Should videolaryngoscopy become standard practice to facilitate tracheal intubation in anaesthesia, critical care and emergency care?

Abstract

Airway management may be the most important skill of the anaesthesiologist and the critical care and emergency physician. The successful passing of an endotracheal tube intubation (ETI) into the trachea facilitates oxygenation and ventilation and protects patients from aspiration of gastric content. Not unexpectedly, ETI is also associated with complications, including hypoxia, hypotension, oesophageal placement and even cardiac arrest. Some of these complications may be related to the administration of the drugs used to facilitate ETI, but failure to place the tube may result in hypoxia, hypoventilation and ultimately cardiac arrest. The proportion of successful intubations on the first attempt has been seen as a performance measure, and not unexpectedly, with more intubation attempts, the prevalence of complications increases. In recent years, the use of videolaryngoscopy has emerged as a means of facilitating ETI, and its use is a part of many airway protocols, both in hospital and in pre-hospital settings. Recently, two important large randomized controlled trials have been published examining the use of videolaryngoscopy compared with direct laryngoscopy. The first was the DEVICE trial published this June in the New England Journal of Medicine. The study, conducted in the United States, randomized 1400 patients needing intubation in the emergency department to ETI with videolaryngoscopy or direct laryngoscopy. The study included specialists in emergency medicine, intensive care and a minority of anaesthetists. The primary outcome was the proportion of successful intubations on the first attempt. The sample size assumed a first-pass intubation rate of 80%; therefore, the study was powered to be able to show a 5% absolute difference with the use of videolaryngoscopy. The study included several secondary endpoints, such as the prevalence of hypoxia and hypotension, and the need for vasopressors and cardiac arrest following the procedure. The study was stopped early after an interim analysis showed the efficacy of the videolaryngoscopy compared with direct laryngoscopy after the inclusion of 1420 patients. The study showed a 15% difference (number needed to treat of 6–7) in achieving the first success of ETI. The ETI was performed by 370 unique operators, with an average experience of around 50 intubations. Before the ETI procedure, about 70%–80% of the ETI were predicted to be easy or moderately easy according to an assessment of the patient by the operator. Importantly, most of the operators already had previous experience with the use of videolaryngoscopy. In addition, the passing of the intubation tube was, in most cases, performed with the help of a bougie or stylet. This may be important, as a previous study that did not use these airway adjuncts with a similar frequency failed to show the superiority of videolaryngoscopy over direct laryngoscopy. With regard to the secondary endpoints, there were no statistically significant differences in the proportion of hypoxia (defined as a peripheral oxygen saturation of less than 80%), hypotension (systolic blood pressure less than 65 mmHg), the need for a new vasopressor and cardiac arrest (non-fatal and fatal). The absolute differences between video and direct laryngoscopy for these outcomes were between 0% and 1.3%, but the point estimate tended to favour videolaryngoscopy. Combining the more severe complications, there was a 0.5% difference in complications favouring videolaryngoscopy. If this difference is true, it would translate into a number needed to treat of 200 for video compared with direct laryngoscopy. This effect size would likely be seen as large enough since ETI is a commonly performed procedure. Thus, the lack of statistical differences may have been due to the lack of a large-enough sample size. Hopefully, the DEVICE investigators will present the results of complications indexed by whether the intubation was successful on the first attempt or not and the prevalence of complications in these two groups. The supplement to the paper provides some interesting additional analyses. Indeed, it appears that videolaryngoscopy is especially effective in operators with limited experience. The difference appears to dissipate when comparing operators who had performed more than 250 intubations. The study also shows that when compared with direct laryngoscopy videolaryngoscopy, most of the improvement is seen in terms of an increase in the proportion of Grade 1 and 2 views. Indeed, in those with a Grade 3 and 4 view with direct laryngoscopy, the view also appears to be restricted with videolaryngoscopy. The second trial was published in the journal Anaesthesia earlier this year. This multicentre trial randomized 2042 patients undergoing elective surgery with an anticipated non-difficult airway to undergo either direct laryngoscopy or videolaryngoscopy. In this study, a stylet was used to aid in the passing of the tube below the vocal chords. The study exclusion criteria included an anticipated difficult airway, a BMI higher than 40 and a high risk of aspiration. The operators performing the intubation were either registrars or consultants of anaesthesia. Like the results of the DEVICE trial, the study showed a higher first-pass intubation rate with videolaryngoscopy (94%) compared with direct laryngoscopy (82%). In a separate analysis Received: 2 July 2023 Accepted: 4 July 2023