|Year : 2016 | Volume
| Issue : 4 | Page : 168-172
A comparative study between the macintosh laryngoscope and the king vision video laryngoscope in endotracheal intubation
Sherif M Elhadi, Wafaa K Rady, Ahmed M Elfadly
Department of Anaesthesia and Surgical Intensive Care, Faculty of Medicine, Alexandria University, Alexandria, Egypt
|Date of Submission||29-Nov-2015|
|Date of Acceptance||11-Jul-2016|
|Date of Web Publication||16-Dec-2016|
Ahmed M Elfadly
Department of Anaesthesia and Surgical Intensive Care, Faculty of Medicine, Alexandria University, 313 Elhorreya st Sporting Alexandria, Alexandria
Source of Support: None, Conflict of Interest: None
Airway management remains a vital primary skill for anaesthesiologists. We aimed at comparing the efficacy of direct laryngoscopy using the conventional Macintosh blade with indirect laryngoscopy using the King Vision video laryngoscope (KVVL) with regard to visualization of the laryngeal view, speed of intubation and intubation success rate.
Patients and methods
A total of 100 adult patients were randomly categorized into two equal groups (50 patients each): group M patients were subjected to general anaesthesia with endotracheal intubation using direct laryngoscopy with the conventional Macintosh blade; and group K patients were subjected to general anaesthesia with endotracheal intubation using the KVVL; the entire procedure of laryngoscopy and intubation was evaluated and all patients were intubated by one anaesthetist experienced in the use of each laryngoscope.
The KVVL performed better in these patients by reducing haemodynamic response to laryngoscopy and intubation, improving the Cormack and Lehane glottis view, reducing the need for optimization manoeuvres and reducing the difficulty Likert scale score compared with the Macintosh laryngoscope (ML). There were no differences in intubation time, success rates and complications between both devices.
This study validated the efficacy of the KVVL compared with the direct ML. The KVVL performed better than the ML.
Keywords: direct laryngoscopy, endotracheal intubation, King Vision video laryngoscope, video laryngoscopy
|How to cite this article:|
Elhadi SM, Rady WK, Elfadly AM. A comparative study between the macintosh laryngoscope and the king vision video laryngoscope in endotracheal intubation. Res Opin Anesth Intensive Care 2016;3:168-72
|How to cite this URL:|
Elhadi SM, Rady WK, Elfadly AM. A comparative study between the macintosh laryngoscope and the king vision video laryngoscope in endotracheal intubation. Res Opin Anesth Intensive Care [serial online] 2016 [cited 2018 Nov 12];3:168-72. Available from: http://www.roaic.eg.net/text.asp?2016/3/4/168/195881
| Introduction|| |
Securing the airway with a cuffed tube in the trachea is a challenging procedure and still one of the most important skills in anaesthesia. However, the placement of a tracheal tube can be expectedly or unexpectedly difficult or even impossible. Difficult tracheal intubation still contributes to anaesthesia-related morbidity and mortality .
Direct laryngoscopy has been the standard technique for tracheal intubation for almost a century. However, the last two decades have seen the development of myriad alternative intubation devices .
Alternative intubation devices with video, optical or fibre optical imaging that have many advantages over direct laryngoscopy, easier laryngeal exposure without alignment of the oral, pharyngeal and tracheal axes, ability to achieve a laryngeal view despite unfavourable anatomy for direct laryngoscopy and an opportunity for multiple clinicians to observe and watch the procedure, have emerged .
Video laryngoscopy is the most significant development in airway management in this century. In 2001, Glidescope was the first generation of direct video laryngoscopes . Subsequently, the development of other video laryngoscopes followed, including the conventional Macintosh video laryngoscope, the Airtraq laryngoscope (AL), the McGrath laryngoscope and the King Vision video laryngoscope (KVVL).
The KVVL is a new intubation device that has been developed for the management of normal and difficult airways. It is an indirect, optical laryngoscope that has been designed to provide a view of the glottis without alignment of the oral, pharyngeal and tracheal axes. It is available in two blades − channelled and nonchannelled .
| Aim of the study|| |
The aim of this study was to compare the efficacy of direct laryngoscopy using the conventional Macintosh blade with indirect laryngoscopy using the KVVL with regard to visualization of the laryngeal view, speed of intubation and intubation success rate.
| Patients and methods|| |
The present study was carried out at Alexandria University Hospitals, and included 100 adult patients belonging to ASA physical status I and II, aged 18–50 years, of either sex scheduled for elective surgery under general anaesthesia with endotracheal intubation.
Patients included in the study had the following airway criteria: interincisor distance greater than 5 cm, modified Mallampati classes I and II, thyromental distance of at least 6.5 cm, neck circumference less than 38 cm for men and less than 35 cm for women and free neck mobility.
Patients were randomly allocated into two equal groups (50 patients each) using the closed envelope method:
Group M: patients had general anaesthesia with endotracheal intubation using direct laryngoscopy with the conventional Macintosh blade number 3.
Group K: patients had general anaesthesia with endotracheal intubation using the indirect KVVL blade number 3.
After obtaining local Ethics Committee approval and informed written consent from each patient, all patients were properly assessed preoperatively. All patients were premedicated with midazolam 0.03 mg/kg intravenously.
On arrival to the operating room, patients were connected to the standard monitors, including ECG, noninvasive arterial blood pressure and pulse oximeter. They were all subjected to the same anaesthetic protocol. Induction was performed using fentanyl 1 μg/kg and propofol 1.5–2 mg/kg. Orotracheal intubation was facilitated with rocuronium 0.6 mg/kg. Orotracheal intubation was performed using the selected intubation device for each group with the endotracheal tube loaded over a stylet and after ensuring full muscle relaxation as assessed by a nerve stimulator.
Heart rate (beats/min), mean arterial blood pressure (MAP) and peripheral oxygen saturation (SpO2%) were assessed. These parameters were measured continuously and recorded before induction, before laryngoscopy, immediately after endotracheal intubation and 10 min after endotracheal intubation.
We used the modified Cormack–Lehane scoring system .
Assessment of laryngoscopy and intubation procedure
- Number of trials to successful intubation.
- Manoeuvres during laryngoscopy.
- BURP manoeuvre ‘backward, upward, rightward and posterior external laryngeal pressure’.
- Changing the blade size in the second trial of laryngoscopy.
- Endotracheal tube insertion time was calculated from the time of introducing the laryngoscope blade through the patient’s mouth until successful intubation confirmed by the normal capnogram waveform.
- Success/failure rate.
- The degree of difficulty for each method by using the Likert scale .
Complications included possible trauma.
Data were tested for normal distribution, and data analysis was performed using the independent t-test for three independent groups, the paired t-test for paired samples and χ2-test and Fisher’s exact test for qualitative data.
Results are presented as ranges, percentages (%), arithmetic means (χ2) and SDs. The P value was considered statistically significant at less than 0.05.
| Results|| |
The mean age of patients was 29.38±5.69 years in group M (Macintosh group) and 30.30±6.45 years in group K (KVVL group) with no significant difference in age between the two studied groups ([Table 1]).
|Table 1: Comparison between the two studied groups according to age (years)|
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With regard to haemodynamic response, comparison between the two groups showed that the heart rate values were significantly less in group K compared with group M after intubation and at 10 min after intubation ([Figure 1]).
|Figure 1: Comparison between the two studied groups according to heart rate (beats/min).|
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By comparing the two groups according to the MAP, there was a significant decrease in MAP between intubation using the KVVL compared with the ML immediately after intubation and at 10 min after intubation ([Figure 2]).
|Figure 2: Comparison between the two studied groups according to mean arterial pressure (MAP) (mmHg).|
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According to the laryngoscopic view, 15 patients who were intubated with the ML had grade 1 Cormack and Lehane glottic view, 18 had grade 2a, 10 grade 2b and five had grade 3a, in comparison with 30 patients who were intubated with the KVVL having grade 1, 15 with grade 2a, four with grade 2b and one with grade 3a. Therefore, there was a significant difference between both groups ([Figure 3]).
|Figure 3: Comparison between the two studied groups according to laryngoscopic view.|
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Regarding the number of trials, 10 patients needed more than one trial in the Macintosh group in comparison with four in the King video group, and this was not significantly different ([Table 2]).
|Table 2: Comparison between the two studied groups according to the number of trials for intubation|
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KVVL reduced the need for optimization manoeuvres, laryngeal pressure manipulation (BURP) required while intubating and changing of blade size; this was statistically significant ([Figure 4] and [Figure 5]).
|Figure 5: Comparison between the two studied groups according to the change in blade size.|
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The total tube insertion time was not significantly different between the two groups; the mean insertion time was 19.10±7.08 in group M and 17.34±4.62 in group K ([Table 3]).
|Table 3: Comparison between the two studied groups according to tube insertion time|
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There was no significant difference between the two groups regarding success/failure rates ([Table 4]).
|Table 4: Comparison between the two studied groups according to success/failure|
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| Discussion|| |
The present study demonstrated that the KVVL maintains haemodynamic stability during endotracheal intubation.
This is in agreement with Ralph et al.  who conducted their study on cardiac patients of ASA physical status class III and IV.
Moreover, the same results were reported by Maharaj et al.  in their study to evaluate the AL and the ML in patients at increased risk for difficult intubation.
Disagreeing with the present study, Park et al. studied the haemodynamic changes while using the Levitan FPS and the ML. There was no significant difference .
The KVVL improves the laryngoscopic view, achieving a better glottic view.
Murphy et al.  obtained similar results in their study when comparing the KVVL with the ML.
Maharaj et al.  obtained similar results when they compared the AL with the ML while performing manual in-line axial stabilization.
Kaplan et al.  also demonstrated significant improvement in the Cormack–Lehane score while using video laryngoscopy to obtain a direct naked-eye view with external laryngeal manoeuvres and a video monitor view within the same attempt.
Regarding the number of intubation attempts in the present study, there was no significant difference.
Maharaj et al. reported nearly the same results in their study on endotracheal intubation using the AL and ML .
As for optimization manoeuvres required, both devices needed some optimization manoeuvres such as external laryngeal manipulations (BURP) and changing the blade size. The KVVL needed less optimization manoeuvres, showing that it offered easier intubating conditions.
Similar results were documented by Black  in a similar study comparing the AL with the ML, showing that all patients intubated using the AL did not require any optimization manoeuvres.
When considering the duration of the intubation procedure, the mean tube insertion time was 19.10±7.08 in group M and 17.34±4.62 in group K. Therefore, no significant difference was present between intubation insertion time with both laryngoscopes.
Different results were documented by Maharaj et al.  in the same study when comparing the AL with the ML.
Similar results were obtained by Serocki et al.  and Carsten et al. , who showed that there was no significant difference between the time needed to achieve laryngeal view and successful intubation between the video laryngoscope group and the direct laryngoscope group.
The present study showed that all patients were successfully intubated by the KVVL, but there was no significant difference between the two groups in comparing success/failure rates.
The same results were obtained by Black  in their study on intubating patients at increased risk for difficult intubation using both the AL and the ML.
The KVVL has been found to be more effective in reducing haemodynamic responses to laryngoscopy and intubation, improvement in the laryngoscopic view with a high success rate, easier procedure of laryngoscopy and intubation and the least usage of assisting manoeuvres during endotracheal intubation.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3], [Table 4]