Division of Respiratory Diseases and Tuberculosis, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada.
Respir Care. 2021 May;66(5):806-813. doi: 10.4187/respcare.08585. Epub 2021 Mar 2.
High-flow oxygen therapy via tracheostomy (HFT) can be used in tracheostomized patients during ventilator disconnection. The physiologic effects of this technique are unknown. We hypothesized that HFT would reduce inspiratory effort and improve breathing pattern compared to conventional oxygen therapy via T-tube. This study aimed to evaluate the physiologic effects of HFT compared to conventional O in patients with prolonged mechanical ventilation.
A randomized crossover physiologic study was conducted in adult tracheostomized patients who experienced temporary periods of ventilator disconnection. Subjects were ventilated with pressure support ventilation (PSV) for 15 min and were then randomly assigned to HFT or conventional O via T-tube for 30 min. After a washout period, subjects were switched to the other system. Esophageal pressure (P), breathing frequency, blood pressure, heart rate, [Formula: see text], and transcutaneously measured pressure of carbon dioxide ([Formula: see text]) were recorded. The primary outcome was inspiratory effort as determined by the simplified esophageal pressure-time product (sPTP). Secondary outcomes were P swing, breathing frequency, heart rate, mean arterial pressure, [Formula: see text], and [Formula: see text] between groups.
Twenty-two subjects were enrolled: sPTP per minute was significantly higher with HFT and conventional O compared to PSV (153.5 ± 97.9, 163.5 ± 111.3, and 86.8 ± 51.1 cm HO × s/min, respectively, = .001), but it was not different between HFT and conventional O ( = .72). Breathing frequency increased significantly after switching from PSV to HFT and conventional O (23 ± 4 vs 26 ± 6 and 23 ± 4 vs 27 ± 5 breaths/min, respectively, = .001). [Formula: see text] was higher with conventional O compared to HFT ( = .02). No differences in [Formula: see text], mean arterial pressure, or heart rate were observed between HFT and conventional O.
Inspiratory effort and breathing frequency increased significantly during unassisted breathing compared to PSV in tracheostomized subjects, but HFT via tracheostomy provided no measurable additional physiologic benefit compared to O therapy via T-tube.
经气管切开高流量氧疗（HFT）可用于气管切开患者呼吸机脱机时。其生理效应尚不清楚。我们假设与经 T 管的常规氧疗相比，HFT 可降低吸气努力并改善呼吸模式。本研究旨在评估与经 T 管的常规氧疗相比，HFT 在接受长时间机械通气的患者中的生理效应。
在经历短暂呼吸机脱机的成年气管切开患者中进行了一项随机交叉生理研究。患者接受压力支持通气（PSV）15 分钟，然后随机分配至 HFT 或经 T 管的常规 O 治疗 30 分钟。在洗脱期后，患者切换至另一种系统。记录食管压力（P）、呼吸频率、血压、心率、动脉血氧分压（[Formula: see text]）和经皮二氧化碳分压（[Formula: see text]）。主要结局为简化食管压力-时间乘积（sPTP）确定的吸气努力。次要结局为 P 摆动、呼吸频率、心率、平均动脉压、[Formula: see text]和[Formula: see text]。
共纳入 22 名患者：与 PSV 相比，HFT 和常规 O 时每分钟 sPTP 显著更高（分别为 153.5 ± 97.9、163.5 ± 111.3 和 86.8 ± 51.1 cm HO × s/min， =.001），但 HFT 和常规 O 之间无差异（ =.72）。与 PSV 切换至 HFT 和常规 O 后，呼吸频率均显著增加（分别为 23 ± 4 次/分、26 ± 6 次/分和 23 ± 4 次/分、27 ± 5 次/分， =.001）。与 HFT 相比，常规 O 时[Formula: see text]更高（ =.02）。HFT 和常规 O 之间未观察到[Formula: see text]、平均动脉压或心率的差异。
与 PSV 相比，气管切开患者自主呼吸时吸气努力和呼吸频率显著增加，但与经 T 管的 O 治疗相比，经气管切开的 HFT 并未提供可测量的额外生理益处。
