C-MAC videolaryngoscope versus Macintosh laryngoscope for tracheal intubation: A systematic review and meta-analysis with trial sequential analysis

doi:10.1016/j.jclinane.2018.06.007

Journal of Clinical Anesthesia

Volume 49, September 2018, Pages 53-62

https://doi.org/10.1016/j.jclinane.2018.06.007 Get rights and content

Highlights

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We conducted a meta-analysis including more studies than the previous meta-analysis.
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We conducted a trial sequential analysis.
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The C-MAC is superior to the Macintosh in terms of glottic visualisation.
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The C-MAC is superior to the Macintosh in terms of success rates in difficult airway.
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TSA suggested that sample size were met with all outcomes.

Abstract

Study objective

The C-MAC laryngoscope (C-MAC) is a videolaryngoscope that uses a modified Macintosh blade. Although several anecdotal reports exist, it remains unclear whether the C-MAC is superior to the Macintosh laryngoscope for tracheal intubation in the adult population.

Design

Systematic review, meta-analysis.

Setting

Operating room, intensive care unit.

Measurements

For inclusion in our analysis, studies had to be prospective randomised trials which compared the C-MAC with the Macintosh laryngoscope for tracheal intubation in the adult population. Data on success rates, intubation time, glottic visualisation and incidence of external laryngeal manipulations (ELM) during tracheal intubation were extracted from the identified studies. In subgroup analysis, we separated those parameters to assess the influence of the airway condition (normal or difficult) and laryngoscopists (novice or experienced). We conducted a trial sequential analysis (TSA).

Main results

Sixteen articles with 18 trials met the inclusion criteria. The C-MAC provided better glottic visualisation compared to the Macintosh (RR, 1.08; 95% CI, 1.03–1.14). TSA corrected the CI to 1.01–1.19; thus, total sample size reached the required information size (RIS). Success rates and intubation time did not differ significantly between the laryngoscopes. TSA showed that total sample size reached the RIS for success rates. The TSA Z curve surpassed the futility boundary. The C-MAC required less ELM compared to the Macintosh (RR, 0.83; 95% CI, 0.72–0.96). TSA corrected the CI to 0.67–1.03; 52.3% of the RIS was achieved. In difficult airways, the C-MAC showed superior success rates, glottic visualisation, and less ELM compared to the Macintosh. Among experienced laryngoscopists, the C-MAC offered better glottic visualisation with less ELM than the Macintosh.

Conclusions

The C-MAC provided better glottic visualisation and less ELM (GRADE: Very Low or Moderate), with improved success rates, glottic visualisation, and less ELM in difficult airways.

Introduction

In the last decade, videolaryngoscopy has become widely used and various types of devices are now available. The C-MAC laryngoscope (C-MAC) (Karl Storz, Tuttlingen, Germany) is one of several videolaryngoscopes consisting of a modified Macintosh blade without a tube-guiding stylet, a portable high-resolution liquid-crystal display monitor unit, and an electronic module that transfers to the monitor unit the glottic image obtained from a digital camera located laterally in the distal third of the blade [1].

In some anecdotal reports, it is reported that the C-MAC has a higher success rate, a shorter intubation time, and a better view of the glottis than the Macintosh laryngoscope during tracheal intubation. [2] [3] However, in other reports, it is reported that the C-MAC has similar efficacy to the Macintosh laryngoscope for tracheal intubation. [4] [5] [6].

A recent meta-analysis comparing the videolaryngoscope and direct laryngoscope for tracheal intubation was published in 2016 [7]. The analysis showed that the success rates of tracheal intubation with the C-MAC was significantly higher compared to the Macintosh laryngoscope, with a relative risk (RR) of 0.32 and 95% confidence interval (CI) 0.15–0.68. However, there were only eight studies included in this meta-analysis. In addition, this meta-analysis included not only the C-MAC (five trials) but also the V-MAC laryngoscope (three trials). Moreover, these studies did not compare the intubation time, glottic visualisation, or number of external laryngeal manipulations (ELM) between the C-MAC and the Macintosh laryngoscope.

In this study, we performed a systematic review and meta-analysis of several randomised controlled trials to compare the utility of the C-MAC with that of the Macintosh laryngoscope for tracheal intubation in the adult population. The aim of this study is to examine success rates, intubation time, glottic visualisation, and number of ELM to determine whether the C-MAC is superior to the Macintosh laryngoscope for tracheal intubation in the adult population. Moreover, we conducted a subgroup analysis to investigate the effect of airway condition (normal airway or difficult airway) and laryngoscopist's experience level (novice or experienced) performing the tracheal intubation.

Section snippets

Materials and methods

This quantitative systematic review was performed according to the criteria outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement [8]. First, we established the analysis methods and set the inclusion and exclusion criteria used in this meta-analysis, and then registered the study protocol in the UMIN Clinical Trials Registry (registration number: UMIN 000023694; principal investigator's name: H. Hoshijima; date of registration: 19 August 2016).

Characteristics of studies included in the meta-analysis

Our search of electronic databases initially identified 322 articles for review. Of these, 271 studies were excluded because they were comparisons between unrelated laryngoscopes, or were unrelated studies. The remaining 51 articles were thoroughly examined to determine whether they met our inclusion criteria. Of these, 35 studies were excluded because they were not randomised controlled trials (n = 17) or manikin trials (n = 11), or review articles (n = 3), or pediatric trials (n = 2) or

Explanation of results

The results of our meta-analysis suggest that the C-MAC offers superior glottis visualisation and less ELM compared with the Macintosh laryngoscope, but showed no advantages in success rates and intubation time. However, in difficult airway settings, the C-MAC offers higher success rates for tracheal intubation and provides better visualisation of the glottis compared with the Macintosh laryngoscope. The C-MAC did not prevent intubation-related adverse events.

Superior glottic visualisation is

Conflicts of interest

We have no conflicts of interest.

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Tracheal intubation in cardiac surgery patients has a higher incidence of difficult laryngoscopic views compared with patients undergoing other types of surgery. The authors hypothesized that using the McGrath Mac videolaryngoscope as the first intubation option for cardiac surgery patients improves the percentage of patients with “easy intubation” compared with using a direct Macintosh laryngoscope.
A prospective, observational, before-after study.
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Consecutive patients undergoing cardiac surgery were intubated using, as the first option, a Macintosh laryngoscope (preinterventional phase) or a McGrath Mac videolaryngoscope (interventional phase).
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Citation Excerpt :
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In this prospective, randomised study, we compared the effects of the Macintosh, McGRATH MAC, and C-MAC laryngoscopes on intraocular pressure (IOP) and haemodynamics of non-ophthalmic patients during endotracheal intubation.
One hundred and twenty adult patients undergoing non-ophthalmic surgeries performed in the supine position under general anaesthesia requiring orotracheal intubation were included in this study. The patients were separated randomly and prospectively into 3 groups: Macintosh group (n = 40), McGRATH MAC group (n = 40), and C-MAC group (n = 40). Mean arterial pressure (MAP), heart rate (HR) and IOP of left and right eye were measured at specified times.
There were no significant differences with regard to patients characteristics. After intubation, the HR increased significantly in the Macintosh group when compared to the other groups (p = 0.001) and the MAP increased significantly in the Macintosh group when compared to the McGRATH MAC group (p = 0.001) and the C-MAC group (p < 0.001). The IOP values increased in the Macintosh group when compared to the McGRATH MAC group (p < 0.001) and the C-MAC group (p < 0.001) after intubation. Additionally, there was a significant difference between the McGRATH MAC group and C-MAC group in the IOP values of the eyes after intubation (p < 0.001). According to the evaluation within the groups, there were significant differences in all of the groups at all times when compared with the baseline values (p < 0.001).
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Original ContributionC-MAC videolaryngoscope versus Macintosh laryngoscope for tracheal intubation: A systematic review and meta-analysis with trial sequential analysis

Highlights

Abstract

Study objective

Design

Setting

Measurements

Main results

Conclusions

Introduction

Section snippets

Materials and methods

Characteristics of studies included in the meta-analysis

Explanation of results

Conflicts of interest

Resuscitation

Br J Anaesth

J Clin Epidemiol

J Clin Epidemiol

Turk J Emerg Med

The C-MAC videolaryngoscope: first experiences with a new device for videolaryngoscopy-guided intubation

Anesth Analg

Performance of the C-MAC video laryngoscope in patients after a limited glottic view using Macintosh laryngoscopy

Anaesthesia

Comparative effectiveness of the C-MAC video laryngoscope versus direct laryngoscopy in the setting of the predicted difficult airway

Anesthesiology

Comparison of three videolaryngoscopes: Pentax Airway Scope, C-MAC, Glidescope vs the Macintosh laryngoscope for tracheal intubation