Using King Vision video laryngoscope with a channeled blade prolongs time for tracheal intubation in different training levels, compared to non-channeled blade

Comparison of Macintosh Laryngoscope, King Vision®, VividTrac®, AirAngel Blade®, and a Custom-Made 3D-Printed Video Laryngoscope for Difficult and Normal Airways in Mannequins by Novices-A Non-Inferiority Trial

Background: Endotracheal intubation (ETI) is a cornerstone of airway management. The gold standard device for ETI is still the direct laryngoscope (DL). However, video laryngoscopes (VLs) are now also widely available and have several proven advantages. The VL technique has been included in the major airway management guidelines. During the COVID-19 pandemic, supply chain disruption has raised demand for 3D-printed medical equipment, including 3D-printed VLs. However, studies on performance are only sparsely available; thus, we aimed to compare 3D-printed VLs to the DL and other VLs made with conventional manufacturing technology. Methods: Forty-eight medical students were recruited to serve as novice users. Following brief, standardized training, students executed ETI with the DL, the King Vision® (KV), the VividTrac® (VT), the AirAngel Blade® (AAB), and a custom-made 3D-printed VL (3DVL) on the Laerdal® airway management trainer in normal and difficult airway scenarios. We evaluated the time to and proportion of successful intubation, the best view of the glottis, esophageal intubation, dental trauma, and user satisfaction. Results: The KV and VT are proved to be superior (p < 0.05) to the DL in both scenarios. The 3DVL's performance was similar (p > 0.05) or significantly better than that of the DL and mainly non-inferior (p > 0.05) compared to the KV and VT in both scenarios. Regardless of the scenario, the AAB proved to be inferior (p < 0.05) even to the DL in the majority of the variables. The differences between the devices were more pronounced in the difficult airway scenario. The user satisfaction scores were in concordance with the aforementioned performance of the scopes. Conclusions: Based upon our results, we cannot recommend the AAB over the DL, KV, or VT. However, as the 3DVL showed, 3D printing indeed can provide useful or even superior VLs, but prior to clinical use, meticulous evaluation might be recommended.

Channelled versus nonchannelled Macintosh videolaryngoscope blades in patients with a cervical collar: a randomized controlled noninferiority trial

PURPOSE

Channelled blades have the advantage of avoiding stylet use and potential airway injury during videolaryngoscopic intubation. Nevertheless, the effectiveness of channelled Macintosh-type blades has not yet been fully established. We sought to assess the utility of channelled Macintosh-type blades for videolaryngoscopic intubation under cervical spine immobilization.

METHODS

We conducted a randomized controlled noninferiority trial in neurosurgical patients with a difficult airway simulated by a cervical collar. Videolaryngoscopic intubation with a reinforced tracheal tube was performed using a channelled Macintosh-type blade without a stylet (channelled group, n = 130) or a nonchannelled Macintosh-type blade with a stylet (nonchannelled group, n = 131). The primary outcome was intubation success rate. Secondary outcomes included time to intubation and incidence or severity of intubation-related complications (subglottic, lingual, and dental injuries; bleeding; sore throat; and hoarseness).

RESULTS

The initial intubation success rate was 98% and 99% in the channelled and nonchannelled groups, respectively, showing the noninferiority of the channelled group (difference in proportions -0.8%; 95% confidence interval [CI], -4.8% to 2.9%; predefined noninferiority margin, -5%; P = 0.62). Fewer participants in the channelled group had subglottic injuries than in the nonchannelled group (32% [32/100] vs 57% [54/95]; difference in proportions, -25%; 95% CI, -39% to -11%; P < 0.001). There were no significant differences between the two groups in the overall intubation success rate, time to intubation, and incidence or severity of other intubation-related complications.

CONCLUSIONS

For videolaryngoscopic intubation in patients with a cervical collar, channelled Macintosh-type blades are an alternative to nonchannelled Macintosh-type blades, with a noninferior initial intubation success rate and a lower incidence of subglottic injury.

STUDY REGISTRATION

CRIS.nih.go.kr ( KCT0005186 ); first submitted 29 June 2020.

The Evolution of Equipment and Technology for Visualising the Larynx and Airway

Laryngoscopy and endotracheal intubation are the core skills of an anaesthetist. The tools and equipment used today are unrecognisable from the methods used in the first recorded attempts at laryngoscopy over 200 years ago. The evolution of the modern-day laryngoscopes has mirrored advancements in technology within general society, and particularly with regard to computer and fibreoptic technology over the last 30 years. The development of these modern visualisation devices would not have been possible without those that went before it, as each new device has been influenced by the previous. Video laryngoscopes have quickly gained popularity as the primary intubating device in many scenarios, driven by ease of use as well as positive patient outcomes. While it is still debated whether videolaryngoscopes can replace direct laryngoscopy for routine intubations, their effectiveness in difficult airways is unquestioned. This chapter will cover the anatomy of the airway and the development of technology from the rudimentary creations in the early 1700s to the modern larynsgocopes created in the twenty-second century which allow the user to view the airway in more detail in order to secure endotracheal intubation even in an airway where intubation would be difficult.

The evaluation of maximum condyle-tragus distance can predict difficult airway management without exposing upper respiratory tract; a prospective observational study

Background

Routine preoperative methods to assess airway such as the interincisor distance (IID), Mallampati classification, and upper lip bite test (ULBT) have a certain risk of upper respiratory tract exposure and virus spread. Condyle-tragus maximal distance(C-TMD) can be used to assess the airway, and does not require the patient to expose the upper respiratory tract, but its value in predicting difficult laryngoscopy compared to other indicators (Mallampati classification, IID, and ULBT) remains unknown. The purpose of this study was to observe the value of C-TMD to predict difficult laryngoscopy and the influence on intubation time and intubation attempts, and provide a new idea for preoperative airway assessment during epidemic.

Methods

Adult patients undergoing general anesthesia and tracheal intubation were enrolled. IID, Mallampati classification, ULBT, and C-TMD of each patient were evaluated before the initiation of anesthesia. The primary outcome was intubation time. The secondary outcomes were difficult laryngoscopy defined as the Cormack-Lehane Level > grade 2 and the number of intubation attempts.

Results

Three hundred four patients were successfully enrolled and completed the study, 39 patients were identified as difficult laryngoscopy. The intubation time was shorter with the C-TMD>1 finger group 46.8 ± 7.3 s, compared with the C-TMD<1 finger group 50.8 ± 8.6 s (p<0.01). First attempt success rate was higher in the C-TMD>1 finger group 98.9% than in the C-TMD<1 finger group 87.1% (P<0.01). The correlation between the C-TMD and Cormack-Lehane Level was 0.317 (Spearman correlation coefficient, P<0.001), and the area under the ROC curve was 0.699 (P<0.01). The C-TMD < 1 finger width was the most consistent with difficult laryngoscopy (κ = 0.485;95%CI:0.286–0.612) and its OR value was 10.09 (95%CI: 4.19–24.28), sensitivity was 0.469 (95%CI: 0.325–0.617), specificity was 0.929 (95%CI: 0.877–0.964), positive predictive value was 0.676 (95%CI: 0.484–0.745), negative predictive value was 0.847 (95%CI: 0.825–0.865).

Conclusion

Compared with the IID, Mallampati classification and ULBT, C-TMD has higher value in predicting difficult laryngoscopy and does not require the exposure of upper respiratory tract.

Trial registration

The study was registered on October 21, 2019 in the Chinese Clinical Trial Registry (ChiCTR1900026775).

Proficiencies of military medical officers in intubating difficult airways

Background

This study sheds light on the proficiency of military medical officers who had received between 2 and 3 years of post-graduate training, in the handling of the difficult airway in a trauma manikin simulator using direct and video laryngoscopes.

Method

One hundred thirty-three doctors from the Singapore Armed Forces Medical Officer Cadet Course were assessed using high-fidelity simulator models with standardised difficult airways (simulator with tongue-swelling and cervical collar). They used the Macintosh direct laryngoscope (DL), King Vision channelled-blade laryngoscope (KVC), King Vision non-channelled blade laryngoscope (KVNC), and the McGrath (MG) laryngoscope on the same model in a randomised sequence. The intubation success rates and time to intubation were recorded and analysed for the study.

Results

The medical officers had a 71.4% intubation success rate with the DL on the difficult airway trauma simulator model and the mean time to intubation of 40.1 s. With the KVC, the success rate is 86.5% with mean intubation time of 40.4 s. The KVNC produced 24.8% success rate, with mean time to intubation of 53.2 s. The MG laryngoscope produced 85.0% success rate, with a mean time of intubation of 37.4 s.

Conclusion

Military medical officers with 2–3 years of post-graduate training had a success rate of 71.4% success rate intubating a simulated difficult airway in a trauma setting using a DL. Success rates were improved with the use of KVC and the MG laryngoscope, but was worse with the KVNC.

Comparison of McGrath, Pentax, and Macintosh laryngoscope in normal and cervical immobilized manikin by novices: a randomized crossover trial

BACKGROUND

The aim of this study was to compare tracheal intubation performance regarding the time to intubation, glottic view, difficulty, and dental click, by novices using McGrath videolaryngoscope (VL), Pentax Airway Scope (AWS) and Macintosh laryngoscope in normal and cervical immobilized manikin models.

METHODS

Thirty-five anesthesia nurses without previous intubation experience were recruited. Participants performed endotracheal intubation in a manikin model at two simulated neck positions (normal and fixed neck via cervical immobilization), using three different devices three times each. Performance parameters included intubation time, success rate of intubation, Cormack Lehane laryngoscope grading, dental click, and subjective difficulty score.

RESULTS

Intubation time and success rate during first attempt were not significantly different between the 3 groups in normal airway manikin. In the cervical immobilized manikin, the intubation time was shorter (p = 0.012), and the success rate with the first attempt was significantly higher (p < 0.001) when using McGrath VL and Pentax AWS compared with Macintosh laryngoscope. Both VLs showed less difficulty score (p < 0.001) and more Cormack Lehane grade I (p < 0.001) in both scenarios. The incidence of dental clicks was higher with Macintosh laryngoscope compared with McGrath VL in cervical immobilized airway (p < 0.001).

CONCLUSIONS

McGrath VL and Pentax AWS did not show clinically significant decrease in intubation time, however, they achieved higher first attempt success rate, easier intubation and better glottis view compared with Macintosh laryngoscope by novices in a cervical immobilized manikin model. McGrath VL may reduce the risk of dental injury compared with Macintosh laryngoscope in cervical immobilized scenario.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03161730), May 22, 2017 https://clinicaltrials.gov/ct2/hom.

Comparison of the time to successful endotracheal intubation using the Macintosh laryngoscope or KingVision video laryngoscope in the emergency department: A prospective observational study

OBJECTIVE:

Intubation is a skill that must be mastered by the emergency physician (EP). Today, we have a host of video laryngoscopes which have been developed to make intubations easier and faster. It may seem that in a busy emergency department (ED), a video laryngoscope (VL) in the hands of an EP would help him intubate patients faster compared to the traditional direct laryngoscope (DL). Our goal was to compare the time taken to successfully intubate patients coming in ED using King Vision VL (KVVL) and DL.

MATERIALS AND METHODS:

This was a prospective observational study on patients coming to the ED requiring emergent intubation. They were allocated one to one alternatively into two groups – KVVL and DL. Accordingly, KVVL or DL intubations were carried out by the EPs. Time taken to intubate, first-pass success, and crossover between laryngoscopes were recorded.

RESULTS:

A total of 350 patients were enrolled in the study. Overall, mean time to intubate patients using the DL was 15.85 s (95% confidence interval [CI] 14.05–17.65), while the meantime with KVVL was 13.75 s (95% CI 12.32–15.18) (P = 0.084). The overall first-pass success rates with DL and KVVL were 89.94% and 85.16%, respectively (P = 0.076). A total of 7.43% (95% CI 5.12–10.66) patients had crossover between laryngoscopes.

CONCLUSION:

We found the KVVL to have a similar performance to the DL in terms of time for intubations and ease in difficult airways. We consider the KVVL a useful device for EDs to equip themselves with.

Video Laryngoscopic Intubation Using the King VisionTM Laryngoscope in a Simulated Cervical Spine Trauma: A Comparison Between Non-Channeled and Channeled Disposable Blades

Videolaryngoscopes may reduce cervical spine movement during tracheal intubation in patients with neck trauma. This manikin study aimed to compare the performance of disposable non-channeled and channeled blades of the King Vision™ videolaryngoscope in simulated cervical spine injury. Fifty-eight anesthesiologists in training intubated the TruMan manikin with the neck immobilized using each blade in a randomized order. The primary outcome was the time needed for tracheal intubation, secondary aims included total success rate, the time required for visualization of the larynx, number of attempts, view of the vocal cords, and subjective assessment of both methods. Intubation time with the channeled blade was shorter, with a median time of 13 s (IQR 9-19) vs. 23 s (14.5-37.5), p < 0.001, while times to visualization of the larynx were similar in both groups (p = 0.54). Success rates were similar in both groups, but intubation with the non-channeled blade required more attempts (1.52 vs. 1.05; p < 0.001). The participants scored the intubation features of the channeled blade significantly higher, while visualization features were scored similarly in both groups. Both blades of the King Vision™ videolaryngoscope are reliable intubation devices in a simulated cervical spine injury in a manikin model when inserted by non-experienced operators. The channeled blade allowed faster intubation of the trachea.

A randomized controlled comparison of non-channeled king vision, McGrath MAC video laryngoscope and Macintosh direct laryngoscope for nasotracheal intubation in patients with predicted difficult intubations

BACKGROUND

King Vision and McGrath MAC video laryngoscopes (VLs) are increasingly used. The purpose of this study was to evaluate the performance of nasotracheal intubation in patients with predicted difficult intubations using non-channeled King Vision VL, McGrath MAC VL or Macintosh laryngoscope by experienced intubators.

METHODS

Ninety nine ASA I or II adult patients, scheduled for oral maxillofacial surgeries with El-Ganzouri risk index 1-7 were enrolled. Patients were randomly allocated to intubate with one of three laryngoscopes (non-channeled King Vision, McGrath MAC and Macintosh). The intubators were experienced with more than 100 successful nasotracheal intubations using each device. The primary outcome was intubation time. The secondary outcomes included first success rate, time required for viewing the glottis, Cormack-Lehane grade of glottis view, the number of assist maneuvers, hemodynamic responses, the subjective evaluating of sensations of performances and associated complications.

RESULTS

The intubation time of King Vision and McGrath group was comparable (37.6 ± 7.3 s vs. 35.4 ± 8.8 s) and both were shorter than Macintosh group (46.8 ± 10.4 s, p < 0.001). Both King Vision and McGrath groups had a 100% first attempt success rate, significantly higher than Macintosh group (85%, p < 0.05). The laryngoscopy time was comparable between King Vision and McGrath group (16.7 ± 5.5 s vs. 15.6 ± 6.3 s) and was shorter than Macintosh group (22.8 ± 7.2 s, p < 0.05) also. Compared with Macintosh laryngoscope, Glottis view was obviously improved when exposed with either non-channeled King Vision or McGrath MAC VL (p < 0.001), and assist maneuvers required were reduced (p < 0.001). The maximum fluctuations of MAP were significantly attenuated in VL groups (47.7 ± 12.5 mmHg and 45.1 ± 10.3 mmHg vs. 54.9 ± 10.2 mmHg, p < 0.05 and p < 0.01). Most device insertions were graded as excellent in McGrath group, followed by Macintosh and King Vision group (p = 0.0014). The tube advancements were easier in VLs compared with the Macintosh laryngoscope (p < 0.001). Sore throat was found more frequent in Macintosh group compared with King Vision group (p < 0.05).

CONCLUSIONS

Non-channeled King Vision and McGrath MAC VLs were comparable and both devices facilitated nasotracheal intubation in managing predicted difficult intubations compared with Macintosh laryngoscope.

TRIAL REGISTRATION

ClinicalTrials registration number NCT03126344 . Registered on April 24, 2017.

Tracheal intubation with channeled vs. non-channeled videolaryngoscope blades

Study objective

Videolaryngoscopes can be fitted either with channeled or non-channeled blades, which may result in a different performance and success of tracheal intubation. We investigated the characteristics of the two different blade types of the commercially available KingVision™ videolaryngoscope.

Design

A prospective, randomized, single center investigation study in a urological operation unit of a tertiary hospital.

Subjects and Methods

Forty adult patients undergoing elective urological surgery in general anaesthesia with tracheal intubation were randomly allocated into group 1 (channeled videolaryngoscopy, n = 20) and group 2 (non-channeled videolaryngoscopy, n = 20). We measured the times from laryngoscope insertion to recognize the glottis and to conclude tracheal intubation. The number of laryngoscopy/intubation attempts and the degree of visual glottis exposure on a visual analog scale from 0 (glottis not visible) to 10 (glottis fully visible) was assessed. The lowest SpO₂ value during airway management was recorded.

Results

There was no statistically significant difference in biometric data between the 2 groups. The time from the laryngoscope insertion to glottis recognition with the non-channeled blades was 5 (4-8) s as compared to the channeled ones with 11 (7-14) s (median and range; p = 0.01). Intubation duration was shorter with the channeled blades 17 (12-27) s vs. 29 (25-51) s (median and range; p < 0.001). Number of laryngoscopy/intubation attempts, grades for glottis visibility, intubation difficulty were not different. The lowest SpO₂ was 98% in both groups.

Conclusions

Videolaryngoscopic glottis recognition time was longer and the total time to secure the airway was shorter with the channeled blades.