Abstract：
BACKGROUND: It is not certain whether the blade geometry of videolaryngoscopes, either a hyperangulated or Macintosh shape, affects glottic view, success rate and/or tracheal intubation time in patients with expected difficult airways. We hypothesised that using a hyperangulated videolaryngoscope blade would visualise a higher percentage of glottic opening compared with a Macintosh videolaryngoscope blade in patients with expected difficult airways.
METHODS: We conducted an open-label, patient-blinded, randomised controlled trial in adult patients scheduled to undergo elective ear, nose and throat or oral and maxillofacial surgery, who were anticipated to have a difficult airway. All airway operators were consultant anaesthetists. Patients were allocated randomly to tracheal intubation with either hyperangulated (C-MAC D-BLADE™) or Macintosh videolaryngoscope blades (C-MAC™). The primary outcome was the percentage of glottic opening. First attempt success was designated a key secondary outcome.
RESULTS: We assessed 2540 adults scheduled for elective head and neck surgery for eligibility and included 182 patients with expected difficult airways undergoing orotracheal intubation. The percentage of glottic opening visualised, expressed as median (IQR [range]), was 89 (69-99 [0-100])% with hyperangulated videolaryngoscope blades and 54 (9-90 [0-100])% with Macintosh videolaryngoscope blades (p < 0.001). First-line hyperangulated videolaryngoscopy failed in one patient and Macintosh videolaryngoscopy in 12 patients (13%, p = 0.002). First attempt success rate was 97% with hyperangulated videolaryngoscope blades and 67% with Macintosh videolaryngoscope blades (p < 0.001).
CONCLUSIONS: Glottic view and first attempt success rate were superior with hyperangulated videolaryngoscope blades compared with Macintosh videolaryngoscope blades when used by experienced anaesthetists in patients with difficult airways.
METHODS: We conducted an open-label, patient-blinded, randomised controlled trial in adult patients scheduled to undergo elective ear, nose and throat or oral and maxillofacial surgery, who were anticipated to have a difficult airway. All airway operators were consultant anaesthetists. Patients were allocated randomly to tracheal intubation with either hyperangulated (C-MAC D-BLADE™) or Macintosh videolaryngoscope blades (C-MAC™). The primary outcome was the percentage of glottic opening. First attempt success was designated a key secondary outcome.
RESULTS: We assessed 2540 adults scheduled for elective head and neck surgery for eligibility and included 182 patients with expected difficult airways undergoing orotracheal intubation. The percentage of glottic opening visualised, expressed as median (IQR [range]), was 89 (69-99 [0-100])% with hyperangulated videolaryngoscope blades and 54 (9-90 [0-100])% with Macintosh videolaryngoscope blades (p < 0.001). First-line hyperangulated videolaryngoscopy failed in one patient and Macintosh videolaryngoscopy in 12 patients (13%, p = 0.002). First attempt success rate was 97% with hyperangulated videolaryngoscope blades and 67% with Macintosh videolaryngoscope blades (p < 0.001).
CONCLUSIONS: Glottic view and first attempt success rate were superior with hyperangulated videolaryngoscope blades compared with Macintosh videolaryngoscope blades when used by experienced anaesthetists in patients with difficult airways.
摘要：
背景：尚不确定视频喉镜的刀片几何形状，超角度或Macintosh形状，影响声门视图，患者的成功率和/或气管插管时间预期困难的气道。我们假设，在预期气道困难的患者中，与Macintosh视频喉镜刀片相比，使用超角度视频喉镜刀片会显示出更高的声门开口百分比。
方法：我们进行了开放标签，病人失明，在计划接受择期耳朵的成年患者中进行的随机对照试验，鼻喉或口腔颌面外科，预计他们的气道会很困难。所有气道操作人员均为顾问麻醉师。患者被随机分配到气管插管与高角度（C-MACD-BLADE™）或Macintosh视频喉镜刀片（C-MAC™）。主要结果是声门开放的百分比。第一次尝试成功被指定为关键的次要结果。
结果：我们评估了2540名择期接受头颈部手术的成年人的资格，并纳入了182名接受经气管插管的预期困难气道患者。可见声门开口的百分比，表示为中位数(IQR[范围])，89(69-99[0-100])%的视频喉镜刀片和54(9-90[0-100])%的Macintosh视频喉镜刀片(p<0.001)。1例患者的一线高角度视频喉镜检查失败，12例患者的Macintosh视频喉镜检查失败（13％，p=0.002)。首次尝试成功率高角度的视频喉镜刀片为97％，Macintosh视频喉镜刀片为67％（p<0.001）。
结论：在有经验的麻醉师治疗气道困难的患者中，与Macintosh视频喉镜刀片相比，高角度视频喉镜刀片的声门视图和首次尝试成功率优于Macintosh。
方法：我们进行了开放标签，病人失明，在计划接受择期耳朵的成年患者中进行的随机对照试验，鼻喉或口腔颌面外科，预计他们的气道会很困难。所有气道操作人员均为顾问麻醉师。患者被随机分配到气管插管与高角度（C-MACD-BLADE™）或Macintosh视频喉镜刀片（C-MAC™）。主要结果是声门开放的百分比。第一次尝试成功被指定为关键的次要结果。
结果：我们评估了2540名择期接受头颈部手术的成年人的资格，并纳入了182名接受经气管插管的预期困难气道患者。可见声门开口的百分比，表示为中位数(IQR[范围])，89(69-99[0-100])%的视频喉镜刀片和54(9-90[0-100])%的Macintosh视频喉镜刀片(p<0.001)。1例患者的一线高角度视频喉镜检查失败，12例患者的Macintosh视频喉镜检查失败（13％，p=0.002)。首次尝试成功率高角度的视频喉镜刀片为97％，Macintosh视频喉镜刀片为67％（p<0.001）。
结论：在有经验的麻醉师治疗气道困难的患者中，与Macintosh视频喉镜刀片相比，高角度视频喉镜刀片的声门视图和首次尝试成功率优于Macintosh。
