Luo Jing-Chao, Lu Mei-Shan, Zhao Zhi-Hong, Jiang Wei, Xu Biao, Weng Li, Li Tong, Du Bin
Medical Intensive Care Unit, Peking Union Medical College Hospital, Beijing, China.
Department of Clinical Medicine, Peking Union Medical College, Beijing, China.
Respir Care. 2017 Jul;62(7):888-895. doi: 10.4187/respcare.05337. Epub 2017 Apr 25.
High-flow nasal cannula (HFNC) is supposed to provide additional PEEP compared with conventional oxygen therapy. However, the exact determinants of this PEEP effect are unclear. We investigated the factors that might affect the PEEP and compared PEEP performance among 3 HFNC devices.
Three available HFNC devices were evaluated: the AIRVO 2 device and 2 mechanical ventilators (SV300 and Monnal T75). A device consisting of a test lung (5600i) and an airway model (AMT(IE)) was used to simulate spontaneous breathing. The flows ranged from 0 to their maximum flow with an interval of 10 L/min. The pressures were measured at 4 sites (nasopharynx, supraglottis, carina, and lung) under compliances of 50 and 100 mL/cm HO and tidal volume of 300, 500, and 700 mL with the mouth closed or open. The influencing factors were determined by multiple linear regression. The sum of squares reduction test was used to compare working curves of PEEP effect among 3 devices. Pairwise comparisons were conducted by using Tukey's multiple comparisons test within an overlap of flow from 0 to 50 L/min.
A quadratic curved relationship between PEEP and flow was observed (coefficients were 8.97 × 10 for flow and 4.79 × 10 for a quadratic element of flow, respectively) but evanished when the mouth was open. The PEEP increased along with lung compliance (coefficient was 2.58 × 10). Despite the difference in working curves, both the mechanical ventilators performed slightly better than the AIRVO 2 device at higher flows (40 and 50 L/min).
The mouth status, flow, and compliance were the 3 major influencing factors of PEEP effect, whereas performance of the 2 mechanical ventilators was slightly superior to that of the AIRVO 2 device at higher flows.
与传统氧疗相比，高流量鼻导管（HFNC）被认为可提供额外的呼气末正压（PEEP）。然而，这种PEEP效应的确切决定因素尚不清楚。我们研究了可能影响PEEP的因素，并比较了3种HFNC设备的PEEP性能。
评估了3种可用的HFNC设备：AIRVO 2设备和2台机械通气机（SV300和Monnal T75）。使用由测试肺（5600i）和气道模型（AMT(IE)）组成的设备来模拟自主呼吸。流量范围为0至其最大流量，间隔为10 L/min。在口闭合或开放的情况下，在顺应性为50和100 mL/cm H₂O以及潮气量为300、500和700 mL时，在4个部位（鼻咽、声门上、隆突和肺）测量压力。通过多元线性回归确定影响因素。使用平方和减少检验来比较3种设备之间的PEEP效应工作曲线。在流量从0至50 L/min的重叠范围内，使用Tukey多重比较检验进行两两比较。
观察到PEEP与流量之间呈二次曲线关系（流量的系数分别为8.97×10⁻³和流量二次项的系数为4.79×10⁻⁵），但在口开放时消失。PEEP随肺顺应性增加（系数为2.58×10⁻²）。尽管工作曲线存在差异，但在较高流量（40和50 L/min）时，两台机械通气机的表现均略优于AIRVO 2设备。
口的状态、流量和顺应性是PEEP效应的3个主要影响因素，而在较高流量时，两台机械通气机的性能略优于AIRVO 2设备。
