Cervical spine movements during laryngoscopy. Comparison of the Macintosh and McCoy laryngoscope blades

We studied cervical spine movement in 10 patients scheduled for elective surgery under general anaesthesia. Each patient was fitted with a rigid cervical collar before undergoing direct laryngoscopy for orotracheal intubation. Laryngoscopy was performed using the McCoy laryngoscope in the activated position and the standard Macintosh blade. Displacement of the cervical spine at laryngeal exposure was measured using lateral cervical spine X-rays. Flexion and extension movements of the cervical spine during the use of the two laryngoscope blades were compared. For each blade, the greatest degree of extension occurred at the joint between the first and second cervical vertebrae. There was no significant difference in cervical spine movement when the two blades were compared.     

Use of the McCoy laryngoscope or fingers to facilitate fibrescope-aided tracheal intubation

In fibrescope-aided tracheal intubation, it can be difficult to advance a tube over a fibrescope, because its passage may be impeded by the epiglottis, arytenoids or pyriform fossa. In two patients with difficult intubation, after successful insertion of a fibrescope into the trachea, it was impossible to advance the tube over the fibrescope. Fibrescope-aided tracheal intubation was accomplished by shifting the epiglottis anteriorly and 'opening up' the glottis either by fingers or the McCoy laryngoscope.     

A comparison of the forces exerted during laryngoscopy

The forces exerted at laryngoscopy with the McCoy and Macintosh blades have been compared in 40 patients. The variables measured were the duration of laryngoscopy, the three maximally-applied forces and the mean force. The mean (SD) forces recorded were 18.9 (7.82) and 10.1 (5.33) N, respectively, with the Macintosh and the McCoy blades (p < 0.001) with a similar duration of laryngoscopy. There was a significant positive correlation between the mean force and patients' weight, height and body mass index for the Macintosh blade but only for weight and height for the McCoy blade. It is concluded that the use of the McCoy blade results in significantly less force being applied during laryngoscopy. This may be the reason for the reduction in the stress response reported previously with the use of the McCoy blade.     

Airtraq喉镜和Macintosh直接喉镜在经口气管插管时血流动力学的比较

目的比较Airtraq视频喉镜和Macintosh直接喉镜经口气管插管时心血管反应。方法40例拟择期经口气管插管全麻下手术的患者,按照随机数字表随机分为两组,Airtraq组（A组）和Macintosh喉镜组（M组）,每组20例。观察麻醉诱导前、诱导后、插管即刻、插管后1、3min时的心率（HR）、血压和心率收缩压乘积（ratepressureproduct,RPP）。结果两组声门暴露时间差异无统计学意义（P〉0．05）,导管置入时间A组（6±4）S短于M组（10±4）S（P〈0．01）。两组诱导后的HR、血压和RPP值都较诱导前的基础值明显下降（P〈0．05）,插管即刻、插管后1min的心血管指标较诱导后明显增高（P〈0．05）。A组插管后3min心血管指标与诱导后比较差异无统计学意义（P〉0．05）,而M组3min时心血管指标[收缩压（SBP）（106±17）mmHg（1mmHg=0．133kPa）,舒张压（DBP）（65±10）mmHg,平均动脉压（MAP）（78±19）mmHg,HR（92±12）次／分,RPP（9748±2072）]与诱导后[SBP（93±15）mmHg,DBP（54±9）mmHg,MAP（67±10）mmHg,HR（85±12）次／分,RPP（8117±1886）]比较差异仍有统计学意义（R0．05）。A组、M组插管后5min心血管指标与诱导后比较差异均无统计学意义。结论与Macintosh直接喉镜相比,应用Airtraq视频喉镜行经口气管插管可减少插管置入时间,且血流动力学反应较轻。     

可视喉镜与直接喉镜在双腔支气管插管中的应用

目的观察比较可视喉镜与直接喉镜在双腔支气管插管中的临床效果,探讨两者在双腔支气管插管中的应用价值。方法选择择期需行双腔支气管插管的胸外科手术患者80例,男50例,女30例,年龄18~70岁,ASAⅠ~Ⅲ级,将患者随机分为两组:可视喉镜组和直接喉镜组,每组40例,分别使用可视喉镜和直接喉镜行双腔支气管插管。观察比较两组声门显露(C-L)分级、插管时间、第一次插管成功率、插管反应阳性例数和术后24h咽喉痛发生率;监测患者入室后(T_0)、诱导后插管前1min(T_1)、插管后1min(T_2)、2min(T_3)、3min(T_4)MAP、HR;记录口腔损伤出血情况以及气管壁及隆突损伤情况。结果与可视喉镜组比较,直接喉镜组声门显露C-L分级和第一次插管成功率明显升高,插管时间明显缩短,插管反应阳性发生率和术后24h咽喉痛发生率明显降低(P0.05)。两组口腔损伤出血情况及气管壁及隆突损伤情况差异无统计学意义。T_2、T_3时两组MAP明显低于T_1时,且T_2、T_3时直接喉镜组MAP明显低于可视喉镜组(P0.05)。结论与可视喉镜比较,对无预计困难气道的患者,直接喉镜更适用于双腔支气管插管。     

The best view at laryngoscopy using the McCoy laryngoscope with and without cricoid pressure

The best view obtained by levering the tip of the McCoy laryngoscope blade with or without modified cricoid pressure was studied in 100 patients presenting for general surgery. The airway was assessed pre-operatively (Mallampati score, thyromental distance, mouth opening, protrusion of the jaw and weight) in an attempt to identify the patients who might benefit from the use of the McCoy laryngoscope. The vocal cords were visible at laryngoscopy with the blade in the neutral position in 32 cases. In the 68 remaining patients the vocal cords were partly visible in 48. The epiglottis only was seen in 18 patients and in two not even the epiglottis could be visualised. Elevation of the blade or modified cricoid pressure improved the view in 38/68 cases and 57/68 cases, respectively (p < 0.001, Wilcoxon signed rank). Using our method of pre-operative assessment we were unable to identify those patients who might benefit from either manipulation.     

The Cardiff paediatric laryngoscope blade: a comparison with the Miller size 1 and Macintosh size 2 laryngoscope blades

The Cardiff paediatric laryngoscope blade is a single blade that has been designed for use in children from birth to adolescence. This open, randomised, crossover study compared the Cardiff blade with the straight, size 1, Miller laryngoscope blade in 39 infants under 1 years of age and the curved, size 2, Macintosh blade in 39 children aged 1-16 years. The same laryngoscopic view was obtained with the Cardiff and Miller blades in 26 patients; the view was better with the Cardiff blade in seven patients and better with the Miller blade in six (median (IQR [range]) grade of laryngoscopy 1 (1-2 [1-3]) vs. 1 (1-2 [1-3]), respectively; p = 0.405). The Cardiff blade was faster at gaining a view than the Miller blade (mean (SD) time 8.5 (2.9) s vs. 10.2 (3.5) s, respectively; 95% CI for difference -2.8 to -0.4; p = 0.009). The Cardiff and Macintosh blades produced the same view in 32 patients; the view was better with the Cardiff blade in seven patients (median (IQR [range]) grade of laryngoscopy 1 (1-1 [1-3]) vs. 1 (1-2 [1-3]), respectively; p = 0.008). There was no difference in time to gain these views: mean (SD) 8.7 (3.0) s vs. 9.3 (2.7) s, respectively (95% CI for difference -1.58 to 0.40; p = 0.237). The Cardiff paediatric laryngoscope blade compares favourably with these two established laryngoscope blades in children.     

McGrath可视喉镜与Macintosh直接喉镜显露颈椎手术患者喉部结构的比较

目的 比较McGrath可视喉镜与Macintosh直接喉镜显露颈椎手术患者喉部结构的效果. 方法 50例颈椎手术患者采用随机数字表法随机分为McGrath组和Macintosh组,每组25例.麻醉诱导后,McGrath组先用Macintosh直接喉镜显露喉部结构并记录Cormack-Lehane分级(C/L分级),不插管,再改用McGrath可视喉镜显露喉部结构并插入气管导管.Macintosh组先用McGrath可视喉镜显露声门,再使用Macintosh直接喉镜显露喉部结构并插管.记录患者一般情况、气道评估指标(甲颏间距、张口度、Mallampati分级、颈部活动度)、喉镜显露C/L分级和插管并发症. 结果 两组间患者一般情况和气道评估指标差异无统计学意义(P＞0.05).McGrath可视喉镜的C/L分级(Ⅰ级∶Ⅱ级∶Ⅲ级为34∶14∶2)显著优于Macintosh直接喉镜(Ⅰ级∶Ⅱ级∶Ⅲ级为13∶32∶5,P＜0.01). 结论 McGrath可视喉镜对喉部结构的显露优于Macintosh直接喉镜,提示该可视喉镜有助于颈椎手术患者的气管插管处理.     

预计困难插管患者使用Airtraq喉镜、Shikani喉镜和Macintosh喉镜行气管插管的比较

目的 探讨Airtraq喉镜、Shikani喉镜和Macintosh喉镜在预计困难插管患者中行气管插管的应用价值.方法 行全麻插管手术预计困难插管患者75例,随机分为Airtraq喉镜组(A组)、Shikani喉镜组(S组)和Macintosh喉镜组(M组),三次内插管成功者入选本研究,每组25例.记录插管时间,麻醉诱导前(T1)、诱导后(T2)、插管结束即刻(T3)和插管后3 min(T4)时的MAP和HR.同时观察各组患者的声门暴露程度以及有无咽喉损伤.结果 A组插管时间最短,其次为S组,M组最慢,A组明显短于S组和M组(P＜0.05).A组插管成功率高于S组和M组(P＜0.05).与T2时比较,T3、T4时M组MAP明显升高、HR明显增快(P＜0.05).T3、T4时M组MAP高于A组,HR快于A组(P＜0.05).A组声门完全显露率最高,其次为S组,M组最低,A组明显优于S组和M组(P＜0.05).A组咽喉损伤发生率低于M组(P＜0.05).结论 在预计困难插管条件下,与Shikani喉镜和Macintosh喉镜比较,使用Airtraq喉镜可以缩短插管时间,提高插管成功率,减少气管插管时心血管应激反应,维持血流动力学稳定,降低咽喉损伤的发生率.     

Airtraq(R)喉镜和Macintosh直接喉镜在经口气管插管时血流动力学的比较

目的比较Airtraq(R)视频喉镜和Macintosh直接喉镜经口气管插管时心血管反应。方法40例拟择期经口气管插管全麻下手术的患者,按照随机数字表随机分为两组,Airtraq(R)组（A组）和Macintosh喉镜组（M组）,每组20例。观察麻醉诱导前、诱导后、插管即刻、插管后1、3 min时的心率(HR)、血压和...     

A new laryngoscope

This is a report of a modification to one design of laryngoscope to increase the angle between blade and handle, to facilitate intubation in cases of difficult access, such as in obstetric practice or in patients in whom neck flexion is limited, for example by skull traction. The modification offers the unique advantage of two useful blade angles in one instrument. The first type described would be suitable for use in small units where it is thought that a laryngoscope solely for use in rare cases of difficult access would not be justified. It would also be suitable for inclusion in resuscitation kits for use both within and outside hospital. The second type would be more suitable for the maternity or spinal injuries unit, or the difficult intubation box of a general operating theatre suite.     

Comparison of two Macintosh laryngoscope blades in 300 patients

Background. There are two forms of Macintosh laryngoscope blade.Compared with the standard blade, the English blade is longer,its curve is more continuous across the entire length of theblade, the flange of the blade continues much closer to theblade tip, and the height of the flange is shorter. Method. We studied 300 patients to compare the ease of laryngoscopywith each type of Macintosh laryngoscope blade. In a randomcrossover design, after induction of anaesthesia and neuromuscularblock, the two blades were inserted in turn, and the views ofthe glottis at laryngoscopy (Cormack and Lehane scores) werecompared. Results. There was a difference in the view of the glottis in80 patients. Among these patients, the view was better for theEnglish blade for 63 patients and the standard blade was betterfor 17 patients. Laryngoscopy was difficult (grade 3 or 4) forat least one blade in 42 of 300 patients (14%). In these 42patients, there was a difference in the score between the bladesin 28 patients; the view was better for the English blade in25 patients (60%) and for the standard blade in three patients(7%). The view was significantly better for the English bladethan for the standard blade (P<0.001; 95% confidence interval45–74%). Conclusions. In patients in whom laryngoscopy was unexpectedlydifficult, the English blade provided a better glottic viewsignificantly more frequently than the standard blade. Br J Anaesth 2003: 90: 457–60     

Upper cervical spine movement during intubation: fluoroscopic comparison of the AirWay Scope, McCoy laryngoscope, and Macintosh laryngoscope

BACKGROUND: The AirWay Scope (AWS) is a new fibreoptic intubation device, which allows visualization of the glottic structures without alignment of the oral, pharyngeal, and tracheal axes, and thus may be useful in patients with limited cervical spine (C-spine) movement. We fluoroscopically evaluated upper C-spine movement during intubation with the AWS or Macintosh or McCoy laryngoscope. METHODS: Forty-five patients, with normal C-spine, scheduled for elective surgery were randomly assigned to one of the three intubation devices. Movement of the upper C-spine was examined by measuring angles formed by adjacent vertebrae during intubation. Time to intubation was also recorded. RESULTS: Median cumulative upper C-spine movement was 22.3 degrees, 32.3 degrees, and 36.5 degrees with the AWS, Macintosh laryngoscope, and McCoy laryngoscope, respectively (P<0.001, AWS vs, Macintosh and McCoy). The AWS reduced maximum movement of the C-spine at C1/C2 in comparison with the Macintosh or McCoy laryngoscope (P=0.012), and at C3/C4 in comparison with the McCoy laryngoscope (P=0.019). Intubation time was significantly longer in the AWS group than in the Macintosh group (P=0.03). CONCLUSIONS: Compared with the Macintosh or McCoy laryngoscope, the AWS produced less movement of upper C-spine for intubation in patients with a normal C-spine.     

TruviewTM EVO2光学喉镜和Macintosh直接喉镜显露喉部结构的比较

目的比较Truview^TM EVO2光学喉镜与Macintosh直接喉镜在经口气管插管中显露喉部结构的效果，探讨该光学喉镜在全麻气管插管中的应用价值。方法经口气管插管全身麻醉下实施择期手术的ASAI-Ⅱ级成人患者200例。麻醉前记录人选患者一般情况和气道评估指标（Mallampati舌咽结构分级、甲颏间距、张口度）。全麻诱导后随机应用直接喉镜或光学喉镜先后显露喉部结构并记录Cormack-Lehane喉部结构显露分级（C／L分级），用后一种喉镜进行气管插管。观察指标包括术前患者一般情况及气道评估指标；C／L分级；喉部结构显露难易度；口咽部损伤；术后咽痛、声音嘶哑等并发症。结果200例患者中男107例，女93例，年龄52岁±13岁，身高164．8cm±11．3cm，体重64．0kg±11．5kg，甲颏间距6．9cm±1．1cm，张口度3．7cm±0．5cm。两种喉镜C／L分级均与Mallampati舌咽结构分级具有相关性（P〈0．01），即Mallampati分级越高，C／L分级越高。有91例两种喉镜C／L分级相同，其中76例为I级，15例为Ⅱ级；4例喉镜C／L分级优于光学喉镜，余105例则光学喉镜优于直接喉镜；在200例病人中，用直接喉镜C／L分级百分比分别为：I级40．O％、Ⅱ级38．5％、Ⅲ级20．5％、IV级1％；而光学喉镜为：I级78．5％、Ⅱ级21.0％、Ⅲ级0．5％。所有患者未记录到明显口咽部损伤和术后咽痛及声音嘶哑。结论Truview^TM EVO2光学喉镜对喉部结构显露C／L分级明显优于Macintosh直接喉镜，从而提示应用光学喉镜可能有助于困难气道的处理。     

Tracheal intubation by non-anesthesia residents using the Pentax-AWS airway scope and Macintosh laryngoscope

Study ObjectiveTo evaluate the performance of the Pentax-AWS airway scope for tracheal intubation compared with the Macintosh laryngoscope by non-anesthesia residents.DesignProspective, randomized, cohort study.SettingUniversity-affiliated hospital.Patients520 patients who underwent tracheal intubation for general anesthesia.Interventions48 non-anesthesia residents performed tracheal intubation using either the Pentax-AWS or the Macintosh laryngoscope.MeasurementsTime to complete tracheal intubation, number of attempts until successful intubation, and number of intubations of the esophagus were recorded.ResultsTime to secure the airway (sec; mean ± SD) was shorter with the Pentax-AWS than with the Macintosh laryngoscope (44 ± 19 vs. 71 ± 44 sec; P < 0.001). Of the 264 tracheal intubations with the Pentax-AWS, 239 (91%) were completed within 60 seconds, while only 148 (58%) of the 256 tracheal intubations performed with the Macintosh laryngoscope were completed within the same period. The rate of successful intubations on the first attempt was higher with the Pentax-AWS than the Macintosh laryngoscope (P < 0.001). No esophageal intubation was experienced with the Pentax-AWS approach, while 18 occurred with the Macintosh laryngoscope (P < 0.001).ConclusionThe Pentax-AWS appears to require less operator skill than the Macintosh laryngoscope. Use of the Pentax-AWS may reduce the time to secure the airway and the incidence of failed tracheal intubation by non-anesthesia residents.