Publication

• Title: Effect of a Strategy of Initial Laryngeal Tube Insertion vs Endotracheal Intubation on 72-Hour Survival in Adults With Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial
• Acronym: PART (Pragmatic Airway Resuscitation Trial)
• Year: 2018
• Journal published in: JAMA
• Citation: Wang HE, Schmicker RH, Daya MR, et al. Effect of a strategy of initial laryngeal tube insertion vs endotracheal intubation on 72-hour survival in adults with out-of-hospital cardiac arrest: a randomized clinical trial. JAMA. 2018;320(8):769-778.

Context & Rationale

• Background

  • Advanced airway management (endotracheal intubation and supraglottic devices) is frequently used during out-of-hospital cardiac arrest, but optimal practice remained uncertain.
  • Endotracheal intubation offers a “definitive” airway and aspiration protection, but can be technically difficult in the field and can disrupt chest compressions.
  • Misplacement/dislodgement and hyperventilation are important failure modes of advanced airway management, with potential to worsen outcomes.
  • Supraglottic airways (e.g., laryngeal tube) are typically quicker and easier to insert, but concerns include imperfect seal, aspiration risk, and frequent subsequent conversion to endotracheal intubation.
  • Pre-trial evidence was dominated by observational studies with strong confounding by indication and time-dependent (“resuscitation time”) bias.
• Research Question/Hypothesis

  • In adult, non-traumatic out-of-hospital cardiac arrest, does an EMS strategy of initial laryngeal tube insertion improve 72-hour survival compared with a strategy of initial endotracheal intubation?
• Why This Matters

  • Airway strategy is a core, resource-intensive component of resuscitation systems and training programmes.
  • A small absolute survival difference at population scale could translate into substantial numbers of lives saved given the incidence of OHCA.
  • Clarifying whether a “simpler-first” airway strategy improves outcomes informs guideline recommendations, paramedic training priorities, and quality assurance benchmarks.

Design & Methods

• Research Question: In adult non-traumatic OHCA, does an initial laryngeal tube strategy improve 72-hour survival compared with an initial endotracheal intubation strategy?
• Study Type: Pragmatic, multicentre, cluster-crossover randomised clinical trial within the Resuscitation Outcomes Consortium (ROC); 27 EMS agencies grouped into 13 clusters; crossover every 3 or 5 months; prehospital setting; unblinded.
• Population:
  • Setting: US prehospital EMS systems participating in ROC.
  • Inclusion: Adult (≥18 years or local definition) with out-of-hospital cardiac arrest of non-traumatic aetiology requiring ventilatory support and eligible for advanced airway management by participating EMS.
  • Included by design: EMS-witnessed arrests and recurrent arrests during the same care episode.
  • Key exclusions: Traumatic arrest, major facial trauma, major bleeding/exsanguination, or obvious asphyxial cause.
  • Key exclusions: Advanced airway already placed before participating EMS arrival, pre-existing tracheostomy, or mechanical circulatory support (LVAD/TAH).
  • Key exclusions: Interfacility transport, DNAR status, or “do not enrol” bracelet.
  • Protected populations excluded: Known pregnancy and known prisoners.
• Intervention:
  • Assigned strategy: Initial laryngeal tube insertion (King LT) as the first advanced airway approach when providers elected to place an advanced airway.
  • Permitted airway pathway: Bag-valve-mask ventilation could be used (including exclusively) at provider discretion and within local scope of practice.
  • Rescue: If the assigned approach was unsuccessful or inadequate, clinicians could use rescue airway approaches (including endotracheal intubation or bag-valve-mask), consistent with pragmatic implementation.
• Comparison:
  • Assigned strategy: Initial endotracheal intubation as the first advanced airway approach when providers elected to place an advanced airway.
  • Permitted airway pathway: Bag-valve-mask ventilation could be used (including exclusively) at provider discretion and within local scope of practice.
  • Rescue: If the assigned approach was unsuccessful or inadequate, clinicians could use rescue airway approaches (including laryngeal tube or bag-valve-mask), consistent with pragmatic implementation.
• Blinding: Unblinded (strategy assignment was operational and could not be masked); primary outcomes were objective (survival), while adverse event reporting could be susceptible to ascertainment differences.
• Statistics: Minimum 2612 patients required to detect a 4.5% absolute difference in 72-hour survival with 85% power at two-sided α=0.05 (group sequential design: 3 interim and 1 final analysis; 5% inflation for the cluster-crossover design); target enrolment 3000; primary analysis intention-to-treat using generalised estimating equations with robust standard errors accounting for clustering and interim monitoring.
• Follow-Up Period: Primary outcome at 72 hours after arrest; secondary outcomes at emergency department (ED) arrival and hospital discharge; last follow-up date reported as November 10, 2017.

Key Results

This trial was not stopped early. Enrolment reached the prespecified target (3004 enrolled; 3000 analysed for the primary outcome).

Outcome	Initial laryngeal tube strategy	Initial endotracheal intubation strategy	Effect	p value / 95% CI	Notes
Survival to 72 h (primary; intention-to-treat)	275/1505 (18.3%)	230/1495 (15.4%)	Risk difference 2.9%	95% CI 0.2 to 5.6; P=0.04	Relative risk 1.19; 95% CI 1.01 to 1.39; accounted for clustering and interim monitoring; 4 ETI-group patients had unknown 72-h status
ROSC on ED arrival	420/1505 (27.9%)	365/1499 (24.3%)	Risk difference 3.6%	95% CI 0.3 to 6.8; P=0.03	Accounted for clustering
Survival to hospital discharge	163/1504 (10.8%)	121/1495 (8.1%)	Risk difference 2.7%	95% CI 0.6 to 4.8; P=0.01	Accounted for clustering; discharge status missing for 1 participant in the laryngeal tube group
Favourable neurological status at discharge (modified Rankin Scale ≤3)	107/1500 (7.1%)	75/1495 (5.0%)	Risk difference 2.1%	95% CI 0.3 to 3.8; P=0.02	Accounted for clustering; neurological status not available for all participants
Unsuccessful insertion of the first airway technique (out-of-hospital adverse event)	159/1353 (11.8%)	573/1299 (44.1%)	Risk difference −32.4%	95% CI −35.6 to −29.1; P<0.001	Denominators exclude patients managed with bag-valve-mask only
≥3 airway insertion attempts across all airway interventions (out-of-hospital adverse event)	61/1353 (4.5%)	245/1299 (18.9%)	Risk difference −14.4%	95% CI −17.0 to −11.7; P<0.001	Denominators exclude patients managed with bag-valve-mask only
Unrecognised airway misplacement or dislodgement (out-of-hospital adverse event)	10/1353 (0.7%)	24/1299 (1.8%)	Risk difference −1.1%	95% CI −2.0 to −0.3; P=0.01	Denominators exclude patients managed with bag-valve-mask only
Inadequate ventilation requiring airway device change (out-of-hospital adverse event)	25/1353 (1.8%)	8/1299 (0.6%)	Risk difference 1.2%	95% CI 0.3 to 2.1; P=0.01	Denominators exclude patients managed with bag-valve-mask only
Pneumothorax (in-hospital adverse event; first ED chest radiograph)	17/485 (3.5%)	30/428 (7.0%)	Risk difference −3.6%	95% CI −6.5 to −0.7; P=0.02	Among ED admissions with a chest radiograph performed
Rib fractures (in-hospital adverse event; first ED chest radiograph)	16/485 (3.3%)	30/428 (7.0%)	Risk difference −3.8%	95% CI −6.9 to −0.7; P=0.01	Among ED admissions with a chest radiograph performed

• Absolute treatment effects were modest and near conventional thresholds; a post hoc adjusted intention-to-treat model attenuated the primary result (adjusted difference 2.1%; 95% CI −0.5 to 4.8; P=0.11).
• As-treated analysis by the initial airway attempted suggested a smaller, non-significant difference in 72-hour survival (laryngeal tube 227/1423 [16.0%] vs endotracheal intubation 165/1224 [13.5%]; difference 2.5%; 95% CI −0.2 to 5.2; P=0.07).
• No evidence of important effect modification across a priori-defined subgroups; by randomisation order (before vs after crossover) the 72-hour survival difference was 2.5% vs 3.6% (interaction P=0.69).

Internal Validity

• Randomisation and allocation:
  • Cluster-crossover assignment (13 clusters) limited patient-level selection bias by making strategy assignment independent of patient characteristics.
  • Allocation concealment at the provider level was not feasible because treatment was a system implementation strategy with defined crossover periods.
• Post-randomisation missingness and exclusions:
  • Primary outcome (72-hour survival) was unknown for 4 participants in the endotracheal intubation strategy group (0.1%).
  • Survival to discharge was missing for 1 participant in the laryngeal tube strategy group.
  • Neurological outcome at discharge (modified Rankin Scale) was not available for all participants (1500/1505 in the laryngeal tube group; 1495/1499 in the endotracheal intubation group).
• Performance and detection bias:
  • Unblinded treatment delivery was unavoidable and could influence procedural persistence (e.g., number of attempts) and reporting of adverse events.
  • Primary outcome (survival) is objective, reducing susceptibility to detection bias for the main endpoint.
• Protocol adherence and crossover:
  • Compliance (as defined by the investigators) was 95.5% in the laryngeal tube strategy group vs 90.7% in the endotracheal intubation strategy group.
  • Treatment received differed from assignment: laryngeal tube group received endotracheal intubation in 67/1505 (4.5%); endotracheal intubation group received laryngeal tube in 138/1499 (9.2%).
  • Bag-valve-mask only occurred in 152/1505 (10.1%) vs 200/1499 (13.3%), with “bag-valve-mask only” counted as compliant in per-protocol analyses.
  • Rescue airway interventions were more frequent in the endotracheal intubation strategy (573 patients) than in the laryngeal tube strategy (159 patients), with rescue laryngeal tube accounting for 75.6% of rescue airways in the endotracheal intubation group.
• Baseline characteristics (comparability):
  • Median age was 64 years (IQR 53–76) in both groups.
  • Male sex: 928/1503 (61.7%) vs 901/1499 (60.1%).
  • Initial shockable rhythm: 301/1504 (20.0%) vs 270/1498 (18.0%); non-shockable rhythm predominated (77.1% vs 79.9%).
  • Epinephrine before hospital arrival: 92.0% vs 93.7%.
• Heterogeneity:
  • Treatment effects varied among clusters and agencies, with benefit favouring laryngeal tube primarily in clusters with lower baseline survival during endotracheal intubation periods.
• Timing (appropriateness and achieved separation):
  • Median time from first EMS arrival to start of the first airway attempt was shorter with laryngeal tube (9.8 minutes; IQR 6.5–14.8) vs endotracheal intubation (12.5 minutes; IQR 8.7–18.0).
  • Time from the start of the first airway attempt to successful insertion or abandonment was 0.5 minutes (IQR 0.2–0.8) vs 0.9 minutes (IQR 0.4–2.0).
• Dose/procedural burden:
  • ≥3 airway insertion attempts across all airway interventions: 4.5% vs 18.9%.
  • Unsuccessful insertion of the first airway technique: 11.8% vs 44.1%.
• Separation of the variable of interest:
  • Initial airway success (reported in the main trial report): 90.3% with laryngeal tube vs 51.6% with endotracheal intubation.
  • Unrecognised misplacement/dislodgement was lower with laryngeal tube (0.7%) vs endotracheal intubation (1.8%).
  • Inadequate ventilation events were higher with laryngeal tube (1.8%) vs endotracheal intubation (0.6%).
• Adjunctive therapy and post-randomisation care:
  • Among transported patients who survived ≥1 hour, therapeutic hypothermia was used in 52.6% vs 46.3% and coronary catheterisation in 23.7% vs 18.3% (potential downstream mediators rather than baseline confounders).
• Outcome assessment and statistical rigour:
  • Primary endpoint (72-hour survival) is objective and clinically meaningful for early resuscitation effects.
  • Neurological outcome used modified Rankin Scale at hospital discharge (patient-centred, but not long-term follow-up).
  • Primary analysis used prespecified methods accounting for cluster-crossover and interim monitoring; post hoc adjusted models omitted 163 patients due to missing covariate data.

Conclusion on Internal Validity: Moderate. Randomised cluster-crossover design and near-complete primary outcome ascertainment support causal inference, but lack of blinding, differential technical performance, and substantial rescue/crossover mean the estimate primarily reflects a pragmatic system-level airway strategy rather than isolated device efficacy.

External Validity

• Population representativeness:
  • Participants were typical adult, non-traumatic OHCA patients treated in North American paramedic-based EMS systems.
  • Exclusions (trauma, obvious asphyxia, advanced airway already in place, tracheostomy, LVAD/TAH, DNAR, protected populations) may limit applicability to these subgroups.
• System dependence:
  • Findings are most applicable to EMS systems with similar training, scope of practice, and endotracheal intubation success rates to the participating ROC agencies.
  • Generalisation to physician-led prehospital systems (with higher intubation proficiency) or to systems using different supraglottic devices (e.g., i-gel rather than laryngeal tube) is uncertain.
• Care pathway relevance:
  • Substantial in-hospital conversion of prehospital laryngeal tubes to endotracheal intubation suggests the trial supports an “initial airway” strategy rather than definitive avoidance of tracheal intubation.
  • Outcomes beyond hospital discharge were not reported, limiting inference for longer-term neurological recovery.

Conclusion on External Validity: Moderate. The results are generalisable to similar North American ALS systems using laryngeal tubes and with variable intubation performance, but may not translate to settings with different provider expertise, devices, or post-resuscitation pathways.

Strengths & Limitations

• Strengths:
  • Large pragmatic RCT (n=3004) embedded in a mature multicentre research network (ROC), enhancing real-world relevance.
  • Cluster-crossover design enabled within-agency comparisons across time, reducing confounding by stable system characteristics.
  • Objective primary outcome with minimal missingness and prespecified analysis accounting for clustering and interim monitoring.
  • Rich process and safety reporting enabled interpretation of mechanistic plausibility and trade-offs.
• Limitations:
  • Unblinded delivery and reliance on EMS documentation for some adverse events introduce potential reporting/ascertainment bias.
  • Comparison was of airway management strategies in a pragmatic pathway (including bag-valve-mask use and rescue/crossover), not a tightly controlled device efficacy study.
  • Endotracheal intubation performance and procedural persistence were system-dependent, potentially limiting generalisability to high-expertise intubation environments.
  • Primary endpoint at 72 hours captures early survival effects but does not directly measure long-term functional outcome.

Interpretation & Why It Matters

• Clinical interpretation

  • An initial laryngeal tube strategy yielded a small absolute improvement in early survival (2.9%) and in survival with favourable neurological status at discharge (2.1%).
  • The net effect is consistent with airway management acting as a component of the resuscitation bundle rather than as an isolated “airway-only” intervention.
• Mechanistic plausibility

  • Laryngeal tube insertion occurred earlier (9.8 vs 12.5 minutes) and with less procedural burden (4.5% vs 18.9% with ≥3 attempts), plausibly reducing interruptions, hypoxia, and unrecognised misplacement.
  • Trade-offs exist: inadequate ventilation events were higher with laryngeal tube (1.8% vs 0.6%), underscoring the need for ventilation quality assurance.
• Implications for practice

  • Supports “supraglottic-first” strategies in EMS systems where tracheal intubation success is variable and where minimising interruptions is prioritised.
  • Reinforces that the key decision is not simply device choice, but how airway management is integrated with high-quality CPR, defibrillation, and post-resuscitation care.

Controversies & Subsequent Evidence

• PART was designed to test a pragmatic EMS airway strategy; interpretation hinges on system performance (including training, procedural persistence, and rescue pathways), not on supraglottic device efficacy in isolation. ¹
• The large disparity in initial airway success (laryngeal tube 90.3% vs endotracheal intubation 51.6%) highlights a key generalisability question: whether benefit reflects simpler airway insertion, lower interruption burden, or comparatively limited endotracheal intubation proficiency in participating systems. ¹
• A contemporaneous UK cluster trial comparing i-gel supraglottic airway vs tracheal intubation (AIRWAYS-2) reported no improvement in patient-centred functional outcome, emphasising device- and system-dependence and the importance of endpoint selection. ²
• A French physician-led RCT (CAAM) comparing bag-mask ventilation vs endotracheal intubation found bag-mask to be non-inferior for favourable neurological outcome, reinforcing that de-emphasising complex airway manoeuvres can be acceptable when ventilation is adequate and CPR quality is preserved. ³
• A Bayesian reanalysis of PART illustrates the sensitivity of inference framing for modest effects (probability of benefit vs frequentist thresholding), particularly in pragmatic, system-level trials where crossover and rescue are intrinsic to delivery. ⁴
• Recent systematic review and meta-analysis integrating PART and other contemporary trials reports small or uncertain differences in patient-centred outcomes across airway strategies, with effect estimates influenced by provider expertise, timing of airway placement, and risk of bias. ⁵
• Modern resuscitation guidance converges on selecting an advanced airway strategy based on provider skill and minimising interruptions to chest compressions, with supraglottic airways treated as reasonable alternatives to endotracheal intubation during OHCA. ⁶⁷⁸

Summary

• PART was a large pragmatic cluster-crossover randomised trial comparing initial laryngeal tube vs initial endotracheal intubation strategies for adult non-traumatic OHCA in US EMS systems.
• Primary outcome favoured laryngeal tube: 72-hour survival 18.3% vs 15.4% (risk difference 2.9%; 95% CI 0.2 to 5.6; P=0.04).
• Secondary outcomes also favoured laryngeal tube: ROSC on ED arrival 27.9% vs 24.3%; survival to discharge 10.8% vs 8.1%; favourable neurological status at discharge 7.1% vs 5.0%.
• Laryngeal tube strategy substantially reduced failed initial airway technique and multiple attempts, but had more inadequate ventilation events.
• Interpretation is primarily at the system-strategy level, with crossover/rescue and technical performance central to understanding both benefit and generalisability.

Further Reading

Other Trials

• 2018Benger JR, Kirby K, Black S, et al. Effect of a strategy of supraglottic airway device vs tracheal intubation during out-of-hospital cardiac arrest on functional outcome: the AIRWAYS-2 randomized clinical trial. JAMA. 2018;320(8):779-791.
• 2018Jabre P, Penaloza A, Pinero D, et al. Effect of bag-mask ventilation vs endotracheal intubation during cardiopulmonary resuscitation on neurological outcome after out-of-hospital cardiorespiratory arrest: a randomized clinical trial. JAMA. 2018;319(8):779-787.
• 2016Benger JR, Voss S, Coates D, et al. Randomised comparison of the i-gel, LMA Supreme and current practice in the initial airway management of out-of-hospital cardiac arrest (AIRWAYS-1): a feasibility study. Br J Anaesth. 2016;116(2):262-270.
• 1986Goldenberg IF, Campion BC, Siebold CM, et al. Esophageal gastric tube airway vs endotracheal tube in prehospital cardiopulmonary arrest. Chest. 1986;90(1):90-96.

Systematic Review & Meta Analysis

• 2024Forestell GJ, Aves T, Benoit JL, et al. Advanced airway interventions during out-of-hospital cardiac arrest: a systematic review and meta-analysis. Crit Care Med. 2024;52(2):e89-e99.
• 2020Wang CH, Chang WT, Huang CH, et al. A network meta-analysis of randomized trials comparing airway strategies for out-of-hospital cardiac arrest. Ann Emerg Med. 2020;76(1):1-10.
• 2018White L, Thang C, Escutnaire J, et al. Advanced airway management in out-of-hospital cardiac arrest: a systematic review and meta-analysis. Am J Emerg Med. 2018;36(12):2298-2306.
• 2014Fouche PF, Simpson PM, Bendall J, Thomas RE, Cone DC, Doi SA. Airways in out-of-hospital cardiac arrest: systematic review and meta-analysis. Prehosp Emerg Care. 2014;18(2):244-256.
• 2010Hubble MW, Brown L, Wilfong DA, Hertelendy A, Benner RW, Richards ME. A meta-analysis of prehospital airway control techniques, part I: orotracheal and nasotracheal intubation success rates. Prehosp Emerg Care. 2010;14(3):377-401.

Observational Studies

• 2015Maignan M, Koch FX, Kraemer M, et al. Impact of laryngeal tube use on chest compression fraction during out-of-hospital cardiac arrest. A prospective alternate month study. Resuscitation. 2015;93:113-117.
• 2014Kim J, Kim K, Kim T, et al. The clinical significance of a failed initial intubation attempt during emergency department resuscitation of out-of-hospital cardiac arrest patients. Resuscitation. 2014;85(5):623-627.
• 2018Andersen LW, Grossestreuer AV, Donnino MW. “Resuscitation time bias”-A unique challenge for observational cardiac arrest research. Resuscitation. 2018;125:79-82.
• 2017Arnup SJ, McKenzie JE, Hemming K, Pilcher D, Forbes AB. Understanding the cluster randomised crossover design: a graphical illustration of the components of variation and a sample size tutorial. Trials. 2017;18(1):381.

Guidelines

• 2025Drennan IR, Berg KM, Bray JE, et al. Advanced life support: 2025 International Liaison Committee on Resuscitation Consensus on Science with Treatment Recommendations. Circulation. 2025;152(16_suppl_1):S72-S115.
• 2025Wigginton JG, Goodman AJ, Abella BS, et al. Part 9: Advanced life support. Circulation. 2025;152(16_suppl_2):S538-S577.
• 2025Soar J, et al. European Resuscitation Council Guidelines 2025: Adult Advanced Life Support. Resuscitation. 2025;215(Suppl 1):110769.
• 2020Panchal AR, Bartos JA, Cabañas JG, et al. Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2020;142(16_suppl_2):S366-S468.

Notes

• PART evaluated the King laryngeal tube within US EMS systems; supraglottic airway effects may differ across device types (e.g., i-gel) and across systems with different endotracheal intubation exposure and quality assurance structures.

Overall Takeaway

PART is a landmark pragmatic resuscitation trial because it moved the airway debate from confounded observational comparisons to a large randomised system-level evaluation. In US paramedic-based EMS systems, an initial laryngeal tube strategy modestly improved early survival and discharge outcomes compared with an initial endotracheal intubation strategy, while highlighting that airway choice is inseparable from procedural success, timing, and integration with high-quality CPR.

Bibliography

• 1Andersen LW, Granfeldt A. Pragmatic Airway Management in Out-of-Hospital Cardiac Arrest. JAMA. 2018;320(8):761-763.
• 2Benger JR, Kirby K, Black S, et al. Effect of a strategy of supraglottic airway device vs tracheal intubation during out-of-hospital cardiac arrest on functional outcome: the AIRWAYS-2 randomized clinical trial. JAMA. 2018;320(8):779-791.
• 3Jabre P, Penaloza A, Pinero D, et al. Effect of bag-mask ventilation vs endotracheal intubation during cardiopulmonary resuscitation on neurological outcome after out-of-hospital cardiorespiratory arrest: a randomized clinical trial. JAMA. 2018;319(8):779-787.
• 4Wang CH, Chang WT, Huang CH, et al. A Bayesian view of the Pragmatic Airway Resuscitation Trial: Endotracheal intubation versus supraglottic airway during out-of-hospital cardiac arrest. Ann Emerg Med. 2019;74(2):199-202.
• 5Forestell GJ, Aves T, Benoit JL, et al. Advanced airway interventions during out-of-hospital cardiac arrest: a systematic review and meta-analysis. Crit Care Med. 2024;52(2):e89-e99.
• 6Drennan IR, Berg KM, Bray JE, et al. Advanced life support: 2025 International Liaison Committee on Resuscitation Consensus on Science with Treatment Recommendations. Circulation. 2025;152(16_suppl_1):S72-S115.
• 7Wigginton JG, Goodman AJ, Abella BS, et al. Part 9: Advanced life support. Circulation. 2025;152(16_suppl_2):S538-S577.
• 8Soar J, et al. European Resuscitation Council Guidelines 2025: Adult Advanced Life Support. Resuscitation. 2025;215(Suppl 1):110769.