PURPOSE Patient characteristics associated with difficult tracheal intubation using a flexible bronchoscope (FB) under general anesthesia have not been prospectively evaluated. This observational study aimed to identify demographic and morphologic factors associated with difficult FB intubation. METHODS We recruited 420 adult elective surgery patients undergoing tracheal intubation during general anesthesia. Patients characteristics were recorded including age, sex, weight, height, body mass index, American Society of Anesthesiologists physical status, history of snoring, obstructive sleep apnea, Mallampati score, upper lip bite test score, neck circumference and skinfold thickness, maximal neck flexion and extension angles, absence of teeth, Cormack and Lehane grade, presence of blood or secretions during intubation, as well as the inter-incisor, thyromental, sternothyroid, and manubriomental distances. The time (duration) needed to complete intubation (primary endpoint) and the number of attempts needed were correlated with these patient characteristics in a multivariable analysis. RESULTS Intubation was successful on the first attempt in 409/420 patients (97%). Seven patients (1.7%) needed more than one attempt. Failure to intubate with the FB occurred in four patients (1%). A correlation was found between intubation duration and visibility impaired by secretions or blood (P < 0.001), higher neck skinfold thickness (P < 0.001), and larger endotracheal tube diameter (relative to a constant 5.5 mm FB; P < 0.001). CONCLUSIONS The presence of secretions or blood that impair FB glottic visualization, a larger diameter endotracheal tube on the same size FB, as well as higher neck skinfold thickness may prolong the duration of FB intubation under general anesthesia. TRIAL REGISTRATION www.clinicaltrials.gov (NCT02769819); registered 5 May, 2016.

中文翻译：

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全身麻醉下与困难的柔性支气管镜插管相关的患者因素：一项前瞻性观察研究。

目的尚未对在全身麻醉下使用柔性支气管镜（FB）进行困难的气管插管相关的患者特征进行评估。这项观察性研究旨在确定与困难的FB插管相关的人口统计学和形态学因素。方法我们招募了420名在全身麻醉期间接受气管插管的成人择期手术患者。记录患者特征，包括年龄，性别，体重，身高，体重指数，美国麻醉医师学会身体状况，打nor史，阻塞性睡眠呼吸暂停，Mallampati评分，上唇咬伤测试评分，颈部圆周和皮褶厚度，最大颈部屈曲和延伸角度，没有牙齿，Cormack和Lehane等级，插管过程中存在血液或分泌物以及门齿间，甲状腺，胸甲和手足的距离。在多变量分析中，完成插管所需的时间（持续时间）（主要终点）和所需的尝试次数与这些患者特征相关。结果409/420例患者首次尝试插管成功（97％）。七名患者（1.7％）需要一次以上的尝试。FB患者未进行气管插管（4％）。发现插管持续时间与分泌物或血液损害的可见性之间存在相关性（P <0.001），颈部皮肤褶皱厚度较高（P <0.001）和较大的气管插管直径（相对于恒定的5.5 mm FB； P <0.001）。结论存在损害FB声门可视化的分泌物或血液，在相同大小的FB上有较大直径的气管导管，以及较高的颈部皮肤褶皱厚度可能会延长全麻下FB插管的持续时间。试验注册www.clinicaltrials.gov（NCT02769819）; 于2016年5月5日注册。