Benumof J L, Cooper S D
Department of Anesthesiology University of California, San Diego Medical Center 92103-8812, USA.
J Clin Anesth. 1996 Mar;8(2):136-40. doi: 10.1016/0952-8180(95)00198-0.
To determine the improvement in laryngoscopic view obtained using both the Macintosh and Miller blades by applying optimal external laryngeal manipulation (OELM).
Prospective, with each patient serving as his or her own control.
Inpatient operating rooms of a University Medical Center.
181 informed and consenting adult nonpregnant patients requiring general anesthesia and tracheal intubation. The only exclusion criteria was the need to apply cricoid pressure to prevent aspiration of gastric contents.
Anesthetized, paralyzed patients underwent laryngoscopy without external laryngeal manipulation and the laryngoscopic view was graded ("A") according to visualized structures [1.0-1.9 = all (1.0) or part of the vocal cords (90% = 1.1 and 10% = 1.9); 2 = just the arytenoids; 3 = just the epiglottis; 4 = just the soft palate]. The larynx was then quickly manipulated by the thumb and index and middle fingers of the laryngoscopist's right hand in both cephalad and posterior directions over the hyoid, thyroid, and cricoid cartilages until it was determined which vector and spot produced the optimal laryngoscopic view ("B").
It was found that in every patient with a "A" greater than 1.0, OELM improved the view; i.e., "B" decreased relative to "A." For both the Macintosh blade patients and Miller blade patients with an "A" equal to 2, "B" decreased by one whole laryngoscopic grade in all patients. For both the Macintosh and Miller blade patients with an "A" equal to 3, "B" decreased by at least one whole laryngoscopic grade in all patients and by two laryngoscopic grades in most patients. No patient had an "A" equal to 4. The distribution of optimal-external-laryngeal-manipulation (OELM) spots for all patients was 1%, 40%, 48%, and 11% for the hyoid, high thyroid, low thyroid, and cricoid cartilages, respectively, and the distribution was not significantly different for either the Macintosh and Miller blade groups or for the "A" and "B" subgroups (i.e., "A" < 1.9, = 2 or = 3).
We conclude that OELM can improve the laryngoscopic view by at least one whole grade, that the best way to determine OELM for an individual patient is on an empirical basis by manipulation of the larynx with the laryngoscopist's right hand, and that OELM should be an instinctive and reflex response to any "A" of 2, 3, or 4.
通过应用最佳外部喉部操作（OELM）来确定使用麦金托什喉镜叶片和米勒喉镜叶片时喉镜视野的改善情况。
前瞻性研究，每位患者自身作为对照。
大学医学中心的住院手术室。
181名知情并同意的成年非妊娠患者，需要全身麻醉和气管插管。唯一的排除标准是需要施加环状软骨压迫以防止胃内容物误吸。
麻醉并肌肉松弛的患者在未进行外部喉部操作的情况下接受喉镜检查，喉镜视野根据可见结构进行分级（“A”）[1.0 - 1.9 = 全部（1.0）或部分声带（90% = 1.1且10% = 1.9）；2 = 仅杓状软骨；3 = 仅会厌；4 = 仅软腭]。然后，喉镜检查者用右手的拇指、示指和中指在舌骨、甲状腺和环状软骨上快速向头侧和后方操作喉部，直到确定哪个方向和位置能产生最佳喉镜视野（“B”）。
发现每个“A”大于1.0的患者，OELM都改善了视野；即，“B”相对于“A”降低。对于“A”等于2的麦金托什喉镜叶片患者和米勒喉镜叶片患者，所有患者的“B”都降低了一个完整的喉镜分级。对于“A”等于3的麦金托什喉镜叶片患者和米勒喉镜叶片患者，所有患者的“B”至少降低了一个完整的喉镜分级，大多数患者降低了两个喉镜分级。没有患者的“A”等于4。所有患者的最佳外部喉部操作（OELM）位置分布分别为舌骨1%、甲状腺高位40%、甲状腺低位48%和环状软骨11%，麦金托什喉镜叶片组和米勒喉镜叶片组以及“A”和“B”亚组（即“A”<1.9、=2或=3）的分布无显著差异。
我们得出结论，OELM可将喉镜视野至少提高一个完整分级，确定个体患者OELM的最佳方法是通过喉镜检查者用右手操作喉部以凭经验确定，并且OELM对于任何“A”为2、3或4的情况都应是一种本能和反射性反应。
