Intraosseous-first access in adult cardiac arrest more likely harmful than beneficialIntravenous access is more likely to improve survival in cardiac arrest

Resuscitation Published November 5, 2026 Study authors: Couper Keith, Ji Chen, Deakin Charles D, Fothergill Rachael T, Kandiyali Rebecca, Nolan Jerry P, Poc… PubMed ↗ DOI ↗ Editorial oversight: Dr. Lars van Dijk, PhD · Surgical, Procedural & Diagnostic

AI-generated summary of the cited source, checked by automated accuracy review. How we work

Key Takeaway

Intraosseous-first vascular access in adult out-of-hospital cardiac arrest is more likely harmful than beneficial.

This Bayesian secondary analysis of a randomised controlled trial examined 6,082 adults with out-of-hospital cardiac arrest who required vascular access. It compared an intraosseous-first strategy with an intravenous-first strategy, focusing on 30-day survival as the primary outcome.

For 30-day survival, the posterior probability that intraosseous-first access improved outcomes (odds ratio above 1.0) was only 18.4%. Conversely, the probability that it was inferior (odds ratio below 1.0) was 81.6% for any effect, 55.0% for a small effect (odds ratio below 0.9), and 13.4% for a moderate effect (odds ratio below 0.75).

Neurological findings at hospital discharge were comparable to the 30-day survival results. For return of spontaneous circulation at hospital handover, the probability that intraosseous-first access was inferior reached 98.0%.

The authors conclude that an intraosseous-first strategy in adult out-of-hospital cardiac arrest is more likely to be harmful than beneficial. They note that the low probability of a moderate or large treatment effect suggests the overall effect is likely to be modest.

Limitations include the Bayesian secondary design, which used non-informative priors. Adverse events, serious adverse events, and discontinuations were not reported, and funding or conflicts of interest were not described.

How this fits prior evidence

How this fits prior evidence: This finding addresses a gap in management strategies for out-of-hospital cardiac arrest. While prior evidence confirmed that bystander CPR increases 30-day survival odds by 50% and that volume-controlled mechanical ventilation shows no difference in ROSC compared to manual ventilation, this study specifically addresses the choice of initial vascular access. It suggests that an intraosseous-first strategy is more likely to be inferior to intravenous-first access for both 30-day survival and ROSC.

When someone collapses in public and their heart stops, every second counts. Doctors must quickly find a way to get life-saving medicine into the body. One common method is intraosseous access, which involves injecting medicine into the bone marrow. Another method is intravenous access, which involves finding a vein.

A large study of over 6,000 adults who suffered cardiac arrest outside of a hospital looked at which of these two methods worked better. The results showed that the intraosseous-first strategy was less likely to be successful. In fact, there was a high probability that the intraosseous-first approach was inferior to the intravenous-first approach for both survival and getting the heart beating again.

While the study notes that the overall difference between the two methods might be modest, the data suggests that choosing the bone-based method first is more likely to be harmful than helpful. These findings help emergency teams make faster, more effective decisions during critical moments.

What this means for you:

Intravenous-first access is more likely to improve survival for patients in out-of-hospital cardiac arrest.

Common questions

What is the difference between intraosseous and intravenous access?

Intraosseous access involves delivering medication into the bone marrow, while intravenous access involves finding a vein. This study looked at which method should be used first when a person's heart stops outside of a hospital setting.

Is the intraosseous-first method safe for patients?

The study found that an intraosseous-first strategy was more likely to be harmful than beneficial for patients. There was a 98.0% probability that this method was inferior to intravenous-first for getting the heart to start beating again.

How does this finding change treatment for cardiac arrest?

The results suggest that an intravenous-first strategy is more likely to improve 30-day survival. Because the intraosseous-first method showed a low probability of being better, doctors may prefer starting with a vein when possible.

Study Details

Study typeRct

EvidenceLevel 2

PublishedNov 2026

PMID42790855

View Original Abstract ↓

OBJECTIVE: To evaluate the clinical-effectiveness of an intraosseous-first strategy compared with an intravenous-first strategy in adult out-of-hospital cardiac arrest in a pre-planned Bayesian secondary analysis of the PARAMEDIC-3 trial. METHODS: In PARAMEDIC-3, adults with out-of-hospital cardiac arrest requiring vascular access were randomised to either an intraosseous-first strategy or an intravenous-first strategy. In this analysis, we describe the probability that an intraosseous-first strategy was superior or inferior to an intravenous-first strategy, and the probability that this exceeds specific odds ratio thresholds. Our outcomes were 30-day survival (primary), favourable neurological outcome at hospital discharge and return of spontaneous circulation at hospital handover. Our primary analysis used non-informative priors, adjusted for key baseline characteristics. RESULTS: In 6082 randomised participants, the posterior probability that an intraosseous-first strategy improved 30-day survival (odds ratio (OR) > 1.0) was 18.4%. The probability that an intraosseous-first strategy was inferior to an intravenous-first strategy was 81.6% for any effect (OR < 1.0), 55.0% for a small effect (OR < 0.9), and 13.4% for a moderate effect (OR < 0.75). For favourable neurological outcome, findings were comparable to 30-day survival. For return of spontaneous circulation, the posterior probability that an intraosseous-first strategy was inferior to an intravenous-first strategy (OR < 1.0) was 98.0%. CONCLUSION: Based on non-informative priors, which represent minimal prior knowledge of the treatment effect, an intraosseous-first strategy in adult out-of-hospital cardiac arrest is more likely to be harmful, rather than beneficial. However, the low probability of a moderate or large treatment effect suggests that the overall treatment effect is likely to be modest. TRIAL REGISTRATION: ISRCTN14223494.

Intraosseous-first access in adult cardiac arrest more likely harmful than beneficialIntravenous access is more likely to improve survival in cardiac arrest

How this fits prior evidence

Common questions

Study Details

Intraosseous route for out-of-hospital cardiac arrest linked to lower outcomes than intravenous access

Using a bone needle instead of a vein line lowers survival chances for cardiac arrest patients

Clinical research that matters. Delivered to your inbox.

Intraosseous-first access in adult cardiac arrest more likely harmful than beneficialIntravenous access is more likely to improve survival in cardiac arrest

How this fits prior evidence

Common questions

More on Cardiac Arrest

Study Details

Intraosseous route for out-of-hospital cardiac arrest linked to lower outcomes than intravenous access

Using a bone needle instead of a vein line lowers survival chances for cardiac arrest patients

Clinical research that matters. Delivered to your inbox.

Related in Emergency Medicine

From Other Specialties