Effect of the use of an endotracheal
tube and stylet versus an endotracheal tube
alone on first‑attempt intubation success: a
multicentre, randomised clinical trial in 999

Jaber et al. ICM 20201;

Clinical Question

  • In critically ill adults, does the use of an intubating stylet compared to tracheal tube alone, increase first-attempt successful intubation?



  • Unblinded, parallel-group, pragmatic randomised controlled trial
  • Power calculations determined that a sample size of 1040 patients would provide 95% power to detect a 10% absolute difference between tracheal tube alone and stylet group with a type 1 error of 5% ; assuming 10% missing data
  • Central randomisation in 1:1 ratio in blocks of variable sizes
    • Treatment assignments were concealed from patients, research staff and the statistician
  • The primary outcome was the proportion of patients with successful first-attempt intubation
    • Success was defined by the presence of normal waveform capnography trace over 4 or more breaths (or in absence of capnography tube position was confirmed by auscultation of lungs and over stomach)
  • The pre-specified secondary outcome was the proportion of patients who had at least one complication related to tracheal intubation (occurring within 1 hour of intubation):
    • Hypoxia (Sats < 80% during intubation attempts)
    • Cardiovascular collapse (sBP < 65 mmHg recorded at least once; sBP < 90 mmHg that lasted 30 mins despite up to 1L fluid loading; required use of vasoactive drugs; cardiac arrest)
    • Death
    • Operator-assessed difficult intubation
    • Oesophageal intubation
    • Operator-reported aspiration
    • Arrhythmia
    • Agitation
  • Serious Adverse Events reported included:
    • Mucosal bleeding
    • Laryngeal, tracheal, mediastinal or oesophageal injuries
    • Lowest peripheral oxygen saturation
    • Highest FiO2
    • Highest PEEP in the first 6 – 24hrs post-intubation
  • Clinical outcomes (in addition to above)
    • ICU length of stay
    • ICU-free days within 1st 28-days post-intubation
    • Invasive ventilator-free days within 1st 28-days post-intubation
    • 28-day mortality
    • 90-day mortality


  • 32 ICUs in France
  • Between October 2019 and March 2020


  • Inclusion:
    • Above 18 years of age
    • Covered by public health insurance
    • Required emergency mechanical ventilation through tracheal tube on the ICU
  • Exclusion:
    • Intubation following cardiac arrest
    • Previous intubation on the ICU during same admission with prior inclusion in the study
    • Pregnant or breastfeeding woman
  • 1626 screened who met inclusion criteria, 1040 randomised; 41 did not complete trial
  • 501 in stylet group, 498 in control group included in final analysis with no protocol deviation
  • No significant difference in baseline or airway characteristics between groups
    • Stylet group had a higher prevalence of low risk MACOCHA score (77.1% vs 75.2%)


  • 1st intubation attempt with a tracheal tube and a stylet with a bend angle of 25 to 35 degrees at the distal tip


  • 1st intubation attempt with tracheal tube alone

Management common to both groups

  • All other aspects of patient care during and after intubation was at the discretion of attending physicians
  • Montpellier intubation protocol was recommended
  • Operator characteristics (supplementary material)
    • Higher proportion of senior anaesthetist in stylet group (13.4% vs 9.0%)
    • Higher proportion of anaesthetic nurse in control group (5.1% vs 2.2%)
  • Drug used for intubation
    • Higher proportion of ketamine use in stylet group (72.2% vs 65.5%)


  • Primary outcome: Higher incidence of successful first-attempt intubation in stylet group compared to control (78.2% vs 71.5%. p=0.01)
    • Predefined subgroup (including operator factors) analysis did not modify this outcome
  • Secondary outcomes:
    • Comparing stylet vs. control group
      • No significant difference in complication rates
        • 38.7% vs 40.2%, p=0.64
      • No significant difference in serious adverse events
        • 4.0% vs 3.6%, p=0.76
      • No significant difference in:
        • Safety outcomes
        • Traumatic injuries
        • Clinical outcomes including length of stay and mortality

Authors’ Conclusions

  • In this multicentre, randomised trial involving critically ill adults undergoing tracheal intubation, the use of a stylet for tracheal intubation was safe and  resulted in significantly higher first-attempt intubation success than the use of a tracheal tube alone.


  • Prepublished trial protocol
  • Well conducted trial attempting to answer a relevant question with regards to airway management practice
  • Inclusion criteria (with few exclusion criteria) reflective of ICU practice and hence likely to be generalisable
  • Good balance of patients from all 32 sites that were involved in randomisation
  • Results similar from previous studies (such as INTUBE) regarding rates of first pass success in ICU intubations
  • NO protocol violations
  • Predefined subgroup analysis of primary outcome included relevant factors
  • Secondary outcomes were relevant


  • Did not achieve recruitment target although the actual 1st attempt success rate in control group was as expected
  • No blinding of the intervention was possible
  • First pass success was primarily defined by capnography trace, yet only ~85% in each group used capnography. The proportion using capnography seems dangerously low for what should be mandated monitoring for all intubations within ICU
  • Some adverse events (difficulty, injuries) were operator reported – this could result in underreporting
  • Management of everything else pre, during and after intubation was at discretion of treating teams. It could be argued this is a bigger determinant of risk for adverse events happening (e.g. choice of drugs used) as opposed to the use of a stylet or not
  • In both groups approximately 58% of intubations were done by anaesthetists – this is not reflective of practice in all ICUs

The Bottom Line

  • Successful intubation is the final outcome of a series of complex interactions between operator and devices used which are continually evolving
  • The rate of successful 1st attempt success is surprisingly low
  • Interestingly, the experience of the operator did not affect the primary outcome
  • My current practice is to use a bougie in both direct and video-laryngoscopy with a low threshold for stylet in video-laryngoscopy depending on the view/situation

External Links


Summary author: Adrian Wong
Summary date: 2nd June 2021
Peer-review editor: George Walker



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