背景:自主呼吸试验(SBT)是从有创机械通气撤机的最后一步。SBT旨在预测拔管后的呼吸功(WOB),最重要的是,患者有资格拔管。最佳SBT模式仍存在争议。仅在临床研究中,在SBT期间测试了高流量氧气(HFO),这就是为什么它对气管内导管的生理作用没有明确的结论。我们的目标是评估,在长凳上,吸气潮气量(VT),总PEEP,和WOB跨越3种不同的SBT模式:T-piece,40L/minHFO,和60L/minHFO。
方法:建立具有阻力和线性顺应性3个条件的测试肺模型,3吸气努力(低,正常,andhigh),每个在2个呼吸频率(低和高20和30次呼吸/分钟,分别)。进行了成对比较和比较SBT模式的准泊松广义线性模型。
结果:吸气性室性心动过速,总PEEP,和WOB从一个SBT模式到另一个不同。与机械条件无关,T形件的吸气室性心动过速高于HFO,努力强度,和呼吸频率(每次比较P<.001)。在使用HFO进行SBT期间,通过吸气室性心动过速调节的WOB显着低于使用T形件进行SBT时(每个比较中P<.001)。在60L/min时,HFO的总PEEP明显高于其他模式(P<.001)。终点受呼吸频率显著影响,努力强度,和机械条件。
结论:在相同的努力强度和呼吸频率下,T形件的吸气室性心动过速高于其他模式。与T形件相比,在HFO条件下WOB显著较低,并且较高的流量是有益的。根据本研究的结果,HFO作为SBT模式似乎需要进行临床试验.
The spontaneous breathing trial (SBT) is the final step of weaning from invasive mechanical ventilation. An SBT is aimed at predicting work of breathing (WOB) after extubation and, most importantly, a patient\'s eligibility for extubation. The optimal SBT modality remains debated. A high-flow oxygen (HFO) has been tested during SBT in clinical study only, which is why no definite conclusion can be drawn on its physiologic effects on the endotracheal tube. Our objective was to assess, on a bench, inspiratory tidal volume (VT), total PEEP, and WOB across 3 different SBT modalities: T-piece, 40 L/min HFO, and 60 L/min HFO.
A test lung model was set with 3 conditions of resistance and linear compliance, 3 inspiratory efforts (low, normal, and high), each at 2 breathing frequencies (low and high for 20 and 30 breaths/min, respectively). Pairwise comparisons and a quasi-Poisson generalized linear model that compared SBT modalities were performed.
Inspiratory VT, total PEEP, and WOB differed from one SBT modality to another. Inspiratory VT remained higher with the T-piece than in the HFO independent of the mechanical condition, effort intensity, and breathing frequency (P < .001 in each comparison). WOB adjusted by the inspiratory VT was significantly lower during SBT performed with an HFO than when performed with the T-piece (P < .001 in each comparison). The total PEEP was significantly higher in the HFO at 60 L/min than in the other modalities (P < .001). The end points were significantly influenced by breathing frequency, effort intensity, and mechanical condition.
With the same effort intensity and breathing frequency, inspiratory VT was higher in the T-piece than in the other modalities. Compared with the T-piece, WOB was significantly lower in the HFO condition and higher flow was a benefit. Based on the results of the present study, the HFO as an SBT modality would seem to require clinical testing.