RATIONALE High flow therapy reduces dyspnea in acute respiratory failure but the underlying mechanisms are not fully elucidated. OBJECTIVES To compare dyspnea, airway occlusion pressure (P0.1) and inspiratory work with and without nasal high flow (NHF, FiO2 21%, temperature 31°C) in intubated patients under pressure support ventilation and during a spontaneous breathing trial (SBT). METHODS Dyspnea (numerical rating scale, NRS and Mechanical Ventilation - Respiratory Distress Observational Scale, MV-RDOS), P0.1, esophageal pressure, respiratory muscles EMG, arterial blood gas were compared in intubated patients on pressure support ventilation presenting a dyspnea-NRS > 3 during two sequences: 1) pressure support ventilation with NHF at 0 L/min followed by 30, 50 and 60 L/min (the last three were randomized) and 2) a SBT with NHF at 0 and 50 L/min (randomized). MEASUREMENTS AND MAIN RESULTS Twenty patients were included. During pressure support ventilation, as compared to dyspnea-NRS that was 5 (4 - 6) at NHF 0 L/min, dyspnea-NRS was 3 (2 - 6) and 3 (2 - 5) at NHF 30L/min and NHF 50L/min, respectively (p<0.05). However, there was no change in MV-RDOS, P0.1, esophageal pressure, respiratory muscles EMG and gas exchange. During the SBT, at NHF 50 L/min, dyspnea-NRS and P0.1 were lower than during the SBT at NHF 0 L/min (p<0.01 and p=0.04 respectively) whereas MV-RDOS, esophageal pressure, respiratory muscles EMG did not change as compared to SBT with NHF 0 L/min. CONCLUSIONS In orally intubated patients, nasal high flow was associated with lower dyspnea and lower respiratory drive without affecting the inspiratory work.

中文翻译：

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经鼻高流量调节经口插管患者的呼吸困难。


基本原理 高流量疗法可减少急性呼吸衰竭患者的呼吸困难，但其潜在机制尚未完全阐明。目的 比较压力支持通气和自主呼吸试验 （SBT） 期间插管患者呼吸困难、气道闭塞压 （P0.1） 和有和没有鼻腔高流量 （NHF， FiO2 21%， 体温 31°C） 的吸气功。方法 比较压力支持通气患者的呼吸困难 （数字评定量表、NRS 和机械通气 - 呼吸窘迫观察量表，MV-RDOS）、P0.1、食管压、呼吸肌 EMG、动脉血气 表现为呼吸困难-NRS > 3 的插管患者在两个序列中表现为呼吸困难 > 3：1） 压力支持通气，NHF 为 0 L/min，然后是 30、50 和 60 L/min（最后三个是随机的）和 2） NHF 为 0 和 50 L/min 的 SBT（随机化）。测量和主要结果 包括 20 名患者。在压力支持通气期间，与 NHF 0 L/min 时呼吸困难-NRS 为 5 （4 - 6） 相比，NHF 30 L/min 和 NHF 50 L/min 呼吸困难-NRS 分别为 3 （2 - 6） 和 3 （2 - 5） （p<0.05）。然而，MV-RDOS 、 P0.1 、食管压、呼吸肌 EMG 和气体交换没有变化。在 SBT 期间，NHF 50 L/min 时呼吸困难-NRS 和 P0.1 低于 NHF 0 L/min 时 SBT 期间 （分别为 p<0.01 和 p=0.04），而 MV-RDOS 、食管压、呼吸肌 EMG 与 NHF 0 L/min 的 SBT 相比没有变化。结论 在经口插管患者中，鼻腔高流量与下呼吸困难和下呼吸驱动相关，而不影响吸气功。