A randomized trial of the glottic views with the classic Miller, Wis-Hipple and C-MAC (videolaryngoscope and direct views) straight size 1 blades in young children

Usefulness of C-curved stylet for intubation with the C-MAC® Miller videolaryngoscope in neonates and infants: a prospective randomized controlled trial

BACKGROUND

Optimizing endotracheal tube (ETT) shape is important for successful videolaryngoscope-aided intubation. This prospective randomized controlled study aimed to compare the tube-handling time between a C-curved and hockey stick-shaped stylet in infants and neonates using the C-MAC® videolaryngoscope Miller blade.

METHODS

A total of 110 infants (age < 1 year) were randomly assigned to either the hockey stick-curved stylet group (group H, n = 53) or the C-curved stylet group (group C, n = 57). The primary outcome was tube handling time after glottis visualization and the secondary outcomes were the total intubation time, incidence of successful intubation, initial tube tip location at the laryngeal inlet, and numerical rating scale for ease of intubation.

RESULTS

Tube insertion time and total intubation duration (both in seconds) were significantly shorter in group C than in group H (13.3 ± 8.9 vs. 25.1 ± 27.0, P = 0.002; 19.9 ± 9.4 vs. 32.8 ± 27.1, P = 0.001, respectively). Group C displayed a higher rate of intubation success within 30 s than group H (87.7% vs. 69.8%, P = 0.029). The initial tube tip was located at the center in 34 children in group C (59.6%) and 12 children in group H (26.1%, P < 0.001). Laryngoscope operators rated intubation as easier when provided with a C-curved stylet.

CONCLUSIONS

In neonates and infants, modification of the ETT shape into a C-curve may reduce tube handling time compared to the conventional hockey stick-shaped tube during intubation using a C-MAC® video laryngoscope Miller blade.

Video screen visualization patterns when using a video laryngoscope for tracheal intubation: A systematic review

OBJECTIVE

Published studies of video laryngoscopes are often limited by the lack of a clear definition of video laryngoscopy (VL). We performed a systematic review to determine how often published studies of VL report on video screen visualization.

METHODS

We searched PubMed, EMBASE and Scopus for interventional and observational studies in which a video laryngoscope equipped with a standard geometry blade was used for tracheal intubation. We excluded simulation based studies. Our primary outcome was data on video laryngoscope screen visualization. Secondary outcomes were explicit methodology for screen visualization.

RESULTS

We screened 4838 unique studies and included 207 (120 interventional and 87 observational). Only 21 studies (10% of 207) included any data on video screen visualization by the proceduralist, 19 in a yes/no fashion only (ie, screened viewed or not) and 2 with detail beyond whether the screen was viewed or not. In 11 more studies, visualization patterns could be inferred based on screen availability and in 16 more studies, the methods section stated how screen visualization was expected to be performed without reporting data collection on how the proceduralist interacted with the video screen. Risk of bias was high in the majority of included studies.

CONCLUSIONS

Published studies of VL, including many clinical trials, rarely include data on video screen visualization. Given the nuances of using a video laryngoscope, this is a critical deficiency, which largely prevents us from knowing the treatment effect of using a video laryngoscope in clinical practice. Future studies of VL must address this deficiency.

Comparative efficacy of C-MAC® Miller videolaryngoscope versus McGrath® MAC size "1" videolaryngoscope in neonates and infants undergoing surgical procedures under general anesthesia: A prospective randomized controlled trial

BACKGROUND

Various anatomical and physiological factors make intubation in infants challenging. C-MAC videolaryngoscope shows better results as compared to the conventional direct laryngoscopy for intubation in infants. McGrath MAC size-1 with a disposable Macintosh type blade has recently been introduced for use in infants and has not been formally evaluated in this population.

AIMS

This study aims to evaluate the intubation characteristics of C-MAC Miller and McGrath MAC in neonates and infants with the primary objective to compare the time with the two devices.

METHODS

After informed consent from the parents, 140 neonates and infants scheduled for surgical procedures were randomized to undergo intubation with either C-MAC Miller or McGrath MAC after standard general anesthesia. The two devices were compared in terms of total intubation time, Percent of Glottic Opening score, Cormack Lehane grades, time to glottis view, intubation difficulty score, overall success rate, first attempt success rate, and complications.

RESULTS

The median glottic view time (6 s [4-9] vs. 6 s [4-9]; p = .40) and intubation time (27 s [25.5-28] vs. 27 s [24.5-29.5]; p = .87) were similar. The mean difference (95% CI) in time to tracheal intubation and time to glottic view was 0.49 s [-3.1 to 2.1] and -1.7 s [-3.8 to 0.47], respectively. However, the Percent of Glottic Opening score, Cormack Lehane grades, and subjective intubation difficulty were significantly better with C-MAC. The first attempt success rates, overall success rates (100% vs. 97.5%), and intubation difficulty scores were comparable. There were two failed intubations with McGrath which were successfully intubated with C-MAC.

CONCLUSION

The C-MAC Miller blade showed similar intubation timings, success rates, and intubation difficulty score as compared to McGrath MAC in neonates and infants, though the former provided superior glottic views. Both the videolaryngoscopes may be safely used in infants and neonates for routine intubation scenarios.

Videolaryngoscopic versus direct laryngoscopic paraglossal intubation for cleft lip/palate reconstructive surgeries: A randomised controlled trial

Background and Aims:

In the cleft lip and palate, the laryngoscope blade often tends to lodge inside midline clefts, causing reduced manoeuvrability and tissue trauma. The paraglossal technique avoids the midline and offers better Cormack Lehane (CL) grades. We aimed to assess the first-pass intubation rate in performing the left paraglossal laryngoscopy with a curved-blade videolaryngoscope (VLS) versus direct laryngoscope (DLS) in children with cleft palate and evaluate the time taken for successful endotracheal intubation (TTI) and Intubation Difficulty Score (IDS) with both devices.

Methods:

This randomised controlled trial included 60 patients with cleft palate, between 3 months and 6 years. Patients were randomised into group V (VLS) (n = 30) and group D (DLS) (n = 30). Left paraglossal laryngoscopy was done with VLS or DLS, and the first-pass intubation, TTI, CL grade and IDS were recorded.

Results:

First-pass intubation (primary outcome) was successful in all cases in group V and in 29 (96%) cases in group D (P = 0.923). Amongst the secondary outcomes, the IDS of the majority in both groups was 1–4 (slight difficulty) (P = 0.98) and the mean TTI In group D was 34.6 s (SD = 19.0) (95% CI: 27.5–41.7) versus 39.8 s (SD = 5.2) (95% CI: 37.8–41.7) in group V (P = 0.151).

Conclusions:

There was no significant difference in the use of a VLS over a DLS in performing the left paraglossal laryngoscopy in terms of first-pass intubation rate, CL Grade, IDS and TTI. Further studies with different VLS may be done to improve the ease of this technique.

The Effects of a Shoulder Roll During Laryngoscopy in Infants: A Randomized, Single-Blinded, Crossover Study

BACKGROUND

The use of a shoulder roll to view the glottic opening during direct laryngoscopy in infants has been recommended but is not evidence based.

METHODS

Twenty infants with normal airways, <6 months of age undergoing elective surgery under general anesthesia were randomized to undergo direct laryngoscopy first with a 2-inch vertical shoulder roll and then without, or vice versa. The primary outcome was the difference in the vertical distance between the angle of the laryngoscopist's eye and the operating room table in the 2 positions. Also, the views of the glottic opening in both positions were recorded for each infant and analyzed by a blinded investigator using the percent of glottic opening (POGO).

RESULTS

Twenty infants completed the study without complications. The vertical distance did not differ significantly whether the shoulder roll was placed first or second, and there was no evidence of a differential carryover effect in the crossover design (P = .268). The main effect of the shoulder roll on the mean (95% confidence interval [CI]) vertical distances without 47.8 cm (43.5-52.1) and with the shoulder roll 37.2 cm (33.3-41) yielded a mean (95% CI) vertical difference of 10.6 cm (9.3-11.79; P = .0001). The median (interquartile range [IQR]) POGO scores without 100 [86.2, 100] and with the shoulder roll 97.5 [80, 100] did not differ (median difference [95% CI]: 0 [-20 to 0]; P = .39).

CONCLUSIONS

A 2-inch shoulder roll lowers the line of sight of the glottic opening compared with no shoulder roll, without affecting the view of the glottic opening during laryngoscopy in infants.

Lower maximum forces on oral structures when using gum-elastic bougie than when using endotracheal tube and stylet during both direct and indirect laryngoscopy by novices: a crossover study using a high-fidelity simulator

BACKGROUND

Applying excessive force during endotracheal intubation (ETI) is associated with several complications, including dental trauma and hemodynamic alterations. A gum-elastic bougie (GEB), a type of tracheal tube introducer, is a useful airway adjunct for patients with poor laryngoscopic views. However, how the use of a GEB affects the force applied during laryngoscopy is unclear. We compared the force applied on the oral structures during ETI performed by novices using the GEB versus an endotracheal tube + stylet.

METHODS

This prospective crossover study was conducted from April 2017 to March 2019 in a public medical university in Japan. In total, 209 medical students (4th and 5th grade, mean age of 23.7 ± 2.0 years) without clinical ETI experience were recruited. The participants used either a Macintosh direct laryngoscope (DL) or C-MAC video laryngoscope (VL) in combination with a GEB or stylet to perform ETI on a high-fidelity airway management simulator. The order of the first ETI method was randomized to minimize the learning curve effect. The outcomes of interest were the maximum forces applied on the maxillary incisors and tongue during laryngoscopy. The implanted sensors in the simulator quantified these forces automatically.

RESULTS

The maximum force applied on the maxillary incisors was significantly lower when using a GEB than when using an endotracheal tube + stylet both with the Macintosh DL (39.0 ± 23.3 vs. 47.4 ± 32.6 N, P < 0.001) and C-MAC VL (38.9 ± 18.6 vs. 42.0 ± 22.1 N, P < 0.001). Similarly, the force applied on the tongue was significantly lower when using a GEB than when using an endotracheal tube + stylet both with the Macintosh DL (31.9 ± 20.8 vs. 37.8 ± 22.2 N, P < 0.001) and C-MAC VL (35.2 ± 17.5 vs. 38.4 ± 17.5 N, P < 0.001).

CONCLUSIONS

Compared with the use of an endotracheal tube + stylet, the use of a GEB was associated with lower maximum forces on the oral structures during both direct and indirect laryngoscopy performed by novices. Our results suggest the expanded role of a GEB beyond an airway adjunct for difficult airways.