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 Table of Contents  
ORIGINAL ARTICLE
Year : 2016  |  Volume : 3  |  Issue : 3  |  Page : 122-128

Comparison between C-MAC D-blade and McCoy laryngoscopes in intubating patients during cervical immobilization


1 Department of Anaesthesia, Medical Research Institute, Alexandria University, Alexandria, Egypt
2 Department of Anaesthesia and Surgical Intensive Care, Faculty of Medicine
3 Department of Anaesthesia and Surgical Intensive Care, Faculty of Medicine, Egypt

Date of Submission11-Dec-2015
Date of Acceptance24-May-2016
Date of Web Publication4-Nov-2016

Correspondence Address:
Amir A Elmasry
Department of Anaesthesia, Medical Research Institute, Alexandria University, 0204 Alexandria
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2356-9115.193412

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  Abstract 

Aims
This study was carried out to compare the efficacy of the C-MAC D-blade with the McCoy laryngoscope in intubating patients during cervical spine immobilization.
Patients and methods
This randomized controlled study was carried out in the Medical Research Institute Hospital, University of Alexandria, on 60 adult ASA I and II patients who were randomly categorized into two equal groups after written informed consent and approval of the ethics committee. All patients were subjected to the same anaesthetic protocol. Group I patients were intubated using the C-MAC D-blade laryngoscope, and group II patients were intubated using the McCoy laryngoscope. Haemodynamic measurements and oxygen saturation were recorded. The following intubation criteria were recorded for both groups: laryngeal view according to modified Cormack and Lehane grade at laryngoscopy, duration of the intubation procedure, number of intubation attempts and complications.
Statistical analysis
Data were statistically analysed with the SPSS software using t-test and χ2-test, and P value less than 0.05 was considered significant.
Results
Haemodynamic parameters (heart rate and mean arterial blood pressure) were significantly lower in the C-MAC D-blade group than in the McCoy group until 4 min after intubation. Oxygen saturation showed no significant difference between the two groups. The use of the C-MAC D-blade resulted in more appearance of modified C–L class 1, whereas the use of the McCoy laryngoscope resulted in more appearance of class 2b and class 3. Duration of intubation was statistically significantly longer in the C-MAC D-blade group than in the McCoy group, whereas for the number of intubation attempts C-MAC D-blade results in more successful intubation in the first attempt than the McCoy laryngoscope.
Conclusion
The C-MAC D-blade laryngoscope offers a new approach for the management of difficult airway, such as in patients in need for cervical immobilization. It causes less haemodynamic stress, it better intubates in the first trial and gives a better view of the larynx without moving the cervical spine, but it may be more time-consuming than direct laryngoscopes.

Keywords: airway management, cervical immobilization, c-mac d-blade, mccoy


How to cite this article:
Sabry LA, Shaarawy SS, Ellakany MH, Elmasry AA. Comparison between C-MAC D-blade and McCoy laryngoscopes in intubating patients during cervical immobilization. Res Opin Anesth Intensive Care 2016;3:122-8

How to cite this URL:
Sabry LA, Shaarawy SS, Ellakany MH, Elmasry AA. Comparison between C-MAC D-blade and McCoy laryngoscopes in intubating patients during cervical immobilization. Res Opin Anesth Intensive Care [serial online] 2016 [cited 2017 Sep 22];3:122-8. Available from: http://www.roaic.eg.net/text.asp?2016/3/3/122/193412


  Introduction Top


Airway management is a major responsibility for the anaesthetist. Difficulties with tracheal intubation significantly contribute to anaesthesia-related morbidity and mortality [1].

The goal of all advances in the management of airway is to achieve better maintenance of the airway and adequate ventilation in both elective and emergency situations. Many devices and techniques have come a long way since the development of Mallampati classification and the use of endotracheal intubation to the present day [2],[3].

Endotracheal intubation is frequently required for trauma patients as a part of the resuscitation for patients with unstable cervical spine. Orotracheal intubation is the preferred technique for airway management in these victims. Failure to adequately immobilize the neck during tracheal intubation in patients with cervical spine injuries can result in devastating neurological outcomes [4].

Videolaryngoscopy has been introduced in anaesthesia, where, in most cases, it has shown to produce better viewing conditions, resulting in a lower incidence of difficult airway [5],[6],[7].

The latest generation of Karl Storz videolaryngoscopes, the C-MAC videolaryngoscope (Karl Storz, Tuttlingen, Germany) [Figure 1], features several distinct improvements in videolaryngoscopy. The optical system and the use of high-intensity light-emitting diodes (LEDs) as a light source produces optimum view of the glottis and permits the operator to navigate the tip of the blade into the vallecula under laryngoscopic vision. Various types of blades are available for the C-MAC videolaryngoscope. Currently, the system can accommodate Macintosh blade sizes 2, 3 and 4, and additional models such as Miller sizes 0 and 1. A special D-blade is also available for use with the C-MAC system. The greater curvature of this blade is specially designed to facilitate intubation of the difficult airway [8].
Figure 1: Showing the C-MAC videolaryngoscope.

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The McCoy levering laryngoscope (InterMed Penlon Ltd, Abingdon, UK) is one of the first levering laryngoscopes designed [Figure 2]. This modification (originally of the standard Macintosh blade) enables the anaesthetist to have a good view of the vocal apparatus without the force often required when using the Macintosh blade in difficult situations. Its tip is hinged, and the angle of the hinged portion can be altered by a lever attached to the handle. Depressing the lever towards the handle elevates the tip, located 25 mm from the end of the blade, by ∼70°. If glottic visualization is poor, the lever can be depressed, activating the distal tip upwards. When activated, the levering tip laryngoscope may have the advantage of providing an optimal tip angle and contact with the hyoepiglottic ligament in situations such as limited neck extension, or prominent upper teeth. The blade is available in sizes 3 and 4 of Macintosh style for intubation of adult patients [9],[10],[11].
Figure 2: Showing the McCoy laryngoscope.

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This study was carried out to compare the efficacy of the C-MAC D-blade with the McCoy laryngoscope in intubating patients with cervical spine immobilization regarding visualization of the laryngeal inlet (according to modified Cormack and Lehane class), duration of the intubation procedure, number of intubation attempts, complications during laryngoscopy and intubation (airway trauma, oxygen desaturation) and haemodynamic response.


  Patients and methods Top


This randomized controlled study was carried out in the Medical Research Institute Hospital, University of Alexandria, on 60 adult ASA I and II patients who were randomly categorized into two equal groups (30 each) after written informed consent and approval of the ethics committee. Patients with previous history of difficult intubation, risk of gastric aspiration, cervical injury or instability or with BMI of at least 35 were excluded from the study. All patients were subjected to the same anaesthetic protocol: the use of intravenous midazolam at a dose of 0.02 mg/kg intravenously 2 min before induction as a premedication, preoxygenation for 3 min and general anaesthesia using intravenous fentanyl at a dose of 1 μg/kg, intravenous propofol at a dose of 2 mg/kg and intravenous atracurium at a dose of 0.5 mg/kg. All patients were attached to a multichannel monitor (Infinity Vista; Fabius GS; Dräger, Lübeck, Germany).

After the onset of neuromuscular blockade, the neck was immobilized using manual in-line axial stabilization, by holding the sides of the neck and the mastoid processes by an assistant standing facing the anaesthetist, and thus preventing flexion/extension or rotational movement of the head and the neck.

Group I patients were intubated using the C-MAC D-blade. To use the device, the blade was inserted into the mouth in the midline, over the centre of the tongue, and the tip was positioned in the vallecula. The view was shown on the LED monitor until the epiglottis and the vocal cords were seen, and then the endotracheal tube (ETT) was advanced until it was seen passing through the vocal cords; a semirigid stylet preshaped as a hockey stick is used to guide the ETT. After verifying ETT placement by capnography and bilateral chest auscultation, the blade was withdrawn slowly.

Group II patients were intubated using the McCoy laryngoscope. The McCoy blade was introduced to the right of the tongue, advanced into the hypopharynx, pushing the tongue to the left until the tip of the laryngoscope is in the vallecula, and then the laryngoscope was lifted upwards and forwards, with activation of the blade through the lever on the back of the handle of the laryngoscope to expose the vocal cords. If insufficient glottic view was encountered in the neutral position, then the ETT was advanced until it was seen passing through the vocal cords; a semirigid stylet preshaped as a hockey stick was used to guide the ETT. After verifying ETT placement by capnography and bilateral chest auscultation, the blade was withdrawn slowly.

Ventilation was through (Fabius GS; Dräger, Lübeck, Germany) an anaesthesia machine using a tidal volume of 6–8 ml/kg and a frequency of 8–12 breaths/min to maintain end tidal CO2 at 36–40 mmHg. Maintenance of anaesthesia was with 1–2% isoflurane in 100% oxygen. Incremental doses of atracurium (0.1 mg/kg) were administered as needed according to the nerve stimulator. At the end of the operation, the residual muscle relaxation was reversed with intravenous atropine (0.015 mg/kg) and neostigmine (0.04–0.08 mg/kg). Pharyngeal suction was done. Once the patient is awake or easily arousable with vocal commands, the ETT was removed and replaced with a facemask.

Haemodynamic measurements including heart rate and mean arterial blood pressure, as well as oxygen saturation, were recorded before induction of general anaesthesia, before intubation, just after intubation, at 2-min intervals for the first 10 min after intubation and every 10 min throughout the time of the operation and until extubation.

The following intubation criteria were recorded for both groups: visualization of the laryngeal inlet according to the modified Cormack and Lehane grade at laryngoscopy; duration of the intubation procedure, which is the time taken from insertion of the blade of the laryngoscope between the lips until the ETT is passed through the vocal cords; the number of intubation attempts; and complications during intubation.


  Results Top


Demographic data were matched in both studied groups. There was no statistically significant difference between both groups as regards the demographic data [Table 1]. Haemodynamic parameters (heart rate and mean arterial blood pressure) showed a significant increase in both groups over baseline values after intubation and after 2 min, and then began to normalize after 4 min. Comparing both groups, these parameters were significantly lower in group I than in group II until 4 min after intubation. Thereafter, there was no significant difference between both groups [Table 2] and [Table 3].
Table 1: Patients' demographic data

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Table 2: Comparison between the two studied groups according to heart rate

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Table 3: Comparison between the two studied groups according to mean arterial blood pressure

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With regard to oxygen saturation (SPO2), there was no significant difference between both groups.

There was a significant difference between both groups as regards appearance of modified Cormack and Lehane (C–L) class 1, 2b and 3, as the use of the C-MAC D-blade resulted in more appearance of modified C–L class 1, whereas the use of the McCoy laryngoscope resulted in more appearance of class 2b and class 3. There was no significant difference between both groups as regards appearance of modified C–L class 2a and class 4 [Table 4] and [Figure 3].
Table 4: Comparison between the two studied groups regarding the glottic view according to modified Cormack–Lehane class

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Figure 3: Showing the modified Cormack and Lehane class percentage in each group.

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The duration of the successful intubation attempt was significantly shorter in group II than in group I [Table 5].
Table 5: Comparison between the two studied groups regarding the duration of the intubation attempt

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With regard to the number of intubation attempts, there was a significant difference between both groups regarding the intubation in the first attempt, as the C-MAC D-blade resulted in more successful intubation in the first attempt, but there was no significant difference between both groups regarding the intubation in the second attempt or intubation after the second attempt (intubation after abolishing the manual in-line axial stabilization manoeuvre) [Table 6] and [Figure 4]. There were no reported complications (oxygen desaturation or airway trauma) in both of the studied groups.
Table 6: Comparison between the two studied groups regarding the number of intubation attempts

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Figure 4: Showing the number of intubation attempts in each group.

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Qualitative data were described by using number and percent and a comparison was made by using χ2-test, whereas normally quantitative data were expressed as mean±SD and comparison was made using Student’s t-test.


  Discussion Top


Airway management is a major responsibility for the anaesthetist. Without adequate visualization of the vocal apparatus, intubation remains unsafe and is associated with elevated risk for trauma, thus essentially contributing to anaesthesia-related morbidity and mortality [1].

The present study was conducted in the medical research institute, University of Alexandria, to compare the efficacy of the C-MAC D-blade with the McCoy laryngoscope in intubating patients during cervical spine immobilization.

In the present study, as regards demographic data (age, sex, BMI), there was no statistically significant difference between both groups.

The haemodynamic measurements in group II were significantly lower compared with group I just after laryngoscopy and intubation and 2 min after intubation, but it began to normalize after 4 min. In agreement with our study, Joseph et al. [12] conducted a study to compare the McCoy and TruView EVO2 (videolaryngoscope) laryngoscopes in patients with cervical spine immobilization. They compared the haemodynamic response with laryngoscopy and intubation with both devices. They found that the cardiovascular response to laryngoscopy and intubation is significantly higher with the McCoy group than with the TruView group. This less haemodynamic response with TruView may be due to the lesser force applied to the base of the tongue by TruView.

In disagreement with our study, McElwain and Laffey [13] conducted a study comparing the performance of the C-MAC, Airtraq and Macintosh laryngoscopes when performing tracheal intubation in patients undergoing neck immobilization using manual in-line axial cervical spine stabilization. They concluded that the effects of laryngoscopy and tracheal intubation on the mean arterial pressure and on heart rate were relatively modest. Heart rate increased significantly in all groups after tracheal intubation, but it had returned to baseline within 5 min in all groups, with no between-group differences.

In our study, and regarding the glottic view according to modified Cormack–Lehane (modified C–L) class, there was significant difference between both groups as regards appearance of modified C–L class 1, class 2b and class 3, as the use of the C-MAC D-blade resulted in more appearance of modified class 1, whereas the use of the McCoy laryngoscope resulted in more appearance of class 2b and class 3. There was no significant difference between both groups as regards appearance of modified C–L class 2 and class 4.

In agreement with our study, Aziz et al. [14] conducted a study to compare the effectiveness of the C-MAC videolaryngoscope with direct laryngoscopy in the setting of the predicted difficult airway. The trial involved 300 patients. Inclusion required at least one of four predictors of difficult intubation. They found that Cormack–Lehane laryngeal view was graded I or II in 139/149 C-MAC attempts versus 119/147 in direct laryngoscopy attempts (P<0.01).

Kaplan et al. [15] conducted a study to compare direct and video-assisted views of the larynx during routine intubation. The views of the glottis were divided into easy (grades 1, 2a or 2b) and difficult (grades 3 or 4). The difference between the two techniques was significant (P<0.001). The study indicated an improved view with video-assisted laryngoscopy.

Jain et al. [16] conducted a study comparing the conventional C-MAC and the C-MAC D-blade with direct laryngoscopes (Macintosh and McCoy laryngoscopes) in simulated cervical spine injury in a manikin. They have found statistically significant improvement in the laryngoscopic view seen with conventional C-MAC and the D-blade in comparison with the Macintosh and McCoy laryngoscopes. The McCoy laryngoscope provided slight improvement in the laryngoscopic view in comparison with the Macintosh laryngoscope, but the difference was not statistically significant.

In our study, and regarding the duration of the successful intubation attempt, it was significantly shorter in group II (McCoy group) than in group I (C-MAC group).

In agreement with our study, Aziz et al. [14] conducted a study to compare the effectiveness of the C-MAC videolaryngoscope with direct laryngoscopy in the setting of the predicted difficult airway. They found that laryngoscopy time averaged 46 s for the C-MAC group, which was significantly longer than the direct laryngoscopy group, 33 s (P<0.001).

Joseph et al. [12] conducted a study to compare the McCoy and TruView (videolaryngoscope) laryngoscopes in patients with cervical spine immobilization. They have found that the duration of intubation was significantly less with the McCoy laryngoscope (mean=22.9±8.5 s) than with the TruView laryngoscope (mean=33.2±12.3 s), with a P value less than 0.001, which shows that it is very highly significant. They think that the main reason for increased duration of tracheal intubation with TruView is the difficulty experienced in advancing the tube through the lateral side of the patient’s mouth.

In our study, and regarding the number of intubation attempts, there was a significant difference between both groups regarding the intubation in the first attempt, as the C-MAC D-blade results in more successful intubation in the first attempt (P=0.028). There was no significant difference between both groups regarding the intubation in the second attempt (P=0.095) or failed intubation in the second attempt (intubation after abolishing the MIAS maneuver) (P=0.492).

In agreement with our study, Aziz et al. [14] conducted a study to compare the effectiveness of the C-MAC videolaryngoscope with direct laryngoscopy in the setting of the predicted difficult airway. They have found that the use of video laryngoscopy resulted in more successful intubations in the first attempt (138/149; 93%) as compared with direct laryngoscopy (124/147; 84%) (P=0.026).

Contrary to the current assumption that videolaryngoscopy improves the success rate for intubation in the first attempt, Bharti et al. [17] conducted a study to compare the McCoy, TruView and Macintosh laryngoscopes for tracheal intubation in patients with immobilized cervical spine. They have found that the success rate of the first attempt was 95% in the TruView laryngoscope group (videolaryngoscope) and 91% in the McCoy group, which was found to be statistically insignificant. The success rate of the second attempt was 100% with both devices.

In addition, McElwain and Laffey [13] conducted a study comparing the performance of the C-MAC, Airtraq and Macintosh laryngoscopes when performing tracheal intubation in patients undergoing neck immobilization using manual in-line axial cervical spine stabilization. They concluded that there was no statistically significant difference between both groups as regards the number of intubation attempts.

In our study, and regarding arterial oxygen saturation (SPO2), there was no significant difference between both groups.

With regard to the complications (airway trauma, oxygen desaturation and oesophageal intubation), there were no reported cases of such complications in our study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Peterson GN, Domino KB, Caplan RA, Posner KL, Lee LA, Cheney FW. Management of the difficult airway: a closed claims analysis. Anesthesiology 2005;103:33–39.  Back to cited text no. 1
    
2.
Gal TJ. Airway management. In: Miller RD, editor. Miller anesthesia. 7th ed. Philadelphia: Churchill Livingstone; 2010. 1617–1651.  Back to cited text no. 2
    
3.
Benumof JL. Management of the difficult adult airway. With special emphasis on awake tracheal intubation. Anesthesiology 1991;75:1087–1110.  Back to cited text no. 3
    
4.
Hastings RH, Kelley SD. Neurologic deterioration associated with airway management in a cervical spine-injured patient. Anesthesiology 1993;78:580–583.  Back to cited text no. 4
    
5.
Weiss M. Video-intuboscopy: a new aid to routine and difficult tracheal intubation. Br J Anaesth 1998;80:525–527.  Back to cited text no. 5
    
6.
Cooper RM. Use of a new videolaryngoscope (GlideScope) in the management of a difficult airway. Can J Anaesth 2003;50:611–613.  Back to cited text no. 6
    
7.
Cooper RM, Pacey JA, Bishop MJ, McCluskey SA. Early clinical experience with a new videolaryngoscope (GlideScope) in 728 patients. Can J Anaesth 2005;52:191–198.  Back to cited text no. 7
    
8.
Doerges V. The C-MAC videolaryngoscopy system in clinical and emergency medicine [Online]. 2014 [cited 20 October 2014]; [100 screens]. Available at: https://www.karlstorz.com/doc/interactivebrochure/3317881/index.html [cited 20 October 2014].  Back to cited text no. 8
    
9.
McCoy EP, Mirakhur RK. The levering laryngoscope. Anaesthesia 1993;48:516–519.  Back to cited text no. 9
    
10.
McCoy EP, Mirakhur RK, McCloskey BV. A comparison of the stress response to laryngoscopy. The Macintosh versus the McCoy blade. Anaesthesia 1995; 50: 943–946.  Back to cited text no. 10
    
11.
McCoy EP, Mirakhur RK, Rafferty C, Bunting H, Austin BA. A comparison of the forces exerted during laryngoscopy. The Macintosh versus the McCoy blade. Anaesthesia 1996;51:912–915.  Back to cited text no. 11
    
12.
Joseph J, Sequeira T, Upadya M. Comparison of the use of McCoy and TruView EVO2 laryngoscopes in patients with cervical spine immobilization. Saudi J Anaesth 2012;6:248–253.  Back to cited text no. 12
[PUBMED]  Medknow Journal  
13.
McElwain J, Laffey JG. Comparison of the C-MAC®, Airtraq®, and Macintosh laryngoscopes in patients undergoing tracheal intubation with cervical spine immobilization. Br J Anaesth 2011;107:258–264.  Back to cited text no. 13
    
14.
Aziz MF, Dillman D, Fu R, Brambrink AM. Comparative effectiveness of the C-MAC video laryngoscope versus direct laryngoscopy in the setting of the predicted difficult airway. Anesthesiology 2012;116:629–636.  Back to cited text no. 14
    
15.
Kaplan MB, Hagberg CA, Ward DS, Brambrink A, Chhibber AK, Heidegger T et al. Comparison of direct and video-assisted views of the larynx during routine intubation. J Clin Anesth 2006;18: 357–362.  Back to cited text no. 15
    
16.
Jain D, Dhankar M, Wig J, Jain A, Jain D, Dhankar M et al. Comparison of the conventional CMAC and the D-blade CMAC with the direct laryngoscopes in simulated cervical spine injury-a manikin study. Braz J Anesthesiol 2014;64:269–274.  Back to cited text no. 16
    
17.
Bharti N, Arora S, Panda NB. A comparison of McCoy, TruView, and Macintosh laryngoscopes for tracheal intubation in patients with immobilized cervical spine. Saudi J Anaesth 2014;8:188–192.  Back to cited text no. 17
[PUBMED]  Medknow Journal  


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