Comparison of Macintosh, McCoy, and Glidescope video laryngoscope for intubation in morbidly obese patients: Randomized controlled trial

Videolaryngoscopy vs. direct laryngoscopy in class 2 and 3 obesity: a systematic review, meta-analysis and trial sequential analysis of randomised controlled trials

INTRODUCTION

The 7th National Audit Project of the Royal College of Anaesthetists revealed an increase in rates of tracheal intubation over the last decade, partially contributed to by the rise in people living with obesity. Notably, airway and respiratory complications were over-represented in patients living with class 2 or 3 obesity (BMI ≥ 35 kg.m-2). Hence, it is timely to evaluate if videolaryngoscopy might improve tracheal intubation-related outcomes when compared with direct laryngoscopy in this high-risk patient group.

METHODS

We conducted a systematic review and meta-analysis of randomised controlled trials published in the last 15 years. We searched five databases for trials comparing videolaryngoscopy with direct laryngoscopy in adult patients living with class 2 or 3 obesity undergoing elective general surgery. Primary outcomes were the incidence of failed tracheal intubation; hypoxaemia; and first attempt tracheal intubation failure. Secondary outcomes were glottic visualisation; time to tracheal intubation; incidence of sore throat; and intubation difficulty scale.

RESULTS

We included 10 trials with 955 patients, of whom 481 received videolaryngoscopy and 474 direct laryngoscopy. Videolaryngoscopy significantly reduced failed tracheal intubation (relative risk (95%CI) 0.15 (0.05-0.35), p < 0.001, nine studies); hypoxaemia (relative risk (95%CI) 0.21 (0.10-0.43), p < 0.001, seven studies); and first attempt failure (relative risk (95%CI) 0.44 (0.25-0.76), p = 0.004, seven studies). While glottic visualisation was also significantly improved, there was no significant difference in time to tracheal intubation, incidence of sore throat or intubation difficulty scale.

CONCLUSIONS

In patients living with class 2 or 3 obesity, videolaryngoscopy significantly reduced failed tracheal intubation incidence, first-attempt failure incidence, incidence of hypoxaemia and poor glottic visualisation. Patients living with class 2 or 3 obesity are likely to benefit from the use of videolaryngoscopy compared with direct laryngoscopy.

Videolaryngoscopy vs. direct laryngoscopy in orotracheal intubation in obese critical patients: Systematic review and meta-analysis

OBJECTIVE

To determine whether the use of videolaryngoscopy (VL) is more effective than direct laryngoscopy (DL) for orotracheal intubation in obese patients.

DESIGN

This is a systematic review and meta-analysis.

SETTING

A comprehensive search was conducted in five databases for studies published up to December 26, 2023, using a PICO strategy. Fifteen studies were identified for quantitative analysis and included in our meta-analysis.

PARTICIPANTS

The participants of the included primary studies (obese patients).

INTERVENTIONS

Orotracheal intubation with videolaryngoscopy or direct laryngoscopy.

MAIN VARIABLES OF INTEREST

Videolaryngoscopy, direct laryngoscopy, intubation time, first--pass success rate, minor complications.

RESULTS

No significant differences were found in intubation time between VL and DL in obese patients (MD: -4.84; 95% CI: -13.49 to 3.80; I2: 90%). In the subgroup analysis, the Airtaq technique showed a significant difference in intubation time compared to the Macintosh technique (MD: -25.29; 95% CI: -49.17 to -1.38; I2: 95%). However, no significant differences were observed in the first--pass success rate (OR: 1.58; 95% CI: 0.77-3.23; I2: 33%) or in complications such as pain (OR: 1.15; 95% CI: 0.75-1.75; I2: 0%) and voice changes (OR: 0.76; 95% CI: 0.46-1.26; I2: 0%) between the two methods.

CONCLUSION

There are no significant differences in intubation time, first--pass success rate, or complications between VL and DL in obese critical patients.

Comparative Efficacy of Videolaryngoscopy and Direct Laryngoscopy in Patients Living With Obesity: A Meta-Analysis

Intubation in patients living with obesity poses unique challenges due to altered airway anatomy and reduced physiological reserve, increasing the risk of complications. In synthesizing evidence from multiple trials, our meta-analysis suggests that videolaryngoscopy may provide a higher likelihood of achieving successful intubation on the first attempt compared to direct laryngoscopy while not substantially increasing the procedure time. Videolaryngoscopy was associated with a significant increase in first-pass intubation success compared to direct laryngoscopy, with a pooled risk ratio (RR) of 0.42 (95% CI 0.22 - 0.78, p = 0.0064). There was no significant difference in time to intubation between the two techniques (standardised mean differences (SMD) 0.13, 95% CI -0.26 to 0.52, p = 0.51), a result approached with low certainty due to the high heterogeneity among studies. Although the underlying studies varied in their methods and patient populations, these findings support the consideration of videolaryngoscopy as a potentially more reliable and safer technique for airway management in patients with obesity.

A Comparison of the Effectiveness of the McCoy Laryngoscope and the C-MAC D-Blade Video Laryngoscope in Obese Patients

Background and Objective: Obesity is associated with difficult or failed intubation attempts, making general anesthesia challenging for anesthesiologists to perform. The purpose of this study was to evaluate and compare the efficacy of a McCoy laryngoscope and a C-MAC D-blade video laryngoscope for intubation in obese patients with a body mass index (BMI) ≥ 35 kg/m2. Methods: In total, 104 patients were randomly assigned to be intubated with a McCoy (McCoy group) or C-MAC D-blade video laryngoscope (C-MAC group). The primary outcome was intubation time. The secondary outcomes were vocal cord exposure time, vocal cord passage time, proportion of successful intubation, mask ventilation scale, intubation difficulty scale (IDS), percentage of glottis opening (POGO) score, and hemodynamic variables. Results: Although the intubation time did not significantly differ, the C-MAC group showed shorter vocal cord exposure times and a higher rate of successful vocal cord exposure within 5 s. The IDS value was significantly lower in the C-MAC group than in the McCoy group. The proportion of patients who required an increase in lifting force during laryngoscopy was higher in the McCoy group than in the C-MAC group, which may explain the difference in MAP between the groups. Conclusions: Both the McCoy laryngoscope and the C-MAC D-blade video laryngoscope were useful during the intubation of obese patients. The C-MAC D-blade video laryngoscope might be more useful for obese patients in terms of hemodynamic stability.

Comparison of UESCOPE VL 400, I-View, Non-Channeled Airtraq Videolaryngoscopes and Macintosh Laryngoscope for Tracheal Intubation in Simulated Out-of-Hospital Conditions: A Randomized Crossover Manikin Study

The aim of the study was to test the hypothesis that the results obtained with three different types of video laryngoscopes (UESCOPE VL-400, I-View, Non-Channeled Aitraq) with and without an endotracheal stylet should be better than the results obtained with a Macintosh laryngoscope in a simulated out-of-hospital scenario by a person without clinical experience. Primary outcome measures were the time taken to successfully achieve tracheal intubation (TI). Secondary outcomes included the grade of glottic view (Cormack and Lehane grades 1-4), the incidence of successful TI, the number of audible dental clicks indicating potential dental damage, the level of effort required to perform TI, and the operator's comfort during the procedure. The time required to achieve tracheal intubation successfully was significantly longer with the Macintosh laryngoscope and Airtraq than with the other video laryngoscopes. The use of the stylet significantly reduced the time required for tracheal intubation with the Macintosh laryngoscope (21.8 sec. vs. 24.0 sec., p = 0.026), UESCOPE VL 400 (18.1 sec. vs. 23.4 sec., p = 0.013), and Airtraq (22.7 sec. vs. 34.5 sec., p < 0.001). There were no significant differences in intubation time when using the I-View with or without stylets. No differences were observed in the Cormack-Lehane grading. The success rate of intubation was 100% for the Macintosh and I-View laryngoscopes used with or without stylets and for the UESCOPE VL 400 and Airtraq laryngoscopes used with stylets. Without stylets, the success rate of intubation was 96.6% for the UESCOPE VL 400 and 86.6% for the Airtraq. There were no significant differences in the risk of dental damage between the Macintosh, UESCOPE VL 400, I-View, and Airtraq laryngoscopes, regardless of the use of stylets (without and with stylets). The use of stylets significantly reduced dental damage only for the Airtraq laryngoscope: 8 (26.6%) vs. 2 (6.6%). Statistically significant differences in perceived exertion were observed between the mentioned laryngoscopes, both with and without stylets. However, there were no differences in the comfort of use between the laryngoscopes, regardless of the use of stylets (without and with stylets. The use of stylets led to better comfort in the case of the Macintosh (2.5 vs. 3, p = 0.043) and UESCOPE VL 400 (2 vs. 3, p = 0.008) laryngoscopes. In our study, the I-View and UESCOPE VL-400 video laryngoscopes provided better intubation results than the Macintosh laryngoscope in terms of time needed to intubate, glottis visibility, and reduction in dental damage. The use of the stylet did not significantly improve the intubation results compared to the results obtained in direct laryngoscopy. Due to the small study group and the manikin model, additional studies should be performed on a larger study group.

Assessment of the Possibility of Using the Laryngoscopes Macintosh, McCoy, Miller, Intubrite, VieScope and I-View for Intubation in Simulated Out-of-Hospital Conditions by People without Clinical Experience: A Randomized Crossover Manikin Study

The aim of the study was to evaluate the laryngoscopes Macintosh, Miller, McCoy, Intubrite, VieScope and I-View in simulated out-of-hospital conditions when used by people without clinical experience, and to choose the one that, in the case of failure of the first intubation (FI), gives the highest probability of successful second (SI) or third (TI). For FI, the highest success rate (HSR) was observed for I-View and the lowest (LSR) for Macintosh (90% vs. 60%; p < 0.001); for SI, HSR was observed for I-View and LSR for Miller (95% vs. 66,7%; p < 0001); and for TI, HSR was observed for I-View and LSR for Miller, McCoy and VieScope (98.33% vs. 70%; p < 0.001). A significant shortening of intubation time between FI and TI was observed for Macintosh (38.95 (IQR: 30.1-47.025) vs. 32.4 (IQR: 29-39.175), p = 0.0132), McCoy (39.3 (IQR: 31.1-48.15) vs. 28.75 (IQR: 26.475-35.7), p < 0.001), Intubrite (26.4 (IQR: 21.4-32.3) vs. 20.7 (IQR: 18.3-24.45), p < 0.001), and I-View (21 (IQR: 17.375-25.1) vs. 18 (IQR: 15.95-20.5), p < 0.001). According to the respondents, the easiest laryngo- scopes to use were I-View and Intubrite, while the most difficult was Miller. The study shows that I-View and Intubrite are the most useful devices, combining high efficiency with a statistically significant reduction in time between successive attempts.

Videolaryngoscopy versus direct laryngoscopy for adults undergoing tracheal intubation

BACKGROUND

Tracheal intubation is a common procedure performed to secure the airway in adults undergoing surgery or those who are critically ill. Intubation is sometimes associated with difficulties and complications that may result in patient harm. While it is traditionally achieved by performing direct laryngoscopy, the past three decades have seen the advent of rigid indirect videolaryngoscopes (VLs). A mounting body of evidence comparing the two approaches to tracheal intubation has been acquired over this period of time. This is an update of a Cochrane Review first published in 2016.

OBJECTIVES

To assess whether use of different designs of VLs in adults requiring tracheal intubation reduces the failure rate compared with direct laryngoscopy, and assess the benefits and risks of these devices in selected population groups, users and settings.

SEARCH METHODS

We searched MEDLINE, Embase, CENTRAL and Web of Science on 27 February 2021. We also searched clinical trials databases, conference proceedings and conducted forward and backward citation searches.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and quasi-RCTs with adults undergoing laryngoscopy performed with either a VL or a Macintosh direct laryngoscope (DL) in any clinical setting. We included parallel and cross-over study designs.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We collected data for the following outcomes: failed intubation, hypoxaemia, successful first attempt at tracheal intubation, oesophageal intubation, dental trauma, Cormack-Lehane grade, and time for tracheal intubation.

MAIN RESULTS

We included 222 studies (219 RCTs, three quasi-RCTs) with 26,149 participants undergoing tracheal intubation. Most studies recruited adults undergoing elective surgery requiring tracheal intubation. Twenty-one studies recruited participants with a known or predicted difficult airway, and an additional 25 studies simulated a difficult airway. Twenty-one studies were conducted outside the operating theatre environment; of these, six were in the prehospital setting, seven in the emergency department and eight in the intensive care unit.  We report here the findings of the three main comparisons according to videolaryngoscopy device type. We downgraded the certainty of the outcomes for imprecision, study limitations (e.g. high or unclear risks of bias), inconsistency when we noted substantial levels of statistical heterogeneity and publication bias. Macintosh-style videolaryngoscopy versus direct laryngoscopy (61 studies, 9883 participants) We found moderate-certainty evidence that a Macintosh-style VL probably reduces rates of failed intubation (risk ratio (RR) 0.41, 95% confidence interval (CI) 0.26 to 0.65; 41 studies, 4615 participants) and hypoxaemia (RR 0.72, 95% CI 0.52 to 0.99; 16 studies, 2127 participants). These devices may also increase rates of success on the first intubation attempt (RR 1.05, 95% CI 1.02 to 1.09; 42 studies, 7311 participants; low-certainty evidence) and probably improve glottic view when assessed as Cormack-Lehane grade 3 and 4 (RR 0.38, 95% CI 0.29 to 0.48; 38 studies, 4368 participants; moderate-certainty evidence). We found little or no clear difference in rates of oesophageal intubation (RR 0.51, 95% CI 0.22 to 1.21; 14 studies, 2404 participants) but this finding was supported by low-certainty evidence. We were unsure of the findings for dental trauma because the certainty of this evidence was very low (RR 0.68, 95% CI 0.16 to 2.89; 18 studies, 2297 participants). We were not able to pool data for time required for tracheal intubation owing to considerable heterogeneity (I2 = 96%). Hyperangulated videolaryngoscopy versus direct laryngoscopy (96 studies, 11,438 participants) We found moderate-certainty evidence that hyperangulated VLs probably reduce rates of failed intubation (RR 0.51, 95% CI 0.34 to 0.76; 63 studies, 7146 participants) and oesophageal intubation (RR 0.39, 95% CI 0.18 to 0.81; 14 studies, 1968 participants). In subgroup analysis, we noted that hyperangulated VLs were more likely to reduce failed intubation when used on known or predicted difficult airways (RR 0.29, 95% CI 0.17 to 0.48; P = 0.03 for subgroup differences; 15 studies, 1520 participants). We also found that these devices may increase rates of success on the first intubation attempt (RR 1.03, 95% CI 1.00 to 1.05; 66 studies, 8086 participants; low-certainty evidence) and the glottic view is probably also improved (RR 0.15, 95% CI 0.10 to 0.24; 54 studies, 6058 participants; data for Cormack-Lehane grade 3/4 views; moderate-certainty evidence). However, we found low-certainty evidence of little or no clear difference in rates of hypoxaemia (RR 0.49, 95% CI 0.22 to 1.11; 15 studies, 1691 participants), and the findings for dental trauma were unclear because the certainty of this evidence was very low (RR 0.51, 95% CI 0.16 to 1.59; 30 studies, 3497 participants). We were not able to pool data for time required for tracheal intubation owing to considerable heterogeneity (I2 = 99%). Channelled videolaryngoscopy versus direct laryngoscopy (73 studies, 7165 participants) We found moderate-certainty evidence that channelled VLs probably reduce rates of failed intubation (RR 0.43, 95% CI 0.30 to 0.61; 53 studies, 5367 participants) and hypoxaemia (RR 0.25, 95% CI 0.12 to 0.50; 15 studies, 1966 participants). They may also increase rates of success on the first intubation attempt (RR 1.10, 95% CI 1.05 to 1.15; 47 studies, 5210 participants; very low-certainty evidence) and probably improve glottic view (RR 0.14, 95% CI 0.09 to 0.21; 40 studies, 3955 participants; data for Cormack-Lehane grade 3/4 views; moderate-certainty evidence). We found little or no clear difference in rates of oesophageal intubation (RR 0.54, 95% CI 0.17 to 1.75; 16 studies, 1756 participants) but this was supported by low-certainty evidence. We were unsure of the findings for dental trauma because the certainty of the evidence was very low (RR 0.52, 95% CI 0.13 to 2.12; 29 studies, 2375 participants). We were not able to pool data for time required for tracheal intubation owing to considerable heterogeneity (I2 = 98%).

AUTHORS' CONCLUSIONS

VLs of all designs likely reduce rates of failed intubation and result in higher rates of successful intubation on the first attempt with improved glottic views. Macintosh-style and channelled VLs likely reduce rates of hypoxaemic events, while hyperangulated VLs probably reduce rates of oesophageal intubation. We conclude that videolaryngoscopy likely provides a safer risk profile compared to direct laryngoscopy for all adults undergoing tracheal intubation.

Comparisons of Videolaryngoscopes for Intubation Undergoing General Anesthesia: Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

BACKGROUND

The efficacy and safety of videolaryngoscopes (VLs) for tracheal intubation is still conflicting and changeable according to airway circumstances. This study aimed to compare the efficacy and safety of several VLs in patients undergoing general anesthesia.

METHODS

Medline, EMBASE, and the Cochrane Library were searched until 13 January 2020. The following VLs were evaluated compared to the Macintosh laryngoscope (MCL) by network meta-analysis for randomized controlled trials (RCTs): Airtraq, Airwayscope, C-MAC, C-MAC D-blade (CMD), GlideScope, King Vision, and McGrath. Outcome measures were the success and time (speed) of intubation, glottic view, and sore throat (safety).

RESULTS

A total of 9315 patients in 96 RCTs were included. The highest-ranked VLs for first-pass intubation success were CMD (90.6 % in all airway; 92.7% in difficult airway) and King Vision (92% in normal airway). In the rank analysis for secondary outcomes, the following VLs showed the highest efficacy or safety: Airtraq (safety), Airwayscope (speed and view), C-MAC (speed), CMD (safety), and McGrath (view). These VLs, except McGrath, were more effective or safer than MCL in moderate evidence level, whereas there was low certainty of evidence in the intercomparisons of VLs.

CONCLUSIONS

CMD and King Vision could be relatively successful than MCL and other VLs for tracheal intubation under general anesthesia. The comparisons of intubation success between VLs and MCL showed moderate certainty of evidence level, whereas the intercomparisons of VLs showed low certainty evidence.

Endotracheal Intubation by Paramedics Using Neodymium Magnet and Modified Stylet in Simulated Difficult Airway: A Prospective, Randomized, Crossover Manikin Study

BACKGROUND

The present study evaluates the success and efficacy of endotracheal intubation (ETI) using a modified intubation stylet and a magnet system to direct the stylet into the trachea. The system was developed by the researchers in an attempt to increase the success and efficacy of ETI.

METHODS

ETI procedures were performed on an airway management manikin by emergency medical technicians with at least four years of experience in ETI. The technicians used a stylet modified with an iron ball affixed to the tip and a neodymium magnet, designed specifically for the study. The intention was to guide the endotracheal tube into the trachea at the level of the thyroid and cricoid cartilages on the manikin with the aid of the modified stylet and the magnetic force of the neodymium magnet. The success rate, completion time, and degree of difficulty of two procedures were compared: magnetic endotracheal intubation (METI) and classic ETI (CETI).

RESULTS

The success rate was 100% in both groups. The mean completion times for the METI and CETI procedures were 18.31 ± 2.46 s and 20.01 ± 1.95 s, respectively. There were significant differences in completion time and degree of difficulty between the METI and CETI procedures (both p=0.001).

CONCLUSIONS

We found the use of a neodymium magnet and modified stylet to be an effective method to guide the endotracheal tube into the trachea. The present study may provide a basis for future studies.