Comparison of the Airway Scope®, gum elastic bougie and fibreoptic bronchoscope in simulated difficult tracheal intubation: a manikin study

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

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

Prevention of Oxygen Desaturation in Morbidly Obese Patients During Electroconvulsive Therapy: A Narrative Review

In general, preoxygenation is performed using a face mask with oxygen in a supine position, and oxygenation is maintained with manual mask ventilation during electroconvulsive therapy (ECT). However, hypoxic episodes during ECT are not uncommon with this conventional method, especially in morbidly obese patients. The most important property of ventilatory mechanics in patients with obesity is reduced functional residual capacity (FRC). Thus, increasing FRC and oxygen reserves is an important step to improve oxygenation and prevent oxygen desaturation in these individuals. Head-up position, use of apneic oxygenation, noninvasive positive pressure ventilation, and high-flow nasal cannula help increase FRC and oxygen reserves, resulting in improved oxygenation and prolonged safe apnea period. Furthermore, significantly higher incidence of difficult mask ventilation is common in morbidly obese individuals. Supraglottic airway devices establish effective ventilation in patients with difficult airways. Thus, the use of supraglottic airway devices is strongly recommended in these patients. Conversely, because muscle fasciculation induced by depolarizing neuromuscular blocking agents markedly increases oxygen consumption, especially in individuals with obesity, the use of nondepolarizing neuromuscular blocking agents may contribute to better oxygenation in morbidly obese patients during ECT.

Supraglottic airway device versus a channeled or non-channeled blade-type videolaryngoscope for accidental extubation in the prone position: A randomized crossover manikin study

BACKGROUND

It is very rare but challenging to perform emergency airway management for accidental extubation in a patient whose head and neck are fixed in the prone position when urgently turning the patient to the supine position would be unsafe. The authors hypothesized that tracheal intubation with a videolaryngoscope would allow effective airway rescue in this situation compared with a supraglottic airway device and designed a randomized crossover manikin study to test this hypothesis.

METHODS

The authors compared airway rescue performances of the 3 devices-the ProSeal laryngeal mask airway (PLMA; Teleflex Medical, Westmeath, Ireland) as a reference; the Pentax AWS (AWS; Nihon Kohden, Tokyo, Japan) as a channeled blade-type videolaryngoscope; and the McGRATH videolaryngoscope (McGRATH; Medtronic, Minneapolis, MN) as a nonchanneled blade type in a manikin fixed to the operating table in the prone position. Twenty-one anesthesiologists performed airway management on the prone manikin with the 3 devices, and the time required for intubation/ventilation and the success rates were recorded.

RESULTS

The median (range) intubation/ventilation times with the PLMA, AWS, and McGRATH were 24.5 (13.5-89.5) s, 29.9 (17.1-79.8) s, and 46.7 (21.9-211.7) s, respectively. There was no significant difference in intubation/ventilation times between the PLMA and AWS. The AWS permitted significantly faster tracheal intubation than did the McGRATH (P = 0.006). The success rates with the PLMA (100%) and AWS (100%) were significantly greater than that with the McGRATH (71.4%). Airway management performance of the PLMA and AWS was comparable between devices and better than that of the McGRATH in the prone position.

CONCLUSIONS

Considering that tracheal intubation can provide a more secure airway and more stable ventilation than the PLMA, re-intubation with a channeled blade-type videolaryngoscope such as the AWS may be a useful method of airway rescue for accidental extubation in patients in the prone position.

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.

A randomised clinical trial comparing the flexible fibrescope and the Pentax Airway Scope (AWS)(®) for awake oral tracheal intubation

We compared awake fibreoptic intubation with awake intubation using the Pentax Airway Scope(®) in 40 adult patients. Sedation was achieved using a target-controlled remifentanil infusion of 1-5 ng.ml(-1) and midazolam. The airway was anaesthetised with lidocaine spray and gargle. The total procedure time - a composite of sedation time, topical anaesthesia time and intubation time - was recorded. The operator's impression of the ease of the procedure and the patients' reported comfort were recorded on a 0-100 mm visual analogue scale. The median (IQR [range]) for total procedure time was 900 (739-1059 [616-1215]) s with the fibrescope and 651 (601-720 [498-900]) s with the Pentax Airway Scope (p = 0.0001). The median (IQR [range]) intubation time was 420 (283-480 [120-608]) s with the fibrescope and 183 (144-220 [107-420]) s with the Pentax Airway Scope (p = 0.0002). The median (IQR [range]) visual analogue scores for the operator's ease of intubation for the fibrescope and Pentax Airway Scope were 83.6 (72.0-98.0 [49.0-100.0]) and 86.8 (84.0-91.0 [61.0-100.0]), respectively (p = 0.3507). The median (IQR [range]) visual analogue score for patient comfort was 85.5 (81.0-97.0 [69.0-100.0]) and 79.4 (74.0-85.0 [59.0-100.0]) for the fibrescope and Pentax Airway Scope, respectively (p = 0.06). Total procedure time was significantly shorter with the Pentax Airway Scope compared with the fibrescope, with no difference in procedure difficulty or patient discomfort.

Comparison of intubation times using a manikin with an immobilized cervical spine: Macintosh laryngoscope vs. GlideScope vs. fiberoptic bronchoscope

Objective

Airway management in patients with suspected cervical spine injury is classified as a “difficult airway.” The best device for managing difficult airways is not known. Therefore, we conducted an intubation study simulating patients with cervical spine injury using three devices: a conventional Macintosh laryngoscope, a video laryngoscope (GlideScope), and a fiberoptic bronchoscope (MAF-TM). Success rates, intubation time, and complication rates were compared.

Methods

Nine physician experts in airway management participated in this study. Cervical immobilization was used to simulate a difficult airway. Each participant performed intubation using airway devices in a randomly chosen order. We measured the time to vocal cord visualization, time to endotracheal tube insertion, and total tracheal intubation time. Success rates and dental injury rates were compared between devices.

Results

Total tracheal intubation time using the Macintosh laryngoscope, GlideScope, and fiberoptic bronchoscope was 13.3 (range, 11.1 to 20.1), 14.9 (range, 12.7 to 22.3), and 19.4 seconds (range, 14.1 to 32.5), respectively. Total tracheal intubation time differed significantly among the devices (P=0.009). Success rates for the Macintosh laryngoscope, GlideScope, and fiberoptic bronchoscope were 98%, 96%, and 100%, respectively, and dental injury rates were 5%, 19%, and 0%, respectively.

Conclusion

The fiberoptic bronchoscope required longer intubation times than the other devices. However, this device had the best success rate with the least incidence of dental injury.

Comparison of intubation performance between the King Vision and Macintosh laryngoscopes in novice personnel: a randomized, crossover manikin study

PURPOSE

The King Vision laryngoscope is a newly developed video laryngoscope. We conducted a simulation study to evaluate the efficacy of the King Vision in novice personnel.

METHODS

Thirty-one registered nurses with no previous experience with tracheal intubation were enrolled. Participants made 6 consecutive attempts at intubation of the manikin's trachea with a Macintosh laryngoscope (MAC) and the King Vision with channeled blade (KVC) and non-channeled blade (KVNC) in a randomized cross-over fashion. The Grading Scale of Intubation Difficulty (GSID) was rated on a 5-point scale.

RESULTS

Overall median (range) intubation times (sec) were 16.9 (8.0-60.0) with the MAC, 20.5 (7.2-60.0) with the KVC, and 60.0 (11.0-60.0) with the KVNC. The KVNC required significantly longer intubation time compared with the MAC or the KVC (p < 0.001). Success rate with the KVNC was 47.3 %, which was significantly inferior to that with the MAC (91.4 %) or KVC (86.6 %). Median GSID was 2 (range 1-5) with the KVC and 3 (1-4) with the MAC, which were both significantly lower than the 4 (2-5) with the KVNC (p < 0.001). Esophageal intubation with the MAC occurred in 18 of 186 attempts, whereas no incidents of esophageal intubation occurred with the KVC or KVNC.

CONCLUSION

The KVC facilitated intubation by novice personnel without incidence of esophageal intubation. However, intubation times, success rates, and GSID scores were similar to the values obtained with the MAC. These findings suggest that the KVC, but not the KVNC, could be used as an alternative device for intubation by novice personnel.

Video Laryngoscopy in the Prehospital Setting

In the prehospital setting, the emergency care provider must anticipate that some patients will manifest with difficult airways. The use of video laryngoscopy to secure an airway in the prehospital setting has not been explored widely, but has the potential to be a useful tool. This article briefly reviews some of the major video laryngoscopes on the market and their usefulness in the prehospital setting. Studies and case reports indicate that the video laryngoscope is a promising device for emergency intubation, and it has been predicted that, in the future, video laryngoscopy will dominate the field of emergency airway management.

Direct laryngoscopy always should be retained as a primary skill; however, the video laryngoscope has the potential to be a good primary choice for the patient with potential cervical spine injuries or limited jaw or spine mobility, and in the difficult-to-access patient.The role of video laryngoscopes in securing an airway in head and neck trauma victims in the prehospital setting has yet to be determined, but offers interesting possibilities. Further clinical studies are necessary to evaluate its role in airway management by prehospital emergency medical services.

Simulation and anaesthesia

Training in anaesthesia relies on the duration and quality of clinical experience. It involves exposure to a range of interventions. This works well in routine cases, but when an uncommon and life-threatening event occurs, the anaesthetist needs to carry out multiple tasks simultaneously. Aviation has remarkable similarities with the practice of anaesthesia. Over the years, the aviation industry has used simulation to train and assess individuals very effectively. Anaesthetists face rapidly evolving clinical situations. This needs appropriate decision-making and communication with others in the theatre team. Simulation, using current technology, offers innovative and reproducible training experience. It enables standardised scenario building and reflective learning. Various non-technical aspects of an anaesthetist's day-to-day work could also be addressed to during such training. The technology could be used very effectively for the assessment of competence too. Simulation has been used for technology development and appraisal over the years.

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.

Effect of cardiopulmonary resuscitation on intubation using a Macintosh laryngoscope, the AirWay Scope, and the gum elastic bougie: A manikin study

BACKGROUND

Physicians could encounter difficult intubation during cardiopulmonary resuscitation (CPR) in trauma patients due to the patient's movement from continuous chest compression and to cervical stabilisation. Therefore, first, we evaluated the impact of chest compression with or without cervical stabilisation on intubation with a Macintosh laryngoscope. Next, we compared difficulty in intubation among the Macintosh laryngoscope, AirWay Scope (AWS), and gum elastic bougie (GEB) with the Macintosh laryngoscope in three simulated CPR scenarios in a randomised, controlled, cross-over study design.

METHODS

Twenty-three anaesthetists intubated the trachea of a manikin (ALS Skill Master, Laerdal Medical Japan, Tokyo, Japan) using the Macintosh laryngoscope, AWS, and GEB in the control scenario, chest compression scenario, and chest compression with cervical stabilisation scenario. Difficulty in intubation was rated on a 5-point scale and the intubation time was measured.

RESULTS

Continuous chest compression increased difficulty in intubation with the Macintosh laryngoscope, compared with the control scenario. Concurrent application of cervical stabilisation further increased the difficulty, compared with application of chest compression alone. Of the three devices compared, the AWS facilitated the easiest intubation, and the GEB facilitated the second-easiest intubation in all scenarios, though the intubation time was slightly longer with the GEB than with other devices.

CONCLUSION

CPR employing continuous chest compression with or without cervical stabilisation caused difficult intubation with the Macintosh laryngoscope. The AWS and GEB facilitated the easiest and second-easiest intubation, respectively, even during CPR employing continuous chest compression with or without cervical stabilisation in a manikin.

Tracheal intubation of a difficult airway using Airway Scope, Airtraq, and Macintosh laryngoscope: a comparative manikin study of inexperienced personnel

BACKGROUND

The Airway Scope (AWS) (Pentax-AWS, Hoya Corp., Tokyo, Japan) and the Airtraq (ATQ) (Prodol, Vizcaya, Spain) have similarities in the novel structures of their blades. In this study, we evaluated the ease of use of the AWS and ATQ compared with the Macintosh laryngoscope (ML) by inexperienced personnel in a simulated manikin difficult airway.

METHODS

Twenty-four fifth-year medical students with no previous experience in tracheal intubation participated in this study. We used an advanced patient simulator (SimMan(R), Laerdal Medical, Stavanger, Norway) to simulate difficult airway scenarios including cervical spine rigidity, limited mouth opening, and pharyngeal obstruction. The sequences in selecting devices and scenarios were randomized. Success rates for tracheal intubation, and the time required for visualization of the glottis, tracheal intubation, and inflation of the lungs, and the number of optimization maneuvers and dental click sounds were analyzed. The 3 different intubation devices were tested in 4 different scenarios by 24 students.

RESULTS

Both the AWS and ATQ had very high success rates of tracheal intubation compared with the ML (AWS 100%*; ATQ 98%*; and ML 89%; *P < 0.05 AWS, ATQ versus ML). The time to intubation with the AWS was significantly shorter than with the ATQ and ML (AWS 11 +/- 6 seconds; ATQ 16 +/- 12 seconds; and ML 16 +/- 11 seconds; *P < 0.05 AWS versus ATQ, ML). The number of optimization maneuvers with the AWS was significantly lower than with the ATQ and ML. There were significantly more audible dental click sounds with the ML than with the AWS and ATQ.

CONCLUSION

Both the AWS and ATQ may be suitable devices for difficult intubation by inexperienced personnel in this manikin simulated scenario. Further studies in a clinical setting are necessary to confirm these findings.

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.

Comparison of Parker-tipped and Murphy-tipped tracheal tubes in Airway Scope-assisted intubation in a manikin

PURPOSE

We tested our hypothesis that a Parker-tipped tracheal tube could improve the reliability of tracheal tube passage as compared to a Murphy-tipped tracheal tube during Airway Scope-assisted intubation in a manikin.

METHODS

Twenty-seven resident doctors performed Airway Scope-assisted intubations using both tracheal tubes, and the number of times the tracheal tube tip touched the glottis or other laryngeal structures was counted on the Airway Scope monitor.

RESULTS

The incidence of the tracheal tube tip touching the glottis during Airway Scope-assisted intubation using the Parker-tipped tracheal tube (7.4%; 2 of 27 attempts) was significantly less than that obtained using the Murphy-tipped tracheal tube (33.3%; 9 of 27 attempts; P = 0.039).

CONCLUSION

When the advancement of a conventional tracheal tube during Airway Scope-assisted intubation is likely to result in collision with the glottis or other laryngeal structures, the selection of a Parker-tipped tracheal tube is a better option.

Comparison of the Glidescope and Pentax AWS laryngoscopes to the Macintosh laryngoscope for use by advanced paramedics in easy and simulated difficult intubation

Background

Intubation of the trachea in the pre-hospital setting may be lifesaving in severely ill and injured patients. However, tracheal intubation is frequently difficult to perform in this challenging environment, is associated with a lower success rate, and failed tracheal intubation constitutes an important cause of morbidity. Novel indirect laryngoscopes, such as the Glidescope^® and the AWS^® laryngoscopes may reduce this risk.

Methods

We compared the efficacy of these devices to the Macintosh laryngoscope when used by 25 Advanced Paramedics proficient in direct laryngoscopy, in a randomized, controlled, manikin study. Following brief didactic instruction with the Glidescope^® and the AWS^® laryngoscopes, each participant took turns performing laryngoscopy and intubation with each device, in an easy intubation scenario and following placement of a hard cervical collar, in a SimMan^® manikin.

Results

Both the Glidescope^® and the AWS^® performed better than the Macintosh, and demonstrate considerable promise in this context. The AWS^® had the least number of dental compressions in all three scenarios, and in the cervical spine immobilization scenario it required fewer maneuvers to optimize the view of the glottis.

Conclusion

The Glidescope^® and AWS^® devices possess advantages over the conventional Macintosh laryngoscope when used by Advanced Paramedics in normal and simulated difficult intubation scenarios in this manikin study. Further studies are required to extend these findings to the clinical setting.

A simple fibreoptic assisted laryngoscope for paediatric difficult intubation: a manikin study

The fibreoptic assisted laryngoscope is a new airway device. We compared the fibreoptic assisted laryngoscope with the Bullard laryngoscope, Macintosh laryngoscope and fibreoptic bronchoscope in a manikin with a simulated Cormack and Lehane Grade 4 laryngoscopic view. Eighteen anaesthetists intubated the manikin's trachea using these devices and the success rate of intubation was measured. They were then asked to rate the subjective difficulty of intubation. The success rate (95% confidence interval) was 100% (94.6-100) with the fibreoptic assisted laryngoscope, 88.9% (80.5-97.3) using the Bullard laryngoscope, 37.0% (24.1-49.9) with the Macintosh laryngoscope, and 22.2% (11.1-33.3) using the fibreoptic bronchoscope. Tracheal intubation using the fibreoptic assisted laryngoscope or Bullard laryngoscope is easier than that using the Macintosh laryngoscope or fibreoptic bronchoscope by subjective difficulty score. All of the intubations were successful with the fibreoptic assisted laryngoscope without practice. These results suggest that fibreoptic assisted laryngoscope may be a useful tool for paediatric difficult intubation.

The Papworth BiVent tube: a new device for lung isolation

Provision of one lung ventilation can be technically challenging, particularly for anaesthetists who are only occasionally required to isolate one lung from the other. A new double lumen endotracheal tube, the Papworth BiVent Tube, has been designed to enable rapid and reliable lung isolation using any bronchus blocker without the need for fibreoptic endoscopic guidance. In this study, an airway-training manikin was used to assess ease of tracheal intubation and lung isolation using the Papworth BiVent tube. Ease of intubation was compared to a single lumen endotracheal tube and a conventional double lumen endobronchial tube. Ease of lung isolation when using a bronchus blocker was compared to a single lumen tube combined with a bronchial blocker. Tracheal intubation using the Papworth BiVent tube was found to be easier than when using a conventional double lumen endobronchial tube. Lung isolation using the Papworth BiVent tube used in combination with a bronchus blocker was achieved more reliably and rapidly than when using a single lumen tube and bronchus blocker.

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

BACKGROUND

We studied whether laryngoscopy and tracheal intubation were easier when using the Pentax-AWS (Tokyo, Japan), a new videolaryngoscope, than when applying the Macintosh laryngoscope, during manual in-line neck stabilization.

METHODS

In 203 anaesthetized patients with manual in-line neck stabilization, we inserted the Pentax-AWS and a Macintosh laryngoscope, in turn, and recorded the view of the glottis and time taken to laryngoscopy. The success rate of tracheal intubation (within 120 s) and time to intubation were also recorded.

RESULTS

The view of the glottis was significantly better with the Pentax-AWS than with the Macintosh laryngoscope (P<0.001). For the Macintosh laryngoscope, the view was obscured in 22 of 203 patients (11%) (Grade 3 in 21 patients and Grade 4 in one patient), whereas for the Pentax-AWS, the glottis was always clearly seen (Grade 1). Time taken to see the glottis with the Pentax-AWS [mean (sd): 6.0 (3.1) s] was significantly shorter than with the Macintosh laryngoscope [11.0 (5.0) s] (95% CI for difference: 4-6 s). The success rate of tracheal intubation with the Pentax-AWS (all of 99 patients) was significantly higher than with the Macintosh laryngoscope (93 of 104 patients) (P=0.001). Time taken for intubation was similar between the Macintosh laryngoscope [51 (27) s] and the Pentax-AWS [54 (14) s] (95% CI for difference: -9 to 3 s).

CONCLUSIONS

In patients with stabilized neck, the Pentax-AWS provided a better view of the glottis and a higher success rate of tracheal intubation, compared with the conventional Macintosh laryngoscope.