Santoni Brandon G, Hindman Bradley J, Puttlitz Christian M, Weeks Julie B, Johnson Nathaniel, Maktabi Mazen A, Todd Michael M
Department of Mechanical Engineering, Orthopaedic Bioengineering Research Laboratory, Colorado State University, USA.
Anesthesiology. 2009 Jan;110(1):24-31. doi: 10.1097/ALN.0b013e318190b556.
Manual in-line stabilization (MILS) is recommended during direct laryngoscopy and intubation in patients with known or suspected cervical spine instability. Because MILS impairs glottic visualization, the authors hypothesized that anesthesiologists would apply greater pressure during intubations with MILS than without.
Nine anesthetized and pharmacologically paralyzed patients underwent two sequential laryngoscopies and intubations, one with MILS and one without, in random order. A transducer array along a Macintosh 3 laryngoscope blade continuously measured applied pressures, and glottic view was characterized.
With MILS, glottic visualization was worse in six patients, and intubation failure occurred in two of these six patients. Maximum laryngoscope pressure at best glottic view was greater with MILS than without (717 +/- 339 mmHg vs. 363 +/- 121 mmHg, respectively; n = 8; P = 0.023). Other measures of pressure application also indicated comparable increases with MILS.
Pressures applied to airway tissues by the laryngoscope blade are secondarily transmitted to the cervical spine and result in cranio-cervical motion. In the presence of cervical instability, impaired glottic visualization and secondary increases in pressure application with MILS have the potential to increase pathologic cranio-cervical motion.
对于已知或疑似颈椎不稳定的患者，在直接喉镜检查和插管过程中推荐采用手动在线稳定（MILS）技术。由于MILS会影响声门视野，作者推测麻醉医生在使用MILS插管时比不使用时会施加更大的压力。
9名接受麻醉并使用药物麻痹的患者按随机顺序依次接受两次喉镜检查和插管，一次使用MILS，一次不使用。沿着麦金托什3号喉镜镜片的传感器阵列持续测量施加的压力，并对声门视野进行评估。
使用MILS时，6名患者的声门视野较差，其中2名患者插管失败。在最佳声门视野下，使用MILS时喉镜的最大压力高于不使用时（分别为717±339 mmHg和363±121 mmHg；n = 8；P = 0.023）。其他压力施加指标也显示使用MILS时压力有类似增加。
喉镜镜片施加于气道组织的压力会间接传递至颈椎并导致颅颈运动。在颈椎不稳定的情况下，声门视野受损以及使用MILS时压力的继发性增加有可能增加病理性颅颈运动。
