To Intubate or Not to Intubate (During In-Hospital Cardiac Arrest)

In this episode, we dissect a game-changing observational study on cardiac arrest outcomes published in JAMA that evaluates the association between tracheal intubation during in-hospital cardiac arrest and survival to discharge. With over 100,000 patients reviewed from the AHA’s Get With The Guidelines registry, this study’s size and implications have stirred serious conversation within critical care circles.

We begin by contrasting observational studies vs randomized controlled trials (RCTs) and why this research—despite its limitations—carries weight. The discussion walks through a critical appraisal framework, diving into the PICO elements, the role of internal and external validity, and the nuances of time-dependent propensity score matching—a statistical method used to account for differences in when patients were intubated during resuscitation efforts.

What did the study find? Across multiple outcome measures—including survival to discharge, return of spontaneous circulation (ROSC), and favorable neurologic outcomes—patients who were intubated during the first 15 minutes of cardiac arrest had worse outcomes than those who were not.

The team explores potential explanations, including pauses in CPR, hyperventilation, and procedural delays, while emphasizing that causation cannot be proven in an observational study of cardiac arrest outcomes. Still, the correlation is striking enough to prompt critical thinking about the best airway strategy in cardiac arrest.

We wrap up with practice implications: Why some ICUs are moving toward early LMA use, how the evidence is changing team dynamics during codes, and why stopping CPR for intubation may do more harm than good. This has major relevance for clinicians reconsidering the role of advanced airway in CPR.

This episode blends deep clinical insight with real-world application, offering an accessible yet rigorous analysis for APPs, intensivists, residents, and anyone working in emergency or critical care.

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Observational studies often get a bad rap—but when randomized controlled trials (RCTs) are impractical or unethical, they may be the best we’ve got. In this episode of the Pulmcast Journal Club, we dig deep into a widely discussed observational study: "Association Between Tracheal Intubation During In-Hospital Cardiac Arrest and Survival" published in JAMA (2017). We critically appraise its methods, limitations, and real-world implications for airway management during codes.

You can find a direct link to the article here:

Why Bother With an Observational Study?

RCTs are the gold standard in evidence-based medicine. But they come with limitations—particularly in generalizability. ICU patients are notoriously heterogeneous, and most RCTs exclude patients with significant comorbidities, which means they may not reflect the real-world population. Observational studies like this one offer broader inclusion and can still generate practice-changing questions.

Observational studies allow us to:

1. Identify associations (not necessarily implying causation)

2. Question our current practice

3. Study things that may otherwise be unethical or logistically unfeasible

Surprisingly, many of our patients would be excluded from some of the major RCTs we've grown to love. What implications does this have on utilizing this study data to care for our patients?

Remember to always look at Figure 1 in an observational study. It contains useful information on how patients were selected and/or excluded from the data. Here's the Figure 1 from the study.

Study Results: Intubation During Cardiac Arrest & Outcomes

PICO Breakdown:

• Population: Adults with in-hospital cardiac arrest

• Intervention: Tracheal intubation

• Comparison: No tracheal intubation

• Outcome: Survival to discharge

Over 100,000 patients from nearly 700 hospitals were analyzed using data from the AHA’s Get With the Guidelines registry. Roughly 70% were intubated during the arrest.

Key Results:

• Survival to discharge was lower in the intubated group (17% vs. 33%)

• Return of spontaneous circulation (ROSC) was lower by 10%

• Functional outcomes were also worse (11% vs. 25%)

What Makes This Study Unique?

Unlike earlier studies, this one used time-dependent propensity score matching to reduce confounding from events like ROSC occurring before intubation. However, it still couldn’t adjust for key variables like:

• Provider experience

• Quality of CPR

• Intubation difficulty or delays

• Human factors influencing intubation timing

So while the study can’t prove causation, it strongly associates intubation during in-hospital cardiac arrest with worse outcomes.

Real-World Application: Should We Change Our Practice?

This study challenges the long-held belief that intubating during a code is always beneficial. It’s not in the AHA or ACLS algorithms, and yet it’s a widespread practice.

At some hospitals in our system, this data has already prompted a shift toward:

• LMA placement instead of intubation

• BVM with good technique when no advanced airway is available

• Delayed intubation until after ROSC

The authors suggest that interruptions in CPR, hyperoxia, and failed intubation attempts may be harming patients.

Supporting Literature: What Came Before

Here are four notable observational studies that help frame the conversation:

• Sakles et al., 1990 – In-hospital resuscitation

• Holmberg et al., 2001 – In-hospital outcomes post-intubation

• Hasegawa et al., 2013 – Japanese prehospital observational study

• Lee et al., 2016 – Korean prehospital observational study

Each provides additional context on the complex question of whether airway management strategies improve outcomes in cardiac arrest.

Expert Takeaways from Our ICU Team

Here’s where we landed after a deep discussion:

• Jeremy - I no longer intubate during cardiac arrest. I use an LMA or BVM and focus on uninterrupted CPR.

• John - If someone’s already intubating, I won’t stop them. But I won’t allow chest compressions to be paused for it.

• Intubation might not be evidence-based during codes. But stopping CPR to intubate is certainly harmful.

Teaching This to Your Team

Educating airway teams is key. Focus on:

• Maintaining continuous high-quality CPR

• Using LMA or BVM first

• Debriefing codes where airway delays disrupted compressions

• Sharing literature to promote system-wide awareness

Frequently Asked Questions

What is the main finding of the observational study on intubation during cardiac arrest?

The study found that patients intubated within the first 15 minutes of in-hospital cardiac arrest had lower survival to discharge and worse neurologic outcomes compared to those not intubated.

Can we say that intubation causes worse outcomes in cardiac arrest?

No. The study shows an association, not causation. Further randomized controlled trials would be needed to determine causality.

Should CPR be stopped to perform intubation during a code?

Current thinking discourages stopping CPR to intubate. If intubation can't be done without interrupting compressions, an LMA is often preferred.

What is the role of LMA vs ET tube in cardiac arrest airway management?

LMAs are increasingly favored for their speed of placement, minimal interruption to compressions, and ability to monitor EtCO2 continuously.

How should clinicians apply this study in practice?

This study encourages critical reflection on airway strategy during cardiac arrest. While not definitive, it may shift practice toward using LMAs and prioritizing uninterrupted CPR.