Pentax-AWS, a new videolaryngoscope, is more effective than the Macintosh laryngoscope for tracheal intubation in patients with restricted neck movements: a randomized comparative study

Successful Tracheal Intubation With Airway Scope After Failure With McGrath

The use of video laryngoscopy is growing in patients with anatomical factors suggestive of a difficult airway. This case report describes the successful tracheal intubation of a 54-year-old female patient with limited mouth opening scheduled for third molar extraction under general anesthesia. The Airway scope (AWS) along with a gum-elastic bougie was used to secure the airway after failed direct laryngoscopy and video laryngoscopy using the McGrath MAC with an X-blade. The AWS has a J-shaped structure in which the blade approximates the curvature of the pharynx and larynx. This blade shape makes it easy to match the laryngeal axis with the visual field direction, enabling successful tracheal intubation even for patients with limited mouth opening. A major key to successful video laryngoscopy is to select a video laryngoscope based on the anatomical characteristics of patients with a difficult airway.

The Use of the Shikani Video-Assisted Intubating Stylet Technique in Patients with Restricted Neck Mobility

Among all the proposed predictors of difficult intubation defined by the intubation difficulty scale, head and neck movement (motility) stands out and plays as a crucial factor in determining the success rate and the degree of ease on endotracheal intubation. Aside from other airway tools (e.g., supraglottic airway devices), optical devices have been developed and applied for more than two decades and have shown their superiority to conventional direct laryngoscopes in many clinical scenarios and settings. Although awake/asleep flexible fiberoptic bronchoscopy is still the gold standard in patients with unstable cervical spines immobilized with a rigid cervical collar or a halo neck brace, videolaryngoscopy has been repeatedly demonstrated to be advantageous. In this brief report, for the first time, we present our clinical experience on the routine use of the Shikani video-assisted intubating stylet technique in patients with traumatic cervical spine injuries immobilized with a cervical stabilizer and in a patient with a stereotactic headframe for neurosurgery. Some trouble-shooting strategies for this technique are discussed. This paper demonstrates that the video-assisted intubating stylet technique is an acceptable alternative airway management method in patients with restricted or confined neck motility.

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.

Educational suitability of new channel-type video-laryngoscope with AI-based glottis guidance system for novices wearing personal-protective-equipment

The aim of this study was to determine which of 4 laryngoscopes, including A-LRYNGO, a newly developed channel-type video-laryngoscope with an embedded artificial intelligence-based glottis guidance system, is appropriate for tracheal intubation training in novice medical students wearing personal protective equipment (PPE).Thirty healthy senior medical school student volunteers were recruited. The participants underwent 2 tests with 4 laryngoscopes: Macintosh, McGrath, Pentax Airway-Scope and A-LRYNGO. The first test was conducted just after a lecture without any hands-on workshop. The second test was conducted after a one-on-one hands-on workshop. In each test, we measured the time required for tracheal intubation, intubation success rate, etc, and asked all participants to complete a short questionnaire.The time to completely insert the endotracheal tube with the Macintosh laryngoscope did not change significantly (P = .177), but the remaining outcomes significantly improved after the hands-on workshop (all P < .05). Despite being novice practitioners with no intubation experience and wearing PPE, the, 2 channel-type video-laryngoscopes were associated with good intubation-related performance before the hands-on workshop (all P < .001). A-LRYNGO's artificial intelligence-based glottis guidance system showed 93.1% accuracy, but 20.7% of trials were guided by the vocal folds.To prepare to manage the airway of critically ill patients during the coronavirus disease 2019 pandemic, a channel-type video-laryngoscope is appropriate for tracheal intubation training for novice practitioners wearing PPE.

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.

Difficult Airway Management in Adult COVID-19 Patients: Statement by the Society of Airway Management

The COVID-19 disease, caused by Coronavirus SARS-CoV-2, often results in severe hypoxemia requiring airway management. Because SARS CoV-2 virus is spread via respiratory droplets, bag-mask ventilation, intubation, and extubation may place health care workers (HCW) at risk. While existing recommendations address airway management in patients with COVID-19, no guidance exists specifically for difficult airway management. Some strategies normally recommended for difficult airway management may not be ideal in the setting of COVID-19 infection. To address this issue the Society for Airway Management (SAM) created a task force to review existing literature and current Practice Guidelines for management of the difficult airway by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. SAM task force created recommendations for management of known or suspected difficult airway in the setting of known or suspected COVID-19 infection. The goal of the task force was to optimize successful airway management while minimizing exposure risk. Each member conducted a literature review on specific clinical practice section utilizing standard search engines (PubMed, Ovid, Google Scholar). Existing recommendations and evidence for difficult airway management in COVID-19 context were developed. Each specific recommendation was discussed among task force members and modified until unanimously approved by all task force members. Elements of AGREE Reporting Checklist for dissemination of clinical practice guidelines were utilized to develop this statement. Airway management in the COVID-19 patient increases HCW exposure risk. and difficult airway management often takes longer, may involve multiple procedures with aerosolization potential, strict adherence to personal protective equipment (PPE) protocols is mandatory to reduce risk to providers. When patient's airway risk assessment suggests awake tracheal intubation is an appropriate choice of technique, procedures that may cause increased aerosolization of secretions should be avoided. Optimal preoxygenation before induction with tight seal facemask may be performed to reduce risk of hypoxemia. Unless the patient is experiencing oxygen desaturation, positive pressure bag-mask ventilation after induction may be avoided to reduce aerosolization. For optimal intubating conditions, patients should be anesthetized with full muscle relaxation. Videolaryngoscopy is recommended as first-line strategy for airway management. If emergent invasive airway access is indicated, we recommend a surgical technique such as scalpel-bougie-tube, rather than an aerosolizing generating procedure, such as transtracheal jet ventilation. This statement represents recommendations by SAM task force for the difficult airway management of adults with COVID-19 with the goal to optimize successful airway management while minimizing the risk of clinician exposure.

Effectiveness of intubation devices in patients with cervical spine immobilisation: a systematic review and network meta-analysis

BACKGROUND

Cervical spine immobilisation increases the difficulty of tracheal intubation. Many intubation devices have been evaluated in this setting, but their relative performance remains uncertain.

METHODS

MEDLINE, EMBASE, and the Cochrane Library were searched to identify randomised trials comparing two or more intubation devices in adults with cervical spine immobilisation. After critical appraisal, a random-effects network meta-analysis was used to pool and compare device performance. The primary outcome was the probability of first-attempt intubation success (first-pass success). For relative performance, the Macintosh direct laryngoscopy blade was chosen as the reference device.

RESULTS

We included 80 trials (8039 subjects) comparing 26 devices. Compared with the Macintosh, McGrath™ (odds ratio [OR]=11.5; 95% credible interval [CrI] 3.19-46.20), C-MAC D Blade™ (OR=7.44; 95% CrI, 1.06-52.50), Airtraq™ (OR=5.43; 95% CrI, 2.15-14.2), King Vision™ (OR=4.54; 95% CrI, 1.28-16.30), and C-MAC™ (OR=4.20; 95% CrI=1.28-15.10) had a greater probability of first-pass success. This was also true for the GlideScope™ when a tube guide was used (OR=3.54; 95% CrI, 1.05-12.50). Only the Airway Scope™ had a better probability of first-pass success compared with the Macintosh when manual-in-line stabilisation (MILS) was used as the immobilisation technique (OR=7.98; 95% CrI, 1.06-73.00).

CONCLUSIONS

For intubation performed with cervical immobilisation, seven devices had a better probability of first-pass success compared with the Macintosh. However, more studies using MILS (rather than a cervical collar or other alternative) are needed, which more accurately represent clinical practice.

CLINICAL TRIAL REGISTRATION

PROSPERO 2019 CRD42019158067 (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=158067).

Recommendations for the evaluation and management of the anticipated and non-anticipated difficult airway of the Societat Catalana d'Anestesiologia, Reanimació i Terapèutica del Dolor, based on the adaptation of clinical practice guidelines and expert consensus

The Airway Division of the Catalan Society of Anaesthesiology, Intensive Care and Pain Management (SCARTD) presents its latest guidelines for the evaluation and management of the difficult airway. This update includes the technical advances and changes observed in clinical practice since publication of the first edition of the guidelines in 2008. The recommendations were defined by a consensus of experts from the 19 participating hospitals, and were adapted from 5 recently published international guidelines following an in-depth analysis and systematic comparison of their recommendations. The final document was sent to the members of SCARTD for evaluation, and was reviewed by 11 independent experts. The recommendations, therefore, are supported by the latest scientific evidence and endorsed by professionals in the field. This edition develops the definition of the difficult airway, including all airway management techniques, and places emphasis on evaluating and classifying the airway into 3 categories according to the anticipated degree of difficulty and additional safety considerations in order to plan the management strategy. Pre-management planning, in terms of preparing patients and resources and optimising communication and interaction between all professionals involved, plays a pivotal role in all the scenarios addressed. The guidelines reflect the increased presence of video laryngoscopes and second-generation devices in our setting, and promotes their routine use in intubation and their prompt use in cases of unanticipated difficult airway. They also address the increased use of ultrasound imaging as an aid to evaluation and decision-making. New scenarios have also been included, such as the risk of bronchoaspiration and difficult extubation Finally, the document outlines the training and continuing professional development programmes required to guarantee effective and safe implementation of the guidelines.

Description and comparison of the performance of the upper lip bite test, the ratio of height to thyromental distance and other methods of preoperative airway assessment in a Nigerian population – a pilot study

Background: The ability to reliably predict difficult intubation can prevent airway related adverse outcomes. The upper lip bite test (ULBT) and ratio of height to thyromental distance (RHTMD) are airway predictive tests that have been evaluated in Caucasian populations with promising results. This study determined the test performance of the ULBT and RHTMD and compared with commonly employed predictive tests (modified Mallampati [MMT], thyromental distance [TMD] and inter-incisor gap [IIG]) in adult Nigerians. Methods: This was a cross-sectional study. Two hundred and sixteen consecutive, consenting ASA I-III patients presenting for surgery and planned for general anaesthesia with endotracheal intubation over a six month period in our teaching hospital, had all five airway assessment tests (ULBT, RHTMD, MMT, TMD and IIG) assessed preoperatively. The Cormack and Lehane grading was used to determine easy or difficult visualisation of the larynx (EVL or DVL). Sensitivity, specificity, predictive values and likelihood ratios of the tests were determined. Results: The sensitivities, specificities, positive and negative predictive values and positive and negative likelihood ratios respectively for the tests were: ULBT (11.8%, 99.0%, 50.0%, 92.9%, 11.71 and 0.89), RHTMD (35.3%, 92.5%, 28.6%, 94.4%, 4.68 and 0.70), TMD (29.4%, 97.5%, 50.0%, 94.2%, 11.71 and 0.72), MMT (52.9%, 86.4%, 25.0%, 95.6%, 3.90 and 0.54), and IIG (11.8%, 97.0%, 25.0%, 92.8%, 3.90 and 0.91). Conclusion: The modified Mallampati test had the highest sensitivity in this study, however all the tests evaluated showed only low to moderate sensitivity. The ULBT and RHTMD had low sensitivities in this population. However, based on the high positive likelihood ratios of the ULBT and the TMD, whenever positive, these tests do show a high probability of DVL and these two tests would probably perform similarly in this population. Anthropometric differences may account for differences in performance of preoperative airway assessment tests in various populations.

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.

Comparison of video and conventional laryngoscopes for simulated difficult emergency tracheal intubations in the presence of liquids in the airway

The presence of vomit, blood, or other foreign liquid materials in the upper airway is a major obstacle in difficult tracheal intubations (TIs) especially in prehospital care. However, the usefulness of video laryngoscopes (VLs) in these situations has not been investigated. The objective of this study was to compare the Airway Scope (AWS) and the Macintosh laryngoscope (ML) for their performance in TIs performed by emergency medical technicians (EMTs) using mannequin models with liquids in the airway. Rice gruel and mock blood were used to fill the upper airways of mannequins to create mock vomit and hematemesis models, respectively. TIs were performed by certified EMTs after visualizing the glottis using an AWS with an 18-Fr suction catheter and a ML with an 18-Fr suction catheter. TIs with AWS and ML were performed in random order in a comparative crossover trial. The TI success rate was evaluated based on the following: (a) the time taken from laryngoscope insertion into the oral cavity to glottis visualization, tracheal tube passage through the glottis, until the initiation of ventilation and (b) the subjective level of difficulty, which was assessed using a visual analog scale (VAS). TIs in vomiting and hematemesis scenarios were performed by 25 and 26 EMTs, respectively. The TI success rates for these scenarios were 100% with both AWS and ML. The median time required until successful ventilation was significantly shorter with AWS than with ML in both the vomiting (42 vs. 58 s) and hematemesis models (33 vs. 39 s), respectively. In the hematemesis scenarios, difficulty assessed using a VAS was lower with AWS than with ML (13 vs. 38 in median), respectively. Compared to the ML, the AWS was capable of faster and easier TIs, in a simulated model of liquid foreign material in the upper airway.

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.

The Difficult Airway after Endoscopic Endonasal Skull Base Surgery: A Case Series and Management Algorithm

OBJECTIVES

To analyze difficult airway situations affecting patients after endoscopic endonasal surgery (EES) for skull base tumors and to develop an airway management algorithm.

STUDY DESIGN

Case series with chart review.

SETTING

Single tertiary care center.

SUBJECTS AND METHODS

Eleven difficult airway events occurred among patients after EES for skull base tumors, as identified through a retrospective review of our institutional Difficult Airway Management Team registry from January 2008 to March 2016. Data from these events included patient demographics, event characteristics, airway management techniques, and outcomes. Results were used to design a difficult airway protocol.

RESULTS

The majority of patients were obese (63.6%) and had a dural defect (90.9%), each of which was repaired with a vascularized flap. The most common reasons for the difficult airway call were concern for using mask ventilation in a patient with a dural defect (27.3%) and difficult airway anatomy (27.3%). Two patients did not require airway intervention; 8 were intubated; and 1 underwent cricothyroidotomy. Videolaryngoscopy was the most common first-attempt intubation technique, followed by conventional direct laryngoscopy. Effective adjunctive techniques included intubation through a laryngeal mask airway and bougie-guided intubation. As compared with simple mask ventilation, laryngeal mask airway-assisted ventilation was associated with a decreased incidence of postevent cerebrospinal fluid leak. There were no incidences of postevent pneumocephalus, cardiopulmonary arrest, or mortality.

CONCLUSIONS

We propose a difficult airway algorithm for patients following EES of the skull base, with sequential recommendations for airway management methods and commentary on adjunctive techniques.

Change in management of predicted difficult airways following introduction of video laryngoscopes

AIM

To determine if video laryngoscopy (VL) has significantly impacted management of difficult airways by decreasing the rate of awake fiberoptic intubation (FOI).

METHODS

Anesthetic records of 3723 patients who underwent general anesthesia at Rush University Medical Center were reviewed over a 2-mo period prior to the introduction of VLs in 2009 (“pre-VL” group) and over the same 2-mo period after the introduction of VLs in 2012 (“post-VL” group). Patient records with predicted difficult airways based on pre-operative airway examination were analyzed. The primary outcome was rate of awake FOI.

RESULTS

To control for possible factors that may influence the FOI rate, a logistic regression was performed with these factors included as covariates. The rate of awake FOI was 13.1% in pre-VL group compared to 9.0% in post-VL group. Although this decrease was not statistically significant individually (P = 0.1768), it showed a trend toward significance when covariates were accounted for (P = 0.0910). Several factors predicting a higher likelihood of awake FOI were found to be statistically significant: Morbid obesity (larger BMI P = 0.0154, OR = 1.5 per 10 point BMI increase), male gender (P = 0.0026, OR = 3.0) and a higher el-Ganzouri airway score (P = 0.0007, OR = 1.5). Although VLs were seen to be used to intubate 51% of predicted difficult airways, the rate of awake FOI has not significantly changed.

CONCLUSION

Although VL may continue to grow in popularity, the most difficult airways are still managed using awake FOI.

Comparison of the McGrath videolaryngoscope and the Macintosh laryngoscope for double lumen endobronchial tube intubation in patients with manual in-line stabilization: A randomized controlled trial

BACKGROUND

Double lumen endobronchial tube (DLT) intubation is commonly used for one-lung ventilation in thoracic surgery. However, because of its large size and shape, it is difficult to perform intubation compared with a single lumen tube. The aim of this randomized controlled trial was to determine whether the McGrath videolaryngoscope has any advantage over the direct Macintosh laryngoscope for DLT intubation in patients with a simulated difficult airway.

METHODS

Forty-four patients (19-60 years of age); scheduled to undergo general anesthesia with one-lung ventilation were assigned to 1 of 2 groups: DLT intubation with the McGrath videolaryngoscope (ML group [n = 22]); or conventional Macintosh laryngoscope (DL group [n = 22]). After manual in-line stabilization was applied as a way of simulating a difficult airway, the time required for intubation and the quality of glottic view were evaluated.

RESULTS

The time to successful intubation was not different between the 2 groups (ML group, 45 s [interquartile range, 38-52 s] versus DL group, 54 s [45-59 s]; P = .089). The McGrath videolaryngoscope, however, provided a significantly better glottic view. Modified Cormack and Lehane grade was better (P < .001), and the percentage of glottis opening score was higher in the ML group (P < .001). Overall intubation difficulty scale score was lower in the ML group (1 [0-2]) versus the DL group (3 [2-4]) (P < .001).

CONCLUSION

The McGrath videolaryngoscope improved glottic view and resulted in lower overall intubation difficulty scale score in patients with in-line stabilization.

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 in Neonates, Infants, and Children

Airway management is vital during anesthetic care and during resuscitative efforts in the PICU, the emergency department, and the delivery room. Given specific anatomic and physiologic differences, neonates and infants may be more prone to complications during airway management. Videolaryngoscopy may offer an alternative to or advantages over direct laryngoscopy in specific clinical scenarios. The following article reviews some of the basic types of videolaryngoscopy and discusses their potential applications in the pediatric population.

Recent trends in airway management

Tracheal intubation remains a life-saving procedure that is typically not difficult for experienced providers in routine conditions. Unfortunately, difficult intubation remains challenging to predict and intubation conditions may make the event life threatening. Recent technological advances aim to further improve the ease, speed, safety, and success of intubation but have not been fully investigated. Video laryngoscopy, though proven effective in the difficult airway, may result in different intubation success rates in various settings and in different providers’ hands. The rescue surgical airway remains a rarely used but critical skill, and research continues to investigate optimal techniques. This review highlights some of the new thoughts and research on these important topics.

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.

Efficacy of various types of laryngoscope (direct, Pentax Airway Scope and GlideScope) for endotracheal intubation in various cervical immobilisation scenarios: a randomised cross-over simulation study

OBJECTIVE

To compare the efficacy of direct laryngoscopy (DL), Pentax Airway Scope (PAWS) and GlideScope video laryngoscope (GVL) systems for endotracheal intubation (ETI) in various cervical immobilisation scenarios: manual in-line stabilisation (MILS), Philadelphia neck collar (PNC) (moderate limit of mouth opening) and Stifneck collar (SNC) (severe limit of mouth opening).

DESIGN

Randomised cross-over simulation study.

SETTING AND PARTICIPANTS

35 physicians who had >30 successful ETI experiences at a tertiary hospital in Seoul, Korea.

PRIMARY AND SECONDARY OUTCOME MEASURES

Participants performed ETI using PAWS, GVL and DL randomly in simulated MILS, PNC and SNC scenarios in our simulation centre. The end points were successful ETI and the time to complete ETI. In addition, modified Cormack-Lehane (CL) classification and pressure to teeth were recorded.

RESULTS

In MILS, there were no significant differences in the rate of success of ETI between the three devices: 33/35(94.3%) for DL vs 32/35(91.4%) for GVL vs 35/35(100.0%) for PAWS; p=0.230). PAWS achieved successful ETI more quickly (19.8 s) than DL (29.6 s) and GVL (35.4 s). For the PNC scenario, a higher rate of successful ETI was achieved with GVL 33/35 (94.3%) than PAWS 29/35 (82.9%) or DL 25/35 (71.4%) (p=0.040). For the SNC scenario, a higher rate of successful ETI was achieved with GVL 28/35(80.0%) than with DL 14/35(40.0%) and PAWS 7/35(20.0%) (p<0.001). For the PNC and SNC scenarios, GVL provided a relatively good view of the glottis, but a frequent pressure to teeth occurred.

CONCLUSIONS

All three devices are suitable for ETI in MILS. DL is not suitable in both neck collar scenarios. PAWS showed faster intubations in MILS, but was not suitable in the SNC scenario. GVL is most suitable in all cervical immobilisation scenarios, but may cause pressure to teeth more frequently.

Airway management in a patient with nuchal, interspinous, and flavum ligament rupture by a sickle: a case report

BACKGROUND

Penetrating neck injury is an important trauma subset but is relatively rare, especially when involving the posterior cervical column. Rupture of the neck restraints, including the interspinous and flavum ligaments, can create serious cervical instability that requires special consideration when managing the airway. However, no detailed information regarding airway management in patients with profound posterior neck muscle laceration and direct cervical ligament disruption by an edged weapon is yet available in the literature.

CASE PRESENTATION

A 63-year-old Japanese man attempted to cut off his head using a sickle after drinking a copious amount of alcohol. On admission, his posterior vertebral column was grossly exposed and the lacerated tissues were actively bleeding, resulting in severe hypovolemic shock. We used a rapid-sequence intubation technique with direct laryngoscopy while manual in-line stabilization of his head and neck was maintained by several people. Surgical exploration revealed nuchal, interspinous, and flavum ligament rupture between his fourth and fifth cervical vertebrae, but no injury to the great vessels was present. The major source of bleeding was a site of oozing from his trapezius and splenius muscles. After surgical hemostasis, wound repair, and subsequent intensive care, our patient was discharged home without any neurological sequelae.

CONCLUSIONS

Deficits of the neck restraints can cause cervical spine subluxation and dislocation secondary to neck movement. Thus, the key to successful airway management in such a scenario is minimization of neck movement to prevent further neurological impairment. We successfully managed an airway using a conventional but trusted endotracheal intubation strategy in a patient with multiple traumas and a suspected spinal cord injury. This case also illustrates that, even when great vessel injury is absent, severe hypovolemic shock may occur after profound neck muscle laceration, requiring immediate surgical intervention.

Comparative effectiveness of McCoy laryngoscope and CMAC(®) videolaryngoscope in simulated cervical spine injuries

Background:

Videolaryngoscopes are increasingly being used in potentially difficult airway. McCoy laryngoscope provides definitive advantage over conventional laryngoscopes in cervical spine patients. The aim of this study was to compare the performance of the CMAC^® videolaryngoscope with the McCoy Laryngoscope in patients with a cervical collar.

Material and Methods:

Sample size of at least 22 patients in each group was calculated using Intubation Difficulty Scale (IDS) score as the primary outcome. 60 American Society of Anesthesiologists I and II patients requiring tracheal intubation for elective surgery were randomly allocated into the McCoy group (n = 30) and the CMAC^® videolaryngoscope group (n = 30). Anesthesia was induced with fentanyl 2 mcg/kg, propofol 2-3 mg/kg and rocuronium 0.6 mg/kg. A rigid collar was applied to immobilize the cervical spine. Comparative data on the IDS scale, Cormack-Lehane (CL) laryngoscopic view, time taken for glottis visualization, time taken to pass endotracheal tube, total time to intubate, number of optimizing maneuvers and hemodynamic variables were recorded in the two groups.

Results:

IDS score was significantly less in the CMAC^® group compared to the McCoy group (median [interquartile range (IQR)], 1 [0-1] vs. 4 [3-6], P < 0.05). CMAC^® videolaryngoscope required significantly less time for glottic visualization with median (IQR), 5 (5-7) versus 14 (8-15), P = 0.000 in McCoy laryngoscope, 29 (96.7%) patients in the CMAC^® group had Modified CL Grade I compared with 16 (53.3%) patients in McCoy group. The hemodynamic variables, number of optimizing maneuvers and incidence of side effects were comparable in the two groups.

Conclusion:

CMAC^® videolaryngoscope forms an effective tool for the airway management of cervical spine patients with a cervical collar.

[A randomised crossover trial comparing the Airtraq(®) NT, McGrath(®) MAC and Macintosh laryngoscopes for nasotracheal intubation of simulated easy and difficult airways in a manikin]

OBJECTIVE

Several devices can aid nasotracheal intubation when managing difficult airways. The McGrath MAC and Airtraq NT were compared with a Macintosh laryngoscope when studying the performance of anaesthetists with different levels of experience, in a manikin model of easy or difficult airway scenarios.

METHODS

Sixty-three anaesthetists were recruited into a randomised trial in which each performed nasotracheal intubation with all laryngoscopes, in both scenarios. The main endpoint was intubation time. Additional endpoints included laryngoscopic view, intubation success, number of optimisation manoeuvres, audible dental clicks and the force applied to the upper airway.

RESULTS

Intubation time was significantly shorter using the McGrath MAC in both scenarios and using the Airtraq in the difficult scenario, when compared with the Macintosh laryngoscope. Both devices gave more Cormack and Lehane grade 1 or 2 views than the Macintosh in the difficult scenario (p<0.001). The McGrath MAC had the best first-attempt success rate (98.4% vs. 96.8% and 95.8%, p<0.001 for the Airtraq NT and Macintosh laryngoscopes respectively). The number of optimisation manoeuvres, audible dental clicks and subjective assessment of the degree of force applied were significantly lower for indirect laryngoscopes versus the Macintosh laryngoscope (p<0.001).

CONCLUSION

In a manikin, the Airtraq and the McGrath laryngoscopes appeared superior to the Macintosh laryngoscope when dealing with simulated airway scenarios. Both devices were associated with better views, intubation times and rates of success, especially in a simulated "difficult airway". Overall satisfaction was highest with the McGrath laryngoscope. Similar clinical studies are needed.

Does C-MAC® video laryngoscope improve the nasotracheal intubating conditions compared to Macintosh direct laryngoscope in paediatric patients posted for tonsillectomy surgeries?

BACKGROUND AND AIMS

C-MAC^® video laryngoscope (VL) with Macintosh blade has been found to improve Cormack-Lehane (C-L) laryngoscopic view as well as intubating conditions for orotracheal intubation. However, studies done on the performance of C-MAC^® VL for nasotracheal intubation (NTI) are very few in number. Hence, we compared laryngoscopy and intubating conditions between Macintosh direct laryngoscope and C-MAC^® VL for NTI.

METHODS

Sixty American Society of Anesthesiologists Physical Status I, II patients, aged 8-18 years, posted for tonsillectomy surgeries under general anaesthesia with NTI were randomised, into two groups. Patients in group 1 were intubated using Macintosh direct laryngoscope and group 2 with C-MAC^® VL. C-L grading, time required for intubation, need for additional manoeuvres and haemodynamic changes during and after intubation were compared between the groups.

RESULTS

C-L grade 1 views were obtained in 26 and 29 patients in group 1 and group 2, respectively (86.7% vs. 96.7%). Remaining patients were having C-L grade 2 (13.3% vs. 3.3%). Duration of intubation was less than a minute in group 2 (93.3%). Need for additional manoeuvres (M1-M5) were more in group 1 (97% vs. 77%). M1 (external manipulation) was needed more in group 2 compared to group 1 (53.3% vs. 30%). Magill's forceps alone (M4) and M4 with additional external manipulation (M5) were needed more in group 1 compared to group 2 (60% vs. 16%).

CONCLUSION

The overall performance of C-MAC^® VL was better when compared to conventional direct Macintosh laryngoscope during NTI in terms of glottis visualisation, intubation time and need for additional manoeuvres.

Pioneers of Laryngoscopy: Indirect, Direct and Video Laryngoscopy

Airway management is one of the core skills of the anaesthetist and various techniques of airway management have developed over many years. Initially, the only view of the glottis that could be obtained was an indirect view (indirect laryngoscopy). Late in the 19th century, a direct view of the glottis was obtained via various direct laryngoscopes. Currently, in the early 21st century, there has been a return to indirect laryngoscopy via videolaryngoscopy using a videolaryngoscope. The aim of this paper is to give a historical overview of the development of both direct and indirect laryngoscopy.

A randomised crossover trial comparing the Airtraq(®) NT, McGrath(®) MAC and Macintosh laryngoscopes for nasotracheal intubation of simulated easy and difficult airways in a manikin

OBJECTIVE

Several devices can aid nasotracheal intubation when managing difficult airways. The McGrath MAC and Airtraq NT were compared with a Macintosh laryngoscope when studying the performance of anaesthetists with different levels of experience, in a manikin model of easy or difficult airway scenarios.

METHODS

Sixty-three anaesthetists were recruited into a randomised trial in which each performed nasotracheal intubation with all laryngoscopes, in both scenarios. The main endpoint was intubation time. Additional endpoints included laryngoscopic view, intubation success, number of optimisation manoeuvres, audible dental clicks and the force applied to the upper airway.

RESULTS

Intubation time was significantly shorter using the McGrath MAC in both scenarios and using the Airtraq in the difficult scenario, when compared with the Macintosh laryngoscope. Both devices gave more Cormack and Lehane grade 1 or 2 views than the Macintosh in the difficult scenario (p<0.001). The McGrath MAC had the best first-attempt success rate (98.4% vs. 96.8% and 95.8%, p<0.001 for the Airtraq NT and Macintosh laryngoscopes respectively). The number of optimisation manoeuvres, audible dental clicks and subjective assessment of the degree of force applied were significantly lower for indirect laryngoscopes versus the Macintosh laryngoscope (p<0.001).

CONCLUSION

In a manikin, the Airtraq and the McGrath laryngoscopes appeared superior to the Macintosh laryngoscope when dealing with simulated airway scenarios. Both devices were associated with better views, intubation times and rates of success, especially in a simulated "difficult airway". Overall satisfaction was highest with the McGrath laryngoscope. Similar clinical studies are needed.

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.

Massive subcutaneous emphysema, bilateral pneumothorax, pneumomediastinum, pneumoperitoneum, pneumoretroperitoneum, and pneumoscrotum after multiple direct laryngoscopies: an autopsy case report

Multiple endotracheal intubation (ETI) attempts increase the risk of airway-related adverse events. However, little is known about autopsy findings after severe ETI-related complications. We present the detailed pathological findings in a patient with severe ETI-related complications. A 77-year-old obese male suffered cardiopulmonary arrest after choking at a rehabilitation facility. Spontaneous circulation returned after chest compressions and foreign-body removal. After multiple failed direct laryngoscopies, the patient was transferred to our hospital. He had massive subcutaneous emphysema, bilateral pneumothorax, pneumomediastinum, pneumoperitoneum, pneumoretroperitoneum, and pneumoscrotum on admission, and died from hypoxic brain injury 15 h later. Autopsy revealed severe oropharyngeal, laryngeal, and left lung lower lobe injury. The likely mechanisms of diffuse emphysema were (1) oropharyngeal injury associated with multiple ETI attempts and excessive ventilation pressures and (2) left lung lower lobe injury associated with chest compressions and other resuscitative procedures. Multiple laryngoscopies can cause severe upper-airway injury, worsen respiratory status, and make ETI more difficult-a vicious circle that can be prevented by limiting ETI attempts. This is particularly important in unfavorable environments, in which backup devices and personnel are not easily obtained. The pathological findings in our patient caution against repeated attempts at ETI during resuscitation.

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.

Video-laryngoscopy introduction in a Sub-Saharan national teaching hospital: luxury or necessity?

Tracheal intubation using Macintosh blade is the technique of choice for the liberation of airways. It can turn out to be difficult, causing severe complications which can entail the prognosis for survival or the adjournment of the surgical operation. The video-laryngoscope allows a better display of the larynx and a good exposure of the glottis and then making tracheal intubation simpler compared with a conventional laryngoscope. It is little spread in sub-Saharan Africa and more particularly in Burkina Faso because of its high cost. We report our first experiences of use of the video-laryngoscope through two cases of difficult tracheal intubation which had required the adjournment of the interventions. It results that the video-laryngoscope makes tracheal intubation easier even in it's the first use because of the good glottal display which it gives and because its allows apprenticeship easy. Therefore, it is not a luxury to have it in our therapeutic arsenal.

Influence of clinical experience of the Macintosh laryngoscope on performance with the Pentax-AWS Airway Scope(®), a rigid video-laryngoscope, by paramedics in Japan

PURPOSE

We sought to establish the clinical utility of the Pentax-AWS Airway Scope(®) (AWS) when used by paramedics to intubate the trachea, and to evaluate whether their performance was influenced by previous clinical experience with the Macintosh laryngoscope (ML).

METHODS

Twenty paramedics attempted tracheal intubation using the AWS in five patients each in the operating room. We recorded the success rate, the number of intubation attempts, and the time for intubation and adverse events, and compared these based on the paramedics' previous clinical experience with the ML. Ten paramedics had no prior clinical experience of the ML (group A) and 10 had used it on more than 30 occasions (group B).

RESULTS

The intubation success rate was 99 % (99/100). Notably, 96 % (47/49) of intubations were achieved on the first attempt by the inexperienced paramedics in group A, compared with 64 % (32/50) by the experienced paramedics in group B (p = 0.0001). The time to intubation (mean ± SD) was significantly shorter in group A than in group B (37 ± 24 vs. 48 ± 21 s, p = 0.002). There were marked variations in the times taken to intubate, but no apparent improvement as the intubators gained experience between their first and fifth cases. No complications were encountered in either group.

CONCLUSION

We found that paramedics could achieve a high tracheal intubation success rate using the AWS independent of previous airway management experience. Better intubation performance with the AWS was observed in paramedics without clinical experience with the ML.

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.

Incidence and predictors of difficult nasotracheal intubation with airway scope

Purpose

The airway scope (AWS) improves views of the larynx during orotracheal intubation. However, the role of the AWS in routine nasotracheal intubation has not been studied adequately.

Methods

One hundred and three patients undergoing dental and maxillofacial surgery that required general anesthesia and nasotracheal intubation were enrolled. The study was approved by our Institution Review Board, and written informed consent was obtained from all patients. We evaluated the success rate of AWS intubation and the incidence of difficult nasotracheal intubation using a modified intubation difficulty scale (IDS) to examine preoperative characteristics and intubation profiles. Categories were difficult intubation (IDS ≥5), mildly difficult (IDS = 1–4), and intubation without difficulty (IDS = 0). We also assessed the incidence of the use of Magill forceps or cuff inflation (the cuff of endotracheal tube is inflated with 10–15 ml air) to guide the endotracheal tube into the glottis.

Results

AWS nasotracheal intubation was 100 % successful. The cuff inflation technique was used in 37 patients. Neither Magill forceps nor other devices were needed for any patient during AWS use. The incidence of difficult nasotracheal intubation was 10 % (n = 10). Of the patients, 61 % (n = 63) had mildly difficult intubation and 29 % (n = 30) had no difficulty. Patients with difficult intubation were more likely to be male and to have a larger tongue and a higher Cormack grade than in the other two groups. Complications, involving minor soft tissue injury, were observed in only 1 patient (1 %).

Conclusion

The AWS achieves a high success rate for nasotracheal intubation with cuff inflation in patients undergoing dental and maxillofacial surgery.