Publication

• Title: Noninvasive Ventilation for Preoxygenation during Emergency Intubation
• Acronym: PREOXI
• Year: 2024
• Journal published in: The New England Journal of Medicine
• Citation: Gibbs KW, Semler MW, Driver BE, et al. Noninvasive Ventilation for Preoxygenation during Emergency Intubation. N Engl J Med. 2024;390:2165-2177.

Context & Rationale

• Background

  • Emergency tracheal intubation in the ED/ICU is frequently complicated by peri-intubation hypoxaemia, which is associated with cardiovascular collapse, cardiac arrest, and death.
  • Common “standard” preoxygenation (non-rebreather facemask or bag-mask without positive-pressure ventilation) can deliver high inspired oxygen but does not recruit atelectatic lung; it may be inadequate in shunt physiology and severe physiological derangement.
  • Noninvasive ventilation (NIV) can deliver high FiO₂ with positive end-expiratory pressure (and pressure support), potentially increasing end-expiratory lung volume and maintaining oxygenation/ventilation after induction.
  • Potential downsides of NIV at induction include aspiration risk in vulnerable patients, difficulty achieving an adequate seal, haemodynamic effects of positive pressure, and increased procedural complexity.
  • Prior RCT evidence for NIV preoxygenation in critically ill adults was limited and often restricted to acute hypoxaemic respiratory failure, leaving uncertainty about general ED/ICU intubation populations and safety.
• Research Question/Hypothesis

  • In critically ill adults undergoing emergency tracheal intubation, does preoxygenation with NIV (vs oxygen mask) reduce the incidence of hypoxaemia (SpO₂ <85%) between induction of anaesthesia and 2 minutes after tracheal intubation?
• Why This Matters

  • Peri-intubation hypoxaemia is an immediately modifiable complication; reducing severe desaturation may prevent downstream haemodynamic collapse and cardiac arrest.
  • NIV is widely available in ED/ICU settings; a pragmatic, multicentre RCT could credibly inform a default preoxygenation strategy and standardise practice.

Design & Methods

• Research Question: Among critically ill adults requiring emergency tracheal intubation, NIV for preoxygenation (vs oxygen mask) reduces peri-intubation hypoxaemia (SpO₂ <85%) between induction and 2 minutes after intubation.
• Study Type: Pragmatic, multicentre, parallel-group randomised controlled trial (1:1), unblinded; conducted in 7 emergency departments and 15 intensive care units at 17 hospitals in the United States; stratified by trial site; physiological data recorded by an independent observer.
• Population:
  • Adults (≥18 years) in an ED or ICU with a clinician decision to perform tracheal intubation using planned induction of anaesthesia and laryngoscopy.
  • Planned operator was a clinician expected to routinely perform tracheal intubation.
  • Key exclusions included: immediate need for intubation that precluded trial procedures; receipt of positive-pressure ventilation at enrolment; and factors increasing aspiration risk or making NIV difficult to apply (vomiting, haematemesis, haemoptysis, epistaxis, facial injury, severe agitation, profound encephalopathy), plus other protocol-specified exclusions (e.g., pregnancy, prisoner, prior enrolment).
  • Trial registration: NCT05267652.
• Intervention:
  • Preoxygenation with NIV from randomisation until initiation of laryngoscopy.
  • Delivered via a tight-fitting facemask connected to an NIV device or ventilator; recommended settings: FiO₂ 1.0, expiratory pressure ≥5 cm H₂O, inspiratory pressure ≥10 cm H₂O, and respiratory rate ≥10 breaths/min.
  • NIV could be continued during the interval between induction and initiation of laryngoscopy (peri-induction positive-pressure support).
• Comparison:
  • Preoxygenation with an oxygen mask (non-rebreather facemask or bag-mask without manual ventilation) from randomisation until initiation of laryngoscopy; oxygen flow rate ≥15 L/min.
  • Supplemental oxygen via nasal cannula or high-flow nasal oxygen was permitted; bag-mask ventilation after induction was permitted at clinician discretion.
• Blinding: Unblinded (interventions not feasibly masked); primary outcome was objective (pulse oximetry) and recorded continuously by an independent observer, mitigating detection bias.
• Statistics: A total of 1264 patients were required to detect a 6 percentage point absolute reduction in hypoxaemia (from 17% to 11%) with 85% power at a two-sided alpha level of 0.05; planned enrolment was 1300 to account for ~3% missing primary outcome data. Primary analysis was intention-to-treat among patients with available oxygen-saturation data; one interim analysis was planned after 650 patients with a stopping boundary for efficacy at P≤0.001. A prespecified protocol and statistical analysis plan were published before trial completion. ¹
• Follow-Up Period: Physiological outcomes from induction through 2 minutes after intubation; safety outcomes to 24 hours; ICU/ventilator-free days and mortality assessed to day 28 (censored at discharge).

Key Results

This trial was not stopped early. Enrolment reached the prespecified target (n=1301); one interim analysis was planned after 650 participants with an efficacy boundary of P≤0.001.

Outcome	NIV	Oxygen mask	Effect	p value / 95% CI	Notes
Hypoxaemia (SpO2 <85%)	57/624 (9.1%)	118/637 (18.5%)	Risk difference −9.4 percentage points	95% CI −13.2 to −5.6; P<0.001	Primary outcome; induction to 2 min post-intubation.
Lowest oxygen saturation, median (IQR)	99 (95–100)	97 (89–100)	Median difference 2 percentage points	95% CI 1 to 3; P not reported	Key secondary outcome (same time window).
Lowest oxygen saturation <80%	39/624 (6.2%)	84/637 (13.2%)	Risk difference −6.9 percentage points	95% CI −10.2 to −3.7; P not reported	Severe hypoxaemia.
Lowest oxygen saturation <70%	15/624 (2.4%)	36/637 (5.7%)	Risk difference −3.2 percentage points	95% CI −5.4 to −1.1; P not reported	Very severe hypoxaemia.
Cardiovascular collapse	113/645 (17.5%)	127/656 (19.4%)	Risk difference −1.8 percentage points	95% CI −6.1 to 2.4; P not reported	Composite: SBP <65 mmHg, new/increased vasopressors, or cardiac arrest.
Cardiac arrest	1/645 (0.2%)	7/656 (1.1%)	Risk difference −0.9 percentage points	95% CI −1.8 to −0.1; P not reported	Rare events; 4/8 arrests died within 1 hour (1 NIV; 3 oxygen mask).
Operator-reported aspiration	6/645 (0.9%)	9/656 (1.4%)	Risk difference −0.4 percentage points	95% CI −1.6 to 0.7; P not reported	Clinical diagnosis at intubation.
New infiltrate on chest imaging within 24 h	144/509 (28.3%)	148/497 (29.8%)	Risk difference −1.5 percentage points	95% CI −7.1 to 4.1; P not reported	Denominator reflects those with available imaging.
Ventilator-free days to day 28, median (IQR)	21 (0–26)	17 (0–25)	Median difference 4 days	95% CI −1 to 9; P not reported	Not adjusted for multiplicity; censored at discharge.
ICU-free days to day 28, median (IQR)	16 (0–23)	14 (0–23)	Median difference 2 days	95% CI −1 to 8; P not reported	Not adjusted for multiplicity; censored at discharge.
In-hospital death to day 28	209/645 (32.4%)	217/656 (33.1%)	Risk difference −0.7 percentage points	95% CI −5.8 to 4.4; P not reported	Trial not powered for mortality.

• NIV reduced hypoxaemia by 9.4 percentage points (9.1% vs 18.5%) and reduced severe hypoxaemia (SpO₂ <80%) by 6.9 percentage points (6.2% vs 13.2%).
• Prespecified subgroup analyses were directionally consistent, including among patients receiving FiO₂ >0.70 in the prior hour (18/106 [17.0%] vs 45/137 [32.8%]) and among those with body-mass index ≥30 (20/222 [9.0%] vs 58/220 [26.4%]).
• Safety outcomes were similar for aspiration (0.9% vs 1.4%) and new infiltrate on imaging (28.3% vs 29.8%); patient-centred outcomes (mortality, ICU-free days) were not different and were not the primary focus.

Internal Validity

• Randomisation and allocation: 1:1 randomisation stratified by trial site; allocation concealment via sequential opaque envelopes; randomisation occurred after the clinical decision to intubate, reducing selection bias from post-decision exclusions.
• Dropout or exclusions: 1301 randomised; primary outcome oxygen-saturation data were missing for 40/1301 (3.1%), leaving 624 and 637 patients in the primary analysis; missingness is small but not completely ignorable if related to severity or workflow.
• Performance/detection bias: Unblinded care team; however, oxygen saturation and haemodynamics were recorded continuously by an independent observer, and the primary endpoint (SpO₂ <85%) is objective; the main residual risk is differential co-interventions rather than biased outcome measurement.
• Protocol adherence: Assigned preoxygenation was delivered in 616/645 (95.5%) of the NIV group and 648/656 (98.8%) of the oxygen-mask group; crossover occurred in 29/645 (4.5%) and 8/656 (1.2%), respectively.
• Baseline characteristics: Groups were well balanced for illness severity (median APACHE II score 17 in both groups) and pre-enrolment oxygenation (median lowest SpO₂ 95% in prior hour); small imbalances (e.g., BMI 27.6 vs 26.6; highest FiO₂ 0.33 vs 0.36 in the prior hour) are unlikely to explain the effect size.
• Heterogeneity: Broad case-mix (ICU ~73%; altered mental status ~60%; sepsis/septic shock ~47%); subgroup analyses (location, acute hypoxaemic respiratory failure, BMI, APACHE II, prior-hour FiO₂) showed consistent direction of effect, supporting robustness across typical ED/ICU phenotypes.
• Timing: Preoxygenation duration ≥3 minutes was achieved in 603/624 (96.6%) vs 605/637 (95.0%), suggesting the intervention was delivered within a clinically plausible timeframe for most enrolled patients.
• Dose: Among those receiving NIV during preoxygenation, median inspiratory pressure was 10 (IQR 10–12) cm H₂O and median expiratory pressure was 5 (IQR 5–5) cm H₂O; this is a pragmatic “moderate” dose that prioritises feasibility over maximal recruitment.
• Separation of the variable of interest:
  • Preoxygenation modality: NIV used in 616/645 (95.5%) vs 4/656 (0.6%).
  • Peri-induction positive pressure: Positive-pressure ventilation between induction and initiation of laryngoscopy occurred in 550/624 (88.1%) vs 198/637 (31.1%); NIV specifically in 515/624 (82.5%) vs 2/637 (0.3%).
  • Control co-interventions: Bag-mask ventilation between induction and laryngoscopy was more common in the oxygen-mask group (196/637 [30.8%]) than in the NIV group (55/624 [8.8%]); high-flow nasal oxygen was used more often in the oxygen-mask group during preoxygenation (80/656 [12.2%] vs 11/645 [1.7%]).
• Key delivery aspects: Most NIV was delivered via an NIV-specific ventilator (412/645 [63.9%]) or conventional ventilator (204/645 [31.6%]); oxygen-mask preoxygenation largely reflected “real-world” non-rebreather use (575/656 [87.7%]).
• Crossover: Low crossover (4.5% and 1.2%) likely biases the primary estimate towards the null; reasons for nonadherence included emesis/secretions and operator error.
• Outcome assessment: Primary outcome window (induction to 2 minutes post-intubation) is clinically coherent and focuses on the period of highest hypoxaemia risk; objective measurement reduces outcome misclassification, though pulse oximetry can be affected by perfusion and artefact in shock.
• Statistical rigour: The primary endpoint met a stringent threshold (P<0.001); prespecified sensitivity analyses (adjusted models, missing-data assumptions, per-protocol) supported robustness; secondary outcomes were not adjusted for multiple comparisons and should be interpreted cautiously.

Conclusion on Internal Validity: Overall, internal validity is strong for the primary physiological endpoint, supported by concealed randomisation, high protocol adherence, objective outcome measurement, and consistent subgroup effects; the main residual threats are lack of blinding and co-intervention variability (which would more plausibly dilute than exaggerate the observed benefit).

External Validity

• Population representativeness: Participants reflect common ED/ICU intubation indications (altered mental status, sepsis, pneumonia, gastrointestinal bleeding) with moderate-to-high illness severity (median APACHE II 17), but the trial preferentially enrolled cases where clinicians judged both NIV and oxygen-mask preoxygenation acceptable.
• Important exclusions: Patients requiring immediate “crash” intubation, those already receiving positive-pressure ventilation, and those with clear aspiration risk or practical contraindications to NIV were commonly not enrolled, limiting inference for these high-risk phenotypes.
• Applicability to other settings: The intervention requires rapid access to NIV-capable equipment and staff familiar with NIV setup during airway management; applicability is strongest in well-resourced ED/ICUs and may be more limited in resource-constrained settings or prehospital environments.
• Interaction with local practice: In settings where routine bag-mask ventilation or high-flow nasal oxygen is already standard during induction, absolute benefits may differ; nevertheless, the physiological rationale of positive-pressure recruitment and continued oxygenation is broadly generalisable.

Conclusion on External Validity: Generalisability is moderate-to-high for adult ED/ICU intubations where NIV is feasible and not contraindicated, but is limited for immediate/emergent intubations, patients already on positive-pressure support, and those with high aspiration risk or facial/behavioural barriers to NIV.

Strengths & Limitations

• Strengths:
  • Large, pragmatic, multicentre RCT across both ED and ICU settings (n=1301), improving credibility and clinical relevance.
  • Objective primary outcome with continuous physiological data collection by an independent observer.
  • High adherence to assigned preoxygenation strategy (95.5% and 98.8%) with low crossover.
  • Broad clinical case-mix with consistent direction of effect across prespecified subgroups.
• Limitations:
  • Open-label design permits differential co-interventions (e.g., bag-mask ventilation and high-flow nasal oxygen), complicating mechanistic attribution and likely attenuating (rather than inflating) the estimated treatment effect.
  • Primary endpoint is a physiological surrogate; the trial was not powered for definitive conclusions about mortality or other patient-centred outcomes.
  • Selection based on clinician judgement that both strategies were acceptable, plus frequent non-enrolment of very urgent cases, limits inference for “crash” intubations and those with clear NIV contraindications.
  • NIV settings and devices were pragmatic and variable across sites; the optimal NIV “dose” for preoxygenation in different physiological phenotypes remains uncertain.

Interpretation & Why It Matters

• Clinical implication

  • For adult ED/ICU intubations where NIV is feasible and not contraindicated, NIV preoxygenation should be considered the default strategy to reduce peri-intubation hypoxaemia (absolute reduction 9.4 percentage points).
  • Given the large between-group difference in peri-induction positive-pressure support (88.1% vs 31.1%), continuing NIV until laryngoscopy (rather than stopping at induction) is likely a key deliverable component of the tested strategy.
• Mechanistic inference

  • The benefit plausibly arises from a bundled effect: improved oxygen stores and recruitment during preoxygenation plus continued positive-pressure oxygenation/ventilation during the high-risk interval after induction.
  • In centres that avoid any post-induction ventilation because of aspiration concerns, the magnitude of benefit may differ, and alternative recruitment/oxygenation strategies should be considered.
• Implementation

  • Implementation requires a reliable NIV setup (mask fit, rapid circuit connection, FiO₂ 1.0, EPAP/pressure support) and explicit contraindication screening (especially aspiration risk and facial trauma).
  • Training and standardised airway checklists can help ensure that NIV is applied early enough (≥3 minutes when feasible) and continued through laryngoscopy in appropriate patients.

Controversies & Subsequent Evidence

• Comparator choice and co-interventions: Critique focused on whether an “oxygen mask” comparator best represents contemporary best practice; the oxygen-mask group received bag-mask ventilation between induction and laryngoscopy in 30.8% and high-flow nasal oxygen during preoxygenation in 12.2%, potentially diluting the incremental effect of NIV and complicating mechanistic attribution. ²
• Relation to bag-mask ventilation evidence: The PREVENT trial demonstrated that routine bag-mask ventilation during tracheal intubation reduces hypoxaemia compared with no ventilation, supporting the argument that the “true” incremental benefit of NIV may depend on how aggressively the control strategy provides peri-induction ventilation. ³
• Bundled intervention vs “pure” preoxygenation: NIV was commonly continued during the interval between induction and laryngoscopy (82.5% received NIV in this interval), so PREOXI tests a package of preoxygenation plus peri-induction positive-pressure support; this complicates translation to environments that avoid post-induction ventilation because of aspiration concerns.
• Harms and rare events: Aspiration (0.9% vs 1.4%) and pneumothorax (1.4% vs 1.4% among those with imaging) were uncommon; the trial cannot exclude small increases in rare complications, so careful patient selection and vigilance for gastric insufflation/aspiration remain necessary.
• Selection and workflow constraints: Screening-to-enrolment attrition was substantial (4567 screened; 3266 not enrolled), with common non-enrolment due to urgency and pre-existing positive-pressure ventilation; findings apply most directly to intubations where clinicians have time and equipoise to apply either strategy.
• Evidence synthesis after PREOXI: A 2025 systematic review and network meta-analysis of preoxygenation strategies for intubation in critically ill adults ranked NIV-based strategies as most effective for reducing hypoxaemia, supporting PREOXI’s direction and magnitude of effect. ⁴
• Emergency-intubation–focused synthesis: A 2025 systematic review and network meta-analysis focusing on emergency intubation similarly found noninvasive respiratory support (including NIV/CPAP strategies) reduced hypoxaemia compared with conventional oxygenation. ⁵
• Interpretation of pooled data: Published commentaries emphasised that inclusion criteria, patient heterogeneity, and the definition of “critically ill” influence generalisability of pooled estimates, and argued that accumulating evidence supports moving away from facemask-only preoxygenation when NIV is feasible. ⁶⁷
• Guideline alignment: Post-PREOXI guidance on emergency intubation and difficult airway management increasingly emphasises structured optimisation of preoxygenation and peri-intubation oxygenation (including consideration of positive-pressure strategies when appropriate), which is directionally consistent with the PREOXI findings. ⁸⁹

Summary

• PREOXI randomised 1301 ED/ICU adults undergoing emergency intubation to NIV vs oxygen-mask preoxygenation.
• NIV reduced peri-intubation hypoxaemia (SpO₂ <85%) from 18.5% to 9.1% (absolute risk difference −9.4 percentage points; 95% CI −13.2 to −5.6; P<0.001).
• NIV increased median lowest peri-intubation SpO₂ (99 vs 97) and reduced severe desaturation (SpO₂ <80%: 6.2% vs 13.2%).
• Large separation in peri-induction positive-pressure support (88.1% vs 31.1%) indicates the tested strategy bundled preoxygenation with continued post-induction NIV for most patients.
• No clear increase in aspiration or radiographic infiltrate was observed, but the trial was not powered to exclude small increases in rare harms or to demonstrate mortality benefit.

Further Reading

Other Trials

• 2019Casey JD, Janz DR, Russell DW, et al. Bag-mask ventilation during tracheal intubation of critically ill adults. N Engl J Med. 2019;380:811-821.
• 2006Baillard C, Fosse JP, Sebbane M, et al. Noninvasive ventilation improves preoxygenation before intubation of hypoxic patients. Am J Respir Crit Care Med. 2006;174(2):171-177.
• 2019Frat JP, Ricard JD, Quenot JP, et al. Non-invasive ventilation versus high-flow nasal cannula oxygen for preoxygenation before intubation in hypoxaemic patients (FLORALI-2): a multicentre, randomised trial. Lancet Respir Med. 2019;7(4):303-312.
• 2019Guitton C, Ehrmann S, Volteau C, et al. Nasal high-flow preoxygenation for endotracheal intubation in the critically ill patient: a randomised clinical trial (PROTRACH). Intensive Care Med. 2019;45(4):447-458.
• 2019Vourc'h M, Baud G, Feuillet F, et al. High-flow nasal cannula oxygen versus noninvasive ventilation for preoxygenation in obese patients: the PREOPTIPOP randomised clinical trial. EClinicalMedicine. 2019;13:112-119.

Systematic Review & Meta Analysis

• 2025Pitre T, Liu D, Low A, et al. Preoxygenation strategies for intubation of critically ill adults: a systematic review and network meta-analysis. Lancet Respir Med. 2025;13(7):550-561.
• 2025Boscolo A, et al. Noninvasive respiratory support for preoxygenation in emergency intubation: a systematic review and network meta-analysis. ERJ Open Res. 2025;11(6):00329-2025.
• 2017Pavlov I, et al. Apneic oxygenation reduces hypoxemia during emergency intubation: a systematic review and meta-analysis. Am J Emerg Med. 2017;35(11):1774-1779.
• 2024Zhong X, et al. Comparison of different devices for adult preoxygenation in emergency intubation: a systematic review and network meta-analysis. Front Med (Lausanne). 2024;11:1379369.
• 2017Mosier JM, Hypes CD, Sakles JC. Understanding preoxygenation and apneic oxygenation during intubation in the critically ill. Intensive Care Med. 2017;43(2):226-228.

Observational Studies

• 2021Russotto V, Myatra SN, Laffey JG, et al. Intubation practices and adverse peri-intubation events in critically ill patients from 29 countries. JAMA. 2021;325(12):1164-1172.
• 2021April MD, Arana A, Pallin DJ, et al. Emergency department intubation success and adverse events among patients with COVID-19. Resuscitation. 2021;163:98-103.
• 2021Smischney NJ, Demers P, Sinclair WJ, et al. A comprehensive evaluation of airway management in critically ill patients. J Intensive Care Med. 2021;36:1-8.
• 2018De Jong A, Rolle A, Molinari N, et al. Cardiac arrest and mortality related to intubation procedure in critically ill adult patients: a multicenter cohort study. Crit Care Med. 2018;46(4):532-539.
• 2004Mort TC. Emergency tracheal intubation: complications associated with repeated laryngoscopic attempts. Anesth Analg. 2004;99:607-613.

Guidelines

• 2025American College of Emergency Physicians. Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients in the Emergency Department Who Require Endotracheal Intubation. Ann Emerg Med. 2025;86(2):e29-e68.
• 2026Ahmad I, Myatra SN, et al. Difficult Airway Society 2025 guidelines for management of unanticipated difficult tracheal intubation in adults. Br J Anaesth. 2026;136(1):283-307.
• 2025All India Difficult Airway Association. All India Difficult Airway Association (AIDAA) 2025 adult guideline for the management of unanticipated difficult airway under general anaesthesia. Indian J Anaesth. 2025;69(11):1117-1141.
• 2026Clavier T, Cesareo E, Frasca D, Adnet F. Guidelines 2024: Emergency intubation of an adult outside the operating room and intensive care unit. Anaesth Crit Care Pain Med. 2026 Jan 22. Epub ahead of print.
• 2018Higgs A, McGrath BA, Goddard C, et al. Guidelines for the management of tracheal intubation in critically ill adults. Br J Anaesth. 2018;120(2):323-352.

Notes

• The primary peri-intubation window was induction of anaesthesia to 2 minutes after tracheal intubation.
• Cardiovascular collapse was a composite outcome; interpret component events and rare outcomes (e.g., aspiration, cardiac arrest) cautiously because absolute event counts were small.

Overall Takeaway

PREOXI provides high-certainty evidence that, in ED/ICU patients eligible for either approach, NIV-based preoxygenation (typically continued through induction) substantially reduces peri-intubation hypoxaemia compared with oxygen-mask strategies. The benefit was achieved without an observed increase in aspiration, but the trial was not designed to prove improvements in mortality or other patient-centred outcomes. When feasible and not contraindicated, NIV should be favoured as the default preoxygenation approach for emergency intubation to reduce severe desaturation.

Bibliography

• 1Gibbs KW, Semler MW, Driver BE, et al. Protocol and statistical analysis plan for the Pragmatic Trial Examining Oxygenation Prior to Intubation (PREOXI). CHEST Crit Care. 2023;1(2):100014.
• 2Li J, Scott JB, Branson RD, et al. Noninvasive Ventilation for Preoxygenation during Emergency Intubation. N Engl J Med. 2024;390:2234-2236.
• 3Casey JD, Janz DR, Russell DW, et al. Bag-mask ventilation during tracheal intubation of critically ill adults. N Engl J Med. 2019;380:811-821.
• 4Pitre T, Liu D, Low A, et al. Preoxygenation strategies for intubation of critically ill adults: a systematic review and network meta-analysis. Lancet Respir Med. 2025;13(7):550-561.
• 5Boscolo A, et al. Noninvasive respiratory support for preoxygenation in emergency intubation: a systematic review and network meta-analysis. ERJ Open Res. 2025;11(6):00329-2025.
• 6Fong KM, Au Yeung KY, Ng GWY. Preoxygenation for tracheal intubation in adults who are critically ill: a closer look at inclusion criteria and patient heterogeneity. Lancet Respir Med. 2025;13(7):531-533.
• 7Myatra SN. Preoxygenation for tracheal intubation in adults who are critically ill: time to abandon the facemask? Lancet Respir Med. 2025;13(7):529-530.
• 8American College of Emergency Physicians. Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients in the Emergency Department Who Require Endotracheal Intubation. Ann Emerg Med. 2025;86(2):e29-e68.
• 9Ahmad I, Myatra SN, et al. Difficult Airway Society 2025 guidelines for management of unanticipated difficult tracheal intubation in adults. Br J Anaesth. 2026;136(1):283-307.