Tracheal intubation by non-anaesthetist physicians using the Airway Scope

Videolaryngoscopy versus direct laryngoscopy for tracheal intubation in neonates

BACKGROUND

Establishment of a secure airway is a critical part of neonatal resuscitation in the delivery room and the neonatal intensive care unit. Videolaryngoscopy has the potential to facilitate successful endotracheal intubation, and decrease adverse consequences of a delay in airway stabilization. Videolaryngoscopy may enhance visualization of the glottis and intubation success in neonates. This is an update of a review first published in 2015, and updated in 2018.

OBJECTIVES

To determine the effectiveness and safety of videolaryngoscopy compared to direct laryngoscopy in decreasing the time and attempts required for endotracheal intubation and increasing the success rate on first intubation attempt in neonates (0 to 28 days of age).

SEARCH METHODS

In November 2022, we updated the search for trials evaluating videolaryngoscopy for neonatal endotracheal intubation in CENTRAL, MEDLINE, Embase, CINAHL, and BIOSIS. We also searched abstracts of the Pediatric Academic Societies, clinical trials registries (www.

CLINICALTRIALS

gov; www.controlled-trials.com), and reference lists of relevant studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs), quasi-RCTs, cluster-RCTs, or cross-over trials, in neonates (0 to 28 days of age), evaluating videolaryngoscopy with any device used for endotracheal intubation compared with direct laryngoscopy.

DATA COLLECTION AND ANALYSIS

Three review authors performed data collection and analysis, as recommended by Cochrane Neonatal. Two review authors independently assessed studies identified by the search strategy for inclusion. We used the GRADE approach to assess the certainty of the evidence.

MAIN RESULTS

The updated search yielded 7786 references, from which we identified five additional RCTs for inclusion, seven ongoing trials, and five studies awaiting classification. Three studies were included in the previous version of the review. For this update, we included eight studies, which provided data on 759 intubation attempts in neonates. We included neonates of either sex, who were undergoing endotracheal intubation in international hospitals. Different videolaryngoscopy devices (including C-MAC, Airtraq, and Glidescope) were used in the studies. For the primary outcomes; videolaryngoscopy may not reduce the time required for successful intubation when compared with direct laryngoscopy (mean difference [MD] 0.74, 95% confidence interval [CI] -0.19 to 1.67; 5 studies; 505 intubations; low-certainty evidence). Videolaryngoscopy may result in fewer intubation attempts (MD -0.08, 95% CI -0.15 to 0.00; 6 studies; 659 intubations; low-certainty evidence). Videolaryngoscopy may increase the success of intubation at the first attempt (risk ratio [RR] 1.24, 95% CI 1.13 to 1.37; risk difference [RD] 0.14, 95% CI 0.08 to 0.20; number needed to treat for an additional beneficial outcome [NNTB] 7, 95% CI 5 to 13; 8 studies; 759 intubation attempts; low-certainty evidence).  For the secondary outcomes; the evidence is very uncertain about the effect of videolaryngoscopy on desaturation or bradycardia episodes, or both, during intubation (RR 0.94, 95% CI 0.38 to 2.30; 3 studies; 343 intubations; very-low certainty evidence). Videolaryngoscopy may result in little to no difference in the lowest oxygen saturations during intubation compared with direct laryngoscopy (MD -0.76, 95% CI -5.74 to 4.23; 2 studies; 359 intubations; low-certainty evidence). Videolaryngoscopy likely results in a slight reduction in the incidence of airway trauma during intubation attempts compared with direct laryngoscopy (RR 0.21, 95% CI 0.05 to 0.79; RD -0.04, 95% CI -0.07 to -0.01; NNTB 25, 95% CI 14 to 100; 5 studies; 467 intubations; moderate-certainty evidence). There were no data available on other adverse effects of videolaryngoscopy. We found a high risk of bias in areas of allocation concealment and performance bias in the included studies.

AUTHORS' CONCLUSIONS

Videolaryngoscopy may increase the success of intubation on the first attempt and may result in fewer intubation attempts, but may not reduce the time required for successful intubation (low-certainty evidence). Videolaryngoscopy likely results in a reduced incidence of airway-related adverse effects (moderate-certainty evidence). These results suggest that videolaryngoscopy may be more effective and potentially reduce harm when compared to direct laryngoscopy for endotracheal intubation in neonates. Well-designed, adequately powered RCTS are necessary to confirm the efficacy and safety of videolaryngoscopy in neonatal intubation.

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.

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.

Videolaryngoscopy versus direct laryngoscopy for tracheal intubation in neonates

BACKGROUND

Establishment of a secure airway is a critical part of neonatal resuscitation in the delivery room and the neonatal unit. Videolaryngoscopy has the potential to facilitate successful endotracheal intubation and decrease adverse consequences of delay in airway stabilization. Videolaryngoscopy may enhance visualization of the glottis and intubation success in neonates.

OBJECTIVES

To determine the efficacy and safety of videolaryngoscopy compared to direct laryngoscopy in decreasing the time and attempts required for endotracheal intubation and increasing the success rate at first intubation in neonates.

SEARCH METHODS

We used the search strategy of Cochrane Neonatal. In May 2017, we searched for randomized controlled trials (RCT) evaluating videolaryngoscopy for neonatal endotracheal intubation in Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, abstracts of the Pediatric Academic Societies, websites for registered trials at www.clinicaltrials.gov and www.controlled-trials.com, and reference lists of relevant studies.

SELECTION CRITERIA

RCTs or quasi-RCTs in neonates evaluating videolaryngoscopy for endotracheal intubation compared with direct laryngoscopy.

DATA COLLECTION AND ANALYSIS

Review authors performed data collection and analysis as recommended by Cochrane Neonatal. Two review authors independently assessed studies identified by the search strategy for inclusion.We used the GRADE approach to assess the quality of evidence.

MAIN RESULTS

The search yielded 7057 references of which we identified three RCTs for inclusion, four ongoing trials and one study awaiting classification. All three included RCTs compared videolaryngoscopy with direct laryngoscopy during intubation attempts by trainees.Time to intubation was similar between videolaryngoscopy and direct laryngoscopy (mean difference (MD) -0.62, 95% confidence interval (CI) -6.50 to 5.26; 2 studies; 311 intubations) (very low quality evidence). Videolaryngoscopy did not decrease the number of intubation attempts (MD -0.05, 95% CI -0.18 to 0.07; 2 studies; 427 intubations) (very low quality evidence). Moderate quality evidence suggested that videolaryngoscopy increased the success of intubation at first attempt (typical risk ratio (RR) 1.44, 95% CI 1.20 to 1.73; typical risk difference (RD) 0.19, 95% CI 0.10 to 0.28; number needed to treat for an additional beneficial outcome (NNTB) 5, 95% CI 4 to 10; 3 studies; 467 intubation attempts).Desaturation episodes during intubation attempts were similar between videolaryngoscopy and direct laryngoscopy (MD -0.76, 95% CI -5.74 to 4.23; 2 studies; 359 intubations) (low quality evidence). There was no difference in the incidence of airway trauma due to intubation attempts (RR 0.10, 95% CI 0.01 to 1.80; RD -0.04, 95% CI -0.09 to -0.00; 1 study; 213 intubations) (low quality evidence).There were no data available on other adverse effects of videolaryngoscopy.

AUTHORS' CONCLUSIONS

Moderate to very low quality evidence suggests that videolaryngoscopy increases the success of intubation in the first attempt but does not decrease the time to intubation or the number of attempts for intubation. However, these studies were conducted with trainees performing the intubations and these results highlight the potential usefulness of the videolaryngoscopy as a teaching tool. Well-designed, adequately powered RCTs are necessary to confirm efficacy and address safety and cost-effectiveness of videolaryngoscopy for endotracheal intubation in neonates by trainees and those proficient in direct laryngoscopy.

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.

Usefulness of video-laryngoscopy with the Airway Scope for intubation performance and learning: an experimental manikin controlled study

Background

Different video-laryngoscopes (VDLs) for endotracheal intubation (ETI) have recently been developed. We compared the performance of the VDL Airway Scope (AWS) with the direct laryngoscopy by Macintosh (DLM) for ETI success, time and learning.

Methods

We performed an experimental manikin controlled study. Twenty experienced (experts) and 40 inexperienced operators (novices) for DLM-ETI were enrolled. None of them had experience with the use of AWS-VDL. Novices were assigned to start learning with DLM or AWS, and two sub-groups of 20 novices were formed. Experts group constituted the control group. Each participant performed 10 ETI attempts with each device on the same standard manikin. The primary endpoint was the ETI success probability. Secondary endpoints were ETI time, technical validity and qualitative evaluation for each technique. We also assessed the learning order and the successive attempts effects for these parameters.

Results

Overall, 1200 ETI attempts were performed. ETI success probability was higher with the AWS than with the DLM for all operators (98 vs. 81 %; p < 0.0001) and for experts compared to novices using devices in the same order (97 vs. 83 %; p = 0.0002). Overall ETI time was shorter with the AWS than with the DLM (13 vs. 20 s; p < 0.0001) and for experts compared to novices using devices in the same order (11 vs. 21 s; p < 0.0001). Among novices, those starting learning with AWS had higher ETI success probability (89 vs. 83 %; p = 0.03) and shorter ETI time (18 vs. 21 s; p = 0.02). Technical validity was found better with the AWS than DLM for all operators. Novices expressed global satisfaction and device preference for the AWS, whereas experts were indifferent.

Conclusions

AWS-VDL permits faster, easier and more reliable ETI compared to the DLM whatever the previous airway ETI experience and could be a useful device for DLM-ETI learning.

Videolaryngoscopy versus direct laryngoscopy for tracheal intubation in neonates

BACKGROUND

Establishment of secure airway is a critical part of neonatal resuscitation both in the delivery room and in the neonatal unit. Videolaryngoscopy is a new technique that has the potential to facilitate successful endotracheal intubation and decrease adverse consequences of delay in airway stabilization. Videolaryngoscopy may enhance visualization of the glottis and intubation success in neonates.

OBJECTIVES

To determine the efficacy and safety of videolaryngoscopy compared to direct laryngoscopy in decreasing the time and attempts required and increasing the success rate for endotracheal intubation in neonates.

SEARCH METHODS

We used the search strategy of the Cochrane Neonatal Review Group. We searched for randomized controlled trials evaluating videolaryngoscopy for neonatal endotracheal intubation in May 2013 in the electronic databases; the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; CINAHL; abstracts of the Pediatric Academic Societies; websites for registered trials at www.clinicaltrials.gov and www.controlled-trials.com; and in the reference lists of relevant studies.

SELECTION CRITERIA

Randomized or quasi-randomized trials in neonates evaluating videolaryngoscopy for endotracheal intubation compared with direct laryngoscopy.

DATA COLLECTION AND ANALYSIS

Review authors performed data collection and analysis as recommended by the Cochrane Neonatal Review Group. Two review authors (KL and MP) independently assessed studies identified by the search strategy for inclusion.

MAIN RESULTS

Our search strategy performed in May 2013 yielded 7057 references. Two review authors (MP and KL) independently assessed all references for inclusion. We did not find any completed studies for inclusion but identified three ongoing trials and one study awaiting classification.

AUTHORS' CONCLUSIONS

There was insufficient evidence to recommend or refute the use of videolaryngoscopy for endotracheal intubation in neonates. Well-designed, adequately powered randomized controlled studies are necessary to address efficacy and safety of videolaryngoscopy for endotracheal intubation in neonates.

Comparison of 3 video laryngoscopes with the Macintosh in a manikin with easy and difficult simulated airways

OBJECTIVES

Tracheal intubation is used to maintain a patent airway and can occasionally be difficult in a potentially difficult airway, especially for novice managers. In this study, we evaluated the time required, extent of the difficulty, and number of dental clicks in the tracheal intubation for novice medical students between the Macintosh (Truphatek International Ltd, Netanya, Israel) and 3 video laryngoscopes in normal and difficult simulated intubation positions on manikins on both the table and floor.

METHODS

We recruited 20 medical students as novice airway managers. They used the Macintosh, Truview (Truphatek International Ltd, Netanya, Israel), Glidescope (Verathon Inc., Bothell, WA), and Airway Scope (AWS) (Pentax Corporation, Tokyo, Japan) laryngoscopes in normal and difficult simulated airways on manikins on both the table and floor. The time to intubate, modified Cormack-Lehane score, intubation difficulty score, and dental click number were estimated and compared.

RESULTS

All 20 medical students completed the study. The AWS required the shortest intubation time, provided the best glottic view and easiest intubation, and resulted in less dental clicks compared with the other 3 laryngoscopes; these phenomena were particularly prominent in the cervical-spine immobilization position on the floor. Although all video laryngoscopes provided better glottic views than the Macintosh laryngoscopy in terms of time to intubate, intubation difficulty score, and the number of dental clicks, the outcomes from the Macintosh laryngoscope were better than those of the Truview and Glidescope.

CONCLUSIONS

The AWS may have the potential for quicker, easier, and safer tracheal intubation in scenarios involving difficult airways for a novice airway manager.

Airway scope laryngoscopy under manual inline stabilization and cervical collar immobilization: a crossover in vivo cinefluoroscopic study

BACKGROUND

Direct laryngoscopy along with manual inline stabilization (MIS) is currently the standard care for patients with suspected neck injuries. However, cervical collar immobilization is more commonly performed in the prehospital environment, and its early removal is necessary before intubation. We hypothesized that if usability of Airway Scope (AWS) in a difficult airway could also bring merits to intubation under cervical collar immobilization, unnecessary risk caused by the removal of a neck collar may be prevented.

METHODS

In this crossover study, 30 consenting patients presenting for surgery were assigned to undergo intubation using AWS. Neck was stabilized manually and by a neck collar in a random order before laryngoscopy was performed by the same anesthesiologist. Measurements include interincisor distance (IID), success rate, intubation time, and fluoroscopic examination of the upper and middle cervical spine.

RESULTS

IID was notably narrower after application of a neck collar (mean ± SE: MIS, 19 mm ± 1 mm; collar, 10 mm ± 1 mm; p < 0.01). One and 9 failures were encountered in MIS and collar groups, respectively (p = 0.012). Intubation time proved no statistical significance. Extension of craniocervical junction was observed in both groups, but occipitoatlantal joint was significantly more extended in collar group (median [range]: AWS, 10-degree angle [-1 to 20-degree angle]; collar, 14-degree angle [5 to 26-degree angle]; p < 0.01).

DISCUSSION

AWS laryngoscopy under cervical collar immobilization fails to meet our expectation. Intubation failed in 30% of the cases in collar group whereas only 3.3% of the cases in MIS group. Significant difference of mouth opening limitation is probably the major reason, as 7 of 9 failed cases in collar group had IID <10 mm. This was insufficient to insert the 18-mm blade of AWS. In addition, occipitoatlantal joint suffered a greater extension when wearing a neck collar. Differences in the method to stabilize the neck may be the reason.

CONCLUSION

When compared with cervical collar immobilization, AWS laryngoscopy along with MIS seems to be a safer and more definite method to secure airway of neck-injured trauma patients because it limits less mouth opening and upper cervical spine movement.

Evaluation of the Pentax-AWS(®) and the Macintosh laryngoscope in difficult intubation: a manikin study

BACKGROUND

The Pentax-AWS (AWS(®)), a new video laryngoscope, has been shown to be useful in cases of difficult intubation. We hypothesized that the AWS(®) would be more useful in the settings of a narrow upper airway than the Macintosh laryngoscope. We compared each device in simulated scenarios of representative difficulty of tracheal intubation using a manikin. The primary endpoint was the rate of successful intubation.

METHODS

With each device, 23 anesthesiologists performed tracheal intubation in a SimMan(®) manikin in the following scenarios: (1) normal airway, (2) tongue edema, (3) cervical spine rigidity, (4) pharyngeal obstruction, (5) jaw trismus, (6) tongue edema with pharyngeal obstruction. The intubation time and success rate were measured. Each participant was asked to rate the difficulty of intubation (1=very easy; 5=very difficult).

RESULTS

In the scenarios of tongue edema and tongue edema with pharyngeal obstruction, the AWS(®) yielded a higher success rate (100% vs. 34.8%; P<0.001, 65.2% vs. 21.7%; P=0.006), a shorter intubation time [14.6 (7.0) vs. 33.4 (13.0) s; P<0.001, 24.5 (12.0) vs. 37.6 (11.9); P=0.047; mean (standard deviation)], and a lower difficulty score [2 (1-4) vs. 5 (1-5); P<0.001, 4 (2-5) vs. 5 (3-5); P<0.001; median (range)], compared with the Macintosh laryngoscope.

CONCLUSION

The AWS(®) has an advantage over the Macintosh laryngoscope in simulated tongue edema and tongue edema with pharyngeal obstruction. Further studies in a clinical setting are necessary to confirm these findings.

Airway scope versus macintosh laryngoscope in patients with simulated limitation of neck movements

BACKGROUND

Tracheal intubation in patients with suspected neck injuries should achieve two contradicting goals-sufficient laryngeal exposure and the least cervical spine movement. Because the former involves displacements of the cervical vertebrae, intubation under immobilization is widely performed today to prevent exacerbation of spinal code injuries. The unique curving blade of the Airway Scope (AWS) is designed to fit the oropharyngeal anatomy. A camera at the tip of the blade displays the view of the larynx, but unlike the direct laryngoscope, it needs no line-of-sight of the oral, pharyngeal, and tracheal axis. Our purpose is to determine whether AWS could be a suitable airway device for the intubation of patients with potential neck injury.

METHODS

Thirty-six patients scheduled for surgery were randomly assigned to undergo intubation using either AWS or Macintosh laryngoscope (MLS). After general anesthetic induction, the patient's head was set in a neutral position, and an appropriately sized semi-rigid neck collar was placed. Measurements include intubation time, number of attempts, success rate, Cormack-Lehane classification, airway optimization maneuver, Intubation Difficulty Scale scores, and complications.

RESULTS

Intubation time proved no statistical significance (mean ± SD, AWS, 62.9 seconds ± 26.0 seconds, MLS, 55.6 seconds ± 26.0 seconds; p = 0.42). AWS scored less in Cormack-Lehane classification (median [range], AWS I [I-I], MLS IIIa [I-IIIb]; p < 0.0001), required fewer additional airway optimization maneuvers (p = 0.0003), and scored less in Intubation Difficulty Scale scores (AWS 0 [0-1], MLS 2 [0-5]; p < 0.0001).

CONCLUSIONS

In neck-immobilized patients using semi-rigid cervical collars, AWS improves laryngeal exposure and facilitates tracheal intubation. AWS may be a suitable intubation device for trauma patients.

Comparison of the Airway Scope and Macintosh laryngoscope with in-line cervical stabilization by the semisolid neck collar: manikin study

BACKGROUND

The usefulness of Airway Scope (AWS) and Macintosh direct laryngoscope (ML) for patients with trauma requiring intubation with in-line cervical stabilization for protection of the cervical spine was compared.

METHODS

Thirty-three residents performed orotracheal intubation using ML and AWS in an intubation model with in-line cervical stabilization. The tracheal intubation success rate, time required for tracheal intubation, and number of trials of inserting the tracheal tube into the trachea were measured in individual residents.

RESULTS

Two residents inserted the tube into the esophagus using ML (success rate: 93.9%), but all residents succeeded in tracheal intubation using AWS (success rate: 100%) (p = 0.492). The time required for intubation was similar using AWS and ML (15 seconds vs. 20 seconds, p = 0.261). The number of trials using AWS was significantly lower (2.0 times vs. 1.0 times, p = 0.001).

CONCLUSION

The usefulness of AWS may be comparable with or greater than that of ML for oral intubation in trauma patients with in-line cervical stabilization.

Airway scope vs Macintosh laryngoscope during chest compressions on a fresh cadaver model

PURPOSES

This study compared the Airway scope (AWS) to the Macintosh laryngoscope (ML) during chest compressions on a fresh cadaver.

METHODS

This was a prospective crossover study. The participants who had experiences with AWS were excluded. The participants intubated with randomly assigned AWS or ML on a fresh cadaver during chest compressions. Primary outcome were as follows: time to intubation, ease of intubation (rated by using the visual analog scale [VAS]), and intubation success rate.

RESULTS

Twenty-five were enrolled. Median time of intubation was similar between the AWS and ML (AWS, 18.5 seconds vs ML, 18.3 seconds; P = .112). The median VAS of AWS and ML were 3.0 and 2.0, respectively (P = .023). There was no failure of intubation. However, participants replied that the AWS was more difficult to use than the ML.

CONCLUSION

Considering the lack of experience with the AWS, AWS could be an alternative intubation device during chest compressions after practices with AWS.

GlideScope videolaryngoscope reduces the incidence of erroneous esophageal intubation by novice laryngoscopists

The purpose of this study was to evaluate the performance of the GlideScope videolaryngoscope for tracheal intubation by novice laryngoscopists compared with that of the Macintosh laryngoscope. Under supervision by staff anesthetists, non-anesthesia residents performed tracheal intubation using either the GlideScope videolaryngoscope (n = 100) or Macintosh laryngoscope (n = 100). The time required for airway instrumentation, the number of attempts required until successful intubation, and erroneous esophageal intubation were investigated. There were no significant differences in the time needed to secure the airway between the GlideScope videolaryngoscope and the Macintosh laryngoscope. Fewer attempts until successful intubation were made with the GlideScope videolaryngoscope than with the Macintosh laryngoscope (p < 0.05). Erroneous esophageal intubation with the GlideScope videolaryngoscope was less frequent than with the Macintosh laryngoscope (p < 0.05). Compared to the Macintosh laryngoscope, the GlideScope videolaryngoscope reduces the incidence of erroneous esophageal intubation by less experienced laryngoscopists.

Video and optic laryngoscopy assisted tracheal intubation--the new era

With advances in technology, videoscopy and optic intubation have been gaining popularity particularly in patients with difficult airways or as rescue devices in failed intubation attempts. Their routine use is, however an uncommon occurrence. This review paper will summarise some of those newly developed devices currently available to assist tracheal intubation, their advantages, disadvantages when compared with the conventional laryngoscope and finally, evidence to support their use in both elective and emergency airway management.

Airway Scope: early clinical experience in 405 patients

The Airway Scope (Pentax, Tokyo, Japan) is a new device used for tracheal intubation. It allows visualization of the glottis through a non-line-of sight view. The aim of the present study was to evaluate the suitability of this device for the tracheal intubation of surgical patients. In this prospective study, the Airway Scope was used for the endotracheal intubation of 405 patients by 74 airway operators. The Airway Scope allowed visualization of the glottis in all 405 patients, including those with a Cormack-Lehane view of grade III (n = 15) or grade IV (n = 1) on Macintosh laryngoscopy. All tracheal intubations using the Airway Scope were successful. The mean time to complete tracheal intubation was 42.4 +/- 19.7 s (+/-SD; range, 13-192 s). No dental damage was encountered, though minor mucosal injury caused by the blade was experienced in 2 patients. The Airway Scope consistently permitted a better intubation environment. With its potential advantages, the Airway Scope could be an effective aid to airway management in surgical patients.