BACKGROUND High-flow nasal cannula (HFNC) oxygen therapy has been widely used in critically ill patients. Despite the effectiveness of HFNC as a treatment, optimal methods to withdraw HFNC after recovery from preexisting conditions have not been investigated to date. In this study, we will evaluate the safety and efficacy of simultaneous reduction of flow and fraction of inspired oxygen (FiO2) compared with sequential reduction of either flow first or FiO2 reduction first in patients with HFNC. METHODS/DESIGN This is a prospective, investigator-initiated, randomized controlled trial with three experimental intervention groups. A total of 100 adult patients receiving HFNC and satisfying weaning criteria will be enrolled and randomly assigned to one of the following groups: flow reduction (FR) first, FiO2 reduction (OR) first, or simultaneous reduction (SR). In the FR group, flow will be reduced first by 10 L/min/h. When it reaches 20 L/min, FiO2 will then be reduced by 0.1 /h until it reaches 0.3. In the OR group, the FiO2 will be gradually reduced first by 0.1 /h until it reaches 0.3, then flow will be reduced by 10 L/min until it reaches 20 L/min. Finally, in the SR group, both the flow and FiO2 will be gradually reduced simultaneously by 10 L/min and 0.1/h, respectively. Weaning will proceed only when patients satisfy the weaning criteria at every weaning point. When the HFNC weaning-off targets are reached (20 L/min and 0.3 for flow and FiO2, respectively), the patient will be transferred to conventional oxygen therapy (mainly low-flow nasal prongs). The primary outcome is the time to successful weaning from HFNC for 24 h. Secondary outcomes will include the success or failure rate in weaning off HFNC and changes in arterial blood gas analyses, intolerance rate, length of hospital stay, and in-hospital mortality. DISCUSSION This study will be the first clinical trial to investigate the safety and efficacy of three different methods of weaning in adult patients receiving HFNC. Once this study is completed, we expect to be able to suggest the better strategy for withdrawal of HFNC based on the results. TRIAL REGISTRATION ClinicalTrials.gov, NCT03845244. Registered on 19 February 2019.

中文翻译：

---

对于准备从高流量鼻导管氧气疗法断奶的患者，同时减少流量和吸入氧气（FiO2）与首先减少流量或首先减少FiO2：一项随机对照试验（SLOWH试验）的研究方案。

背景技术高流量鼻插管（HFNC）氧气疗法已被广泛用于危重患者。尽管HFNC可以有效治疗，但从现有疾病中恢复后退出HFNC的最佳方法尚未进行研究。在这项研究中，我们将评估HFNC患者同时减少流量和吸入氧气分数（FiO2）与先减少流量或先减少FiO2的安全性和有效性。方法/设计这是一项由研究人员发起的前瞻性随机对照试验，共有三个实验干预组。共有100名接受HFNC且符合断奶标准的成年患者入组，并随机分配至以下组之一：流量减少（FR）首先，FiO2减少（OR）首先，或同时还原（SR）。在FR组中，流量将首先减少10 L / min / h。当达到20 L / min时，FiO2将减少0.1 / h，直到达到0.3。在OR组中，FiO2将首先逐渐降低0.1 / h，直到达到0.3，然后流量降低10 L / min，直到达到20 L / min。最后，在SR组中，流量和FiO2会同时分别逐渐减少10 L / min和0.1 / h。仅当患者在每个断奶点均满足断奶标准时，才进行断奶。当达到HFNC断奶目标（流量和FiO2分别为20 L / min和0.3）时，患者将被转入常规氧气治疗（主要是低流量鼻塞）。主要结果是从HFNC成功断奶24小时的时间。次要结果包括断奶HFNC的成功或失败率以及动脉血气分析的变化，不耐受率，住院时间和住院死亡率。讨论本研究将是第一个研究三种不同的断奶方法对成年HFNC患者的安全性和有效性的临床试验。这项研究一旦完成，我们希望能够根据结果提出更好的HFNC退出策略。试验注册ClinicalTrials.gov，NCT03845244。于2019年2月19日注册。讨论本研究将是第一个研究三种不同的断奶方法对成年HFNC患者的安全性和有效性的临床试验。这项研究一旦完成，我们希望能够根据结果提出更好的HFNC退出策略。试验注册ClinicalTrials.gov，NCT03845244。于2019年2月19日注册。讨论本研究将是第一个研究三种不同的断奶方法对成年HFNC患者的安全性和有效性的临床试验。这项研究完成后，我们希望能够根据结果提出更好的HFNC停用策略。试验注册ClinicalTrials.gov，NCT03845244。于2019年2月19日注册。