Freeman Kalev, Miller Zachary D, Herrington Robert Ramsey, Dreyfus Nathan T, Buttaravoli Philip, Burgess Adam, Nickerson Joshua P, Daphtary Nirav, Bates Jason H T
University of Vermont Burlington Vermont USA.
West Palm Beach VA Medical Center West Palm Beach Florida USA.
J Am Coll Emerg Physicians Open. 2021 Apr 29;2(2):e12440. doi: 10.1002/emp2.12440. eCollection 2021 Apr.
No oropharyngeal devices exist for use in conscious and semiconscious trauma patients during emergency evacuation, transport, or resuscitation. We aimed to test the hypotheses that the ManMaxAirway (MMA) is better tolerated than the standard Guedel-style device in awake volunteers and that it produces a jaw thrust and improves air flow.
This was a randomized cross-over study of healthy volunteers with either the MMA or standard device. The primary outcome of tolerability was defined as maintaining the device in place for 60 seconds. Secondary outcomes included respiratory system function and jaw thrust. Resistance to airflow through the device lumen was measured in situ and when placed in subjects in the pulmonary laboratory alone. Jaw thrust was quantified as displacement between the mandibular condyle and condylar fossa apex relative to baseline visualized with magnetic resonance imaging (MRI).
We enrolled 19 subjects. Of these, a convenience sample of 5 individuals was selected for MRI; the remaining individuals (n = 14) were randomized for the cross-over study. All 14 subjects were able to maintain the MMA for 60 seconds compared with 2/14 (14%) with the standard device (odds ratio, 145; 95% confidence interval, 6.3-3314). Subjects reported that the experimental device was more comfortable and its placement did not trigger the gag reflex. Airway resistance produced by the MMA in an oscillatory flow model was nearly an order of magnitude lower than that of the standard device (experimental vs standard, 8 Hz-0.092 vs 0.786 cmH0·s/L; 15 Hz-0.193 vs 1.321 cmH0·s/L). Rapid induction of the gag reflex precluded further measurements with the standard device. Forced oscillation pulmonary testing in conscious volunteers with and without the MMA demonstrated that the device decreased respiratory system resistance to airflow and reduced respiratory elastance (31% ± 8% and 44% ± 13.4%, respectively; < 0.05). MRIs of the subjects (n = 5) with the MMA in place showed a significant jaw thrust compared with baseline (7 ± 1 mm).
The MMA proved well tolerated in conscious subjects, resulting in an opening of the anatomic airway and a decreased resistance to airflow.
在紧急疏散、转运或复苏过程中，尚无用于清醒和半清醒创伤患者的口咽装置。我们旨在验证以下假设：在清醒志愿者中，ManMax气道（MMA）比标准的Guedel型装置耐受性更好，并且它能产生下颌前推并改善气流。
这是一项针对健康志愿者的随机交叉研究，分别使用MMA或标准装置。耐受性的主要结局定义为将装置保持在位60秒。次要结局包括呼吸系统功能和下颌前推。在原位以及单独置于肺部实验室的受试者中测量通过装置内腔的气流阻力。下颌前推通过磁共振成像（MRI）可视化，量化为下颌髁突与髁窝顶点相对于基线的位移。
我们招募了19名受试者。其中，选取5名个体的便利样本进行MRI检查；其余个体（n = 14）被随机分配进行交叉研究。所有14名受试者都能将MMA保持60秒，而使用标准装置的只有2/14（14%）（优势比，145；95%置信区间，6.3 - 3314）。受试者报告说，实验装置更舒适，其放置不会引发 gag 反射。在振荡流模型中，MMA产生的气道阻力比标准装置低近一个数量级（实验装置与标准装置，8 Hz - 0.092 对 0.786 cmH₂O·s/L；15 Hz - 0.193 对 1.321 cmH₂O·s/L）。gag反射的快速诱发使无法使用标准装置进行进一步测量。在有意识的志愿者中，使用和不使用MMA进行强迫振荡肺功能测试表明，该装置降低了呼吸系统对气流的阻力并降低了呼吸弹性（分别为31% ± 8%和44% ± 13.4%；P < 0.05）。佩戴MMA的受试者（n = 5）的MRI显示与基线相比有明显的下颌前推（7 ± 1 mm）。
MMA在清醒受试者中耐受性良好，可使解剖气道开放并降低气流阻力。
