Video Laryngoscopy vs Direct Laryngoscopy on Successful First-Pass Orotracheal Intubation Among ICU patients

Lascarrou, JB et al. JAMA 2017; 317(5): 483-403. don: 10.1001/jama.2016.20603

Clinical Question

• In intensive care patients requiring orotracheal intubation, does video laryngoscopy (VL) compared to the Macintosh direct laryngoscope (DL) increase the frequency of first pass intubation?

Design

• Non-blinded, multicentre, open-label, 2 parallel group RCT
• Randomisation in blocks of 4, balanced and stratified by centre and experience of intubators (“experts” vs “non-experts”)
  • “Experts” – 5 years of ICU experience OR 1 year of ICU and 2 years of anaesthesia experience.
  • “Non-expert” – All others
• Randomisation sequence generated by blinded statistician
• Computerised allocation provided full concealment
• Both intention to treat and per protocol analyses performed
• Missing data was considered a failed first pass intubation
• 370 participants planned, assuming first pass success rate of 65% with DL, increased to 80% with VL, type I error of 5%, and type II error of 10%

Setting

• 7 ICUs in France
• May – December 2015

Population

• Inclusion:
  • ICU admission and need for orotracheal intubation to facilitate  mechanical ventilation
• Exclusion:
  • Contraindications to oral intubation, e.g. unstable C-spine
  • Insufficient time to include and randomise, e.g. cardiac arrest
  • Age <18
  • Pregnant or breastfeeding
  • Correctional facility inmate
  • Under guardianship
  • Without health insurance
  • Refusal by patient or next of kin
  • Previous enrolment in an RCT with intubation as the primary end point
• 489 patients screened, 371 randomised
  • 186 randomised to VL, 185 randomised to DL  (ITT analysis)
  • 183 received VL as intended, 182 received DL as intended (per protocol analysis)
• Baseline statistics similar between groups

Intervention

• McGrath MAC Videolaryngoscope (without stylet)

Control

• Macintosh direct laryngoscope with either a 3 or 4 blade

Standard to both groups:

• All physicians in all centres were trained in the use of all equipment on mannequins before starting the studyI All “non-experts” were supervised by an “expert” during the study
• Preoxygenation with device of the intensivist’s choosing
  • Non-rebreathe mask of at least 15L/min for >3 mins
  • NIV with 100% oxygen for at least 3 mins
  • High flow nasal cannula oxygen at 60L/min with 100% oxygen for at least 3 mins
• IV induction with EITHER etomidate 0.2/0.3mg/kg OR ketamine 1-2mg/kg
• Muscle relaxation with suxamethonium 1mg/kg OR rocuronium 1mg/kg (if sugammadex immediately available)
• Cricoid pressure was at user’s discretion
• If first pass failed, individual was allowed to choose between repeat laryngoscopy or alternative device as per French difficult airway guidelines

Outcome

• Primary outcome: Successful first pass intubation, as defined by capnography over 4 breaths or more – no significant difference
  • VL 67.7% vs DL 70.3%, absolute difference -2.5%, P= 0.60
• Predefined Secondary outcomes:
  • Proportion of patients with successful intubation at any attempt – no significant difference
  • Total time to successful intubation – no significant difference
  • Proportion of patients with difficult intubation – no significant difference
  • Proportion of patients intubated with alternative techniques – no significant difference
  • Duration of mandatory ventilation – no significant difference
  • ICU length of stay – no significant difference
  • Hospital length of stay – no significant difference
  • ICU mortality – no significant difference
  • 28 day mortality – no significant difference
• Cormack and Lehane grade of glottic visibility, % of glottic opening scores, reasons for intubation failure, and severe life threatening complications were significantly different between groups:

 

Authors’ Conclusions

• Amongst patients in ICU requiring intubation, video laryngoscopy compared with direct laryngoscopy did not improve first pass orotracheal intubation rates and was associated with higher rates of severe life-threatening complications

Strengths

• Important clinical question
• Accurate power calculation
• Appropriate methodology with good efforts to minimise bias, such as concealed allocation, maintenance of intended intervention and intention-to-treat analysis
• Objective, patient centred primary outcome
• Registered with clinicaltrials.gov
• All users were familiar with the devices, improving internal validity

Weaknesses

• The intubation protocol allowed for some user variability – this could affect both internal and external validity
• Suxamethonium 1mg/kg was used in the vast majority of intubations – some would debate this would not give optimal conditions for intubation (1.5mg/kg may be better (Naguib et al, 2006)
• Etomidate/sux were used in the vast majority (75-80%) of intubations – this is not  common practice worldwide and reduces external validity
• The McGrath is one of many video laryngoscopes
  • This trial is really a comparison of the McGrath and the Macintosh, and not a global view of VL versus DL
  • In a unit where the McGrath is not the video laryngoscope of choice, I would question the applicability of these results
• The glottic view was significantly improved with the McGrath, however the intubation success was the same – there may have been an issue with technique or training

The Bottom Line

• In this trial comparing the McGrath VL and the Macintosh DL in intubating intensive care patients, there was no difference seen in the primary outcome of first pass success rate
• An association was seen with improved glottic view, and with a worsening of severe complications – however these are secondary outcomes that the study is not powered for and thus hypothesis generating only (and this is clearly stated by the authors in the paper)
• I will focus on gaining expertise with my local devices and protocols, and encouraging my team members to do the same

External Links

• [article] Lascarrou JB et al. Video Laryngoscopy vs Direct Laryngoscopy on Successful First-Pass Orotracheal Intubation among ICU patients. A Randomised clinical trial. JAMA 2017; 317 (5): 483-493 (abstract only)
• [Editorial] O’Gara B et al. Video Laryngoscopy in the Intensive Care Unit. JAMA 2017; 317(5):479-480 (abstract only)
• [Review] Lewis SR et al. Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation. Cochrane Database of Systematic Reviews 2016, Issue 11. Art. No.: CD011136. DOI: 10.1002/14651858.CD011136.pub2. (free full text)
• [Further reading] Silverberg MJ et al. Comparison of video laryngoscopy versus direct laryngoscopy during urgent endotracheal intubation: A randomised control trial. Crit Care Med 2015; 43(3):636-641 (abstract only)
• [Further reading] ICU Revisited. Video Laryngoscopy vs Direct Laryngoscopy. Fooled eyes

Metadata

Summary author: Segun Olusanya
Summary date: 7 April 2017
Peer-review editor: Duncan Chambler