Normal Variations in Upper Esophageal Sphincter Function During Deglutition: A Secondary Analysis of Videofluoroscopic Data

OBJECTIVE

Cricopharyngeal dysfunction is a common potential cause of pharyngoesophageal dysphagia. Contextual factors (i.e., personal demographics and bolus properties) appear to impact upper esophageal sphincter (UES) function but have yet to be assessed collectively in a large-scale study using psychometrically sound swallow task procedures. Using a standardized and validated videofluoroscopic approach, we investigated the collective effects of age, sex, and swallow task on UES opening duration (UESOdur) and UES maximum distension (UESmax) in a large sample of healthy adults.

METHODS

UESOdur and UESmax data were analyzed from existing videofluoroscopic images of 195 healthy adults (21-89 years old) across seven swallow tasks (thin liquid to viscous liquids, puree, and a solid). Generalized estimating equation modeling captured the effects of the aforementioned contextual factors (α = 0.05).

RESULTS

UESOdur significantly increased with age, while UESmax had an inverse relationship. Females had significantly wider UESmax. UESOdur of 5 mL thin liquid was significantly shorter than all other liquid swallow tasks, while solid had an inverse effect. Compared to 5 mL thin liquid, all other swallow tasks resulted in significantly wider UESmax. Mildly and moderately thick liquid significantly increased UESOdur when isolating viscosity. UESmax was significantly wider with mildly and moderately thick liquid and puree than thin liquid. When isolating volume, cup sip thin liquid increased both measures significantly relative to 5 mL.

CONCLUSION

Age, sex, and swallow task can influence the normal timing and extent of UES movement. These collective effects contribute to normal variability in UES function and should be considered for clinical decision-making.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:2306-2315, 2024.

Feasibility study of intubation in lateral position using Viva-sight double-lumen tube combined with video laryngoscope in patients undergoing pulmonary lobectomy

BACKGROUND

Double-lumen tube (DLT) intubation in lateral decubitus position is rarely reported. We designed this study to evaluate the feasibility of VivaSight double-lumen tube (VDLT) intubation assisted by video laryngoscope in lateral decubitus patients.

METHODS

Patients undergoing elective video-assisted thoracoscopic surgery (VATS) for lung lobectomy were assessed for eligibility between January 2022 and December, 2022. Eligible patients were randomly allocated into supine intubation group (group S) and lateral intubation group (group L) by a computer-generated table of random numbers. The prime objective was to observe whether the success rate of VDLT intubation in lateral position with the aid of video laryngoscope was not inferior to that in supine position.

RESULTS

A total of 116 patients were assessed, and 88 eligible patients were randomly divided into group L (n = 44) and group S (n = 44). The success rate of the first attempt intubation in the L group was 90.5%, lower than that of S group (97.7%), but there was no statistical difference (p > 0.05). Patients in both groups were intubated with VDLT for no more than 2 attempts. The mean intubation time was 91.98 ± 26.70 s in L group, and 81.39 ± 34.35 s in S group (p > 0.05). The incidence of the capsular malposition in the group L was 4.8%, less than 36.4% of group S (p < 0.001). After 24 h of follow-up, it showed a higher incidence of sore throat in group S, compared to that in group L (p = 0.009).

CONCLUSION

Our study shows the comprehensive success rate of intubation in lateral decubitus position with VDLT assisted by video laryngoscope is not inferior to that in supine position, with less risk of intraoperative tube malposition and postoperative sore throat.

TRIAL REGISTRATION

Chinese Clinical Trail Register (ChiCTR2200062989).

A Case of Anterior Arytenoid Cartilage Dislocation During Nasal Tracheal Intubation Using an Indirect Video Laryngoscope

Arytenoid cartilage dislocation can occur as a complication of tracheal intubation and laryngeal trauma, but its occurrence with indirect video laryngoscopy has not been reported. This paper reports anterior arytenoid dislocation occurring after nasotracheal intubation performed under indirect laryngoscopy using a video laryngoscope (McGRATH MAC; Medtronic). The dislocation is presumed to have resulted from the laryngoscope blade being initially inserted too deeply and applying pressure to the posterior aspect of the left cricoarytenoid joint. This patient's anterior arytenoid dislocation was treated conservatively using speech therapy with resolution occurring approximately 40 days postoperatively. On the 74th day after surgery, fibroscopic examination confirmed recovery and healing of the dislocation. However, other types of arytenoid dislocations and laryngeal injuries may require alternative treatment. Early consultation with an otolaryngologist is recommended if arytenoid dislocation is suspected.

GlideScope versus C-MAC D-blade videolaryngoscope for double-lumen tube intubation in patients with anticipated difficult airways: A multi-center, prospective, randomized, controlled trial

STUDY OBJECTIVE

Videolaryngoscopes are widely used to visualize difficult airways. Our aim was to compare the GlideScope and C-MAC D-blade videolaryngoscopes for double-lumen tube (DLT) intubation in patients with difficult airways.

DESIGN

A multi-center, prospective, randomized controlled trial.

SETTING

Three comprehensive tertiary, high-volume hospitals from 5 December 2020 to 4 November 2021.

PATIENTS

We included 348 adult patients with anticipated difficult airways who underwent elective thoracic surgery.

INTERVENTIONS

Patients were randomized into two groups: GlideScope and C-MAC D-blade. Following anesthesia induction, DLT intubation was performed using different videolaryngoscopes.

MEASUREMENTS

The primary outcome was the first-pass success rate of DLT intubation. All other results were recorded as secondary outcomes.

MAIN RESULTS

No significant differences were observed in the first-pass success rate of DLT intubation between the GlideScope and C-MAC D-blade (86.21% and 89.66%, respectively; P = 0.323). However, compared with the GlideScope, the C-MAC D-blade provided a lower Cormack-Lehane grade (P < 0.001), lower rates of external laryngeal pressure (48 vs. 15, P < 0.001), and postprocedure sore throat (26 vs. 8, P < 0.001). The numerical rating score for difficulty of videolaryngoscope insertion into the oral cavity, delivery to the glottis, and intubation into the main bronchus were significantly lower when using the C-MAC D-blade (P < 0.001). Moreover, the duration of DLT intubation was shorter in the C-MAC D-blade group (81 s [70-97 s] vs. 95 s [78-115 s], P < 0.001). In each group, two patients underwent fiberoptic intubation after three attempts with a videolaryngoscope failed.

CONCLUSIONS

In patients with difficult airways, the GlideScope and C-MAC D-blade provided a similar success rate on the first DLT intubation attempt; however, the C-MAC D-blade offers a better glottic view, easier and faster intubation, and lower incidence of sore throat.

Single-use versus reusable metallic laryngoscopes for non-emergent intubation: A retrospective review of 72,672 intubations

STUDY OBJECTIVE

Increased regulatory requirements for sterilization in recent years have prompted a widespread transition from reusable to single-use laryngoscopes. The purpose of this study was to determine if the transition from metallic reusable to metallic single-use laryngoscopes impacted the performance of direct laryngoscopy at an academic medical center.

DESIGN

Single-site retrospective cohort study.

SETTING

General anesthetic cases requiring tracheal intubation.

PATIENTS

Adult patients undergoing non-emergent procedures.

INTERVENTIONS

Data were collected two years before and two years after a transition from metallic reusable to metallic single-use laryngoscopes.

MEASUREMENTS

The primary outcome was need for intubation rescue with an alternate device. Secondary outcomes were difficult laryngeal view (modified Cormack-Lehane grade ≥ 2b) and hypoxemia (SpO2 < 90% for >30 s) during direct laryngoscopy intubations. Subgroup analyses for rapid sequence induction, Macintosh blades, Miller blades, and patients with difficult airway risk factors (Obstructive Sleep Apnea, Mallampati ≥3, Body Mass Index >30 kg/m2) were performed.

MAIN RESULTS

In total, 72,672 patients were included: 35,549 (48.9%) in the reusable laryngoscope cohort and 37,123 (51.1%) in the single-use laryngoscope cohort. Compared with reusable laryngoscopes, single-use laryngoscopes were associated with fewer rescue intubations with an alternate device (covariates-adjusted odds ratio [OR] 0.81 95% CI 0.66-0.99). Single-use laryngoscopes were also associated with lower odds of difficult laryngeal view (OR 0.86; 95% CI 0.80-0.93). Single use laryngoscopes were not associated with hypoxemia during the intubation attempt (OR 1.03; 95% CI 0.88-1.20). Similar results were observed for subgroup analyses including rapid sequence induction, Macintosh blades, Miller blades, and patients with difficult airway risk factors.

CONCLUSIONS

Metallic single-use laryngoscopes were associated with less need for rescue intubation with alternate devices and lower incidence of poor laryngeal view compared to reusable metallic laryngoscopes.

Successful Tracheal Intubation With Airway Scope After Failure With McGrath

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

[Clinical report of hoding cricoarytenoid joint reduction with visual laryngoscope under intravenous anesthesia]

Objective: To investigate the reduction effect of hoding cricoarytenoid joint reduction with visual laryngoscope under intravenous anesthesia. Methods: The therapeutic effects of 40 patients with arytenoid dislocation(AD)treated by closed reduction in the single center from January 2020 to September 2021 were retrospectively analyzed, including 21 males and 19 females, median age 48 years. The etiology, symptoms, preoperative evaluation methods, reduction mode, reduction times, and the recovery of arytenoid cartilage movement and sound after reduction were evaluated and analyzed. Results: All patients had obvious hoarseness and breath sound before treatment. Under stroboscopic laryngoscope or electronic nasopharyngoscope, different degrees of vocal cord movement disorder and poor glottic closure can be seen. There were 28 cases of left dislocation, 9 cases of right dislocation and 3 cases of bilateral dislocation. The etiology of dislocation of cricoarytenoid joint: 25 cases (62.5%) of tracheal intubation under general anesthesia were the most common causes, was as follows by laryngeal trauma, gastroscopy, cough, vomiting and so on. Among them, 28 cases of reduction were initially diagnosed in our department, and 12 cases were diagnosed later after failure of reduction treatment. Of the 40 patients, 6 underwent reduction 24 hours after dislocation; 18 cases from 3 days to 1 month; 7 cases from 1 to 3 months; 6 cases were reset in 3~6 months; Over 6 months in 3 cases. After one reduction, 10 cases (10/40, 25%) recovered normal pronunciation, 14 cases (14/40, 35%) recovered normal pronunciation after two reduction, 10 cases (10/40, 25%) recovered normal pronunciation after three times, 2 cases (2/40, 5%) recovered normal pronunciation after four times, and 1 case (2.5%) recovered normal pronunciation after five times. Thin slice CT scan of larynx and cricoarytenoid joint reconstruction showed the types of AD: subluxation in 37 cases (92.5%) and total dislocation in 3 cases; 28 cases of left dislocation, 9 cases of right dislocation and 3 cases of bilateral dislocation; 29 cases (72.5%) had posterior dislocation and 11 cases (27.5%) had anterior dislocation. All patients were treated by intravenous anesthesia with arytenoid cartilage clamped by cricoarytenoid joint reduction forceps under visual laryngoscope. The curative effect was evaluated by stroboscopic laryngoscope and/or voice analysis at 1-2 weeks after operation. The vocal cord movement returned to normal and the pronunciation was good in 37 cases (92.5%). Conclusions: Hoding cricoarytenoid joint reduction with the vision laryngoscope under intravenous anesthesia is easy to operate and the reduction effect is more stable. It is a effective method for AD.

Comparison of C-MAC vs. McGrath video laryngoscopes on glottic exposure and endotracheal intubation success with stylet usage in obese patients

OBJECTIVE

Cases of obesity are rising in parallel with the number of obese patients scheduled for anesthesia in which difficult airway is encountered. Video laryngoscopes (VL) have emerged as a popular device for the management of patients with difficult airway. The present study compares the success rate of intubation in obese patients using stylet in the ramped position using either a McGrath or C-MAC VLs.

PATIENTS AND METHODS

Class II/III obese patients who were intubated with either McGrath (Group M, n=50) or C-MAC (Group C, n=50) laryngoscopes were assessed for the presence of difficult airway using the Difficult Airway Assessment tool, the Airway Difficulty Score and the Total Airway Score. The intubation attempts were made after the best glottic view, direct and indirect Cormack-Lehane (CL) score, and intubation time were recorded. In the event of failure, a further intubation attempt was made using a styled, and the intubation time was again recorded. If the intubation failed again, a third attempt was made using a C-MAC D-Blade. The Intubation Difficulty Scale score was recorded after the intubation.

RESULTS

There was no statistically significant difference between groups in terms of demographic data, the number of patients with decreased CL score, the number of attempts required for intubation, or the first and second intubation time. The ADS Score, TAS Score, CL Score DL, and CL Score IN were found to be important risk factors for a second intubation requirement, and the cut-off value was found to be 8.50 for the ADS Score and 4.50 for the TAS Score in these patients. In the 38 patients who required a second intubation attempt, the procedure was successful in all, but one patient required a third attempt of intubation with C-MAC D-blade.

CONCLUSIONS

Both McGrath and C-MAC were effective and comparable for best glottic view with no failed intubation. It was concluded that regardless of the type of video laryngoscope used, the use of a stylet in the first intubation attempt increases the success of intubation.

Intubation biomechanics: Computational modeling to identify methods to minimize cervical spine motion and spinal cord strain during laryngoscopy and tracheal intubation in an intact cervical spine

STUDY OBJECTIVE

To minimize the risk of cervical spinal cord injury in patients who have cervical spine pathology, minimizing cervical spine motion during laryngoscopy and tracheal intubation is commonly recommended. However, clinicians may better aim to reduce cervical spinal cord strain during airway management of their patients. The aim of this study was to predict laryngoscope force characteristics (location, magnitude, and direction) that would minimize cervical spine motions and cord strains.

DESIGN

We utilized a computational model of the adult human cervical spine and spinal cord to predict intervertebral motions (rotation [flexion/extension] and translation [subluxation]) and cord strains (stretch and compression) during laryngoscopy.

INTERVENTIONS

Routine direct (Macintosh) laryngoscopy conditions were defined by a specific force application location (mid-C3 vertebral body), magnitude (48.8 N), and direction (70 degrees). Sixty laryngoscope force conditions were simulated using 4 force locations (cephalad and caudad of routine), 5 magnitudes (25-200% of routine), and 3 directions (50, 70, 90 degrees).

MAIN RESULTS

Under all conditions, extension at Oc-C1 and C1-C2 were greater than in all other cervical segments. Decreasing force magnitude to values reported for indirect laryngoscopes (8-17 N) decreased cervical extension to ~50% of routine values. The cervical cord was most likely to experience potentially injurious compressive strain at C3, but force magnitudes ≤50% of routine (≤24.4 N) decreased strain in C3 and all other cord regions to non-injurious values. Changing laryngoscope force locations and directions had minor effects on motion and strain.

CONCLUSIONS

The model predicts clinicians can most effectively minimize cervical spine motion and cord strain during laryngoscopy by decreasing laryngoscope force magnitude. Very low force magnitudes (<5 N, ~10% of routine) are necessary to decrease overall cervical extension to <50% of routine values. Force magnitudes ≤24.4 N (≤50% of routine) are predicted to help prevent potentially injurious compressive cord strain.

The effect of laryngoscope types on hemodynamic response and optic nerve sheath diameter. McCoy, Macintosh, and C-MAC video-laryngoscope

OBJECTIVES

This study aims to investigate the effect of McCoy, Macintosh laryngoscope, and C-MAC video-laryngoscopes on optic nerve sheath diameter (ONSD) and hemodynamic responses to laryngoscopy and intubation.

METHODS

This prospective randomized study was conducted in Zonguldak Bülent Ecevit University Hospital, Zonguldak, Turkey, between July 2019 and January 2020. Informed written consent was obtained from all patients. Patients with previous intracranial/ocular surgery or glaucoma were excluded from the study. The patients were randomized to use McCoy, Macintosh, and C-MAC (30 per group). Intubations were performed by the same person. Mean arterial pressure, heart rate (HR), and ONSD were recorded before the induction and repeated in 1, 3, 5, and 10 minutes after the intubation.

RESULTS

The effects of laryngoscopy and intubation on hemodynamic responses and ONSD were similar between groups (p greater than 0.05). While the comparison within groups showed ONSD increase in McCoy group and HR and ONSD increase in the Macintosh group compared to baseline 1 min after the intubation, no change was observed in hemodynamic responses and ONSD measurements in the C-MAC® group (p greater than 0.05).

CONCLUSIONS

In this study, there was no significant difference between the groups in terms of ONSD and hemodynamic responses to laryngoscopy and intubation. It was observed that there were no significant changes in ONSD values just in C-MAC® video-laryngoscope group. Therefore, intubations with C-MAC® video-laryngoscope are thought to be more appropriate for patients with an increase in intracranial pressure.

Radiographic comparison of cervical spine motion using LMA Fastrach, LMA CTrach, and the Macintosh laryngoscope

Background/aim

The optimal technique for airway management in patients with cervical pathology remains unclear. Intubating laryngeal mask airway devices such as LMA CTrach and LMA Fastrach have not been compared for cervical spine (C-spine) movements in the context of cervical pathology. The present study aimed to determine upper C-spine movements by radiography during intubation with different devices as well as comparing the duration and success of intubation in cervical surgery.

Materials and methods

Sixty patients scheduled for elective cervical surgery were registered in this prospective, randomized study. Patients with cervical trauma/injury, previous neck surgery, and body mass index (BMI) of >35 kg/m² were excluded. Participants were randomized to one of the 3 groups: LMA CTrach, LMA Fastrach, or the Macintosh laryngoscope. C-spine motion was evaluated by measuring angles created by bordering vertebrae at cervical 1/2 and 2/3 (C1/2, C2/3) segments on 2 lateral cervical radiographs for each patient. Intubation time, ease of intubation, number of attempts, and success rate were also documented.

Results

Demographic data were similar in all the groups. The cervical movement with LMA CTrach and LMA Fastrach compared to the Macintosh laryngoscope were similar at C1/2. However, LMA CTrach significantly reduced extension compared to LMA Fastrach and Macintosh laryngoscopes at C2/3. Duration of intubation was significantly shorter with the Macintosh laryngoscope. The rate of successful intubation was 80% with LMA Fastrach and 100% with both LMA CTrach and the Macintosh laryngoscopes.

Conclusion

The LMA CTrach laryngoscopy involves less upper C-spine movement than the LMA Fastrach and does not increase the duration of the intubation period.

Usefulness of C-MAC video laryngoscope in direct laryngoscopy training in the emergency department: A propensity score matching analysis

Objectives

We determined the usefulness of C-MAC video laryngoscope (C-MAC) as a safe training tool for the direct laryngoscopy technique in the emergency department.

Methods

We retrospectively analyzed an institutional airway registry of adult (≥18 years old) patients from April 2014 through October 2016. In this study, the operator used C-MAC as a direct laryngoscope (DL) with limited access to the screen, and the supervisor instructed the operator via verbal feedback while watching the screen. Patients were categorized into the DL group if a conventional DL was used and the C-DL group if a C-MAC used as a DL.

Results

Of 744 endotracheal intubations, 163 propensity score-matched pairs were generated (1-to-n matching: C-DL group, 163 vs. DL group, 428). For the propensity-matched groups, the overall first pass success rate was 69%, while those in the C-DL and DL groups were 79% and 65%, respectively. Overall, multiple attempts were required in 8% of patients, with 4% in the C-DL group and 9% in the DL group. The overall complication rate was 11%, with 4% in the C-DL group and 14% in the DL group. In multivariable analysis, the adjusted odds ratios of C-DL use for first pass success, multiple attempts, and complications were 2.05 (95% confidence interval [CI] 1.18–2.87, p < 0.01), 0.38 (95% CI 0.15–0.94; p < 0.01), and 0.28 (95% CI 0.12–0.63; p < 0.01), respectively.

Conclusions

Our study suggests that the C-MAC could be useful for training residents in the direct laryngoscopy while ensuring patient safety in the emergency department.

Endotracheal intubation in elective cervical surgery: A randomized, controlled, assessor-blinded study

BACKGROUND

We compared the effectiveness and safety of endotracheal intubation using the GlideScope (GS) video laryngoscope, CTrach laryngeal mask airway (LMA), or Shikani optical stylet rigid laryngoscope (SOS) during elective cervical surgery.

METHODS

Forty-five patients undergoing elective cervical surgery were randomly and equally assigned to endotracheal intubation via GS, LMA, or SOS airway management.

RESULTS

Endotracheal intubation was successfully completed in all patients. The mean intubation times of the groups differed significantly (P < .01): GS, 17.9 ± 3.1 s; SOS, 40.4 ± 13.7 s; and LMA, 80.5 ± 22.5 s. The groups had similar heart rates and mean arterial pressures throughout the intubation, except that at 2 minutes after intubation the mean arterial pressure of the GS group (106.1 ± 18.5 mm Hg) was significantly higher than that of the LMA (89.7 ± 18.5 mm Hg) or SOS (89.7 ± 18.5 mm Hg; P < .01). The change in C2-5 Cobb angle from baseline was significantly higher in the GS group (GS, 34.2° ± 7.3°) than the LMA (24.4° ± 5.8°) or SOS (25.5° ± 6.4°); P < .01).

CONCLUSIONS

The CTrach LMA and SOS rigid laryngoscope are effective, safe alternatives to the GS video laryngoscope for patients undergoing elective cervical surgery.

A comparison of the Airtraq®, McGrath®, and Macintosh laryngoscopes for difficult paediatric intubation: A manikin study

BACKGROUND

The efficacy of devices for difficult intubation in paediatric patients, especially with a Cormack-Lehane grade 4 view, has yet to be established. We compared intubating parameters among three devices (the Airtraq®, McGrath®, and Macintosh laryngoscopes).

METHODS

This study is a randomised cross-over trial. Participants were 20 anaesthetists. Each device was tested three times using a paediatric manikin with a Cormack-Lehane grade 4 view. The order to use each device was randomised by a computer-generated random sequence. The primary endpoint was the rate of successful intubation. Secondary endpoints included the time taken to intubate, percentage of glottic opening score, and severity of potential dental trauma.

RESULTS

The successful intubation rates of the Airtraq®, McGrath®, and Macintosh laryngoscopes were 100%, 72%, and 45%, respectively. The risk ratio of the success rates of Airtraq® compared with McGrath® and Macintosh laryngoscopes were 1.40 (95% CI; 1.19-1.64, P < 0.001) and 2.22 (95% CI; 1.68-2.94, P < 0.001), respectively. The modified Cormack-Lehane grade and percentage of the glottic opening score were better for the Airtraq® than for the other devices. The dental trauma score was lower for the Airtraq® than for the other devices. There were no significant differences in the intubation time among the groups.

CONCLUSIONS

The Airtraq® had higher success rate, had better visibility, and was associated with less dental trauma than the other devices in a difficult paediatric intubation model with a Cormack-Lehane grade 4 view.

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

OBJECTIVE

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

DESIGN

Randomised cross-over simulation study.

SETTING AND PARTICIPANTS

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

PRIMARY AND SECONDARY OUTCOME MEASURES

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

RESULTS

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

CONCLUSIONS

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

A Case of Mediastimal Emphysema Possibly Caused by the Insertion of a Laryngoscope

Insertion of a laryngoscope to a patient with a strong pharyngeal reflex resulted in pharyngeal injury and subsequent development of mediastinal emphysema. An increase in airway pressure accompanying a strong pharyngeal reflex, as well as pharyngeal injury were thought to be factors associated with the development of mediastinal emphysema.

[Pentax AWS-s200: Its Advantages and Possible Problems]

The Pentax AWS-s200 (Hoya, Japan : s-200) is a new videolaryngoscope. Its weight is 190 g, and it is lighter than the original AWS (AWS-s100L: s-100). It has a USB port, and its screen is wider and clearer than the s-100. The INTROCK for the s-100 is all usable with the s-200. The target mark is positioned at the center of the screen in the s-200. We used the s-200 in 20 patients, and could see a full view of the glottis, and tracheal intubation was successful in all patients. But tracheal intubation was not smooth in 10 of 20 patients, mainly because the tube impacted the right arytenoid. We felt the target mark of the s-200 may be incorrectly positioned.

Randomized controlled pilot trial of the rigid and flexing laryngoscope versus the fiberoptic bronchoscope for intubation of potentially difficult airway

BACKGROUND

The flexible fiberoptic bronchoscope (FOB) is viewed as the gold standard device for awake intubation in the difficult airway. The newer rigid flexible laryngoscope (RIFL) was developed for similar indications. In this study we compare these two devices for management of potentially difficult airways after induction of general anesthesia.

METHODS

Adult surgical patients requiring endotracheal intubation and having a predicted difficult airway based on airway examination, BMI≥35, and/or history of prior difficult intubation were randomized to undergo endotracheal intubation with either the RIFL or FOB. Induction was performed in usual manner, and intubation was performed by providers proficient with both airway devices after induction of general anesthesia. The primary outcomes measured were intubation success, time to intubation, number of attempts, and the need for airway assist maneuvers. The lowest observed oxygen saturation and airway trauma were also recorded.

RESULTS

A total of 41 patients were enrolled, with 20 randomized to each group and 1 withdrawal. Intubation was successful in all patients with both devices. The median time for successful intubation was significantly shorter in the RIFL group compared to the FOB group (49 vs. 64 seconds; P=0.048). Airway assist maneuvers were required in 2 (10%) intubations with the RIFL compared to 16 (80%) intubations with the FOB (P<0.001). There were no significant differences in lowest oxygen saturation or airway trauma.

CONCLUSION

The RIFL required significantly less time and fewer airway assist maneuvers for successful endotracheal intubation compared to FOB when used by experienced providers in patients with anticipated difficult airways.

[Problems with the Structure of a New Pentax-Airwayscope S200]

BACKGROUND

Pentax-Airwayscope (AWS-S100) is useful for tracheal intubation, and a new version S200 has recently been introduced to clinical practice. We felt that S200 was more difficult than the S100 in attaching and detaching a single-use Introck blade.

METHODS

In a randomized cross-over design, we compared S100 and S200, for the ease of attaching to and detaching from the Introck, fixation of the Introck using the fixation ring of the main body, and insertion time.

RESULTS

Compared with S100, it was easier for S200 to fix the Introck using the fixation ring (78% vs 72%) (P < 0.05), but it was more difficult for S200 to attach (the incidence 43% vs 2%) and detach (53% vs 11%) the Introck (both P < 0.001). Insertion time was also significantly longer for S200 than S100 (median 9 [IQR : 6-19] s vs 4 [IQR : 3-6] s) (P < 0.001). The flexible scope of one of two S200s kinked and was broken during attachment.

CONCLUSIONS

It is necessary to apply lubricant to the distal part of the scope to prevent damage to the scope.

Comparison of McGRATH MAC and Macintosh laryngoscopes for double-lumen endotracheal tube intubation by anesthesia residents: a prospective randomized clinical trial

STUDY OBJECTIVE

This study aimed to compare the utility of McGRATH MAC (McG) and Macintosh (McL) laryngoscopes for double-lumen endotracheal tube intubation in patients undergoing elective surgery.

DESIGN

Randomized clinical trial.

SETTING

Operating room.

PATIENTS

Fifty adult patients scheduled for elective surgery under 1-lung ventilation with American Society of Anesthesiologists physical status 1 to 3.

INTERVENTIONS

Double-lumen endotracheal tube intubation was performed with the McG (McG group; 25 patients) or conventional McL (McL group; 25 patients) laryngoscope by anesthesia residents.

MEASUREMENTS

The number of attempts to successful intubation, intubation time, percentage of glottis opening score, and subjective difficulty of laryngoscopy and tube passage through the glottis were assessed.

MAIN RESULTS

The total numbers of intubation attempts were 1 (McG group, 24 patients; McL group, 16 patients), 2 (McG group, 1 patient; McL group, 8 patients), and 3 (McG group, 0 patient; McL group, 1 patient), with significant differences between the two groups (P = .018). Intubation time was significantly shorter in the McG group compared with the McL group (McG: 17.1 ± 4.6 seconds vs McL: 20.8 ± 5.9 seconds, P = .026). The percentage of glottis opening score was significantly higher in the McG group compared with the McL group (McG: 88.4% ± 13.7% vs McL: 71.4% ± 20.4%, P = .004).

CONCLUSIONS

The McG demonstrated a better intubation profile compared with the McL, possibly due to its ease of use for double-lumen endotracheal tube intubation. Clinical Trial registry number: UMIN000014636.

The use of Airtraq laryngoscope versus Macintosh laryngoscope and fiberoptic bronchoscope by experienced anesthesiologists

OBJECTIVE

The aim was to compare the hemodynamic parameters, intubation times, upper airway trauma and postoperative sore throat scores of the patients with normal airway anatomy, intubated with the Airtraq, Macintosh laryngoscope and fiberoptic bronchoscope, by experienced anesthesiologists.

METHODS

Ninety patients, scheduled to undergo elective surgery under general anesthesia were randomly divided into three groups (n = 30): Group A: Airtraq laryngoscope, Group M: Macintosh laryngoscope and Group FB: fiberoptic bronchoscope. The time to intubation and success rates were recorded. The hemodynamic parameters before and one minute after the anesthesia induction were recorded and the measurements were repeated 3, 4 and 5 minutes after the endotracheal intubation. The postoperative sore throat scores and signs of any trauma were also recorded.

RESULTS

Mean arterial blood pressure and heart rate were not significantly different between the three groups. The mean intubation time interval did not differ between groups. Highest postoperative sore throat scores were recorded at the 6th hour post extubation. The scores were 37.6 +/- 20.9 in Group A, 13.3 +/- 16.8 in Group M and 13.6 +/- 14.0 in Group FB. The scores in Group A were significantly higher compared to other groups. The number of patients requiring additional analgesia to relieve sore throat was also significantly higher in Group A.

CONCLUSION

The Airtraq laryngoscope seems to be a more traumatic airway device in the routine endotracheal intubation compared to Macintosh laryngoscope and fiberoptic bronchoscope, when used by experienced anesthesiologists. It also does not offer advantage over the first-attempt success rates, the intubation times and hemodynamic parameters.

[Case of pharyngeal laceration associated with the use of airwayscope in a patient with difficult airway]

A 54-year-old woman with atlantoaxial subluxation in rheumatoid arthritis was scheduled for total elbow arthroplasty. Since her neck was stabilized with a cervical collar and her interincisor distance was 1.5 finger-breadth, a difficult airway was anticipated. Anesthesia was induced with propofol and fentanyl. Mask ventilation was barely achieved with difficulty Then insertion of an Intlock with Airwayscope (AWS) into the pharynx was attempted but could not be performed because of restriction of neck mobility and small mouth opening. Although only Intlock separated from AWS could be inserted into the pharynx, oropharyngeal bleeding occurred and we could not obtain an appropriate view on the monitor. Following aspiration of blood, the trachea was intubated using a flexible fiberoptic bronchoscope under AWS guidance. After the operation, a view of bronchoscopy by an otolaryngologist revealed three lacerations from the mucosa to muscle layer in the pharynx. The lacerations could have resulted from use of AWS in a patient with a small mouth opening and with vulnerable mucosa due to long-term steroid therapy.

A comparative study of the efficacy of Pediatric Airtraq® with conventional laryngoscope in children

BACKGROUND

Management of pediatric airway may pose a challenge to anesthesiologists. Many modifications in maneuvers and equipments have been made overtime to overcome the problem. Pediatric optical laryngoscope (Airtraq®) is one of the newer equipments for managing simple and difficult pediatric airway. Here we have evaluated the comparative efficacy of pediatric Airtraq® optical laryngoscope with conventional laryngoscope in children scheduled for routine surgeries.

METHODS

After written informed consent from the parents/guardian of the children, they were allocated into two groups of 17 patients each using the pediatric Airtraq® in one and a conventional laryngoscope in the other. Airtraq® intubation patients were those in which pediatric Airtraq® was used to intubate whereas the patients who were intubated with conventional laryngoscope were labelled as conventional intubation group. The primary outcome measure was time needed for successful intubation whereas secondary outcome measures were number of attempts to intubate, POGO (percentage of glottic opening) scoring and complications like airway trauma and esophageal intubation.

RESULTS

It took significantly shorter time to intubate in Airtraq® intubation group of patients as compared to Conventional intubation group of patients (P<0.05). Similarly the POGO scoring was significantly better in Airtraq intubation compared to Conventional intubation (P <0.001). Number of attempts to intubate and complications like airway trauma and esophageal intubation using Airtraq® was less frequent compared to conventional laryngoscopy but the difference was statistically insignificant.

CONCLUSION

Pediatric Airtraq® provides better intubating conditions in children compared to conventional laryngoscope with less frequent complications.

[Kinking of the endotracheal tube in a prone patient associated with the inadequate withdrawal maneuver of the Pentax-AWS Airway Scope]

We report a case of intraoperative kinking of an endotracheal tube (ETT) in a prone patient during spine surgery. We postulate that one of the risk factors involved with kinking was the inadequate withdrawal maneuver of Pentax-AWS Airway Scope (AWS). Patient was a 69-year-old woman with hypertension, diabetes mellitus, and rheumatoid arthritis, undergoing C4-6 laminoplasty under general anesthesia in the prone position. A 7.0-mm polyvinyl endotracheal tube (Paker Flex-Tip Tube) was placed to 21 cm at the right angle of the mouse without difficulty using the AWS. Both peak inspiratory pressure (PIP) and partial pressure of end-tidal carbon dioxide began to rise gradually from 24 to 28 cmH2O and 38 to 44 mmHg, respectively. Although over 30 cmH2O in PIP repeatedly appeared after that, we did not find any remarkable change of ventilation except for weak breath sound. Thereafter, when we checked the tube with a flexible fiberoptic bronchoscope, it could not pass through the tube. At first, we asked the surgeon to release neck flexion as much as possible. This procedure could not correct the kink completely but allowed the passage of bronchoscope in the ETT. Then, we tried to reposition the ETT by inserting the bronchoscope beyond the point of kinking for maintaining luminal patency and adequate ventilation. The subsequent anesthetic course was uneventful. Kinking of the ETT in the oral cavity is an uncommon problem but we must keep in mind as one of the differential diagnoses. When using the AWS for endotracheal intubation, we recommend the confirmation of the position of the ETT to be normal in the oral cavity by direct laryngoscopy.

[Causes of vocal cord dyscinesia and its original factors after endotracheal intubation]

OBJECTIVE

To research the causes of postintubation vocal cord dyskinesia and its contributing factors.

METHOD

The causes of vocal cord dyskinesia were confirmed by laryngoscope, three-dimensional spiral CT, stroboscope, and the analysis of therapy. The factors relevant to the causes of vocal cord dyskinesia were analysed based on the following elements: (1) the anatomic or pathological condition of patients or the technical skills of anesthetists. (2) emaciated or obese body and neck. (3) the age of patients. (4) the duration of endotracheal tube retention. (5) the types of operations. (6) anesthesia procedure.

RESULT

Among 135 patients, 128 cases (94.81%) manifested arytenoid dislocation, 7 cases (5.19%) vocal cord paralysis. The study showed that the vocal cord dyskinesia associated with anatomic or pathological condition of patients and technical skills of anesthetists (with intubation difficulty) accounted for 76.30%. The patients with relative emaciated body or neck accounted for 90.62% in cases without intubation difficulty. Age had no significant analytical relationship with vocal cord dyskinesia. Prolonged intubation (endotracheal tube retention over 12 hours) was accounted for only 17.64%. The incidence of vocal cord dyskinesia was nearly 0.5% in patients underwent cardio-thoracic surgery, accounting for 59.26% of all the patients.

CONCLUSION

There are two major causes of vocal cord dyskinesia: arytenoid dislocation and vocal cord paralysis, and the rate of vocal cord dyskinesia could be reduced by the improvement of technical skill of anesthetists and/or sufficient attention to the intubation condition of patients.

Out-of-hospital tracheal intubation with single-use versus reusable metal laryngoscope blades: a multicenter randomized controlled trial

STUDY OBJECTIVE

Emergency tracheal intubation is reported to be more difficult with single-use plastic than with reusable metal laryngoscope blades in both inhospital and out-of-hospital settings. Single-use metal blades have been developed but have not been compared with conventional metal blades. This controlled trial compares the efficacy and safety of single-use metal blades with reusable metal blades in out-of-hospital emergency tracheal intubation.

METHODS

This randomized controlled trial was carried out in France with out-of-hospital emergency medical units (Services de Médecine d'Urgence et de Réanimation). This was a multicenter prospective noninferiority randomized controlled trial in adult out-of-hospital patients requiring emergency tracheal intubation. Patients were randomly assigned to either single-use or reusable metal laryngoscope blades and intubated by a senior physician or a nurse anesthetist. The primary outcome was first-pass intubation success. Secondary outcomes were incidence of difficult intubation, need for alternate airway devices, and early intubation-related complications (esophageal intubation, mainstem intubation, vomiting, pulmonary aspiration, dental trauma, bronchospasm or laryngospasm, ventricular tachycardia, arterial desaturation, hypotension, or cardiac arrest).

RESULTS

The study included 817 patients, including 409 intubated with single-use blades and 408 with a reusable blade. First-pass intubation success was similar in both groups: 292 (71.4%) for single-use blades, 290 (71.1%) for reusable blades. The 95% confidence interval (CI) for the difference in treatments (0.3%; 95% CI -5.9% to 6.5%) did not include the prespecified inferiority margin of -7%. There was no difference in rate of difficult intubation (difference 3%; 95% CI -7% to 2%), need for alternate airway (difference 4%; 95% CI -8% to 1%), or early complication rate (difference 3%; 95% CI -3% to 8%).

CONCLUSION

First-pass out-of-hospital tracheal intubation success with single-use metal laryngoscopy blades was noninferior to first-pass success with reusable metal laryngoscope blades.

The video laryngoscopes blind spots and possible lingual nerve injury by the Gliderite rigid stylet--case presentation and review of literature

We report the first case of near serious lingual nerve injury in an 80-y-old female caused by the Rigid GlideScope Stylet. This complication was discovered during oral surgery and may have been missed if the site of surgery was not oral cavity.

[Airtraq optical laryngoscopy]

Endotracheal intubation using direct laryngoscopy continues to be the "gold standard" amongst all the techniques for isolating the airway. Generally this is a secure manoeuvre, but it might become a situation of extreme emergency when dealing with an unexpected difficult airway. The Airtraq laryngoscope (Prodol Meditec, Vizcaya, Spain) is a new tool for use with the patient. The fact that it is easy to learn to use and simple to handle makes it a practical device in many situations where managing the airway is indicated. Its advantages over the Macintosh laryngoscope have been demonstrated in patients with an airway that it is difficult to manage and in adverse situations outside the surgical setting, when endotracheal intubation has been achieved in a simple way following unsuccessful attempts with conventional laryngoscopes. The greatest benefits in using the Airtraq laryngoscope have been shown in patients with a pronounced limitation of cervical mobility, and in those where the airway is distorted for anatomical reasons, such as pregnant women and obese patients.

[A pitfall of AirWay Scope--an experience of distinctive airway edema after palatal laceration caused by irWay Scope]

Pentax AirWay Scope (AWS) is a new videolaryngoscope which allows indirect visualization of the vocal cords and provides a better laryngeal view compared with the conventional Macintosh laryngoscope. We report a female patient who developed distinctive upper airway edema after palatal laceration at the time of insertion of the AWS. She was scheduled for tympanoplasty. After anesthesia induction, there was technical difficulties in tracheal intubation with Macintosh laryngoscope (her Cormack grade was rated as 3), and we used the AWS, but could not obtain an appropriate view on the monitor. When the device was removed, we detected bleeding derived from the right palatal laceration. Following the aspiration of the blood, we could barely achieve tracheal intubation with a flexible fiberscope without hypoxemic episode. The upper airway including the arytenoid and vocal cords were distinctively edematous after the operation. Then, the tracheal tube was left for three days after the operation, to secure the airway until the reduction of airway edema. On the postoperative day 4, following the fibroscopic confirmation that the airway edema was reduced, the patient was extubated successfully. AWS should be used more carefully, especially at the time of insertion along the palate.

Preliminary case series report: use of the laryngeal mask airway Fastrach oral endotracheal tube with the Bullard laryngoscope

Use of the Bullard laryngoscope has been fraught with difficulties, especially for inexperienced users who often end up placing the instrument on the back shelf of the airway cart without further use. A recent hypothesis suggests that the use of a flexible tip tube on the Bullard stylet might facilitate intubation. Initially, the Fastrach laryngeal mask airway (LMA North America, Inc, San Diego, California) flexible tip endotracheal tube was loaded on the Bullard laryngoscope stylet (Circon ACMI, Stamford, Connecticut) and used for intubation. The ease of intubation was noteworthy. Intubations on 6 patients assessed as difficult to intubate were performed on the first attempt without any difficulty. In fact, the effortlessness of these potentially difficult intubations led to the conclusion that the preliminary finding should be reported immediately.

Thermal injury to the tongue from an operative laryngoscope

OBJECTIVE

To understand risk and possible mechanisms of thermal injury to the tongue during suspension laryngoscopy.

STUDY DESIGN AND SETTING

Tongue injury was noted following suspension laryngoscopy in a cluster of cases; the findings raised suspicion for thermal injury. To characterize the potential for thermal injury, a lighted laryngoscope was placed in contact with samples of tongue. Tissue heating was recorded over time at fixed distances from the light carrier within a laryngoscope. Comparisons were made between two light sources and carriers.

RESULTS

Maximal tissue heating using a newer-model light source and new carrier was 16.7 degrees F immediately beneath the light carrier tip and 19.8 degrees F at 1 cm distal to the carrier tip. Other combinations of an older source and carriers failed to raise temperatures. Heating up to 10.7 degrees F occurred with the new source and an older carrier.

CONCLUSION AND SIGNIFICANCE

Tissue heating may occur from contact with operative laryngoscopes. This is an important patient safety issue in laryngology.

A comparison of the Truview blade with the Macintosh blade in adult patients

The Truview blade facilitates a view of the vocal cords by indirect laryngoscopy. We prospectively compared the view obtained at laryngoscopy and intubating conditions of Truview (Group 1) or Macintosh (Group 2) blades in 170 patients who were scheduled to undergo general anaesthesia. We studied pre-operative airway evaluation, laryngoscopic view, duration of intubation, maximal force applied during intubation, anaesthetist's estimation of intubation effort on a 1-3 scale, bleeding, teeth and soft tissue damage, and postoperative stridor and hoarseness. The results demonstrated that, whilst the Truview produced a better laryngoscopic view and less maximal force applied during intubation, the duration of intubation was longer. No significant difference was found in the anaesthetist's estimation of intubation effort, tooth damage or postoperative stridor and hoarseness. Significantly fewer patients suffered bleeding and soft tissue damage following intubation with the Truview than with the Macintosh blade. The Truview blade is a useful option for tracheal intubation in patients with normal and anticipated difficult airways.

Comparison of intubating laryngeal mask airway and Bullard laryngoscope for oro-tracheal intubation in adult patients with simulated limitation of cervical movements

BACKGROUND

Intubation of a patient with limited cervical spine movement or in whom movement of the cervical spine is not desirable is always a challenge even to the most experienced anaesthesiologist. The intubating laryngeal mask airway (ILMA) and the Bullard laryngoscope (BL) are two instruments recommended for endotracheal intubation of such patients. We compared their utility and safety in patients with simulated cervical spine immobility using manual inline stabilization (MILS).

METHODS

Sixty-two patients, ASA I or II, between 18 and 65 yr, were enrolled in this prospective and randomized study. They were randomly allocated to one of the two groups: Group BL (Bullard laryngoscope) and Group IL (Intubating Laryngeal Mask Airway). The patients were intubated orally using either equipment after induction of general anaesthesia.

RESULTS

The success rate for intubation in the first or second attempt was higher in Group BL [90.32% (28/31)] than in Group IL [74.2% (23/31)] but was not statistically significant. The number of attempts taken for intubation and the total time to intubate were similar between the groups. Trauma as evidenced by blood on endotracheal tube or sore throat was similar in both groups.

CONCLUSIONS

Both the BL and the ILMA are useful equipment in intubating patients with limitation of cervical movements. Although not statistically significant, the BL may provide a higher success rate of intubation when compared with the ILMA.

A clinical assessment of the Glidescope videolaryngoscope in nasotracheal intubation with general anesthesia

STUDY OBJECTIVES

To evaluate the efficacy and safety of the Glidescope videolaryngoscope as a device to aid nasotracheal intubation, and to determine whether the GSVL provides a better laryngeal view in patients with difficult laryngoscopy compared with the Macintosh laryngoscope.

DESIGN

Prospective, clinical study.

SETTING

Two university hospitals.

PATIENTS

156 healthy adult ASA physical status I and II undergoing elective plastic and intraoral surgery with general anesthesia.

INTERVENTIONS

After anesthesia induction with intravenous injection of fentanyl 2 microg/kg, propofol 2 mg/kg, and vecuronium 0.1 mg/kg, nasotracheal intubation was performed using GSVL.

MEASUREMENTS

Preoperative airway measurements were taken to predict potential difficult airways. During nasotracheal intubation using GSVL, laryngeal views, times required for full visualization of glottis and successful intubation, difficulty encountered and auxiliary maneuvers adopted, and upper airway trauma were recorded. The laryngeal views obtained by GSVL and by Macintosh laryngoscope were compared.

MAIN RESULTS

The laryngeal views obtained by GSVL in all patients were Cormack and Lehane (C&L) grades I and II, and the success rate of intubation using GSVL at one attempt was 98.1%. The times required for visualization of the glottis and successful intubation were 40.2 +/- 11.5 s and 52.7 +/- 12.3 seconds, respectively. Patients with C&L grade II needed more auxiliary maneuvers to achieve successful intubation than did those with C&L grade I (P < 0.001). In 36 patients with potential difficult airways, the frequency of difficult laryngoscopy (C&L grades III and IV) with the Macintosh laryngoscope (58.3%) was significantly higher than with the GSVL (0%, P < 0.05). The frequency of minor upper airway trauma was 4.5%.

CONCLUSIONS

The GSVL is an effective device for nasotracheal intubation and may be incorporated easily into routine clinical practice. Compared with the Macintosh laryngoscope, the GSVL can provide an improved laryngeal view in the patient with difficult airway.