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Three Part Question

In [patients requiring emergency endotracheal intubation within an emergency department setting] does [video laryngoscopy used first line, rather than direct laryngoscopy] result in improved [first pass success rate and/or clinical outcomes]?

Clinical Scenario

You are present in resus when a 35 year old arrives as a standby, with a low GCS. The anaesthetic team is in attendance. This history is of recent overdose of sedative and antidepressant medication, but there is also a history of recent respiratory illness. Blood gas analysis reveals a mixed acidosis and a decision is taken early to sedate and ventilate for airway protection and predicted clinical course. You don PPE, discuss roles during the team brief and agree to be the primary intubator, with anaesthesia administering induction drugs and providing team leadership. During the checklist you suggest an airway plan that starts with direct laryngoscopy (DL). The anaesthetic team recommend use of videolaryngoscopy (VL), stating that not only will this allow them to see a bit more of what is happening but also now has an evidence base suggesting better first pass success rates. They also suggest it is recommended for intubation of COVID-19 patients in several international guidelines. You did not know this and resolve to have a look at the evidence. Right after you’ve intubated this patient….

Search Strategy

Using the National Institute of Clinical Excellence (NICE) Healthcare Databases Advanced Search programme, Medline (1946) and Embase (1980) were searched using the following thread:



(Video Laryngoscop* OR Video-assisted Laryngoscop* or Video-guided Laryngoscop* OR Larnygoscopy or Laryngoscopes) AND (Direct Laryngoscopy OR Laryngoscopy or Laryngoscopes) AND (endotracheal*intubat* OR Intubat* OR Intubation,intratracheal ) AND (first pass OR complicat* OR mortalit*)

Search Outcome

Search strategy identified 838 papers (Medline 375, Embase 453). Screened to 192 relevant papers, and 61 duplicates removed to leave 131 papers. Reference lists for all relevant studies were searched in addition. These abstracts were sifted to four papers with the highest levels of evidence that directly addressed the three-part question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Lewis et al. September 2017 United Kingdom	Adult patients requiring endotracheal intubation for elective surgery (with and without predicted difficulty), emergency prehospital care or critical care indications. 64 RCTs including >7000 patients.	Cochrane Systematic Review and meta-analysis (level 1a evidence)	Failed intubation	Significant reduction in failed intubation rate for both normal and anticipated difficult airways using VL (OR 0.35, 95% CI 0.19-0.65, and OR 0.28, 95% CI 0.15-0.55 respectively)	Few studies were prospectively registered, increasing risk of selective reporting bias Few studies reported adverse events or mortality Heterogeneity of studies and variability of definitions limits conclusions that can be drawn 61/64 studies were performed in an elective setting, with limited study data on intubation in critically unwell patients. Studies compared VL across a range of devices to DL.
			Hypoxaemia and/or mortality	No evidence of benefit with VL
			Serious airway complications, airway trauma, sore throat.	Video laryngoscopy significantly reduced airway trauma and post-operative hoarseness
			Proportion of successful first attempt intubations, number of intubation attempts	No difference in number of intubation attempts or proportion of successful first attempts
Bhattacharjee et al. June 2018 India/USA	1250 adult patients presenting to the Emergency Department requiring endotracheal intubation	Meta-analysis of 5 RCTs (level 1b evidence)	Intubation success rate	First intubation success and overall success rates were similar with DL and VL.	Individual studies are small with significant statistical heterogeneity Studies failed to report hypoxaemia as an adverse outcome, which is a clinically important parameter to compare Patients with a potentially difficult airway were excluded, which removes a group where video laryngoscopy is suspected to perform better than direct laryngoscopy
			in-hospital mortality & oesophageal intubation rate	No difference in mortality outcomes was found between DL and VL. Video laryngoscopy significantly reduced the oesophageal intubation rate in a subset of patients (OR 0.09 95% CI 0.01-0.70)
Brown et al. Jan 2020 USA	6,938 emergency department adult intubations at participating National Emergency Airway Registry (NEAR) sites	Prospective multicentre observational cohort study (Level of evidence – 2b)	First attempt intubation success	First attempt success was significantly higher with VL compared to Augmented-DL (adjusted OR [AOR] = 2.8, 95% CI = 2.4 to 3.3), This benefit continued on logistic regression analysis after accounting for operator specialty, training grade, indication and difficult airway features.	Observational nature of study risks confounding, despite efforts to control for variables Augmented-direct laryngoscopy choice may have been made for suspected difficult airways, giving the appearance of poor performance when compared to videolaryngoscopy
			Percentage of patients with peri-intubation complications	Fewer esophageal intubations were observed in the VL cohort (0.4% vs. 1.3%, AOR = 0.2, 95% CI = 0.1 to 0.5).
Arulkumaran et al. December 2017 United Kingdom	32 studies comprising 15,064 emergency intubations outside the operating room.	Systematic review and meta-analysis Level of evidence 2a	First pass intubation	mproved rates of first pass intubation with VL in the ICU (OR 2.02, 95% CI 1.43 to 2.64) and the emergency department (OR 1.25, 95% CI 0.96 to 1.62)	Majority of included studies were uncontrolled cohort studies, at moderate or serious risk of bias. Several studies had industry sponsorship. Significant heterogeneity between trials. Limited accounting of confounding variables.
			Complication rates	Less oesophageal intubation episodes with VL (OR 0.32, 95% CI 0.14 to 0.70)

Comment(s)

Emergency endotracheal intubation of the unwell patient is associated with significantly higher rates of complication, when compared to elective intubation.5 There are multiple potential reasons for this, but the unanticipated difficult airway is often cited. Traditional predictors of airway difficulty, including Mallampati scoring, have poor predictive values of detecting unanticipated airway difficulties in the emergency setting.6 Multiple attempts or delayed intubation/oxygenation can lead to hypoxaemia and hypotension, which in turn precipitate cardiac arrest.7 Videolaryngoscopy (VL) has been proposed as a solution to this issue and is now widely available in most emergency settings. However, VL can take differing approaches (hyperangulated vs standard geometry) and is not without challenges, including technical proficiency, secretions or blood obscuring the camera and challenging tube delivery (despite adequate laryngeal view). The previous evidence has been limited. As such, 2018 UK recommendations suggest video laryngoscopy should be available for intubation of all critically unwell patients, as either primary or rescue device for difficult intubations8. No current guidelines mandate use as first line. Indeed, recent trial evidence from Intensive Care has raised concerns about widespread adoption, suggesting VL may confer higher complication rates.9 Since the original Cochrane review on the topic, there have been multiple additional publications.1 Arulkaman et al report improved rates of first pass success with VL use in an emergency care setting in a systematic review comprising >15,000 intubation episodes.4 Brown et al also report higher rates of first pass success with VL in a prospective observational cohort, even when compared to augmented DL using ramped positioning, external laryngeal manipulation and bougie use.3 Does this potential increase in first pass success result in improved clinical outcomes? This has been harder to prove. Both the above studies and a systematic review focussed on the emergency department setting report reduced rates of oesophageal intubation with VL. However, none of these studies demonstrate a reduction in hypoxic events, aspiration, mortality or other serious clinical outcomes through use of VL. Where does this leave us? Current evidence suggests VL allows more reliable first pass success and is at least as good as direct laryngoscopy in preventing complications, with particular success in reducing oesophageal intubations. With event rates as low as they are for clinically relevant complications, we may never see studies of sufficient power to reliably conclude the impact of VL on event rates. There are also soft benefits from VL, such as shared visualisation of the glottis, improved teaching opportunity and imaging capture with modern devices. In addition, some agencies have recently recommended routine use of VL for intubation of patients with suspected COVID-19, to allow easier distancing of the laryngoscopist from the airway in addition to the above advantages.10-13 Given the evidence, purported benefits and the increasing availability of VL it seems likely that clinicians will opt for it routinely. Finally, several studies report little difference in first pass success or oesophageal intubation rates when VL is compared to DL use in experienced operators.4 It is highly likely that senior staff who have extensive experience and familiarity with DL are so proficient with this technique that VL adds little benefit.

Clinical Bottom Line

Current evidence suggests videolaryngoscopy is likely to improve first pass success and reduce oesophageal intubation rates, when used in an emergency department setting. There is no evidence at present that mandating use of VL improves clinically relevant outcomes and senior/experienced operators should use techniques with which they are familiar and experienced.

Level of Evidence

Level 1 - Recent well-done systematic review was considered or a study of high quality is available.

References

1. Lewis SR, Butler AR, Parker J, Cook TM, Schofield-Robinson OJ, Smith AF. Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation: a Cochrane Systematic Review. British Journal of Anaesthesia 2017; 119(3): 369-83
2. Bhattacharjee S, Maitra S, Baidya DK. A comparison between video laryngoscopy and direct laryngoscopy for endotracheal intubation in the emergency department: A meta-analysis of randomized controlled trials. Journal of Clinical Anaesthesia 2018; 47: 21-6.
3. Brown CA, 3rd, Kaji AH, Fantegrossi A, et al. Video Laryngoscopy Compared to Augmented Direct Laryngoscopy in Adult Emergency Department Tracheal Intubations: A National Emergency Airway Registry (NEAR) Study Academic Emergency Medicine 2020; 27(2): 100-8.
4. Arulkumaran N, Lowe J, Ions R, Mendoza M, Bennett V, Dunser MW Videolaryngoscopy versus direct laryngoscopy for emergency orotracheal intubation outside the operating room: a systematic review and meta-analysis. British Journal of Anaesthesia 2018; 120(4): 712-24.
5. Cook TM, Woodall N, Harper J, Benger J, Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 2 British Journal of Anaesthesia 2011; 106(5): 632-42.
6. Roth D, Pace NL, Lee A, et al Bedside tests for predicting difficult airways: an abridged Cochrane diagnostic test accuracy systematic review Anaesthesia 2019; 74(7): 915-28.
7. Mort TC, Waberski BH, Clive J Extending the preoxygenation period from 4 to 8 mins in critically ill patients undergoing emergency intubation Critical Care Medicine 2009; 37(1): 68-71.
8. Higgs A, McGrath BA, Goddard C, et al. Guidelines for the management of tracheal intubation in critically ill adults British Journal of Anaesthesia 2018; 120(2): 323-52.
9. Lascarrou JB, Boisrame-Helms J, Bailly A, et al. Video Laryngoscopy vs Direct Laryngoscopy on Successful First-Pass Orotracheal Intubation Among ICU Patients: A Randomized Clinical Trial. The Journal of the American Medical Association 2017; 317(5): 483-93.
10. Cook TM, El-Boghdadly K, McGuire B, McNarry AF, Patel A, Higgs A. Consensus guidelines for managing the airway in patients with COVID-19: Guidelines from the Difficult Airway Society. the Association of Anaesthetists the Intensive Care Society, the Faculty of Intensive Care Medicine and the Royal College of Anaesthetists. Anaesthesia 2020
11. Hall D, Steel A, Heij R, Eley A, Young P. Videolaryngoscopy increases 'mouth-to-mouth' distance compared with direct laryngoscopy Anaesthesia 2020
12. Luo M, Cao S, Wei L, et al. Precautions for Intubating Patients with COVID-19 Anesthesiology 2020
13. Yao W, Wang T, Jiang B, et al. Emergency tracheal intubation in 202 patients with COVID-19 in Wuhan, China: lessons learnt and international expert recommendations. British Journal of Anaesthesia 2020