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).

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.

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.

A multicentre randomised controlled trial of the McGrath™ Mac videolaryngoscope versus conventional laryngoscopy.

Before completion of this study, there was insufficient evidence demonstrating the superiority of videolaryngoscopy compared with direct laryngoscopy for elective tracheal intubation. We hypothesised that using videolaryngoscopy for routine tracheal intubation would result in higher first-pass tracheal intubation success compared with direct laryngoscopy. In this multicentre randomised trial, 2092 adult patients without predicted difficult airway requiring tracheal intubation for elective surgery were allocated randomly to either videolaryngoscopy with a Macintosh blade (McGrath™) or direct laryngoscopy. First-pass tracheal intubation success was higher with the McGrath (987/1053, 94%), compared with direct laryngoscopy (848/1039, 82%); absolute risk reduction (95%CI) was 12.1% (10.9-13.6%). This resulted in a relative risk (95%CI) of unsuccessful tracheal intubation at first attempt of 0.34 (0.26-0.45; p < 0.001) for McGrath compared with direct laryngoscopy. Cormack and Lehane grade ≥ 3 was observed more frequently with direct laryngoscopy (84/1039, 8%) compared with McGrath (8/1053, 0.7%; p < 0.001) No significant difference in tracheal intubation-associated adverse events was observed between groups. This study demonstrates that using McGrath videolaryngoscopy compared with direct laryngoscopy improves first-pass tracheal intubation success in patients having elective surgery. Practitioners may consider using this device as first choice for tracheal intubation.

Evaluation of chronological changes in videofluorographic findings after transoral videolaryngoscopic surgery to reveal mechanism of dysphagia.

OBJECTIVES: Transoral surgery preserves good swallowing function in most cases, however, postoperative dysphagia sometimes leads to fatal complication such as aspiration pneumonia. We investigated the chronological changes in swallowing function have not been revealed relationship with dysphagia. The primary aim of this study was to reveal the mechanism of dysphagia following transoral surgery by analyzing chronological videofluorography (VF) findings. Moreover, the secondary aim of this study was to evaluate the relationship between mechanism of dysphagia and risk factors of patients to clarify the risk for dysphagia lead to prevention of postoperative complications. METHODS: 22 patients who underwent transoral videolaryngoscopic surgery (TOVS) for either supraglottic or hypopharyngeal cancer were evaluated swallowing function. We performed VF during the preoperative, postoperative acute, and stable phases and investigated the chronological changes in the VF findings. The following parameters were evaluated by VF: horizontal distance of laryngeal movement, vertical distance of laryngeal elevation, laryngeal elevation delay time (LEDT), Bolus Residue Scale (BRS) scores, and Penetration Aspiration Scale (PAS) scores. Additionally, we evaluated risk factors for postoperative aspiration by investigating relationships between preoperative VF parameters, age of patients, history of radiation therapy, resection area, tumor (T) stage, postoperative Numeric Rating Scale (NRS), and PAS and BRS scores. RESULTS: The median time at which oral feeding was resumed in this study was 9 (2-200) days. The patients who had postoperative acute PAS scores of 4 and above exhibited delays in resuming oral ingestion after surgery. TOVS did not impair laryngeal elevation and LEDT; however, the BRS and PAS scores temporarily worsened in the acute phase compared to the preoperative scores. These scores almost recovered to their preoperative states in the stable phase, and both the BRS and PAS scores worsened and recovered concurrently. Patients who exhibited poor vertical distance in laryngeal elevation as observed via preoperative VF or who had histories of radiation therapy had worse PAS scores in postoperative acute phase VF. Patients with broad resection areas had worse BRS scores in postoperative acute phase VF. CONCLUSION: TOVS didn't impair the function of laryngeal elevation and elicitation of the swallowing reflex whereas pharyngeal bolus clearance, laryngeal penetration, and aspiration temporarily deteriorated concurrently but eventually almost recovered to their baseline values. Patients with histories of radiotherapy, poor laryngeal elevation, and broad resection areas are at the risk of postoperative dysphagia after TOVS. Patients with these risk factors need appropriate evaluation before resuming postoperative oral intake.

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.

[Clinical characteristics of 1330 elderly patients with voice diseases diagnosed by electronic laryngoscope].

Objective:To investigate the clinical features of electronic laryngoscope in the diagnosis of senile voice diseases. Methods:Elderly patients who visited the outpatient department of Otolaryngology Head and Neck Surgery, Nanjing Drum Tower Hospital from September 2014 to September 2018 were collected. All patients came in with hoarseness. All patients were routinely diagnosed by electronic laryngoscopy and the results were analyzed. Results:A total of 1330 elderly patients aged 60 years and over were enrolled in this study, including 924 males and 406 females. There are significant differences in the distribution of various voice diseases in different genders（P<0.05）. Among male elderly patients, the top three were: 239 cases of throat malignant tumor（25.87%）, 182 cases of vocal cord benign proliferative disease（19.70%）, 147 cases of vocal cord leukoplakia（15.91%）. Among female elderly patients, the top three diseases were: 183 cases（45.07%） of vocal cord benign proliferative disease, 70 cases（17.24%） of laryngitis, 66 cases（16.26%） of vocal cord paralysis. There were significant differences in the distribution of different voice disorders among the three different age groups of elderly patients. The top three elderly patients aged 60-69 years were: 298 cases（35.06%） of vocal cord benign proliferative diseases, 132 cases（15.53%） of laryngopharyngeal malignant tumors, 104 cases（12.24%） of vocal cord paralysis. The top three elderly patients aged 70-79 years were: 91 cases（24.20%） of laryngopharyngeal malignant tumors, 57 cases（15.16%） of vocal cord benign proliferative diseases, 55 cases（14.63%） of vocal cord paralysis. The top three elderly patients aged 80 years and above were: 25 cases（24.04%） of laryngopharyngeal malignant tumors, 21 cases（20.19%） of vocal cord paralysis, 16 cases（15.38%） of the vocal cords are not closed completely. There were also significant differences in the distribution of various voice diseases among smokers（P<0.05）. Conclusion:With the acceleration of the aging of society, we should pay more attention to the voice of the elderly. The most common disease in elderly women with hoarseness is benign hyperplastic vocal cord disease. The high incidence of laryngeal malignant tumors in elderly male hoarseness patients who smoke should be paid special attention to. Electronic laryngoscope plays an important role in the diagnosis of voice diseases in elderly patients.

Risk Factors for Postoperative Sore Throat After Nasotracheal Intubation.

OBJECTIVE: Postoperative sore throat is relatively frequent complication after orotracheal intubation. However, there are few reports about postoperative sore throat in nasotracheal intubation. In this retrospective study, we investigated the risk factors of postoperative sore throat in nasotracheal intubation. METHODS: Anesthesia records of patients 16 to 80 years of age who underwent nasotracheal intubation were included. Patients underwent oral and maxillofacial surgery from February 2015 until September 2018. Airway device (Macintosh laryngoscope, Pentax-AWS, or McGRATH video laryngoscope, or fiberoptic scope), sex, age, height, weight, American Society of Anesthesiologists classification, intubation attempts, duration of intubation, intubation time, tube size, and fentanyl and remifentanil dose were investigated. Fisher exact test, Wilcoxon rank sum test, Welch t test, and Steel-Dwass multiple test were used, and a multivariable analysis was performed using stepwise logistic regression to determine the risk factors of postoperative sore throat. RESULTS: A total of 169 cases were analyzed, and 126 patients (74.6%) had a postoperative sore throat. Based on the univariate analysis of the data, 12 factors were determined to be potentially related to the occurrence of a postoperative sore throat. However, after evaluation using stepwise logistic regression analysis, the 2 remaining variables that correlated with postoperative sore throat were airway device (P < .05) and intubation attempts (P = .04). In the model using logistic regression analysis, the fiberoptic scope had the strongest influence on the incidence of sore throat with reference to Pentax-AWS (odds ratio = 5.25; 95% CI = 1.54-17.92; P < .05). CONCLUSION: Use of a fiberoptic scope was identified as an independent risk factor for postoperative throat discomfort. Compared with direct laryngoscopy and other video laryngoscopes, the use of a fiberoptic scope had a significantly higher incidence of sore throat.

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.

[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.

Use of a Video Laryngoscope to Reduce Complications of Transesophageal Echocardiography Probe Insertion: A Multicenter Randomized Study.

OBJECTIVE: The objective of this multicenter study was to test the hypothesis of whether the use of a video laryngoscope (VL) reduces complications related to transesophageal echocardiography (TEE) probe insertion. DESIGN: A multicenter randomized control study. SETTING: At 5 tertiary care level hospitals. PARTICIPANTS: Three hundred sixty-three adult patients undergoing elective cardiac surgery. INTERVENTIONS: The patients were randomized into 2 groups-the conventional group (C group; n = 177) and the VL group (n = 186) for TEE probe insertion. MEASUREMENTS AND MAIN RESULTS: The primary endpoint of the study was the incidence of oropharyngeal injury, which was defined as blood at the tip of the TEE probe at the end of surgery and/or evidence of injury on VL examination at the end of surgery. The secondary endpoints of the study were the number of attempts required for successful TEE probe insertion and the relation between the esophageal inlet and the larynx. There was a higher incidence of injuries in the C group (n = 26; 14.7%) compared to the VL group (n = 14; 7.5%; p = 0.029). The number of attempts for probe insertion was significantly lower in the VL group (p = 0.0023). The most common relation between the esophageal inlet and the larynx was posterolateral (n = 88; 47%), followed by posterior (n = 77; 41%) and lateral (n = 21;12%). CONCLUSION: The use of VL was associated with a lesser incidence of injury compared to the conventional technique, and its use for this purpose is recommended. The use of VL for probe insertion resulted in fewer attempts compared with the conventional technique. Significant variations do exist in the relation between the esophageal inlet and the larynx, and direct visualization with VL may contribute to better safety.

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.

Comparison of the success with two bending angles for lighted stylet intubation in children: A prospective randomised study.

BACKGROUND AND AIM: The bend angle of a lighted stylet is an important factor for successful orotracheal intubation. The aim of this study was to test the differences in the success of endotracheal intubation using lighted stylet with 70° versus 90° bend angles in children aged 4-6 years with normal airways. METHODS: A total of 136 children with normal airways required orotracheal intubation were enrolled and were randomly allocated to the 90° or 70° bend angle groups. The first-attempt success rate was assessed as the primary outcome. The intubation time, lighted stylet search time, lighted stylet withdrawal time, hemodynamic responses, and perioperative complications were recorded as secondary outcomes. RESULTS: All intubations were completed within three attempts (the 90° group, 63/5/0; the 70° group, 55/11/2). The first-attempt success rate was higher in the 90° group than that in the 70° group (92.6% [63/68 patients] versus 80.9% [55/68 patients], respectively; risk ratio, 1.15; 95% CI, 1.01-1.31; p = .04). Esophageal entry occurred in nine of 83 intubation attempts in the 70° group and two of 73 intubation attempts in the 90° group (risk ratio, 1.09; 95% CI, 1.01-1.19; p = .04). The intubation time and the lighted stylet search time were significantly shorter in the 90° group than that in the 70° group (intubation time: 12.2 ± 2.0 s versus 14.9 ± 2.6 s, respectively; mean difference, 2.65; 95% CI, 1.87-3.43; p < .01; effect size, 1.16; lighted stylet search time: 5.4 ± 1.0 s versus 8.0 ± 1.6 s, respectively; mean difference, 2.66; 95% CI, 2.21-3.12; p < .01; effect size, 1.95). CONCLUSIONS: Lighted stylet intubation with a 90° bend angle improved the first-attempt success rate and reduced esophageal intubation in children aged 4-6 years with normal airways.

An optimal tracheal tube preshaping strategy for endotracheal intubation using video laryngoscopy: a randomized controlled trial.

Although video laryngoscopy solves the problem of glottis exposure, it is difficult to deliver the tube to the glottic opening when the tracheal tube is unevenly shaped. This study aimed to compare the effects of different tube shapes on the first-pass success (FPS) rate in patients undergoing video laryngoscopy-assisted tracheal intubation. Three hundred patients above 18 years of age who underwent general anaesthesia and required endotracheal intubation were included in the study. The participants were randomly allocated to three groups with 100 participants in each group as follows: Group A, video laryngoscopes with a self-equipped stylet are used for tube preshaping; Group B: curvature of the video laryngoscope blade is modelled for tube preshaping; Group C: tube preshaping angle is consistent with the video laryngoscope blade, and the bending point is set 1 cm above the tracheal tube cuff. The primary outcome was FPS rates. The secondary outcomes included time to tracheal intubation, haemodynamic responses and adverse events. No significant differences in patient characteristics or airway assessments were noted (P > 0.05). Compared with Groups A, Group B and Group C exhibited a higher FPS rate (68% vs. 86% vs. 92%; P < 0.001). However, there is no significant difference in FPS rate between Group B and Group C (P > 0.05). And the time to tracheal intubation in Group C was significantly less than that in Group A and Group B (22.21 ± 4.01 vs. 19.92 ± 4.11 vs. 17.71 ± 3.47; P < 0.001). The straight-to-cuff stylet preshape angulation of curvature of the blade could provide a higher FPS rate and shorter time to tracheal intubation during video laryngoscopy-assisted endotracheal intubation. Trial registration: Chinese Clinical Trial Registry, ChiCTR1900026019.

Comparison of the C-MAC D-Blade videolaryngoscope and direct laryngoscope in pediatric patients: Randomized controlled trial.

BACKGROUND: Endotracheal intubation is a key skill for clinicians and may be challenging in some patients due to various reasons. Nowadays, various kinds of videolaryngoscopes are available and usually used as a rescue device when direct laryngoscopy failed. Pediatric airway has some differences when compared with adults and may be challenging. This study aims to compare and evaluate C Mac D-Blade and commonly used Macintosh laryngoscope in pediatric patients. METHODS: In this study, 56 pediatric patients, 5-10 years old (10-40 kgs) who had undergone elective surgery and need endotracheal intubation were included after obtaining ethical board approval and informed consent from parents. The patients were randomized into two equal groups for laryngoscopy and intubation by either with Macintosh laryngoscope or C Mac D-Blade videolaryngoscope. Glottic view, number of attempts, intubation time, any complications and hemodynamic variables were recorded. A value of p<0.05 was considered significant. RESULTS: In pediatric patients with unanticipated difficult airway, the mean intubation time was significantly shorter with C Mac D-Blade (21±9 and 41±7 seconds, respectively (p<0.001). The results of the two groups were similar concerning the remaining parameters. CONCLUSION: C Mac D-Blade videolaryngoscope shortened intubation time about twice when compared to Macintosh blade C Mac D-Blade videolaryngoscope, Videolaryngoscopes may be a good alternative for routine intubation, education and a rescue device for difficult intubation.