Cervical Spine Motion During Tracheal Intubation Using an Optiscope Versus the McGrath Videolaryngoscope in Patients With Simulated Cervical Immobilization: A Prospective Randomized Crossover Study

Visual rigid laryngoscopy versus video laryngoscopy for endotracheal intubation in elderly patients: A randomized controlled trial

OBJECTIVE

To assess the efficacy and safety of visual rigid laryngoscopy and video laryngoscopy and to provide clinical information for developing a more suitable intubation tool for elderly patients.

METHODS

In 75 consecutive elderly patients undergoing elective surgery in a single institution, tracheal intubation was randomly performed by 2 experienced anaesthesiologists using visual rigid laryngoscopy (Group I, n = 38) or video laryngoscopy (Group II, n = 37). The primary outcome was intubation time. Secondary outcomes were the first-attempt success rate of tracheal intubation, haemodynamic responses at 1, 3, and 5 min after intubation and the incidence of postoperative airway complications, including immediate complications and postoperative complaints.

RESULTS

The intubation times were 35.0 (30.0-41.5) s and 42.5 (38.0-51.3) s in Groups I and II, respectively (P < 0.001). The difference in direct complications between the two groups was statistically significant (P < 0.05). In contrast, there was no significant difference between the two groups regarding the follow-up of the main complaint 30 min and 24 h after tracheal extubation (P > 0.05). There was no difference in the intubation success rate between the 2 groups (P > 0.05). The haemodynamic responses at 1, 3, and 5 min after intubation were not significantly different (P > 0.05).

CONCLUSION

Compared with that of video laryngoscopy, the intubation time of visual rigid laryngoscopy in elderly patients was shorter. At the same time, visual rigid laryngoscopy reduced the incidence of immediate complications. However, during endotracheal intubation, there was no significant difference in haemodynamics between the two groups.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR2100054174.

Direct versus indirect epiglottis elevation in cervical spine movement during videolaryngoscopic intubation under manual in-line stabilization: a randomized controlled trial

BACKGROUND

During videolaryngoscopic intubation, direct epiglottis elevation provides a higher percentage of glottic opening score than indirect epiglottis elevation. In this randomized controlled trial, we compared cervical spine movement during videolaryngoscopic intubation under manual in-line stabilization between the two glottis exposure methods.

METHODS

Videolaryngoscopic intubation under manual in-line stabilization was performed using C-MAC® D-blade: direct (n = 51) and indirect (n = 51) epiglottis elevation groups. The percentage of glottic opening score was set equally at 50% during videolaryngoscopic intubation in both groups. The primary outcome measure was cervical spine movement during videolaryngoscopic intubation at the occiput-C1, C1-C2, and C2-C5. The secondary outcome measures included intubation performance (intubation success rate and intubation time).

RESULTS

Cervical spine movement during videolaryngoscopic intubation was significantly smaller at the occiput-C1 in the direct epiglottis elevation group than in the indirect epiglottis elevation group (mean [standard deviation] 3.9 [4.0] vs. 5.8 [3.4] °, P = 0.011), whereas it was not significantly different at the C1-C2 and C2-C5 between the two groups. All intubations were successful on the first attempt, achieving a percentage of glottic opening score of 50% in both groups. Intubation time was longer in the direct epiglottis elevation group (median [interquartile range] 29.0 [24.0-35.0] vs. 22.0 [18.0-27.0] s, P < 0.001).

CONCLUSIONS

When performing videolaryngoscopic intubation under manual in-line stabilization, direct epiglottis elevation can be more beneficial than indirect epiglottis elevation in reducing cervical spine movement during videolaryngoscopic intubation at the occiput-C1.

TRIAL REGISTRATION

Clinical Research Information Service (number: KCT0006239, date: 10/06/2021).

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.

Comparison of video-stylet and conventional laryngoscope for endotracheal intubation in adults with cervical spine immobilization: A PRISMA-compliant meta-analysis

BACKGROUND

Although minimization of cervical spine motion by using a neck collar or manual in-line stabilization is recommended for urgent tracheal intubation (TI) in patients with known or suspected cervical spine injury (CSI), it may worsen glottic visualization. The overall performance of video-stylets during TI in patients with neck immobilization remains unclear. The current meta-analysis aimed at comparing the intubation outcomes of different video-stylets with those of conventional laryngoscopes in patients with cervical immobilization.

METHOD

The databases of Embase, Medline, and the Cochrane Central Register of Controlled Trials were searched from inception to June 2021 to identify trials comparing intubation outcomes between video-stylets and conventional laryngoscopes. The primary outcome was first-pass success rate, while secondary outcomes included overall success rate, time to intubation, the risk of intubation-associated sore throat, or tissue damage.

RESULTS

Five randomized controlled trials published between 2007 and 2013 involving 487 participants, all in an operating room setting, were analyzed. The video-stylets investigated included Bonfils intubation fiberscope, Levitan FPS Scope, and Shikani optical stylet. There was no difference in first-pass success rate (risk ratio [RR] =1.08, 95% confidence interval [CI]: 0.89-1.31, P = .46], overall success rate (RR = 1.06, 95% CI: 0.93-1.22, P = .4), intubation time [mean difference = 4.53 seconds, 95% CI: -8.45 to 17.51, P = .49), and risk of tissue damage (RR = 0.46, 95% CI: 0.16-1.3, P = .14) between the 2 groups. The risk of sore throat was lower with video-stylets compared to that with laryngoscopes (RR = 0.45, 95% CI: 0.23-0.9, P = .02).

CONCLUSION

Our results did not support the use of video-stylets as the first choice for patients with neck immobilization. Further studies are required to verify the efficacy of video-stylets in the nonoperating room setting.

The effects of backward, upward, rightward pressure maneuver for intubation using the OptiscopeTM: a retrospective study

BACKGROUND

The OptiscopeTM and the backward, upward, rightward pressure (BURP) maneuver are widely used in clinical practice because the BURP maneuver facilitates intubation by improving visualization of the larynx. However, the effect of the BURP maneuver is unclear when using the OptiscopeTM. Therefore, we retrospectively investigated the effect of the BURP maneuver on intubation using the OptiscopeTM.

METHODS

Sixty-eight patients intubated with the OptiscopeTM were enrolled. We used the BURP maneuver in Group A (n = 33) and the conventional maneuver (which does not use the BURP maneuver) in Group B (n = 35). BURP application status was a binary variable representing whether the BURP maneuver was used during the intubation. A multiple linear regression analysis was performed to assess the effects of the BURP application status on intubation time controlling for body mass index, preoperative dental injury status, obstructive sleep apnea history, thyromental distance, sternomental distance, interincisor distance, history of neck rotation restriction, and Mallampati classification.

RESULTS

There was no difference in the intubation time between the two groups. According to the regression model (R2 = 0.308, P = 0.007), the BURP maneuver (Group A) decreased the intubation time by 6.089 seconds (95% confidence interval 1.303-10.875, P = 0.014) compared to Group B.

Comparison of video-stylet and video-laryngoscope for endotracheal intubation in adults with cervical neck immobilisation: A meta-analysis of randomised controlled trials

BACKGROUND

The efficacy of video-stylet versus video-laryngoscope for tracheal intubation in patients with cervical spine immobilisation, which is known to impede the intubation process, remains unclear.

METHODS

We searched electronic databases including EMBASE, MEDLINE, Google Scholar, and Cochrane Library for randomised controlled trials comparing video-stylets with video-laryngoscopes in human subjects with cervical spine immobilisation from inception to the 25^th of January 2021. The primary outcome was the rate of successful first-attempt intubation, while secondary outcomes included overall intubation success rate, time for successful intubation, and risk of tissue damage.

RESULTS

Five trials (709 patients) published between 2009 and 2020 met the inclusion criteria. There were four types of video-stylets and three types of video-laryngoscopes examined. Hard cervical collar was applied in four studies, while manual inline stabilisation was used in one study for cervical immobilisation. There was no difference in successful first-attempt intubation rate between the video-stylet and the video-laryngoscope groups [risk ratio (RR) = 0.96, 95% CI: 0.90-1.03, p = 0.3; I² = 47%] (5 trials, 709 patients). The overall success rate (RR = 0.98, 95% CI: 0.96-1.0, p = 0.05; I² = 0%), intubation time [mean difference (MD) = 5.24, 95% CI: -8.95 to 19.43, p = 0.47; I² = 92%], and risk of tissue damage (RR = 0.87, 95% CI: 0.26-2.85, p = 0.81; I² = 39%) were also comparable between the two groups.

CONCLUSIONS

This study validates the efficacy of both video-stylets and video-laryngoscopes for tracheal intubation in the situation of cervical spine immobilisation. Further large-scale trials are warranted to support our findings in this clinical setting.

Airway management in the adult patient with an unstable cervical spine

PURPOSE OF REVIEW

The ideal airway management of patients with unstable spinal injury presents a perennial challenge for anaesthesiologists. With competing interests, potentially catastrophic complications, and a scarcity of evidence to support common practices, it is an area rich with dogma and devoid of data. This review seeks to highlight recent evidence that improves our assurance that what we do to manage the airway in the unstable cervical spine is supported by data.

RECENT FINDINGS

The increasing range of available technology for intubation provides important opportunities to investigate the superiority (or otherwise) of various techniques - and a chance to challenge accepted practice. Long-held assumptions regarding spinal immobilisation in the context of airway management may require refinement as a true base of evidence develops.

SUMMARY

Video laryngoscopy may replace direct laryngoscopy as the default technique for endotracheal intubation in patients with suspected or confirmed spinal instability. Immobilisation of the unstable cervical spine, manually or with rigid cervical collars, is increasingly controversial. It may be that hard collars are used in specific circumstances, rather than as universal precaution in the future.There are no recent data of significantly high quality to warrant wholesale changes to recommended airway management practice and in the absence of new information, limiting movement (in the suspected or confirmed unstable cervical spine) remains the mainstay of clinical practice advice.

Effects of External Laryngeal Manipulation on Cervical Spine Motion during Videolaryngoscopic Intubation under Manual In-Line Stabilization: A Randomized Crossover Trial

We hypothesized that external laryngeal manipulation would reduce cervical spine motion during video laryngoscopic intubation under manual in-line stabilization by reducing the force required to lift the videolaryngoscope. In this randomized crossover trial, 27 neurointerventional patients underwent two consecutive videolaryngoscopic intubation attempts under manual in-line stabilization. External laryngeal manipulation was applied to all patients in either the first or second attempt. In the second attempt, we tried to reproduce the percentage of glottic opening score obtained in the first attempt. Primary outcomes were cervical spine motion during intubation at the occiput-C1, C1–C2, and C2–C5 segments. The intubation success rate (secondary outcome measure) was recorded. Cervical spine motion during intubation at the occiput-C1 segment was significantly smaller with than without external laryngeal manipulation (7.4° ± 4.6° vs. 11.5° ± 4.8°, mean difference −4.1° (98.33% confidence interval −5.8° to −2.3°), p < 0.001), showing a reduction of 35.7%. Cervical spine motion during intubation at the other segments was not significantly different with versus without external laryngeal manipulation. All intubations were achieved successfully regardless of the application of external laryngeal manipulation. External laryngeal manipulation is a useful method to reduce upper cervical spine motion during videolaryngoscopic intubation under manual in-line stabilization.

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).

Randomized crossover trial comparing cervical spine motion during tracheal intubation with a Macintosh laryngoscope versus a C-MAC D-blade videolaryngoscope in a simulated immobilized cervical spine

BACKGROUND

Maintaining cervical immobilization is essential during tracheal intubation in patients with unstable cervical spines. When using the Macintosh laryngoscope for intubation in patients with cervical immobilization, substantial neck extension is required for visualization of the glottis. However, the C-MAC D-Blade videolaryngoscope may require less neck extension due to its acute angulation. We hypothesized that C-MAC D-Blade videolaryngoscopic intubation would result in less cervical spine movement than Macintosh laryngoscopic intubation. We compared the effects of C-MAC D-Blade videolaryngoscopic intubation and Macintosh laryngoscopic intubation in terms of cervical spine motion during intubation in patients with simulated cervical immobilization.

METHODS

In this randomized crossover study, the cervical spine angle was measured at the occiput-C1, C1-C2, and C2-C5 segments before and during tracheal intubation with either a C-MAC D-Blade videolaryngoscope or Macintosh laryngoscope in 20 patients, with application of a neck collar for simulated cervical immobilization. Cervical spine motion was defined as the change in angle measured before and during tracheal intubation.

RESULTS

The cervical spine motion at the occiput-C1 segment was measured at 12.1 ± 4.2° and 6.8 ± 5.0° during Macintosh laryngoscopic and C-MAC D-blade videolaryngoscopic intubation, respectively, corresponding to a 44% reduction in cervical spine motion when using the latter device (mean difference, - 5.3; 98.33% CI: - 8.8 to - 1.8; p = 0.001). However, there was no significant difference between the two intubation devices at the C1-C2 segment (- 0.6; 98.33% CI: - 3.4 to 2.2; p = 0.639) or C2-C5 segment (0.2; 98.33% CI: - 6.0 to 6.4; p = 0.929).

CONCLUSIONS

The C-MAC D-Blade videolaryngoscope causes less upper cervical spine motion than the Macintosh laryngoscope during tracheal intubation of patients with simulated cervical immobilization.

TRIAL REGISTRATION

This study was registered at ClinicalTrials.gov on June 26, 2018 ( NCT03567902 ).

Radiographic Predictors of Difficult McGrath MAC Videolaryngoscopy in Patient Undergoing Cervical Spine Surgery

BACKGROUND

McGrath MAC videolaryngoscopy is a useful technique for successful intubation in cervical spine-injured patients with manual in-line stabilization of the neck during intubation. We aimed to identify radiographic predictors of difficult McGrath MAC videolaryngoscopy in patient undergoing cervical spine surgery.

METHODS

Patients undergoing cervical spine surgery who were intubated with a McGrath MAC videolaryngoscope under manual in-line stabilization of the neck between June 2016 and August 2018 were included in this study. Data on airway-related variables and radiographic indices obtained from preoperative lateral cervical spine x-ray, magnetic resonance imaging, and computed tomography (CT) scans were retrospectively collected. Patients were divided into difficult and easy McGrath MAC videolaryngoscopic intubation groups on the basis of intubation time and the number of intubation attempts.

RESULTS

In total, 183 patients were included in the study of which 33 (18%) showed difficult videolaryngoscopic intubation. In multivariate logistic regression analysis, atlanto-occipital distance (odds ratio [OR], 0.74; 95% confidence interval [CI], 0.62-0.89; P=0.001) on lateral cervical spine x-ray, incisor-C1-C6 angle in neck extension on lateral cervical spine x-ray (OR, 1.12; 95% CI, 1.02-1.22; P=0.015), tongue area/oral cavity area ratio in the mid-sagittal plane of cervical magnetic resonance imaging or computed tomography (OR, 1.12; 95% CI, 1.05-1.19; P<0.001), and interincisor gap (OR, 0.92; 95% CI, 0.86-0.98; P=0.015) were independent risk factors for difficult videolaryngoscopic intubation.

CONCLUSIONS

Radiographic variables indicating enlarged tongue relative to the oral cavity and limited neck extension were associated with difficult McGrath MAC videolaryngoscopy in patients undergoing cervical spine surgery with manual in-line cervical stabilization during intubation.

No radiographic index predicts difficult intubation using the Optiscope™ in cervical spine surgery patients: a retrospective study

Background

The Optiscope™ can be used for intubation with minimal neck motion. We retrospectively investigated radiographic predictors of difficult intubation using the Optiscope™ by analyzing preoperative radiographic images.

Methods

One hundred eighty-four patients who were intubated with the Optiscope™ under manual in-line cervical stabilization for cervical spine surgery were enrolled. Radiographic indices were measured on preoperative cervical spine lateral X-ray and magnetic resonance imaging images. Difficult intubation was defined as failure or time consumption more than 90 s on the first attempt. To identify significant predictors of difficult intubation using the Optiscope™ and evaluate their diagnostic value, multivariable logistic regression and receiver operating characteristic analyses were used.

Results

Fourty-seven patients showed difficult intubation. There was no significant difference in radiographic indices between the difficult and easy intubation groups, but higher body mass index (BMI) (26.5 [3.0] vs. 24.6 [3.5] kg/m², P = 0.001), shorter sternomental distance (SMD) (122.0 [104.0 to 150.0] vs. 150.0 [130.0 to 170.0] mm, P = 0.001), shorter interincisor gap (40.0 [35.0 to 45.0] vs. 43.0 [40.0 to 50.0] mm, P = 0.006), and higher incidence of excessive oral secretions (10.6% vs. 2.9%, P = 0.049) were observed in patients with difficult intubation. In multivariable analysis, BMI (odds ratio [95% confidence interval]; 1.15 [1.03 to 1.28], P = 0.011) and SMD (odds ratio [95% confidence interval]; 0.98 [0.97 to 1.00], P = 0.008) were associated with difficult intubation with the Optiscope™. In receiver operating characterstic analysis, the area under the curve for body mass index was 0.68 (95% confidence interval; 0.60 to 0.77, P < 0.001) and that for sternomental distance was 0.66 (95% confience interval; 0.57 to 0.75, P = 0.001).

Conclusions

The incidence of difficult intubation using the Optiscope™ under manual in-line cervical stabilization was 25.5% in cervical spine surgery patients. No significant predictor of difficult intubation with the Optiscope™ was identified among the measured radiographic indices. Although high BMI and short SMD were predictive of difficult intubation with the Optiscope™, their discrimination power was weak.