Comparison of Different Oxygen Flow Rates During Preoxygenation Using High-Flow Nasal Oxygen
试验速览
- 阶段
- 不适用
- 状态
- 进行中（未招募）
- 入组人数
- 75
- 试验地点
- 1
- 主要终点
- Safe apnoea time
研究概览
简要总结
High-flow nasal oxygen (HFNO) has been used for many years to help people with breathing difficulties in the intensive care and after surgery. More recently, it has become a helpful tool during induction of anaesthesia to prevent oxygen levels from dropping when managing the airway. HFNO is particularly effective at delivering oxygen even when a patient is not breathing (apnoea), making it useful during surgeries on the voice box (larynx) because it eliminates the need for a breathing tube, giving surgeons a clear view.
HFNO is now also being used to prepare patients for anaesthesia (preoxygenation). Research shows that it works just as well as traditional tight-fitting oxygen masks while offering added benefits like better comfort for patients, easier handling for anaesthetists, and a smooth transition to oxygen delivery during apnoea.
One reason HFNO is effective is that it creates a mild pressure in the lungs, called positive end-expiratory pressure (PEEP), which improves oxygen storage in the lungs. This pressure depends on the flow rate of oxygen and is higher when the patient keeps their mouth closed. For every increase of 10 liters per minute in flow rate, HFNO generates 1 cmH2O of PEEP. This pressure helps increase the lung's capacity to hold oxygen, making the process of preoxygenation more efficient.
Most studies on HFNO for preoxygenation have used flow rates of up to 60 liters per minute. However, we don't yet know if higher flow rates could further improve preoxygenation or extend the time patients can safely go without breathing.
详细描述
High-flow nasal oxygen (HFNO) has long been employed to address respiratory distress in both the intensive care unit and post-anaesthesia unit. Over the past decade, HFNO has emerged as a valuable tool for preventing oxygen desaturation during airway management in the operating theatre. Notably, HFNO demonstrates effectiveness in oxygenating patients during extended periods of apnoea, providing a reliable method for apnoeic oxygenation. This technique serves as an alternative to mechanical ventilation in laryngeal surgical procedures, offering potential advantages such as a clear operating field for surgeons without the interference of a tracheal tube.
More recently, HFNO has found application in preoxygenation before anaesthesia induction. Studies indicate that the preoxygenation efficacy of HFNO is comparable to that of a standard tight-fitting facemask, with added benefits including enhanced patient comfort, improved ease of use as assessed by anaesthetists, and the potential for a seamless transition to apnoeic oxygenation.
One of the suggested mechanisms contributing to the favourable outcomes observed with HFNO in managing patients with respiratory distress is a flow-dependent positive end-expiratory pressure (PEEP) effect. When patients breathe with a closed mouth, HFNO appears to generate a PEEP effect of 1 cmH2O for every 10 l.min-1 of flow. Prior data has demonstrated that an elevated PEEP leads to a greater functional residual capacity (FRC) and improved preoxygenation effectiveness.
Previous studies investigating HFNO for preoxygenation have used flow rates ≤ 60 l.min-1. Consequently, the impact of higher flow rates on preoxygenation effectiveness and the extension of safe apnoea time remains uncertain.
In this randomised prospective study, we aim to investigate the effectiveness of preoxygenation from HFNO using different flow rates. Seventy-five patients (25 per group) scheduled for elective surgery at the Karolinska University Hospital, will be recruited. After a signed consent, the subject will be enrolled and randomised to preoxygenation using HFNO at flow rates of 45 l/min, 70 l/min or 95 l/min.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Double (Participant, Care Provider)
入排标准
- 年龄范围
- 18 Years 至 84 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Adult, 18-84 years old
- •BMI < 35
- •Planned for elective surgery
排除标准
- •Cardiac disease (ischemic heart disease, heart failure (NYHA ≥2), ongoing arrhythmias, pulmonary hypertension)
- •Severe asthma, moderate to severe COPD
- •Pregnancy
- •Smokers or former smoker last finished 1 year before inclusion
- •Baseline oxygen saturation < 95%
- •Nasal obstruction
- •Known or anticipated difficult airway
- •Patients with electrical active implants where lung impedance analysis is contraindicated
- •Not capable of understanding study information and signing a written consent
研究组 & 干预措施
High-flow nasal oxygen, flow rate 45 l/min
Preoxygenation using high-flow nasal oxygen with a flow rate of 45 l/min
干预措施: High-flow nasal oxygen (Device)
High-flow nasal oxygen, flow rate 70 l/min
Preoxygenation using high-flow nasal oxygen with a flow rate of 70 l/min
干预措施: High-flow nasal oxygen (Device)
High-flow nasal oxygen, flow rate 95 l/min
Preoxygenation using high-flow nasal oxygen with a flow rate of 95 l/min
干预措施: High-flow nasal oxygen (Device)
结局指标
主要结局
Safe apnoea time
时间窗: From start of apnoea after anaesthesia induction until peripheral oxygen saturation drops to 93%. This time fram will probably be between 5 and 15 minutes.
Comparison of the time from start of apnoea until reaching a SpO2 = 93% between the different flow rates
次要结局
- Tolerance of 360 seconds of apnoea(From apnoea start until 5 minutes of apnoea)
- Arterial oxygen levels during preoxygenation(From start of preoxygenation until end of preoxygenation (approximately 3 to 4 minutes))
- Discomfort assessment(From start of preoxygenation until the end of preoxygenation, this time fram will be three minutes.)
- Lung impedance changes(From start of preoxygenation until end of apnoea (approximately 5 to 15 minutes))
研究者
Albin Sjöblom
Principal Investigator
Region Stockholm