Written by Alex Clark
Spoon Feed
The EVERDAC trial found delayed invasive blood-pressure monitoring to be noninferior to early arterial catheterization in patients with shock in terms of 28-day mortality.
A-lines for all or A-lines for none?
Arterial catheterization is routinely used for blood draws, monitoring oxygenation, and providing granular blood pressure monitoring during shock resuscitation. However, recent observational studies question its use due to potential risk and delays in care. This open-label, multicenter, noninferiority trial in France (the EVERDAC Trial) randomly assigned 1,006 critically ill adults with shock (ICU admission within 24 h) to either early arterial-catheter insertion (<4h; n=502) or noninvasive blood-pressure monitoring with delayed catheterization only if needed (n=504). The primary outcome was 28-day all-cause mortality (noninferiority margin 5%) and occurred in 34.3% (noninvasive) vs. 36.9% (invasive); (adjusted risk difference -3.2 percentage points; 95%CI -8.9 to 2.5; p=0.006 for noninferiority, p=0.2 for superiority). Secondary outcomes––including vasopressor exposure and organ-support metrics––were similar. Regarding safety, hematoma or hemorrhage related to the arterial catheter occurred in 41 patients (8.2%) in the invasive strategy group compared to 5 patients (1.0%) in the delayed group. Device-related discomfort was reported in 45/502 (9.0%) in the invasive group vs. 66/504 (13.1%) in the delayed group (weird right?). Limitations included an unblinded intervention, exclusion of patients with profound hemodynamic instability, variable thresholds for rescue arterial access (leading to potential confounding from crossover), a cohort consisting of primarily medical ICU patients suffering from distributive shock, and limited assessment of long-term outcomes.
How does this change my practice?
Arterial lines are polarizing, and their utility is nuanced. This study provides evidence that arterial lines are not an immediate resuscitative priority. Even REBOA, a therapeutic application of arterial lines, is questionable. As an emergency physician, I will manage the ABCs, resuscitate via large-bore intravenous access, and determine shock etiology in parallel. Most arterial lines can wait. However, before we throw A-lines out completely, I will continue to advocate for them in certain patients (e.g., aortic dissections, physiologically difficult intubation, brain/spinal cord injury) and scenarios (volume responsiveness in mechanically ventilated patients & intra-cardiac arrest in high resource centers).
Source
CRICS-TRIGGERSEP F-CRIN Network and the EVERDAC Trial Group. Deferring Arterial Catheterization in Critically Ill Patients with Shock. N Engl J Med. 2025 Nov 13;393(19):1875-1888. doi: 10.1056/NEJMoa2502136. Epub 2025 Oct 29. PMID: 41159885.
A 5 percent noninferiority margin for all-cause mortality is not reasonable. Not sure how the authors got that through peer review.
The choice of 28-day all-cause mortality as the primary outcome is interesting, too – it’s an important outcome, obviously, but I don’t think anyone would have thought it was plausible that early art lines would lead to a >5% absolute mortality difference. It looks like the trial was designed in a way that was practically guaranteed to show noninferiority. Not sure we learned much from it.
A great point. Thankfully, the upper bound 95%CI was 2.5, although up to a 2.5% greater mortality is a bit unsettling. That said, I’ll bet if a Bayesian analysis was done, the probability it causes increased mortality would be near zero. But I’m just speculating there. My take home is that we don’t need to rush to start an art line.