Comparison of the Effectiveness of the Miller Laryngoscope and the McGrath-MAC Video Laryngoscope in Direct Visualization of the Glottic Opening

Background and Objective: Placing the laryngoscope blade directly under the epiglottis (known as the direct view (DV) method) during videolaryngoscopy offers a superior view of the glottis when compared to the indirect method of lifting the epiglottis by positioning the Macintosh blade tip over the vallecula. While there are few studies comparing glottic views using Miller and Macintosh blades in pediatric patients, we have not come across such a study in adults. In this study, we aimed to compare the effectiveness and hemodynamic responses of the Miller laryngoscope and the McGrath-MAC videolaryngoscope (VL) in visualizing the glottic opening using the DV method. Material and Methods: A prospective study was conducted between August and December 2022 at XXX Hospital on 85 patients scheduled for surgical procedures involving endotracheal intubation. Patients were divided into two groups: Miller laryngoscope (Group M) and McGrath-MAC videolaryngoscope (Group VL) and intubated using the direct lifting method of the epiglottis. Hemodynamic responses before and after induction, as well as during laryngoscopy, intubation time, number of attempts, Cormack and Lehane (C&L) score, percentage of glottic opening (POGO), duration of the view of the opening, and need for external laryngeal pressure during intubation were recorded. Results: Both laryngoscopes showed similar effectiveness in terms of POGO and C&L score when used with the direct lifting method of the epiglottis. The median POGO values according to the DV method were 80% in Group M and 70% in Group VL (p = 0.099). Hemodynamic responses, intubation time, number of attempts, duration of view of the glottis opening, and the need for external laryngeal pressure were similar between the groups. Conclusions: Due to its ability to provide effective intubation conditions, we believe that the McGrath-MAC VL, when used with the indirect view method, can also be utilized in anesthesia practices alongside the DV method.

Change in glottic view during intubation using a KoMAC videolaryngoscope: A retrospective analysis

Intubation with videolaryngoscopy has become popular in various clinical settings. However, despite the use of a videolaryngoscope, difficult intubation still exists and intubation failure has been reported. This retrospective study assessed the efficacy of the 2 maneuvers in improving the glottic view during videolaryngoscopic intubation. The medical records of patients who underwent videolaryngoscopic intubation and whose glottal images were stored in electronic medical charts were reviewed. The videolaryngoscopic images were divided into 3 categories according to the applied optimization techniques as follows: conventional method, with the blade tip located in the vallecular; backward-upward-rightward pressure (BURP) maneuver; and epiglottis lifting maneuver. Four independent anesthesiologists scored the visualization of the vocal folds using the percentage of glottic opening (POGO, 0-100%) scoring system. A total of 128 patients with 3 laryngeal images were analyzed. The glottic view was the most improved in the epiglottis lifting maneuver among all the techniques. The median POGO scores were 11.3, 36.9, and 63.1 in the conventional method, BURP, and epiglottis lifting maneuver, respectively (P < .001). There were significant differences in the distribution of POGO grades according to the application of BURP and epiglottis lifting maneuvers. In the POGO grades 3 and 4 subgroups, the epiglottis lifting maneuver was more effective than the BURP maneuver in improving the POGO score Inadequate visualization of the vocal folds occurred even when intubation was performed using a videolaryngoscope. The application of optimization maneuvers, such as BURP and epiglottis lifting by the blade tip, could improve the glottic view.

Partial vs full glottic view with CMACTM D blade intubation of airway with simulated cervical spine injury: a randomized controlled trial

PURPOSE

A previous study reported a shorter time to tracheal intubation by reducing percentage of glottic opening (POGO) view to <50% when intubating a normal adult airway using the Glidescope^TM blade. We evaluate the efficacy of reducing POGO to <50% when intubating patients with rigid cervical immobilization using CMAC^TM D blade.

METHODS

One hundred and four adult patients were randomized to group POGO 100% or POGO <50% . Laryngoscopy was performed by advancing tip of the D blade at vallecula. POGO 100% was achieved by exerting upward force to displace epiglottis until glottic opening from the anterior commissure to inter arytenoid notch. POGO < 50% was acquired by withdrawing the D blade tip dorsally from vallecula. The primary outcome was time to intubation.

RESULTS

The median time (IQR) to successful intubation was 29 (25-35) seconds for group POGO < 50% and 34 (28-40) seconds for group with POGO 100% (difference in medians, 5 seconds; 95% confidence interval, 2 to 8, p = 0.003). Complications were minor.

CONCLUSION

Using the CMAC^TM D blade with a reduced POGO in patients with cervical spine immobilization resulted in faster tracheal intubation.

TRIAL REGISTRATION

The trial is registered at ClinicalTrial.gov (CT.gov identifier: NCT04833166).

Comparison of direct laryngoscope and McGrath videolaryngoscope in terms of glottic view and hemodynamics in bariatric surgery

Background/aim

In the recent years, videolaryngoscopes (VL) have emerged as alternative devices to direct laryngoscopes (DL) in difficult intubation situations. Therefore, we aimed to compare the Macintosh DL and McGrath VL in terms of the glottic image quality, intubation success, intubation time, hemodynamic response after intubation, and complications in bariatric surgery patients.

Material and methods

After obtaining approval by the ethics committee and receiving informed consent, we recorded the demographic and physical data of patients undergoing bariatric surgery. Patients were divided into 2 groups: Group M was intubated with the Macintosh DL, and Group V was intubated with the McGrath VL. After intubation, we noted the Cormack–Lehane score, the duration of intubation, the number of intubation interventions, and the hemodynamic data of patients.

Results

A total of 62 patients (ASA II, body mass index of >35 kg/m2) were included in the study. All patients except 1 patient were intubated on the first attempt. Although there was a decrease in heart rate and blood pressure with induction, similar hemodynamic data were obtained between groups during the operation. In group V, we obtained a better glottic image (P = 0.011), but intubation success was similar between the study groups. We also measured the intubation time in group M as 45.9 ± 19.1 s and group V as 57.1 ± 15.8 s (P = 0.015).

Discussion

Although we measured longer intubation times with the McGrath VL compared with the Macintosh DL, we obtained a better glottic image without causing hemodynamic changes. However, these findings did not make any difference in terms of intubation success.

Evaluation of glottic view through Air-Q Intubating Laryngeal Airway in the supine and lateral position and assessing it as a conduit for blind endotracheal intubation in children in the supine position

INTRODUCTION

We assessed the feasibility of blind orotracheal intubation in children using the Air-QILA as a conduit in supine position and the glottic view grading by fiberoptic bronchoscope (FOB) through it both in supine and lateral positions.

METHODS

After ethical approval and consent, 60 children were enrolled in the study. In the operating room, after attaching standard monitors to all children, anesthesia was induced with sevoflurane (2-8%) in oxygen (100%). Once the children became sedated, an i.v. access was established and injection glycopyrrolate (10 μg · kg(-1)), fentanyl (2 μg · kg(-1)), and atracurium (0.5 mg · kg(-1)) were administered. After 3 min, the Air-QILA was placed in supine position and glottic view was assessed by using FOB, in supine and right lateral decubitus position. In all children, gradings of glottic view in two different positions were noted. After that all children were turned supine, and orotracheal intubation was done blindly through the Air-QILA. The success rate, insertion time of the Air-QILA, and endotracheal intubation were noted.

RESULTS

The Air-QILA placement was successful in 57 children in first attempt and three children required second attempt. However, blind endotracheal intubations through the Air-QILA were successful in 38 children in first attempt and 12 children required second attempt. In the remaining 10 children, where blind endotracheal intubation through the Air-QILA remained unsuccessful, conventional laryngoscopy was performed. In supine and lateral positions, Grade 1 glottic view was seen in 41 and 38 of total 60 patients, respectively. Turning of all children from supine to lateral decubitus position resulted in the deterioration of grading of glottic view in eight children and improvement in two children (P = 0.001).

CONCLUSION

The Air-QILA is an easy to place supraglottic airway device with excellent airway seal and low airway morbidity. It may be useful as a conduit for blind orotracheal intubation in supine position and can be used as an effective alternative to FOB in low resource settings.

A comparative study between Truview(PCD) laryngoscope and Macintosh laryngoscope in viewing glottic opening and ease of intubation: A crossover study

Background:

Truview^PCD laryngoscope is specially designed to aid positioning of the endotracheal tube as well as to record entry of the tube into glottis. Aim of the study is to compare the view of glottic opening and ease of intubation between Truview^PCD laryngoscope and Macintosh laryngoscope in patients undergoing general anesthesia (GA).

Methodology:

Two hundred patients undergoing elective surgery, under GA were randomized into two groups, Group TV and Group ML. In Group TV, Trueview^PCD laryngoscope was used initially to visualize the vocal cords for Cormack and Lehane grading (CLG) and to spray the vocal cords with 10% lignocaine. Then the patient was ventilated for 1 min and Macintosh laryngoscope was used to visualize the vocal cords for CLG and proceed with intubation. In Group ML, Macintosh laryngoscope was used initially and later Truview^PCD laryngoscope. Time to intubation, CLG, number of attempts and hemodynamic parameters were recorded.

Results:

Ninety-six and 89 patients had CLG1 visualization when Truview^PCD laryngoscope was used as 1^st and 2^nd device respectively compared to 41 and 68 with Macintosh laryngoscope (P = 0.00). Four patients had CLG 4 visualization with Macintosh laryngoscope that turned out to be grade II visualization with Truview^PCD laryngoscope (P = 0.00). Mean time taken for intubation with Truview^PCD and Macintosh laryngoscope was 21.10 ± 5.64 s and 15.79 ± 2.76 s respectively (P = 0.00).

Conclusion:

Better visualization with lesser CLG was found with Truview^PCD laryngoscope but it took longer time for intubation than Macintosh laryngoscope. The hemodynamic response to intubation was significantly less with the use of Truview^PCD laryngoscope when compared to that of Macintosh laryngoscope.