In out-of-hospital cardiac arrest, should paramedics prioritize early endotracheal intubation (ETI) or uninterrupted chest compressions with basic airway management?

Paramedics Should Prioritize Uninterrupted Chest Compressions with Basic Airway Management Over Early Endotracheal Intubation in Out-of-Hospital Cardiac Arrest

For witnessed shockable out-of-hospital cardiac arrest, paramedics should focus on minimally interrupted chest compressions with basic airway management (bag-mask ventilation or supraglottic airway) and delay endotracheal intubation until after initial CPR and defibrillation attempts fail or ROSC is achieved. 1

Primary Recommendation

The American Heart Association explicitly states that if advanced airway placement will interrupt chest compressions, providers may consider deferring insertion of the airway until the patient fails to respond to initial CPR and defibrillation attempts or demonstrates ROSC (Class IIb, LOE C). 1 This recommendation is particularly important because:

• Endotracheal intubation causes prolonged interruptions in chest compressions, with median first-attempt interruptions of 46.5 seconds and total interruptions exceeding 109.5 seconds, comprising approximately 22.8% of all CPR interruptions. 2

• Delayed endotracheal intubation combined with passive oxygen delivery and minimally interrupted chest compressions was associated with improved neurologically intact survival after out-of-hospital cardiac arrest in patients with adult witnessed VF/pulseless VT. 1

Evidence for Witnessed Shockable Rhythms

For witnessed arrest with shockable rhythm specifically, the 2015 International Consensus found that bundles of care involving minimally interrupted cardiac resuscitation (which included delayed intubation) showed significant benefit:

• OR 3.6 (95% CI, 1.77–7.35) for survival with favorable neurologic outcome 1
• OR 5.24 (95% CI, 2.16–12.75) for survival with favorable neurologic outcome 1
• Adjusted OR 2.5 (95% CI, 1.3–4.6) for survival with favorable neurologic outcome 1

The International Consensus suggests that where EMS systems have adopted bundles of care involving minimally interrupted cardiac resuscitation, the bundle is a reasonable alternative to conventional CPR for witnessed shockable out-of-hospital cardiac arrest (weak recommendation, very-low-quality evidence). 1

Airway Management Strategy During Initial Resuscitation

Basic Airway Management First

• Bag-mask ventilation is effective during initial CPR efforts and should be performed with a two-person technique when possible (one person holding the mask, one person ventilating). 3

• Compressions should be delivered at a 30:2 ratio initially, with breaths provided over less than 1 second with enough tidal volume to cause chest rise. 3

• Supraglottic airways are reasonable alternatives that can be placed without interrupting chest compressions, unlike endotracheal intubation. 1

When to Consider Advanced Airway

Advanced airway placement may be considered in specific circumstances:

• Asphyxial cause of arrest (where ventilation is more critical) 3
• Prolonged arrest or transport times 3
• Inability to ventilate adequately with bag-mask 1
• After initial CPR and defibrillation attempts fail 1

Critical Pitfalls to Avoid

Interruption of Chest Compressions

The most critical pitfall is interrupting chest compressions for intubation attempts:

• Interruptions must be limited to less than 10 seconds for laryngoscopy and tube passage through the vocal cords. 1, 4

• The intubating provider must be fully prepared with laryngoscope blade and tube ready before compressions are paused. 1, 4

• If the initial intubation attempt is unsuccessful, early consideration should be given to using a supraglottic airway rather than repeated attempts. 1

Provider Experience Requirements

• Frequent experience or frequent retraining is required for providers who perform endotracheal intubation (Class I, LOE B). 1

• Inexperienced providers produce unacceptably high complication rates, including prolonged interruptions, unrecognized esophageal intubation, tube displacement, and hypoxemia. 1, 4

• EMS systems performing prehospital intubation must provide ongoing quality improvement programs to minimize complications (Class IIa, LOE B). 1, 4

Hyperventilation

• Avoid hyperventilation, which compromises venous return and causes hypotension. 4

• Once an advanced airway is placed, deliver 10 breaths per minute (one breath every 6-8 seconds) with continuous compressions. 1, 4

• Target normocapnia (PaCO2 35-40 mmHg) when possible. 4

Supraglottic Airways as Alternative

Supraglottic airways are reasonable alternatives to both bag-mask ventilation (Class IIa, LOE B) and endotracheal intubation (Class IIa, LOE A) during CPR performed by trained providers. 1

Key advantages of supraglottic airways:

• Can be inserted without interrupting chest compressions 1
• Easier initial training and skill maintenance compared to endotracheal intubation 1
• No direct visualization required, reducing interruption time 1
• Comparable ventilation effectiveness to endotracheal intubation in multiple studies 1

No Survival Advantage for Early Intubation

No prospective randomized clinical trials have demonstrated a survival advantage for endotracheal intubation over bag-mask ventilation in adult victims of cardiac arrest. 1 A 2023 network meta-analysis of 9 RCTs involving 13,949 patients found that endotracheal intubation showed no statistically significant benefit over other airway management methods for survival to discharge. 5

Confirmation of Tube Placement

If endotracheal intubation is performed:

• Continuous waveform capnography is recommended as the most reliable method of confirming and monitoring correct placement (Class I, LOE A). 1

• Waveform capnography has demonstrated 100% sensitivity and 100% specificity for identifying correct endotracheal tube placement in cardiac arrest victims. 1

• Confirmation should occur immediately after placement and continuously throughout resuscitation to reduce risk of unrecognized tube misplacement or displacement. 1