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Videolaryngoscopy vs. Direct Laryngoscopy for Elective Airway Management in Paediatric Anaesthesia

A prospective randomised controlled trial

Klabusayová, Eva; Klučka, Jozef; Kosinová, Martina; Ťoukálková, Michaela; Štoudek, Roman; Kratochvíl, Milan; Mareček, Lukáš; Svoboda, Michal; Jabandžiev, Petr; Urík, Milan; Štourač, Petr

Author Information
European Journal of Anaesthesiology: November 2021 - Volume 38 - Issue 11 - p 1187-1193
doi: 10.1097/EJA.0000000000001595
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Tracheal intubation is an essential skill in the management of the perioperative airway in paediatric anaesthesia. Difficult airways and failed intubations can lead to airway injury, a need for intensive care unit (ICU) admission, cardiovascular instability, desaturation, and even hypoxic-based morbidity and mortality.1–4 There is a close correlation between the number of intubation attempts and the incidence of airway-related complications and morbidity.5,6 The recommended number of intubation attempts in paediatric patients should be limited to maximum of 2 or 3 attempts (the second attempt ideally performed by the most experienced operator at the site).7,8 Videolaryngoscopes are specialised equipment for airway management. The operator may obtain a superior view of the laryngeal inlet during intubation because the camera is located at the tip of the videolaryngoscope blade. The camera can enable visualisation of airway structures that cannot be seen on direct laryngoscopy. Currently, videolaryngoscopy is not routinely used for intubation and is generally utilised in only those patients with known difficult airways or when this is discovered. According to previously published data, in patients with predicted difficult airways, videolaryngoscopy is associated with better glottic visualisation and higher success rates of both first attempts and overall intubation.9–11 It remains unclear whether the implementation of routine videolaryngoscopy for elective airway management in paediatric patients would confer any benefit to airway management. We conducted this study to compare elective videolarygoscopy versus direct laryngoscopy in paediatric patients with normal airways scheduled for general anaesthesia with tracheal intubation. The hypothesis of the study was that, due to better glottic visualisation, the success rate of first intubation attempts with videolaryngoscopy might be better than those with direct laryngoscopy. The primary outcome was the first attempt intubation success rate. Secondary outcomes were: the time needed for successful intubation (to the first EtCO2 wave), the overall intubation success, the incidence of complications, and the impact of the length of operator's clinical practice in anaesthesiology on other measured indicators between the groups.


Study design, setting and participants

The trial was designed as prospective randomised controlled single-blinded (patient) trial conducted at the tertiary paediatric anaesthesia centre – Department of Paediatric Anaesthesiology and Intensive Care Medicine, University Hospital Brno and Faculty of Medicine, Masaryk University, Czech Republic.

All anaesthesiology operators were trained in both techniques of direct laryngoscopy and videolaryngoscopy according to a local protocol. C-Mac® and McGrathTM videolaryngoscopes were used with training on manikins and in clinical practice for at least 6 months prior the study initiation. All training adhered to approved clinical guidelines and practice. All anaesthetists working at our centre (the Department of Paediatric Anaesthesiology and Intensive Care Medicine, University Hospital Brno, Czech Republic) were involved in the study, all of them worked in both study groups and also all of them used both videolaryngoscope devices. The trial was designed as a pragmatic trial and its aim was to compare two intubation methods: the videolaryngoscopy and the direct laryngoscopy (not the equipment itself). Two different videolaryngoscopes were available: C-Mac with the separate display and McGrath with the build-in display and disposable blades. The choice of the videolaryngoscope was based on clinicians’ decisions only. Both videolaryngoscopes were used in line with the manufacturer's recommendations. The C-Mac videolaryngoscope was used with reusable Miller and Macintosh blades and the McGrath videolaryngoscope was used with single-use Macintosh blades. The D-blade was not used at all and the sizes of the blades were chosen according to the manufacturer's recommendations. The patients were screened during the pre-anaesthesia visit. The inclusion criteria were: paediatric patients without predicted difficult airway scheduled for elective surgery requiring general anaesthesia with tracheal intubation, and after informed consent by the patient's legal representative. The exclusion criteria were: age below 29 days or over 19 years, and predicted difficult airway.


The trial was initiated after the approval of the Ethics Committee for randomised controlled trials of the University Hospital Brno, Jihlavská 20, 62500, Brno, Czech Republic (Approval Number: 10/2018; chairperson: Pharm. Dr. Kozáková; date of approval: 1st October 2018) and after the registration on (NCT03747250). Written informed consent was obtained in all subjects.

Statistical methods

The patients were randomised either to the interventional group (videolaryngoscopy) or to the control group (direct laryngoscopy). Randomisation was facilitated by sealed envelopes located in the operating room that were prepared by the Institute of Biostatistics and Analyses Ltd., Brno, Czech Republic. The necessary number of patients deemed necessary for each group was determined according to the results of power analysis, the probability of type I error (false positive rate) α = 0.05, the probability of type II error (false negative rate) β = 0.20 (power of test is 1-β = 0.80) and the supposed probabilities of successes of both laryngoscopies. Based on previously published data and unpublished pilot data conducted at our tertiary pediatric anaesthesia centre (Department of Paediatric Anaesthesiology and Intensive Care Medicine, University Hospital Brno and Faculty of Medicine, Masaryk University, Czech Republic), the probability of success of the first intubation outcome was set at 96% for direct laryngoscopy and at 99% for videolaryngoscopy. The projected number of patients per group was 500 (including possible 15% drop-out) with pre-planned interim anaylsis after inclusion of 500 patients. According to the O’Brien-Fleming approach, the interim analysis was conducted with P-value = 0.005 and final analysis with P-value = 0.048. If the P-value of the binomial test for two proportions (comparing the success of the first intubation attempts) at the moment of the interim analysis was <0.005, the patients’ inclusion would be stopped and the trial would be terminated for futility (inability to reach the set superiority margin). Cross-over was not allowed by the protocol. The superiority margin was set to 3% difference between the groups. In cases where the intubation method failed, patients were excluded from the final analysis. After the randomisation, the following data were collected: the demographics, the first attempt intubation success rate, the overall intubation success rate, the time needed for successful intubation (to the first EtCO2 wave), the overall intubation success, glottic visualisation (Cormack-Lehane score), the incidence of complications (desaturation <90% on pulse oximetry, bradycardia <50 beats per minute, traumatic intubation, aspiration, regurgitation, vomiting during anaesthesia induction), the impact of the length of operator's clinical practice in anaesthesiology on the outcomes, the type of anaesthesia induction, and the airway management specification.

For the data analysis, standard descriptive methods were used. Mean (SD) and median (range or percentiles) were used for continuous variables and absolute (relative) frequencies were used for categorical measures. All the measured data were compared between the two groups (videolaryngoscopy and direct laryngoscopy). For the evaluation of the primary outcome (comparison of the successes of videolaryngoscopy and direct laryngoscopy), a binomial test for two proportions with the level of significance α = 0.05 was used. The premise that the successes of direct laryngoscopy and video laryngoscopy are equal was set as a null hypothesis. The influence of other measurements (e.g. the time required for an intubation, Cormack-Lehane score, desaturation and bradycardia, etc.) on the success of the first intubation attempt was analysed using the logistic regression. The analysis was made using SPSS Statistics®, Armonk, NY: IBM Corp.


The patients were recruited from 1st January 2019 to 30th March 2020. In total, 535 patients were included but only 501 were eligible for the pre-planned interim analysis. Overall 34 patients were excluded for multiple reasons: non-randomised (n = 1), method failure (videolaryngoscopy n = 8, direct laryngoscopy n = 3), missing data (n = 22), (Fig. 1). After interim analysis results, the study was terminated for futility (a failure to reach the set superiority margin between the groups for the primary outcome, the first intubation attempt success rate). Demographics of the cohort are described in Table 1. Baseline characteristics of the study population in both groups were similar except for gender (Table 1). Intention-to-treat and per-protocol analyses were both performed with similar results. According to the identification of the effect of videolaryngoscopy as a method, the per-protocol analysis data are presented. The anaesthesia management was comparable between the two groups when considering the type of anaesthesia induction, the use of muscle relaxation for intubation and the type of tracheal tube; the differences between data were not statistically significant (Table 2). The first attempt intubation success rate was lower in the interventional group (videolaryngoscopy) 86.8%, n = 211, compared with the control group (direct laryngoscopy) 92.6%, n = 239, P = 0.046. The McGrath videolaryngoscope was used in 76.5% of the video-intubations (n = 186), the C-Mac videolaryngoscope was used in 23.5% (n = 57). The first attempt success rate when considering the type of videolaryngoscope was comparable (Table 3). The mean time needed for intubation was longer in the videolaryngoscopy group (39.0 s ± 36.7) compared to the direct laryngoscopy group (23.6 s ± 24.7), P < 0.001. The glottic visualisation (Cormack-Lehane score) was significantly superior in the videolaryngoscopy group, P = 0.001 (Table 4). The overall intubation success rate was 100% in both groups. Regarding the first intubation attempt success rate, the use of muscle relaxation prior to the intubation did not differ statistically within the videolarnygoscopy group (P = 0.384) or within the direct laryngoscopy group (P = 0.999). Again, regarding the first intubation success rate, the type of anaesthesia induction did not statistically differ within the videolaryngoscopy group (P = 0.648), or within the direct laryngoscopy group (P = 0.138). The overall incidence of the complications was not significantly higher in the videolaryngoscopy group than in the direct laryngoscopy group (P = 0.740): the incidence of bradycardia was 0.4% (n = 1) vs. 0.0% (n = 0), respectively; the incidence of desaturation during anaesthesia induction below 90% measured by pulse oximetry was 4.5% (n = 11) vs. 3.9% (n = 10), respectively; the incidence of aspiration, regurgitation and active vomiting during anaesthesia induction was zero in both of the groups and incidence of traumatic intubation was 0.4% (n = 1) vs. zero, respectively. The level of training and the length of the operator's clinical practice were associated with slightly higher, but statistically nonsignificant, first attempt intubation success rate in the direct laryngoscopy group: in training (87.8%, n = 65), <10 years of clinical practice (92.6%, n = 63), 10–15 years of clinical practice (96.8%, n = 30) and >15 years of clinical practice (96.3%, n = 78), P = 0.204 for all categories.

Fig. 1
Fig. 1:
Table 1 - Demographics
Videolaryngoscopy (n=243) Direct laryngoscopy (n=258) Total (n=501)
 Male 128 (52.7%) 162 (62.8%) 290 (57.9%)
 Female 115 (47.3%) 96 (37.2%) 211 (42.1%)
Age (years)
 Mean ± SD 6.6 ± 3.5 6.6 ± 3.6 6.6 ± 3.5
 Median 5.9 5.6 5.6
 IQR 4.2 to 7.7 4.1 to 8.2 4.2 to 8.2
 Min-max 0.7 to 18.3 0.3 to 18.5 0.3 to 18.5
Weight (kg)
 Mean ± SD 26.0 ± 14.9 26.5 ± 16.3 26.3 ± 15.6
 Median 21.0 21.0 21.0
 IQR 17.0 to 29.0 17.0 to 29.0 17.0 to 29.0
 Min-max 7.6 to 110.0 4.0 to 108.0 4.0 to 110.0
IQR, interquartile range; SD, standard deviation.

Table 2 - Anaesthesia and airway management
Videolaryngoscopy (n=243) Direct laryngoscopy (n=258) Overall (n=501) P value
Anaesthesia induction P > 0.05 for all categories
 Inhalation 197 (81.1%) 209 (81.0%) 406 (81.0%)
 Intravenous 46 (18.9%) 49 (19.0%) 95 (19.0%)
Relaxation for intubation
 Yes 47 (19.3%) 55 (21.3%) 102 (20.4%)
 No 196 (80.7%) 203 (78.7%) 399 (79.6%)
Airway management
 Cuffed tracheal tube 55 (22.6%) 54 (20.9%) 109 (21.8%)
 Uncuffed tracheal tube 188 (77.4%) 204 (79.1%) 392 (78.2%)
 Laryngeal mask 0 (0.0%) 0 (0.0%) 0 (0.0%)

Table 3 - Comparison of laryngoscopes’ efficiency
Airway securing attempt success rate
First attempt Second attempt and more P valuea
Type of laryngoscopy
 Videolaryngoscopy (n=243) 211 (86.8%) 32 (13.2%) 0.046
 Direct laryngoscopy (n=258) 239 (92.6%) 19 (7.4%)
Type of videolaryngoscope
 McGrathTM (n=186) 160 (86.0%) 26 (14.0%) 0.500
 C-Mac (n=57) 51 (89.5%) 6 (10.5%)
aP value represents comparison of the first attempt intubation success rate.

Table 4 - Glottic visualisation
Cormack–Lehane score (available data) Videolaryngoscopy (n=207) Direct laryngoscopy (n=256) Overall
1 172 (83.1%) 174 (68.0%) 346 (74.7%)
2A 25 (12.1%) 57 (22.3%) 82 (17.7%)
2B 9 (4.3%) 14 (5.5%) 23 (5.0%)
3 1 (0.5%) 10 (3.9%) 11 (2.4%)
4 0 (0.0%) 1 (0.4%) 1 (0.2%)

In the videolaryngoscopy group the results for first attempt intubation success rate were similar: in training (87.8%, n = 43), <10 years of clinical practice (84.62%, n = 64), 10–15 years of clinical practice (80.0%, n = 20) and >15 years of clinical practice (89.4%, n = 76), P = 0.567 for all categories.


Videolaryngoscopy was invented to improve glottic visualisation and consequently to reduce the incidence of difficult and even failed intubation by improving the first attempt and overall intubation success rate. Over the past decades, several types of videolaryngoscopes with different blade angulation (e.g. GlideScope®, C-Mac, etc.) were manufactured and introduced into clinical practice. When considering videolaryngscope blade design, there are several different types available (Macintosh, Miller, angulated – D-blades, blades specifically designed by the manufacturer), however it seems reasonable that higher efficacy (higher first-attempt intubation success rate) might be more easily achieved with a standard blade design.12 As the development progressed, portable videolaryngoscopes also became available, such as the McGrath. Due to lack of data and initially limited distribution, the utilisation of portable videolaryngoscopes has been limited to potential scenarios of unanticipated difficult intubations or difficulties with oxygenation by facemask ventilation.13 In paediatric patients, wider videolaryngoscopy usage may be hampered and prolonged due to the need for several blade sizes and even for different blade designs (e.g. the Miller, a straight blade preferred by some paediatric anaesthesiologists in neonates and toddlers, and the Macintosh blade for older children). However, after price reductions and subsequent wider availability, videolaryngoscopes have become preferred or even recommended as a method of choice for obese patients’ intubation14 or for the management of predicted difficult airway in adult and paediatric patients.15–17

In our cohort of 501 patients, videolaryngoscopy (C-Mac 23.5%, n = 57 and McGrath 76.5%, n = 186) was associated with inferior first attempt intubation success rate in comparison to direct laryngoscopy; 86.8% (McGrath 86.0% vs. C-Mac 89.5%) versus 92.6%, respectively. However, there was 100% overall success rate in both groups, but with better glottic visualisation video compared to direct; Cormack-Leehane grade 1: 83.1%, n = 172 vs. 68%, n = 174, respectively. The mean intubation time was longer in the videolaryngoscopy group at 39.0 s ± 36.7 vs. 23.6 s ± 24.7 in the direct laryngoscopy group. There are several reasons which might explain the lower first attempt success rate in the videolaryngoscopy group. It may be caused by a combination of insufficient training and the technology limitation in a clinical scenario where a better visualisation does not necessarily lead to the higher success rate, due to the possible technical difficulties based on indirect intubation.18,19 The results are partially similar to Abdelgadir et al.,20 where the incidence of unsuccessful intubation was significantly higher in the indirect laryngoscopy, or videolaryngoscopy group; risk ratio RR 4.93 (95% CI 1.33 to 18.31). In that study, they found no difference in the first intubation attempt success rate, RR 0.96 (95% CI 0.91 to 1.02), and also there was longer intubation time in the videolaryngoscopy group with a mean difference of 5.49 s (95% CI 1.37 to 9.60). However, these findings were categorised as low quality, based on the significant heterogeneity of the analysed data. A recently published prospective multicentric randomised study, the VISI trial by Garcia-Marcinkiewicz et al.,21 found that videolaryngosopy was quicker compared to direct laryngoscopy in the first attempt intubation success rate (93% vs. 88%, P = 0.024) and also showed a lower incidence of associated complications in videolaryngoscopy group (2% vs. 5%, P = 0.0087). However, these results were based on a different population (smaller children, excluding neonates) with a median age of 5.5 months compared to a median age of 5.6 years in our cohort. Although the VISI trial was a semi-pragmatic based trial, all of the patients were paralysed for intubation after neuromuscular blocking agent administration compared with 20.4% patients in our cohort, and all of them were intubated with cuffed tracheal tubes (21.8% in our cohort). Further data are found in the Hu et al.22 meta-analysis of 27 randomised controlled trials comparing videolaryngoscopy and direct laryngoscopy in paediatric patients, where videolaryngoscopy was associated with longer intubation time with a mean difference = 3.41 s (95% CI 1.29–5.53), P = 0.002, with no effect on the first intubation attempt success rate (RR 1.34 (95% CI 0.68–2.62), P = 0.392, similar to Abdelgadir et al.20 The problem could be partially explained by the heterogeneity of the airway management practice in combination with a predicted large variability of videolaryngoscopy skill and training.

With the technology of videolaryngoscopy, the operator may achieve better laryngeal and glottic visualisation.23 This might lead to a higher intubation success rate or even higher first attempt intubation success rate. However, these results are based on an appropriate training and operator's skill in the indirect tracheal intubation. Although the results of our trial did not demonstrate that videolaryngoscopy was superior to direct for higher first attempt intubation success rates and overall success rates, we would like to support the views published by Zaouter et al.17 The implementation of videolaryngoscopy as a new standard of care, with documentation and visualisation of patient's previous intubations, should become part of the standardised pre-anaesthesia visit to optimise the anaesthesia and airway management in the perioperative period. The importance of elective videolaryngoscopy needs to be emphasized especially in the current context of pandemic of SARS-CoV-2 infection, where there is a need to secure the airway with orotracheal intubation, videolaryngoscopy is recommended as a method of choice.24


In the selected cohort of elective paediatric patients without predicted difficult airway, elective videolaryngoscopy was inferior for the first attempt intubation success rate despite better glottic visualisation. The time needed for successful intubation with videolaryngoscopy was longer compared with the direct laryngoscopy.

Acknowledgements relating to this article

Assistance with the study: authors would like to thank all colleagues from the Department of Paediatric Anesthesiology and Intensive Care Medicine.

Financial support and sponsorship: this work was supported by Specific University Research provided by MŠMT (MUNI/A/1153/2020, MUNI/A/1178/2020), supported by MH CZ - DRO (FNBr, 65269705) and supported by funds from the Faculty of Medicine MU to the junior researcher (Jozef Klučka, Martina Kosinová, ROZV/28/LF/2020).

The funding sources had no involvement in study design, in the collection, analysis and interpretation of data; in the writing of the report and in the decision to submit the article for publication.

Conflicts of interest: none.

Presentation: this study was presented as a poster presentation at the Euroanaesthesia Virtual Congress, 28–30 November 2020.


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Eva Klabusayová and Jozef Klučka contributed to this manuscript equally.

Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the European Society of Anaesthesiology and Intensive Care.