Meininger D, Strouhal U, Weber C F, Fogl D, Holzer L, Zacharowski K, Byhahn C
Klinik für Anästhesiologie, Intensivmedizin und Schmerztherapie, Klinikum der J W Goethe-Universität Frankfurt am Main.
Anaesthesist. 2010 Sep;59(9):806-11. doi: 10.1007/s00101-010-1753-3. Epub 2010 Aug 13.
Previous studies have shown that video laryngoscopy enhances laryngeal view in patients with apparently normal and difficult airways. The utility of the novel, portable, battery-powered C-MAC video laryngoscope is as yet unproven. It was hypothesized that in routine patients undergoing ENT surgery, the rate of glottic views considered unsatisfactory, i.e. Cormack and Lehane grades IIb, III, and IV, could be significantly reduced with the C-MAC video laryngoscope compared to direct laryngoscopy.
Following ethical approval and sample size estimates 108 consecutive patients undergoing ENT surgery under general anesthesia were studied. First, direct laryngoscopy was performed with the naked eye. The best view obtained was graded by the first anesthesiologist without looking at the video monitor. A second anesthesiologist blinded to the laryngeal view obtained under direct laryngoscopy graded the laryngeal view on the video monitor. Endotracheal intubation using Ring-Adair-Elwyn (RAE) tracheal tubes was then attempted under video-aided visualization. The tubes were not reinforced with a stylet. The C-MAC video laryngoscopy system (Karl Storz, Tuttlingen, Germany) is a novel device that can be used with Macintosh laryngoscope blades in different sizes. A camera and light source are located recessed from the tip of the blade. The camera unit sits in a handle attached to the laryngoscope blade and is connected by a wire to a TFT video monitor. It allows for both direct and indirect laryngoscopy and the low profile of the original British Macintosh blades may prove advantageous in patients with limited mouth opening.
A total of 108 patients were enrolled in the study but for various reasons only 94 completed the study (post hoc power 97%). In 89 patients a size 3 Macintosh laryngoscope was used while a size 4 blade was used in the remaining 5 patients. With direct laryngoscopy the glottic view was considered unsatisfactory in 40 patients (42%), but this was the case in only 15 patients (16%) when video laryngoscopy was used (p<0.0001). Endotracheal tube placement was successful in all but one patient where the Bonfils intubation fiberscope needed to be employed. No complications related to the C-MAC system were observed.
Compared to direct laryngoscopy with a Macintosh laryngoscope blade in unselected patients undergoing ENT surgery and thus patients more susceptible to an unexpected difficult airway than a general patient population, the mobile C-MAC video laryngoscope significantly enhanced laryngeal view. Using RAE tracheal tubes seems to compensate the unfavorable deviation of optical and anatomical axes when indirect laryngoscopy is performed with the C-MAC system.
先前的研究表明，视频喉镜可改善气道外观正常和困难患者的喉镜视野。新型便携式电池供电的C-MAC视频喉镜的效用尚未得到证实。据推测，在接受耳鼻喉科手术的常规患者中，与直接喉镜检查相比，使用C-MAC视频喉镜可显著降低声门视野不满意率，即Cormack和Lehane分级为IIb、III和IV级。
在获得伦理批准和样本量估计后，对108例连续接受全身麻醉下耳鼻喉科手术的患者进行了研究。首先，用肉眼进行直接喉镜检查。第一位麻醉医生在不看视频监视器的情况下对获得的最佳视野进行分级。第二位麻醉医生对直接喉镜检查下获得的喉镜视野不知情，对视频监视器上的喉镜视野进行分级。然后在视频辅助可视化下尝试使用Ring-Adair-Elwyn（RAE）气管导管进行气管插管。导管未用管芯加强。C-MAC视频喉镜系统（德国图特林根的卡尔·史托斯公司）是一种新型设备，可与不同尺寸的Macintosh喉镜叶片配合使用。摄像头和光源位于叶片尖端的凹槽内。摄像头单元位于连接到喉镜叶片的手柄中，并通过电线连接到TFT视频监视器。它允许直接和间接喉镜检查，原始英国Macintosh叶片的低轮廓可能对张口受限的患者有利。
共有108例患者纳入研究，但由于各种原因，只有94例完成了研究（事后检验效能为97%）。89例患者使用3号Macintosh喉镜，其余5例患者使用4号叶片。直接喉镜检查时，40例患者（42%）的声门视野被认为不满意，但使用视频喉镜检查时，只有15例患者（16%）出现这种情况（p<0.0001）。除1例患者需要使用邦菲尔斯插管纤维镜外，所有患者气管插管均成功。未观察到与C-MAC系统相关的并发症。
与在接受耳鼻喉科手术的未选择患者中使用Macintosh喉镜叶片进行直接喉镜检查相比，这些患者比一般患者群体更容易出现意外困难气道，移动式C-MAC视频喉镜显著改善了喉镜视野。使用RAE气管导管似乎可以补偿使用C-MAC系统进行间接喉镜检查时光学轴和解剖轴的不利偏差。
