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

Using a Disposable Flexible Fiberoptic Scope as a Bougie for Difficult Intubation

In this case report, we describe two difficult intubations in which an endotracheal tube was threaded over a fiberoptic bronchoscope that was acting as a bougie. Our patients initially presented with limited neck extension, narrow mouth opening, and restricted view of the glottic region. A fiberoptic bronchoscope was guided through while the patient was oxygenated through a laryngeal mask. After the scope provided an unrestricted view of the vocal cords, the digital module was removed by cutting the fiberoptic thread, and an endotracheal tube was passed through. After proper confirmation of the endotracheal tube position, the intubation was deemed successful and thereby, we share our experience with the novel technique. This technique may potentially improve critical patient outcomes whether in trauma or an unexpectedly difficult intubation.

Comparison of the Efficacy of Macintosh Laryngoscope Versus Airtraq Videolaryngoscope for Visualization of Laryngeal Structures at the End of Thyroidectomy: A Randomized Control Study

To compare the efficacy of conventional Macintosh laryngoscope with Airtraq videolaryngoscope for visualization of laryngeal structures to rule out recurrent laryngeal nerve injury at the end of thyroidectomy. This randomized double-blind control study was conducted following IEC-Human approval, prospective CTRI registration and written informed consent from participants. Patients of either sex, aged 18-65 years, ASA grade I/II, scheduled for thyroidectomy under GA were included. Group DL underwent direct laryngoscopy using Macintosh blade whereas group VL underwent laryngoscopy using Airtraq® videolaryngoscope. CL(Cormack-Lehane) grade of laryngeal view, time taken to achieve optimal view, haemodynamic parameters, Patient reactivity score(PRS) and complications were noted. Unpaired t-test, chi-square test were used. A total of 73 patients were included for study with 38 in group DL and 35 in group VL. The grade of laryngeal view was found to be significantly better with Airtraq® VL compared to Macintosh laryngoscope without the application of BURP (p < 0.05). In the DL group, 34.2% (n = 13) had a CL grade I, 36.8% (n = 14) had CL grade 2A, 13.2% had CL grade 2B (n = 5) and 15.8% (n = 6) had CL Grade 3 at the end of thyroidectomy. On the contrary, in the VL Group, 71.5% (n = 25) of the participants had a CL Grade I; whereas, 20% (n = 7) had a CL Grade 2A, 5.7% (n = 2) had CL grade 2B and 2.8% (n = 1) of participants had CL grade 3. The mean "time taken to achieve optimal view' was comparable between the two groups (DL = 39.16 ± 105.53 s vs. VL = 38.89 ± 20.69 s) (p = 0.988).The haemodynamic parameters, Patient reactivity score and complications were comparable between the two groups. The performance of Airtraq® videolaryngoscope, a channelled VL is better than conventional Macintosh laryngoscope in terms of the optimal glottic view obtained to rule out recurrent laryngeal nerve palsy at the end of thyroidectomy.

A Systematic Review and Meta-Analysis of Randomized Controlled Trials on Supine vs. Nonsupine Endotracheal Intubation

Background

This systematic review and meta-analysis of randomized controlled trials (RCTs) was performed to compare the safety and efficacy of supine vs. nonsupine positions during intubation.

Methods

Based on the literature from inception to October 2020, 13 studies with nonemergent intubation in supine and nonsupine positions were chosen using PRISMA and MOOSE protocols. Pooled estimates were calculated using random-effects models with 95% confidence interval (CI). The primary outcome was a successful intubation, attempt, and duration of intubation. The secondary outcome was adverse events (trauma and hypoxia). Bias was evaluated qualitatively, by visual analysis, and quantitatively through the Egger test.

Results

The final analysis included 13 clinical trials with 1,916 patients. The pooled success rates in the supine vs. lateral positions were 99.21% and 98.82%. The supine vs. semierect positions were 99.21% and 98.82%. The 1st attempt success rate in the supine vs. lateral position was 85.35% and 88.56% compared to 91.38% and 90.76% for the supine vs. semierect position. The rate of total adverse events in the supine position was 3.73% vs. 6.74% in the lateral position, and the rate of total adverse events in the supine position was 0.44% vs. 0.93% in semierect position. Low to substantial heterogeneity was noted in our analysis. Discussion. There is no significant difference between total successful intubations and success from 1st intubation attempt between supine and nonsupine positions. However, there are slightly higher rates of adverse events in nonsupine position. Addition of more recent studies on supine vs. nonsupine intubations would improve this study. Given these findings, it is important to develop more studies regarding different intubation positions and techniques with the aim of improving efficacy and decreasing adverse outcomes. Other. This review is not registered in a public database. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Comparison of video laryngoscopy with direct laryngoscopy for intubation success in critically ill patients: a systematic review and Bayesian network meta-analysis

Introduction

This review compares the efficacy of video laryngoscopy (VL) with direct laryngoscopy (DL) for successful tracheal intubation in critically ill or emergency-care patients.

Methods

We searched the MEDLINE, Embase, and Cochrane Library databases for randomized controlled trials (RCTs) that compared one or more video laryngoscopes to DL. Sensitivity analysis, subgroup analysis, and network meta-analysis were used to investigate factors potentially influencing the efficacy of VL. The primary outcome was the success rate of first-attempt intubation.

Results

This meta-analysis included 4244 patients from 22 RCTs. After sensitivity analysis, the pooled analysis revealed no significant difference in the success rate between VL and DL (VL vs. DL, 77.3% vs. 75.3%, respectively; OR, 1.36; 95% CI, 0.84-2.20; I² = 80%; low-quality evidence). However, based on a moderate certainty of evidence, VL outperformed DL in the subgroup analyses of intubation associated with difficult airways, inexperienced practitioners, or in-hospital settings. In the network meta-analysis comparing VL blade types, nonchanneled angular VL provided the best outcomes. The nonchanneled Macintosh video laryngoscope ranked second, and DL ranked third. Channeled VL was associated with the worst treatment outcomes.

Discussion

This pooled analysis found, with a low certainty of evidence, that VL does not improve intubation success relative to DL. Channeled VL had low efficacy in terms of intubation success compared with nonchanneled VL and DL.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=285702, identifier: CRD42021285702.

Predictors of difficult intubation when using a videolaryngoscope with an intermediate-angled blade during the first attempt: a prospective observational study

The curvature of a videolaryngoscope blade has been diversified from the standard macintosh-type to the hyperacute-angle-type, resulting in different performances. We aimed to determine the intubation success rate and identify predictors of difficult intubation when using an intermediate-angled videolaryngoscope in the first attempt of intubation under routine anaesthesia settings. We enrolled 808 patients between 19 and 79 years of age, scheduled for elective surgeries under general anaesthesia with orotracheal intubation from July 2017 to November 2018; patients who were candidates for awake intubation were excluded. We obtained patient demographic data and performed airway evaluation before induction of anaesthesia for elective surgeries. We used the UEScope for tracheal intubation with a hockey stick-shaped malleable stylet. The intubation time was defined as the total duration from the entry of the blade into the oropharynx to the detection of first end-tidal carbon dioxide capnogram; this duration was recorded along with the number of intubation attempts. Difficult intubation was defined as either > 60 s duration for tracheal intubation, or > 1 intubation attempt. The use of the UEScope demonstrated a 99.4% success rate for intubation; however, increased difficulties were observed in patients who were male, obese, had a short thyromental distance, limited mouth opening, and high upper-lip-bite test class. Despite the high intubation success rate using an intermediate-angled videolaryngoscope, we recommend preparing backup plans, considering the increased difficulty in patients with certain preoperative features.Clinical trial number and registry URL: Clinical Trials.gov Identifier: NCT03215823 (Date of registration: 12 July).

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.

Comparing the first-attempt tracheal intubation success of the hyperangulated McGrath® X-blade vs the Macintosh-type CMAC videolaryngoscope in patients with cervical immobilization: a two-centre randomized controlled trial

We compared the hyperangulated McGrath X-blade with the Macintosh-type CMAC videolaryngoscope through the use of manual in-line stabilization on patients. The primary hypothesis was that the McGrath X-blade has a similar first-attempt success rate as the CMAC videolaryngoscope. 210 patients of ASA physical status I to III, aged 21 to 80 years old, undergoing general anesthesia requiring tracheal intubation were prospectively recruited into this two-centre randomized controlled trial, from June 2016 to April 2019. Patients with history of or predicted difficult airway, pre-existing dental risks, BMI > 35 kg/m², cervical spondylosis or myelopathy, aspiration risks, patients who declined to participate or lacked the mental capacity to give consent were excluded. Participants were intubated using either hyperangulated McGrath X-blade (MGX) or Macintosh-type CMAC (CM) videolaryngoscopy, with manual in-line stabilization. Primary outcome measured was first-attempt tracheal intubation success. Secondary outcomes included overall successful intubation within 2 attempts or 120 s, time to intubation, glottic view obtained and intubation-related complications. First-attempt success rates were 71.4% in the MGX group vs. 79.0% in the CM group (p = 0.26), with an absolute difference of -7.6% (95%CI -20%, 5.0%, p value = 0.26), but this trial was underpowered to detect a difference. Overall success was 91.4% (MGX) vs. 92.4% (CM) (p > 0.99). The Cormack & Lehane laryngeal grade was superior in the MGX group compared to CM group (Grade I: MGX 44%, CM 23%; Grade II: MGX 53%, CM 45%; Grade III: MGX 3%, CM 32%; p < 0.001). The median time to intubation using the MGX was longer than the CM [MGX 55.5 s (42.1-78.3), CM 43.8 s (38-55.3); p < 0.001]. Our study did not demonstrate a significant difference in efficacy between the McGrath X-blade and the CMAC videolaryngoscope. In patients with manual in-line stabilization, no anticipated airway difficulty and in the hands of experienced operators, the McGrath X-blade provided superior glottic views but conferred no advantage over the C-MAC, with a longer median time to intubation compared to the CMAC videolaryngoscope.Trial registration: Australian New Zealand Clinical Trial Registry (ACTRN12616000668404).

Evaluation of transmitted glow point at a priori chosen depth (1 cm below vocal cords) for lightwand intubation: a prospective observational study

Objective

When performing lightwand intubation, an improper transmitted glow position before tube advancement can cause intubation failure or laryngeal injury. This study was performed to explore the transmitted glow point corresponding to a priori chosen depth for lightwand intubation.

Methods

Before lightwand intubation, we marked the transmitted glow point from a bronchoscope on the neck when it reached 1 cm below the vocal cords. Lightwand intubation was then performed using this marking point. The distances from the mark to the upper border of the thyroid cartilage, upper border of the cricoid cartilage, and suprasternal notch were measured.

Results

In total, 107 patients were enrolled. The success rate of lightwand intubation using the mark was 93.5% (95% confidence interval, 88.7%–99.2%) at the first attempt. The marking point was placed 12.0 mm (95% confidence interval, 10.6–13.4 mm) below the upper border of the cricoid cartilage.

Conclusion

Anaesthesiologists should be aware of the appropriate point of the transmitted glow on the patient’s neck when performing lightwand intubation. We suggest that this point is approximately 1 cm below the upper border of the cricoid cartilage.

Trial registration: ClinicalTrials.gov NCT03480035

Time to adapt in the pandemic era: a prospective randomized non -inferiority study comparing time to intubate with and without the barrier box

Background

The challenges posed by the spread of COVID-19 disease through aerosols have compelled anesthesiologists to modify their airway management practices. Devices such as barrier boxes are being considered as potential adjuncts to full PPE’s to limit the aerosol spread. Usage of the barrier box raises concerns of delay in time to intubate (TTI). We designed our study to determine if using a barrier box with glidescope delays TTI within acceptable parameters to make relevant clinical conclusions.

Methods

Seventy-eight patients were enrolled in this prospective non-inferiority controlled trial and were randomly allocated to either group C (without the barrier box) or the study group BB (using barrier box). The primary measured endpoint is time to intubate (TTI), which is defined as time taken from loss of twitches confirmed with a peripheral nerve stimulator to confirmation of end-tidal CO _2. 15 s was used as non-inferiority margin for the purpose of the study. We used an unpaired two-sample single-sided t-test to test our non- inferiority hypothesis (H ₀: Mean TTI diff ≥15 s, H _A: Mean TTI diff < 15 s). Secondary endpoints include the number of attempts at intubation, lowest oxygen saturation during induction, and the need for bag-mask ventilation.

Results

Mean TTI in group C was 42 s (CI 19.2 to 64.8) vs. 52.1 s (CI 26.1 to 78) in group BB. The difference in mean TTI was 10.1 s (CI -∞ to 14.9). We rejected the null hypothesis and concluded with 95% confidence that the difference of the mean TTI between the groups is less than < 15 s (95% CI -∞ to 14.9,p = 0.0461). Our induction times were comparable (67.7 vs. 65.9 s).100% of our patients were intubated on the first attempt in both groups. None of our patients needed rescue breaths.

Conclusions

We conclude that in patients with normal airway exam, scheduled for elective surgeries, our barrier box did not cause any clinically significant delay in TTI when airway manipulation is performed by well-trained providers.

The study was retrospectively registered at clinicaltrials.gov (NCT04411056) on May 27, 2020.

Video Versus Direct Laryngoscopy for Inpatient Emergency Intubation in Adults

BACKGROUND

Emergency intubation carries a higher risk of complications than elective airway management. Video laryngoscopy (VL) could potentially improve patient safety. The goal of this study was to determine whether VL is superior to direct laryngoscopy for the emergency intubation of adults in the inpatient setting.

METHODS

Pertinent studies were retrieved by a systematic literature search in the MEDLINE, Embase, and CENTRAL databases. The selection of studies, data extraction, and assessment of the potential for bias were carried out independently by two of the authors. Effect sizes were reported as odds ratios (OR) or mean differences (MD). The primary endpoint was successful intubation at the first attempt. Further variables were considered as secondary endpoints.

RESULTS

1098 titles and abstracts were retrieved, and the full texts of 43 articles were examined. Eight randomized and controlled trials, with a total of 1796 patients, were analyzed. VL was not found to confer any statistically significant advantage with respect to successful intubation at the first attempt (OR 0.72, 95% confidence interval [0.47; 1.12]) or with respect to the time to successful intubation (MD -8.99 seconds [-24.00; 6.01]). On the other hand, the use of VL was significantly associated with a lower number of intubation attempts (MD -0.17 [-0.31; -0.03]) and with a lower frequency of esophageal intubation (OR 0.27 [0.10; 0.75]).

CONCLUSION

The routine use of VL for airway management in emergency medicine might improve patient safety, as VL is associated with a lower number of intubation attempts and with a lower frequency of esophageal intubation. Further randomized controlled trials are needed before any definitive conclusions can be drawn about the advantages of video laryngoscopy.

Comparison of Pentax Airway Scope and Macintosh laryngoscope for orotracheal intubation in children: A randomised non-inferiority trial

BACKGROUND

Pentax Airway Scope (AWS) is a recently developed videolaryngoscope for use in both normal and difficult airways, yet its use in paediatric patients has not been established. The purpose of this study was to evaluate the efficacy of the Pentax AWS regarding intubation time, laryngeal view and ease of intubation in paediatric patients with normal airway, compared to Macintosh laryngoscope.

METHOD

A total of 136 paediatric patients aged 1-10 with American Society of Anaesthesiologists physical status I or II undergoing general anaesthesia were randomly allocated into two groups: Macintosh laryngoscope (n = 68) and Pentax Airway Scope (n = 68). Primary outcome was intubation time. Cormack-Lehane laryngeal view grade, application of optimal laryngeal external manipulation, intubation difficulty scale, intubation failure rate and adverse events were also measured.

RESULT

No significant difference was observed between the two groups regarding intubation time (P = 0.713). As for the laryngeal view grade, the Pentax group resulted in lower graded cases compared to the Macintosh group (P = 0.000). No optimal laryngeal external manipulation application was required in the Pentax group. Intubation difficulty scale resulted in lower values for Pentax group (P = 0.001). Failure rate was not different between the two groups (P = 0.619). There were significantly more teeth injury cases in the Pentax group than Macintosh group (P = 0.042).

CONCLUSION

Pentax Airway Scope provided similar intubation time and success rate, while improving laryngeal view, compared to Macintosh laryngoscopy in children with normal airway. When using Pentax AWS in children, however, the risk of teeth injury may increase.

Effect of Dynamic Versus Stylet-Guided Intubation on First-Attempt Success in Difficult Airways Undergoing Glidescope Laryngoscopy: A Randomized Controlled Trial

BACKGROUND

Tracheal intubation failure in patients with difficult airway is still not uncommon. While videolaryngoscopes such as the Glidescope offer better glottic vision due to an acute-angled blade, this advantage does not always lead to an increased success rate because successful insertion of the tube through the vocal cords may be the limiting factor. We hypothesize that combined use of Glidescope and fiberscope used only as a dynamic guide facilitates tracheal intubation compared to a conventional Glidescope technique with a preshaped nondynamic stylet.

METHODS

One hundred sixty adult patients with predicted difficult airway were randomly assigned to a conventional Glidescope (standard Glidescope group) or a combined Glidescope + fiberscope group intubation. In the Glidescope + fiberscope group under direct vision from the Glidescope, tracheal intubation was performed using the fiberscope as a guide without using fiberoptic vision, while in the standard Glidescope group, a conventional stylet-guided intubation technique was performed. We evaluated the rate of tracheal intubation success at first attempt as the primary end point (Fisher exact test). The difference between groups in airway injury, time to successful intubation, and the need for an alternative technique was also evaluated.

RESULTS

First-attempt intubation success was higher in the Glidescope + fiberscope group than in the standard Glidescope group (91% vs 67%; P = .0012; fragility index, 8; absolute risk reduction, 24% [95% CI, 12%-36%]). Median time to successful tracheal intubation was shorter in the Glidescope + fiberscope group (50 vs 64 seconds; P = .035). Airway injury rate was lower in the Glidescope + fiberscope group than in the standard Glidescope group (1% vs 11%; P = .035; fragility index, 1; absolute risk reduction, 10% [95% CI, 3%-18%]). Alternative rescue technique requirements to achieve tracheal intubation were higher in the standard Glidescope group (24% vs 4%; P < .001; fragility index, 7).

CONCLUSIONS

The use of a dynamic, flexible guide during a Glidescope laryngoscopy in patients with a predicted difficult airway compared to a standard intubation technique improves first-attempt intubation success, decreases the incidence of airway injury and time to successful intubation, as well as the need of an alternative technique to succeed.

A single-centre, randomised controlled feasibility pilot trial comparing performance of direct laryngoscopy versus videolaryngoscopy for endotracheal intubation in surgical patients

Introduction

Most trials comparing effectiveness of laryngoscopy technique use surrogate endpoints. Intubation success is a more appropriate endpoint for comparing effectiveness of techniques or devices. A large pragmatic clinical trial powered for intubation success has not yet been performed.

Methods

We tested the feasibility of a randomised controlled trial to compare the performance of direct laryngoscopy versus videolaryngoscopy for endotracheal intubation. The trial was conducted in the Department of Adult and Emergency Anaesthesia at the Auckland City Hospital, New Zealand. Patients over 18 years who required endotracheal intubation and were not known or predicted to be difficult to bag-mask ventilate were eligible for the study. Patients were excluded if they required rapid sequence induction, fibreoptic intubation or were unable to consent due to language barriers or cognitive impairment.

Patients were permuted block randomised in groups of 8 to either direct laryngoscopy (DL) or videolaryngoscopy (VL) for the technique of endotracheal intubation. Patients were blinded to laryngoscopic technique; the duty anaesthetist, outcome assessors and statistician were unblinded.

Feasibility was assessed on recruitment rate, adherence to group assignment and data completeness. Primary outcome was first-pass success rate, with secondary outcomes of time to intubation (seconds), Intubation Difficulty Score and complication rate.

Results

One hundred and six patients were randomised and 100 patient results were analysed. Completed data from patients randomised to the DL group (n = 49) was compared with those in the VL group (n = 51). Group adherence and data completeness were 100% and 97%, respectively. First-pass success rate was 83.7% in the direct laryngoscopy group and 72.5% in the videolaryngoscopy group (p = 0.18). Median time to intubation was significantly shorter for direct laryngoscopy when compared to videolaryngoscopy (34 s v 43 s, p = 0.038). Complications included mucosal trauma and airway bleeding which are recognised complications of endotracheal intubation.

Conclusion

A large, pragmatic, multicentre, randomised controlled trial comparing the relative effectiveness of direct laryngoscopy and indirect videolaryngoscopy is feasible.

Trial registration

Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN12615001267549

Comparison of three video laryngoscopes and direct laryngoscopy for emergency endotracheal intubation: a retrospective cohort study

OBJECTIVE

Video laryngoscopes are used for managing difficult airways. This study compared three video laryngoscopes' (Pentax-Airway Scope [Pentax], King Vision[King] and McGrath MAC [McGrath]) performances with the Macintosh direct laryngoscope (Macintosh) as emergency tracheal intubations (TIs) reference.

DESIGN

Retrospective cohort study.

SETTING

The emergency department (ED) and the intensive care unit (ICU) of two Japanese tertiary-level hospitals.

PARTICIPANTS

All consecutive video-recorded emergency TI cases in EDs and ICUs between December 2013 and June 2015.

PRIMARY OUTCOME MEASURES

The primary study endpoint was first-pass intubation success. A subgroup analysis examined the first-pass intubation success of expert versus non-expert operators. A logistic regression analysis was performed to identify the predictors of first-pass intubation success.

RESULTS

A total of 287 emergency TIs were included. The first-pass intubation success rates were 78%, 58%, 78% and 58% for the Pentax, King, McGrath and Macintosh instruments, respectively (p=0.004, Fisher's exact test). The non-expert operators' success rates were significantly higher (p=0.00004, Fisher's exact test) for the Pentax (87%) and McGrath (78%) instruments than that for the King (50%) and Macintosh (46%) instruments, unlike that of the experts (67%, 67%, 78% and 78% for Pentax, McGrath, King and Macintosh, respectively; p=0.556, Fisher's exact test). After TI indication, difficult airway characteristics, and expert versus non-expert operator parameters adjustments, the Pentax (OR=3.422, 95% CI 1.551 to 7.550; p=0.002) and McGrath (OR= 3.758, CI 1.640 to 8.612; p=0.002) instruments showed significantly higher first-pass intubation success odds when compared with the Macintosh laryngoscope (reference, OR=1). The King instrument, however, (OR=1.056; 95% CI 0.487 to 2.289, p=0.889) failed to show any significant superiority.

CONCLUSION

The Pentax and McGrath laryngoscopes showed significantly higher emergency TI first-pass intubation success rates than the King laryngoscope when compared with the Macintosh laryngoscope, especially for non-expert operators.

TRIAL REGISTRATION NUMBER

UMIN000027925; Results.

Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation: a Cochrane Systematic Review

Difficulties with tracheal intubation commonly arise and impact patient safety. This systematic review evaluates whether videolaryngoscopes reduce intubation failure and complications compared with direct laryngoscopy in adults. We searched CENTRAL, MEDLINE, Embase and clinicaltrials.gov up to February 2015, and conducted forward and backward citation tracking. We included randomized controlled trials that compared adult patients undergoing laryngoscopy with videolaryngoscopy or Macintosh laryngoscopy. We did not primarily intend to compare individual videolaryngoscopes. Sixty-four studies (7044 participants) were included. Moderate quality evidence showed that videolaryngoscopy reduced failed intubations (Odds Ratio (OR) 0.35, 95% Confidence Interval (CI) 0.19-0.65) including in participants with anticipated difficult airways (OR 0.28, 95% CI 0.15-0.55). There was no evidence of reduction in hypoxia or mortality, but few studies reported these outcomes. Videolaryngoscopes reduced laryngeal/airway trauma (OR 0.68, 95% CI 0.48-0.96) and hoarseness (OR 0.57, 95% CI 0.36-0.88). Videolaryngoscopy increased easy laryngeal views (OR 6.77, 95% CI 4.17-10.98) and reduced difficult views (OR 0.18, 95% CI 0.13-0.27) and intubation difficulty, typically using an 'intubation difficulty score' (OR 7.13, 95% CI 3.12-16.31). Failed intubations were reduced with experienced operators (OR 0.32, 95% CI 0.13-0.75) but not with inexperienced users. We identified no difference in number of first attempts and incidence of sore throat. Heterogeneity around time for intubation data prevented meta-analysis. We found evidence of differential performance between different videolaryngoscope designs. Lack of data prevented analysis of impact of obesity or clinical location on failed intubation rates. Videolaryngoscopes may reduce the number of failed intubations, particularly among patients presenting with a difficult airway. They improve the glottic view and may reduce laryngeal/airway trauma. Currently, no evidence indicates that use of a videolaryngoscope reduces the number of intubation attempts or the incidence of hypoxia or respiratory complications, and no evidence indicates that use of a videolaryngoscope affects time required for intubation.

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

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.

Incidence and severity of postoperative sore throat: a randomized comparison of Glidescope with Macintosh laryngoscope

BACKGROUND

Postoperative sore throat (POST) is a common problem following endotracheal (ET) intubation during general anesthesia. The objective was to compare the incidence and severity of POST during routine intubation with Glidescope (GL) and Macintosh laryngoscope (MCL).

METHODS

One hundred forty adult patients ASA I and II with normal airway, scheduled to undergo elective surgery under GA requiring ET intubation were enrolled in this prospective randomized study and were randomly divided in two groups, GL and MCL. Incidence and severity of POST was evaluated at 0, 6, 12 and 24 h after surgery.

RESULTS

At 0 h, the incidence of POST was more in MCL than GL (n = 41 v.s n = 22, P = 0.001), and also at 6 h after surgery (n = 37 v.s n = 23, P = 0.017). Severity of POST was more at 0, 6 and 12 h after surgery in MCL (P < 0.001, P = 0.001, P = 0.004 respectively).

CONCLUSIONS

Routine use of GL for ET tube placement results in reduction in the incidence and severity of POST compared to MCL.

TRIAL REGISRATION

ClinicalTrials.gov NCT02848365 . Retrospectively Registered (Date of registration: July, 2016).

Efficacy of Pentax airway scope versus Macintosh laryngoscope when used by novice personnel: A prospective randomized controlled study

Objective

To determine whether intubation education using the Pentax Airway Scope (AWS) in normal airways is more useful than direct laryngoscopy (Macintosh laryngoscope) in novice personnel.

Methods

Eleven intern doctors without intubation experience performed 60 sequential intubations with each device on a manikin and 10 sequential intubations in adult patients. The time required for successful intubation, percentage of glottic opening (POGO) score, number of intubation attempts, and number of dental injuries were analyzed for each intubation technique.

Results

The mean (standard deviation) time required for successful intubation decreased as the number of intubations increased and was significantly shorter with the Pentax AWS than direct laryngoscope [22.6 (7.3) vs. 29.6 (10.0) and 33.0 (8.0) vs. 44.7 (5.6) s, respectively] in both the manikin and clinical studies. The Pentax AWS was also associated with higher POGO scores than the direct laryngoscope [81.7 (8.9) vs. 55.1 (13.2) and 80.9 (9.7) vs. 49.6 (16.5), respectively] and fewer intubation attempts. Fewer dental injuries occurred with the Pentax AWS in the manikin study.

Conclusions

Novices performed intubation more rapidly and easily with an improved laryngeal view using the Pentax AWS. We suggest that intubation education with video laryngoscopy should be mandatory along with direct laryngoscope training.

Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation

BACKGROUND

Successful tracheal intubation during general anaesthesia traditionally requires a line of sight to the larynx attained by positioning the head and neck and using a laryngoscope to retract the tongue and soft tissues of the floor of the mouth. Difficulties with intubation commonly arise, and alternative laryngoscopes that use digital and/or fibreoptic technology have been designed to improve visibility when airway difficulty is predicted or encountered. Among these devices, a rigid videolaryngoscope (VLS) uses a blade to retract the soft tissues and transmits a lighted video image to a screen.

OBJECTIVES

Our primary objective was to assess whether use of videolaryngoscopy for tracheal intubation in adults requiring general anaesthesia reduces risks of complications and failure compared with direct laryngoscopy. Our secondary aim was to assess the benefits and risks of these devices in selected population groups, such as adults with obesity and those with a known or predicted difficult airway.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase on 10 February 2015. Our search terms were relevant to the review question and were not limited by outcomes. We carried out clinical trials register searches and forward and backward citation tracking. We reran the search on 12 January 2016; we added potential new studies of interest from the 2016 search to a list of 'Studies awaiting classification', and we will incorporate these studies into the formal review during the review update.

SELECTION CRITERIA

We considered all randomized controlled trials and quasi-randomized studies with adult patients undergoing laryngoscopy performed with a VLS or a Macintosh laryngoscope in a clinical, emergency or out-of-hospital setting. We included parallel and cross-over study designs.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data, consulting a third review author to resolve disagreements. We used standard Cochrane methodological procedures, including assessment of risk of bias.

MAIN RESULTS

We included 64 studies identified during the 2015 search that enrolled 7044 adult participants and compared a VLS of one or more designs with a Macintosh laryngoscope. We identified 38 studies awaiting classification and seven ongoing studies. Of the 64 included studies, 61 included elective surgical patients, and three were conducted in an emergency setting. Among 48 studies that included participants without a predicted difficult airway, 15 used techniques to simulate a difficult airway. Seven recruited participants with a known or predicted difficult airway, and the remaining studies did not specify or included both predicted and not predicted difficult airways. Only two studies specifically recruited obese participants. It was not possible to blind the intubator to the device, and we noted a high level of inevitable heterogeneity, given the large number of studies.Statistically significantly fewer failed intubations were reported when a VLS was used (Mantel-Haenszel (M-H) odds ratio (OR), random-effects 0.35, 95% confidence Interval (CI) 0.19 to 0.65; 38 studies; 4127 participants), and fewer failed intubations occurred when a VLS was used in participants with an anticipated difficult airway (M-H OR, random-effects 0.28, 95% CI 0.15 to 0.55; six studies; 830 participants). We graded the quality of this evidence as moderate on the basis of the GRADE system. Failed intubations were fewer when a VLS was used in participants with a simulated difficult airway (M-H OR, random-effects 0.18, 95% CI 0.04 to 0.77; nine studies; 810 participants), but groups with no predicted difficult airway provided no significant results (M-H OR, random-effects 0.61, 95% CI 0.22 to 1.67; 19 studies; 1743 participants).Eight studies reported on hypoxia, and only three of these described any events; results showed no differences between devices for this outcome (M-H OR, random-effects 0.39, 95% CI 0.10 to 1.44; 1319 participants). Similarly, few studies reported on mortality, noting no differences between devices (M-H OR, fixed-effect 1.09, 95% CI 0.65 to 1.82; two studies; 663 participants), and only one study reporting on the occurrence of respiratory complications (78 participants); we graded these three outcomes as very low quality owing to lack of data. We found no statistically significant differences between devices in the proportion of successful first attempts (M-H OR, random-effects 1.27, 95% CI 0.77 to 2.09; 36 studies; 4731 participants) nor in those needing more than one attempt. We graded the quality of this evidence as moderate. Studies reported no statistically significant differences in the incidence of sore throat in the postanaesthesia care unit (PACU) (M-H OR, random-effects 1.00 (95% CI 0.73 to 1.38); 10 studies; 1548 participants) nor at 24 hours postoperatively (M-H OR random-effects 0.54, 95% CI 0.27 to 1.07; eight studies; 844 participants); we graded the quality of this evidence as moderate. Data combined to include studies of cross-over design revealed statistically significantly fewer laryngeal or airway traumas (M-H OR, random-effects 0.68, 95% CI 0.48 to 0.96; 29 studies; 3110 participants) and fewer incidences of postoperative hoarseness (M-H OR, fixed-effect 0.57, 95% CI 0.36 to 0.88; six studies; 527 participants) when a VLS was used. A greater number of laryngoscopies performed with a VLS achieved a view of most of the glottis (M-H OR, random-effects 6.77, 95% CI 4.17 to 10.98; 22 studies; 2240 participants), fewer laryngoscopies performed with a VLS achieved no view of the glottis (M-H OR, random-effects 0.18, 95% CI 0.13 to 0.27; 22 studies; 2240 participants) and the VLS was easier to use (M-H OR, random-effects 7.13, 95% CI 3.12 to 16.31; seven studies; 568 participants).Although a large number of studies reported time required for tracheal intubation (55 studies; 6249 participants), we did not present an effects estimate for this outcome owing to the extremely high level of statistical heterogeneity (I2 = 96%).

AUTHORS' CONCLUSIONS

Videolaryngoscopes may reduce the number of failed intubations, particularly among patients presenting with a difficult airway. They improve the glottic view and may reduce laryngeal/airway trauma. Currently, no evidence indicates that use of a VLS reduces the number of intubation attempts or the incidence of hypoxia or respiratory complications, and no evidence indicates that use of a VLS affects time required for intubation.

Direct Versus Video Laryngoscopy Using the C-MAC for Tracheal Intubation in the Emergency Department, a Randomized Controlled Trial

BACKGROUND

Direct laryngoscopy (DL) has long been the most common approach for emergency endotracheal intubation, although the use of video laryngoscopy (VL) is becoming more widespread. Current observational data suggest that VL has higher first-pass success, although randomized trials are lacking.

OBJECTIVES

The objective was to compare first-pass success in patients undergoing emergency intubation with DL or VL using a C-MAC device.

METHODS

This was an open-label, prospective, randomized, controlled trial in an academic emergency department of patients undergoing emergency intubation with a plan of DL for the first attempt. Patients were randomly assigned in a 1:1 ratio to either DL or VL using a C-MAC device for the first intubation attempt. The primary outcome was first-pass success. Secondary outcomes included time to intubation, development of aspiration pneumonia, and hospital length of stay (LOS). The study was registered at Clinicaltrials.gov, number NCT01710891.

RESULTS

A total of 198 patients were enrolled and intubated with either DL (n = 95) or VL (n = 103). First-attempt success was 86 and 92% for the DL and VL groups, respectively (difference = -5.9%, 95% confidence interval = -14.5% to 2.7%, p = 0.18). Time to intubation, rates of aspiration pneumonia, and hospital LOS were not different between the two groups.

CONCLUSIONS

In patients undergoing emergency intubation in whom DL was planned for the first attempt, we did not detect a difference between VL or DL using the C-MAC device in first-pass success, duration of intubation attempt, aspiration pneumonia, or hospital LOS.

Facial Image Analysis for Fully Automatic Prediction of Difficult Endotracheal Intubation

GOAL

Difficult tracheal intubation is a major cause of anesthesia-related injuries with potential life threatening complications. Detection and anticipation of difficult airway in the preoperative period is, thus, crucial for the patients' safety. We propose an automatic face-analysis approach to detect morphological traits related to difficult intubation and improve its prediction.

METHODS

For this purpose, we have collected a database of 970 patients including photos, videos, and ground truth data. Specific statistical face models have been learned using the faces in our database providing an automated parametrization of the facial morphology. The most discriminative morphological features are selected through the importance ranking provided by the random forest algorithm. The random forest approach has also been used to train a classifier on these selected features. We compare a threshold tuning method based on class prior with two methods, which learn an optimal threshold on a training set for tackling the inherent imbalanced nature of the database.

RESULTS

Our fully automated method achieves an AUC of 81.0% in a simplified experimental setup, where only easy and difficult patients are considered. A further validation on the entire database has proven that our method is applicable for real-world difficult intubation prediction, with AUC = 77.9%.

CONCLUSION

The system performance is in line with the state-of-the-art medical diagnosis, based on ratings provided by trained anesthesiologists, whose assessment is guided by an extensive set of criteria.

SIGNIFICANCE

We present the first completely automatic and noninvasive difficult intubation detection system that is suitable for use in clinical settings.

Advances in Laryngoscopy

Recent technological advances have made airway management safer. Because difficult intubation remains challenging to predict, having tools readily available that can be used to manage a difficult airway in any setting is critical. Fortunately, video technology has resulted in improvements for intubation performance while using laryngoscopy by various means. These technologies have been applied to rigid optical stylets, flexible intubation scopes, and, most notably, rigid laryngoscopes. These tools have proven effective for the anticipated difficult airway as well as the unanticipated difficult airway.

Does the incidence of sore throat postoperatively increase with the use of a traditional intubation blade or the GlideScope?

STUDY OBJECTIVE

The GlideScope video-guided laryngoscope is an alternative standard of care for rescue laryngoscopies when direct laryngoscopy is unsuccessful. During postoperative checks by an anesthesiologist, it was noticed that patients who reported sore throat often required GlideScope laryngoscopy. Consequently, it is difficult to determine whether postoperative sore throats are caused by irritation inflicted by multiple laryngoscopic attempts or the actual utilization of the GlideScope itself. The goal of this study was to determine whether the use of the GlideScope leads to a greater or lesser incidence of sore throat when compared with traditional laryngoscope blades used for intubation.

DESIGN

Eligible patients scheduled for elective inpatient surgeries requiring endotracheal tube intubation were enrolled into this single-blinded prospective cohort study. χ(2) Test, Fisher exact test, and t tests were used to compare differences across the primary end point and other demographic categories.

SETTING

Operating rooms and postanesthesia recovery unit, Albany Medical Center, Albany, NY.

PATIENTS

There were a total of 151 patients with American Society of Anesthesiologists grades 1 to 3 included in the study.

INTERVENTIONS

Eighty-one patients were randomized to a control group that received traditional laryngoscopy via Macintosh/Miller blades and 70 patients received video-guided intubation via the GlideScope.

MEASUREMENTS

The incidence of postoperative sore throat was recorded via a yes/no questionnaire within 24 hours after extubation. Secondary parameters such as provider type, sex, and perceived difficulty were also recorded.

MAIN RESULTS

There was no significant difference in the proportion of patients reporting sore throat by type of blade used (Mac/Miller 36.3% vs GlideScope 32.4%, P = .619). For secondary outcomes, women were significantly more likely to report sore throat as compared with men (men 24.3% vs women 43.2%, P = .015), and the provider type was significantly associated with the occurrence of postoperative sore throat (attendings 26.8% vs certified registered nurse anesthetists 52.3% vs third-year clinical anesthesia residents 30%, P = .012).

CONCLUSIONS

Use of the GlideScope videolaryngoscopy was not significantly associated with increased occurrence of postoperative sore throat when compared with traditional intubation techniques. Our results may enable more trainees to acquire intubation skills with the GlideScope during an initial intubation attempt in patients with American Society of Anesthesiologist grades 1 to 3, with optimization of patient satisfaction in respect to postoperative sore throats. In addition, a provider's choice of intubation technique based on either Macintosh/Miller blades or the GlideScope does not significantly impact a patient's risk of postoperative sore throat.

Comparison of the Airtraq laryngoscope and the GlideScope for double-lumen tube intubation in patients with predicted normal airways: a prospective randomized trial

BACKGROUND

The Airtraq laryngoscope and the GlideScope are commonly used in many airway scenarios. However, their features have not been fully described for double-lumen tube intubation. A prospective randomized study was designed to compare their intubation performances in thoracic surgery patients.

METHODS

Seventy ASA physical status I and II patients with predicted normal airway were scheduled for thoracic surgeries with double-lumen tube intubation. They were randomly assigned to one of two groups and intubated with either the Airtraq laryngoscope (group A, n = 35) or the GlideScope (group G, n = 35). Airway assessments were performed prior to anesthesia, and all patients were induced with a standard anesthetic regimen. The Cormack-Lehane grades were initially evaluated with a Macintosh laryngoscope and subsequently with the group-specific laryngoscope before intubation. Intubation time was recorded as the primary outcome. The Cormack-Lehane grade, the success of the first intubation attempt, the intubation difficulty scales and ease of tube advancement were noted. Hemodynamic variables during intubation and incidence of post-operative sore throat were documented as well.

RESULTS

The intubation time of group A was shorter than that of group G (36.6 ± 20.2 s vs. 54.6 ± 25.7 s, p = 0.002). The Cormack-Lehane grade (I/II/III/IV) was significantly better in group A (33/2/0/0 vs. 28/7/0/0, p = 0.042). The mean arterial pressure and heart rate rose to higher levels during intubation with the GlideScope than with the Airtraq laryngoscope. The success of the first intubation attempt and the intubation difficulty scales were comparable between the two groups. The numbers of patients who experienced postoperative sore throat were similar (6 vs. 8) in the two groups.

CONCLUSIONS

Compared with the GlideScope, the specially designed Airtraq laryngoscope might be more suitable for double-lumen tube intubations in patients with predicted normal airway.

TRIAL REGISTRATION

www.chictr.org Identifier: ChiCTR-TRC-11001628.

Efficacy of the Airway Scope (Pentax-AWS) for training in pediatric intubation

BACKGROUND

The aim of this study was to evaluate the efficacy of the Airway Scope (AWS) in the training of residents in pediatric intubation using high-performance simulators.

METHODS

A total of 51 residents were recruited. Baby SIM is a high-performance simulator with a built-in physiological program that reduces SpO2 if it stops breathing and increases SpO2 if assisted ventilation is provided using a bag mask. Therefore, real-life situations can be simulated with this program. Trial 1: after respiration of Baby SIM was stopped, intubation was initiated. If the intubation time was too long, a built-in physiological program led to desaturation. The intubation time and frequency of SpO2 <90% were compared between the Miller laryngoscope and the AWS. Trial 2: an ALS Baby, which is more difficult to intubate than Baby SIM, was used in comparison of intubation time and frequency of failure to intubate within 60 s between the two laryngoscopes. Mann-Whitney and chi-squared tests were used for statistical analysis.

RESULTS

Intubation time was significantly shorter using the AWS than the Miller laryngoscope in both trials. Furthermore, desaturation occurred significantly less frequently with the AWS than the Miller laryngoscope in trial 1. The frequency of intubation failure within 60 s was also significantly lower for the AWS than the Miller laryngoscope in trial 2.

CONCLUSION

The inclusion of both direct laryngoscopy and the AWS in pediatric resident programs might give pediatricians the option of using a safer and more reliable intubation method for children.

Video laryngoscopes and the obstetric airway

The pitfalls surrounding securing the airway in the obstetric patient are well documented. From Tunstall's original failed intubation drill onwards, there has been progress both in recognition of the difficulties of airway management in the pregnant patient and development of algorithms to enhance patient safety. Current trends in obstetric anaesthesia have resulted in a significant decrease in exposure of anaesthetists, especially trainees, to caesarean section under general anaesthesia, compounding the difficulties in safely managing the airway. Video laryngoscopes have recently appeared in airway algorithms. They improve glottic visualisation and are useful in the management of the difficult non-obstetric airway, including those in morbidly obese patients and in the setting of a rapid-sequence induction. There is growing interest in the potential use of video laryngoscopes in the obstetric population and as a teaching tool to maximise training opportunities.

The Availability of Advanced Airway Equipment and Experience with Videolaryngoscopy in the UK: Two UK Surveys

Fibreoptic intubation, high frequency jet ventilation, and videolaryngoscopy form part of the Royal College of Anaesthetists compulsory higher airway training module. Curriculum delivery requires equipment availability and competent trainers. We sought to establish (1) availability of advanced airway equipment in UK hospitals (Survey I) and (2) if those interested in airway management (Difficult Airway Society (DAS) members) had access to videolaryngoscopes, their basic skill levels and teaching competence with these devices and if they believed that videolaryngoscopy was replacing conventional or fibreoptic laryngoscopy (Survey II). Data was obtained from 212 hospitals (73.1%) and 554 DAS members (27.6%). Most hospitals (202, 99%) owned a fiberscope, 119 (57.5%) had a videolaryngoscope, yet only 62 (29.5%) had high frequency jet ventilators. DAS members had variable access to videolaryngoscopes with Airtraq 319 (59.6%) and Glidescope 176 (32.9%) being the most common. More DAS members were happy to teach or use videolaryngoscopes in a difficult airway than those who had used them more than ten times. The majority rated Macintosh laryngoscopy as the most important airway skill. Members rated fibreoptic intubation and videolaryngoscopy skills equally. Our surveys demonstrate widespread availability of fibreoptic scopes, limited availability of videolaryngoscopes, and limited numbers of experienced videolaryngoscope tutors.

Awake tracheal intubation using Pentax airway scope in 30 patients: A Case series

BACKGROUND AND AIMS

Pentax airway scope (AWS) has been successfully used for managing difficult intubations. In this case series, we aimed to evaluate the success rate and time taken to complete intubation, when AWS was used for awake tracheal intubation.

METHODS

We prospectively evaluated the use of AWS for awake tracheal intubation in 30 patients. Indication for awake intubation, intubation time, total time to complete tracheal intubation, laryngoscopic view (Cormack and Lehane grade), total dose of local anaesthetic used, anaesthetists rating and patient's tolerance of the procedure were recorded.

RESULTS

The procedure was successful in 25 out of the 30 patients (83%). The mean (standard deviation) intubation time and total time to complete the tracheal intubation was 5.4 (2.4) and 13.9 (3.7) min, respectively in successful cases. The laryngeal view was grade 1 in 24 and grade 2 in one of 25 successful intubations. In three out of the five patients where the AWS failed, awake tracheal intubation was successfully completed with the assistance of flexible fibre optic scope (FOS).

CONCLUSION

Awake tracheal intubation using AWS was successful in 83% of patients. Success rate can be further improved using a combination of AWS and FOS. Anaesthesiologists who do not routinely use FOS may find AWS easier to use for awake tracheal intubation using an oral route.

A review of video laryngoscopes relevant to the intensive care unit

The incidence of difficult direct intubation in the intensive care unit (ICU) is estimated to be as high as 20%. Recent advances in video-technology have led to the development of video laryngoscopes as new intubation devices to assist in difficult airway management. Clinical studies indicate superiority of video laryngoscopes relative to conventional direct laryngoscopy in selected patients. They are therefore an important addition to the armamentarium of any clinician performing endotracheal intubation. We present a practical review of commonly available video laryngoscopes with respect to design, clinical efficacy, and safety aspects relevant to their use in the ICU.

Pentax Airway Scope® vs Macintosh laryngoscope for tracheal intubation in adult patients: a systematic review and meta-analysis

The Pentax Airway Scope(®) is a single-use optical videolaryngoscope designed to assist with difficult tracheal intubation. We systematically reviewed the efficacy of the Pentax Airway Scope with that of a conventional laryngoscope for tracheal intubation in adults with 'normal' and 'difficult' airways. We included 17 randomised controlled trials with a total of 1801 participants. We used the DerSimonian and Laird random-effects model to calculate pooled relative risk or weighted mean differences. The relative risk (95% CI) of a Cormack-Lehane grade-1 laryngeal view was 2.40 (1.76-2.49) with the Pentax Airway Scope compared with the Macintosh laryngoscope, p < 0.00001. We found no other differences between the two laryngoscopes. Despite a superior laryngeal view, the Pentax Airway Scope provides little clinical benefit over the conventional laryngoscope.

Comparison of the conventional CMAC and the D-blade CMAC with the direct laryngoscopes in simulated cervical spine injury--a manikin study

BACKGROUND

CMAC videolaryngoscope has recently been introduced for videoscope guided intubation. The aim of our study was to compare and evaluate the efficacy of the conventional blade and the angulated D blade of the CMAC videolaryngoscope with the direct laryngoscopes in simulated cervical spine injury patients on the airway manikin.

MATERIALS AND METHODS

Following power analysis, 33 resident doctors were enrolled to perform endotracheal intubation using all the 4 different laryngoscopes namely the Macintosh laryngoscope, McCoy laryngoscope, conventional CMAC videolaryngoscope and the D blade of the CMAC videolaryngoscopes on the airway manikin in simulated cervical spine injury. The demographic variables of the resident doctors were recorded. The outcomes measured included vocal cord visualization (Cormack-Lehane grading), time taken to intubate, number of attempts for successful intubation and optimizing maneuvers required.

RESULTS

The use of indirect videolaryngoscopes resulted in better glottic visualization in comparison to the direct laryngoscopes (CL-I) in 20/33 (60.6%) in the Macintosh group, 24/33 (72.7%) in McCoy group, 30/33 in (90.9%) in Vlc group and 32/33 (96.9%) in Vld group. The time taken to intubate averaged to 15.54±2.6 in Macintosh group, 18.90±4.47 in McCoy group, 20.21±7.9 in Vlc group and 27.42±9.09 in Vld group. The 1st attempt intubation success rate was 84.8% (Macintosh), 72.7% (McCoy), 90.9% (Vlc) and, 78.7% (Vld).

CONCLUSIONS

The overall performance of the conventional CMAC blade proved to be the best when compared with the D-blade CMAC, Macintosh blade and the McCoy blade for intubation in simulated cervical spine patients by anesthesia residents.

A comparison of the GlideScope video laryngoscope to the C-MAC video laryngoscope for intubation in the emergency department

STUDY OBJECTIVE

There is growing use of video laryngoscopy in US emergency departments (EDs). This study seeks to compare intubation success between the GlideScope video laryngoscope and the C-MAC video laryngoscope (C-MAC) in ED intubations.

METHODS

This was an analysis of quality improvement data collected during a 3-year period in an academic ED. After each intubation, the operator completed a standardized data form reporting patient demographics, indication for intubation, device(s) used, reason for device selection, difficult airway characteristics, number of attempts, and outcome of each attempt. An attempt was defined as insertion of the device into the mouth regardless of attempt at tube placement. The primary outcomes were first pass and overall intubation success. The study compared success rates between the GlideScope video laryngoscope and the C-MAC groups, using multivariable logistic regression and adjusting for potential confounders.

RESULTS

During the 3-year study period, there were 463 intubations, including 230 with the GlideScope video laryngoscope as the initial device and 233 with the C-MAC as the initial device. The GlideScope video laryngoscope resulted in first-pass success in 189 of 230 intubations (82.2%; 95% confidence interval [CI] 76.6% to 86.9%) and overall success in 221 of 230 intubations (96.1%; 95% CI 92.7% to 98.2%). The C-MAC resulted in first-pass success in 196 of 233 intubations (84.1%; 95% CI 78.8% to 88.6%) and overall success in 225 of 233 intubations (96.6%; 95% CI 93.4% to 98.5%). In a multivariate logistic regression analysis, the type of video laryngoscopic device was not associated with first-pass (odds ratio 1.1; 95% CI 0.6 to 2.1) or overall success (odds ratio 1.2; 95% CI 0.5 to 3.1).

CONCLUSION

In this study of video laryngoscopy in the ED, the GlideScope video laryngoscope and the C-MAC were associated with similar rates of intubation success.

A systematic review of the role of videolaryngoscopy in successful orotracheal intubation

BACKGROUND

The purpose of our study was to organize the literature regarding the efficacy of modern videolaryngoscopes in oral endotracheal intubation, then perform a quality assessment according to recommended external criteria and make recommendations for use.

METHODS

Inclusion criteria included devices with recent studies of human subjects. A total of 980 articles were returned in the initial search and 65 additional items were identified using cited references. After exclusion of articles failing to meet study criteria, 77 articles remained. Data were extracted according to the rate of successful intubation and improvement of glottic view compared with direct laryngoscopy. Studies were classified according to whether they primarily examined subjects with normal airways, possessing risk factors for difficult direct laryngoscopy, or following difficult or failed direct laryngoscopy.

RESULTS

The evidence of efficacy for videolaryngoscopy in the difficult airway is limited. What evidence exists is both randomized prospective and observational in nature, requiring a scheme that evaluates both forms and allows recommendations to be made.

CONCLUSIONS

In patients at higher risk of difficult laryngoscopy we recommend the use of the Airtraq, CTrach, GlideScope, Pentax AWS and V-MAC to achieve successful intubation. In difficult direct laryngoscopy (C&L >/= 3) we cautiously recommend the use of the Airtraq, Bonfils, Bullard, CTrach, GlideScope, and Pentax AWS, by an operator with reasonable prior experience, to achieve successful intubation when used in accordance with the ASA practice guidelines for management of the difficult airway. There is additional evidence to support the use of the Airtraq, Bonfils, CTrach, GlideScope, McGrath, and Pentax AWS following failed intubation via direct laryngoscopy to achieve successful intubation. Future investigation would benefit from precise qualification of the subjects under study, and an improvement in overall methodology to include randomization and blinding.

Observations on the assessment and optimal use of videolaryngoscopes

Due to the large number of videolaryngoscopes now available, it might be difficult for novice users to assess the various devices or use them optimally. We have collated the experiences of several airway management experts to assist in the assessment and optimal use of seven commonly used videolaryngoscopes. While all videolaryngoscopes have unique features, they can be broadly divided into those inserted via a midline approach over the tongue and those inserted laterally along the floor of the mouth. Videolaryngoscopes that are placed on the floor of the mouth displace the tongue antero-laterally and flatten the submandibular tissues. They generally require a conventional shaped bougie for tracheal intubation. Videolaryngoscopes that use the midline approach may have an in-built airway conduit for the tracheal tube or may require a 'J-shaped' stylet in the tracheal tube to negotiate the upper airway. This may cause difficulty when the tracheal tube is inserted through the glottis and the tip abuts the anterior wall of the subglottic space. Knowledge of the mechanism used by videolaryngoscopes to achieve laryngoscopy is essential for safe and successful tracheal intubation when using these devices.

A randomised trial comparing the CEL-100 videolaryngoscope(TM) with the Macintosh laryngoscope blade for insertion of double-lumen tubes

We performed a randomised trial comparing the CEL-100 videolaryngoscope(TM) with the Macintosh laryngoscope blade in 170 patients undergoing double-lumen tube placement for thoracic surgery. Compared with the Macintosh laryngoscope blade, use of the CEL-100 resulted in significantly more patients with a Cormack and Lehane Grade-1 laryngeal view (90.4% vs 61.0%, p < 0.001), a higher rate of successful intubation on the first attempt (92.8% vs 79.3%, p = 0.012), a lower median (IQR [range]) intubation difficulty score (0 (0-0 [0-60]) vs 15 (0-30 [0-80]), p < 0.001), a higher incidence of correct positioning of the tube (90.3% vs 79.2%, p = 0.041) and significantly fewer patients requiring external laryngeal pressure (19.3% vs 32.9%, p = 0.046). Median (IQR [range]) time to successful intubation was 45 (38-55 [22-132]) s with the CEL-100 compared with 51 (40-61 [30-160] s using the Macintosh laryngoscope blade. We conclude that the CEL-100 videolaryngoscope is superior to the Macintosh laryngoscope blade for double-lumen tube insertion.