Mahadevaiah Thejeswini, T S Deepak, Rani Roopa, K N Vikas, G M Shwetha
Department of Anaesthesiology, Mathikere Sampangi Ramaiah Medical College, Bangalore, IND.
Department of Emergency Medicine, Mathikere Sampangi Ramaiah Medical College, Bangalore, IND.
Cureus. 2022 May 11;14(5):e24914. doi: 10.7759/cureus.24914. eCollection 2022 May.
The most commonly used equipment to aid endotracheal intubation is a laryngoscope, and the procedure performed is known as laryngoscopy, which leads to profound cardiovascular effects. The process of laryngoscopy causes the release of catecholamines, thereby leading to marked pressor responses and tachycardia. The process of laryngoscopy can be made easier by the use of various types of laryngoscopic blades. The McCoy blade is a modification of the standard Macintosh blade that incorporates a hinged tip blade. It allows elevation of the epiglottis while decreasing overall laryngeal movement. A Miller blade is a straight blade with a slight upward curve near the tip. It is found that the force exerted, head extension, and cervical spine movement are less with the Miller blade. This study was undertaken to compare changes in haemodynamic parameters before, during, and after laryngoscopy using these two blades.
Following institutional ethical committee approval and obtaining informed written consent, 100 patients of American Society of Anesthesiologists (ASA) grades I and II in the age group of 18-45 years of either sex undergoing elective surgeries under general anaesthesia were included in the study. The patients were randomly allocated into two groups of 50 patients each. Group Mc - laryngoscopy was performed using a no. 3 McCoy blade. Group Ml - laryngoscopy was performed using a no. 2 Miller blade. The laryngoscopic view was compared using Cormack and Lehane grading. Haemodynamic parameters before, during, and after laryngoscopy were recorded.
Hemodynamic parameters including heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were increased in both the groups but were statistically and clinically significant in the Miller group with p≤0.001.
McCoy blade is associated with a significantly more stable hemodynamic response to laryngoscopy in comparison with the Miller blade.
辅助气管插管最常用的设备是喉镜，所进行的操作称为喉镜检查，这会产生显著的心血管效应。喉镜检查过程会导致儿茶酚胺释放，从而引起明显的升压反应和心动过速。使用各种类型的喉镜镜片可使喉镜检查过程更轻松。麦考伊镜片是标准麦金托什镜片的一种改良型，其特点是镜片尖端带有铰链。它在减少整体喉部活动的同时能抬起会厌。米勒镜片是一种直镜片，在尖端附近有轻微向上弯曲。研究发现，使用米勒镜片时施加的力量、头部伸展和颈椎活动较少。本研究旨在比较使用这两种镜片进行喉镜检查前、检查期间和检查后血流动力学参数的变化。
经机构伦理委员会批准并获得知情书面同意后，将100例年龄在18 - 45岁、美国麻醉医师协会（ASA）分级为I级和II级、接受全身麻醉下择期手术的患者纳入研究。患者被随机分为两组，每组50例。Mc组使用3号麦考伊镜片进行喉镜检查。Ml组使用2号米勒镜片进行喉镜检查。使用科马克和莱汉内分级法比较喉镜视野。记录喉镜检查前、检查期间和检查后血流动力学参数。
两组的心率（HR）、收缩压（SBP）、舒张压（DBP）和平均动脉压（MAP）等血流动力学参数均升高，但米勒组在统计学和临床上具有显著意义，p≤0.001。
与米勒镜片相比，麦考伊镜片在喉镜检查时血流动力学反应明显更稳定。
