Intubation without use of stylet for McGrath videolaryngoscopy in patients with expected normal airway: A randomized noninferiority trial

Effects of head-elevated position on tracheal intubation using a McGrath MAC videolaryngoscope in patients with a simulated difficult airway: a prospective randomized crossover study

Background

The head-elevated laryngoscopy position has been described to be optimal for intubation, particularly in obese patients and those with anticipated difficult airways. Horizontal alignment of the external auditory meatus and sternal notch (AM-S) can be used as endpoints for optimal positioning. Thus, we aligned the head-elevated position with the AM-S in the horizontal plane and evaluated its effect on laryngeal visualization and ease of intubation using a McGrath MAC videolaryngoscope in patients with a simulated difficult airway.

Methods

Sixty-four patients were included in this prospective, crossover, randomized controlled trial. A cervical collar was used to restrict neck movement and mouth opening. The head-elevated position was achieved by raising the back section of the operation room table and ensuring that the end point was horizontally aligned with the AM-S (table-ramp method). The laryngeal view was randomly assessed in both head-flat and head-elevated positions based on the percentage of glottic opening (POGO) score and modified Cormack–Lehane (MCL) grade. External laryngeal manipulation was not permitted when laryngeal visualization was scored. The trachea was intubated only once (in the second position). The ease of intubation was assessed based on the need for optimization maneuvers, intubation difficulty scale (IDS) scores and time to intubation.

Results

The mean table-ramp angle required to achieve the horizontal alignment of AM-S was 17.5 ± 4.1°. The mean POGO score improved significantly in the head-elevated position (59.4 ± 23.8%) when compared with the head-flat position (37.5 ± 24%) (P <  0.0001). MCL grade 1 or 2a was achieved in 56 (85.9%) and 28 (43.7%) of patients in the head-elevated and head-flat positions, respectively (P <  0.0001). Optimization maneuvers for intubation were required in 7 (21.9%) and 17 (53.1%) patients in the head-elevated and head-flat positions, respectively (P <  0.0001). The IDS scores and time to intubation did not differ significantly between the two positions.

Conclusion

In the head-elevated position, aligning the AM-S in the horizontal plane consistently improved laryngeal visualization without worsening the view when the McGrath MAC videolaryngoscope was used in patients with simulated difficult airways. It also improved the ease of intubation, which reduced the need for optimization maneuvers.

Trial registration

This trial was registered with www.clinicaltrials.gov, NCT04716218, on 20/01/2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01706-5.

Comparison of two different shapes of stylets for intubation with the McGrath MAC® video laryngoscope: a randomized controlled trial

Objective

This study was performed to compare two different shapes of stylets, 60° and J-shaped stylets, for intubation using the McGrath MAC® video laryngoscope (MVL).

Methods

Two hundred twenty-two patients undergoing surgery under general anesthesia were randomly allocated to Group J (n = 111) or Group 60° (n = 111) and intubated using the MVL with the stylet bent into the allocated shape. The time to intubation (TTI) and other intubating profiles were compared between the groups. Multivariate regression analysis was used to determine the relationship between factors related to difficult intubation and TTI.

Results

The TTI was not different between the two groups. There were also no differences in the intubating profiles between the two groups. In both groups, the TTI was longer with a modified Mallampati score (mMS) of ≥3 and percentage of glottic opening (POGO) score of <50. In Group J, the TTI was longer with a body mass index (BMI) of ≥30 kg/m².

Conclusion

The TTI during tracheal intubation with the MVL was not different between the two groups. The TTI was longer with an mMS of ≥3 and POGO score of <50. In Group J, the TTI was longer with a BMI of ≥30 kg/m².

Laryngoscopes for difficult airway scenarios: a comparison of the available devices

INTRODUCTION

According to the American Society of Anesthesiologists, the incidence of difficult intubation in the operating room is 1.2-3.8%; however, in emergency conditions, this rate is higher and reaches even 5.3%. Successful emergency airway management is an essential component of the modern practice of medicine.

AREAS COVERED

The aim of the study is to review the literature regarding different devices used to perform endotracheal intubation (Macintosh, Miller, and McCoy laryngoscopes; ETView, GlideScope, TruView, Airtraq, McGrath MAC, Pentax AWS, Trachlight, Shikani, and Bullard) and discuss their clinical and experimental role in difficult airway management.

EXPERT COMMENTARY

Owing to the development of medical technology, there are an increasing number of videolaryngoscopes and other devices facilitating endotracheal intubation in difficult airway scenarios, including cardiopulmonary resuscitation, cervical spine injury, or face-to-face intubation. Each of these devices may bring benefits in the form of increasing the intubation effectiveness, as well as shortening the procedure, provided that the person performing intubation is familiar with the use of the device.

Effect of C-MAC Video Laryngoscope-aided intubations Using D-Blade on Incidence and Severity of Postoperative Sore Throat

Background:

Video laryngoscope-aided intubations require less force to align oral, pharyngeal, and laryngeal planes to visualize the glottis opening during intubation.

Aim:

The primary objective of the study was to assess the incidence and severity of postoperative sore throat (POST) in patients who were intubated with C-MAC video laryngoscope using D-blade versus traditional Macintosh laryngoscope.

Settings and Design:

This prospective, randomized, open label study was conducted in a tertiary care institution.

Subjects and Methods:

A total of 130 patients undergoing short elective laparoscopic surgeries lasting <2 h were recruited. All patients received general anesthesia as per a standardized protocol. Laryngoscopy was performed using traditional Macintosh laryngoscope in Group M and with Storz^® C-MAC video laryngoscope using D-Blade in Group V. The endotracheal tube cuff pressure was maintained at 20–22 cm of H2O intraoperatively.

Statistical Analysis Used:

Pearson's Chi-square test, Fisher's exact test, and Independent sample t-test were used in this study.

Results:

As compared to Group M, number of patients who had POST, hoarseness of voice, and cough was significantly low in Group V at 2, 6, 12, and 24 h. Severity, as well as the incidence of all these symptoms, showed a downward trend in both groups with time. Significantly more number of patients in Group M required rescue therapy for POST (44.6% as compared to 7.7%, P < 0.001).

Conclusion:

C-MAC video laryngoscope-aided intubations using D-blade significantly reduced the incidence and severity of POST, hoarseness of voice, and cough following orotracheal intubation as compared to use of traditional Macintosh laryngoscope.

A comparison between McGrath MAC videolaryngoscopy and Macintosh laryngoscopy in children

BACKGROUND

This prospective, randomised, controlled study was performed to evaluate the usefulness of the McGrath VL compared with Macintosh laryngoscopy in children with expected normal airway during endotracheal intubation, by comparing the time to intubation and difficulty of intubation.

METHODS

Eighty-four patients aged 1-10 years who underwent endotracheal intubation for elective surgery were randomly assigned to the McGrath group (n = 42) or the Macintosh group (n = 42). Anaesthesia was induced with 2.5-3.0 mg/kg of propofol and sevoflurane 5-8 vol%. Orotracheal intubation was performed 2 min after injection of rocuronium 0.6 mg/kg with McGrath VL or Macintosh laryngoscope; the primary outcome was the time to intubation. The Cormack and Lehane glottic grade, intubation difficulty score (IDS), and success rate on intubation were assessed. Haemodynamic changes were also recorded.

RESULTS

As the primary outcome, median time to intubation [interquartile range] did not differ between the McGrath group and the Macintosh group (25.0 [22.8-28.3] s vs. 26.0 [24.0-29.0] s, P = 0.301). The incidence of grade I glottic view was significantly higher in the McGrath group than in the Macintosh group (95% vs. 74%, P = 0.013). Median IDS was lower in the McGrath group than in the Macintosh group (0 [0-0] vs. 0 [0-1], P = 0.018). There were no significant differences in success rate on intubation or haemodynamics between the two groups.

CONCLUSIONS

McGrath VL provides better laryngeal views and lower IDS but similar intubation times and success rates compared with the Macintosh laryngoscope in children with normal airway.

Ease of Intubation with C-MAC Videolaryngoscope: Use of 60° Angled Styletted Endotracheal Tube versus Intubation over Bougie

Background:

Although videolaryngoscopes improve glottic visualization, their actual usefulness in intubation is not yet established.

Aims:

The primary objective was to compare the ease of oral intubation with the use of 60° angled styletted endotracheal tube versus that performed over bougie inserted under videolaryngoscopic guidance. The secondary objectives were assessment of incidence of airway loss, hemodynamic changes, and time and number of attempts at intubation.

Settings and Design:

This prospective randomized study was conducted in a tertiary care institution.

Patients and Methods:

Seventy surgical patients requiring oral intubation were randomly allotted to Group S or Group B. Laryngoscopy was performed with Storz^® C-MAC videolaryngoscope using D-Blade. In Group S, patients were intubated with a 60° angled stylletted endotracheal tube. In Group B, a bougie was introduced into the trachea and endotracheal tube was railroaded over the bougie.

Statistical Analysis Used:

Chi-square test and independent sample t-test were used as applicable.

Results:

The ease of intubation was significantly more in patients of Group S as compared to Group B (88.6% vs. 25.7%, respectively, P < 0.001) with significantly shorter intubation time (16.97 ± 7.91 vs. 77.43 ± 35.55 s, respectively, P < 0.001). The requirement of more than one attempt at intubation was significantly higher in Group B [57.1% vs. 5.7% P < 0.001, respectively]. Group B showed a significantly high mean arterial pressure at 1 and 3 min following intubation with no significant change in heart rate.

Conclusion:

Use of 60° angled styletted endotracheal tube resulted in easier and faster intubation as compared to intubation over a bougie when used with C-MAC videolaryngoscope.