ventilator-associated pneumonia, ventilator-induced lung injury, diaphragm disuse atrophy, delirium, and long-term neuromuscular weakness. Consequently, NRS is increasingly delivered not only in intensive care units (ICUs) but also in emergency departments, high-dependency units, and general wards.
However, despite widespread use, NRS failure rates remain substantial. A significant proportion of patients deteriorate and require delayed intubation, which is consistently associated with worse outcomes compared with early escalation. One of the major challenges in managing patients receiving NRS is the limited ability to directly assess respiratory muscle workload and lung mechanics at the bedside. As a result, clinicians often rely on indirect clinical markers that may lag behind physiological deterioration.
The primary pathophysiological determinant of ARF progression and NRS failure is the imbalance between ventilatory load and respiratory muscle capacity. Excessive inspiratory effort can lead to respiratory muscle fatigue, impaired ventilatory efficiency, and patient self-inflicted lung injury due to high transpulmonary pressures during spontaneous breathing. Importantly, these processes may occur even when conventional oxygenation metrics appear stable.
Traditional bedside metrics, such as respiratory rate, peripheral oxygen saturation, arterial blood gas measurements, and composite indices including the ROX index or HACOR score, provide indirect and incomplete insight into respiratory effort. While these measures are useful for population-level risk stratification, they cannot reliably quantify work of breathing or identify early respiratory muscle overload at the individual patient level. Furthermore, these indices are influenced by multiple confounders, including sedation, oxygen delivery settings, and clinician intervention.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- None
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
- •Adult (≥18 years old)
- •with acute respiratory failure with hypoxia (i.e. arterial oxygen tension (PaO2) of <8.0 kPa), and/or with or without hypercapnia (i.e. arterial carbon dioxide tension (PaCO2) of >6.0 kPa) from any underlying disease or cause
- •requiring any non-invasive respiratory support (i.e. HFNO, CPAP, BiPAP)
- •Multidisciplinary critical care staff involved in the management of those recruited patients with acute respiratory failure requiring non-invasive respiratory supports. Staff will possibly have an interview and are also required to complete a questionnaire.
排除标准
- •Patients in respiratory arrest defined as the total cessation of airflow and breathing effort and absent ventilation (24,25)
- •Patients requiring immediate intubation
- •Patients with Glasgow Coma Scale (GCS) < 8
- •Patients with severe facial trauma or burns
- •Patients with fixed upper airway obstruction or inability to protect the airway
- •Patients with severe agitation and/or confusion that prevent use of the device mask
- •Patients with severe vomiting
- •Pregnancy
- •Patients with pacemakers and other electronic devices in the thorax
- •Patients on end-of-life care or palliative care (defined as expected to die and/or not receiving active treatment)
- •Contra-indication to EIT or ultrasound monitoring (e.g. burns, severe obesity, thoracic wounds limiting instrument placement, and thoracic drain)
研究组 & 干预措施
Patients with acute respiratory failure requiring non invasive respiratory support
Patients with acute respiratory failure requiring non invasive respiratory support
干预措施: Advanced respiratory monitoring (Other)
结局指标
主要结局
Usability
时间窗: 72 hours
The usability of respiratory muscle ultrasound and electrical impedance tomography to effectively support clinical decision making measured by asking clinical staff to complete the Healthcare System Usability Scale (HSUS). The Healthcare System Usability Scale (HSUS) will be used to assess usability, which score is converted into percentage in a system ranging from 0 to 100 for rating of usability to allow interpretation. Acceptability scales range: "Not Acceptable"\< 50, "Marginally acceptable" 50-70, "Acceptable"\> 70.
次要结局
- Feasibility evaluation(72 hours)
- Observational evaluation(72 hours)