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
patients

Jaber et al. ICM 20201; doi.org/10.1007/s00134-021-06417-y

Clinical Question

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

Background

• Acute respiratory failure requiring mechanical ventilation is one of the leading causes of ICU admission
• Intubation in the ICU setting has a higher complication rate compared to the operating theatre
• Various devices and strategies have been developed with varying success, complication and adoption rates
• The use of a preformed stylet has been proposed to increase first-attempt success rate
• Previous trial comparing bougie and stylet in the ED setting showed a higher 1st attempt intubation rate in the bougie group

Design

• 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

Setting

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

Population

• 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%)

Intervention

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

Control

• 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%)

Outcome

• 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.

Strengths

• 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

Weaknesses

• 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

• 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 patients
• Editorial
• ESICM Podcast with Samir Jaber
• INTUBE Study

Metadata

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