Not so fast: More evidence needed in head-up CPR
While the CPR intervention may prove beneficial, more evidence is needed before it can become a standard of care
The Metro chiefs, in response to NAEMSP, rescinded position papers on neuroprotective CPR and pre-hospital transfusion of blood products.
Recently, a document has been circulating claiming that “neuroprotective CPR,” better known as head-up CPR, is the “standard of care” for prehospital resuscitation of cardiac arrest . Leaving aside the unclear providence of this document (it was published anonymously and, while it has the logo of the Metropolitan Fire Chiefs and appeared on the NFPA website, it isn’t clear if this represents the official position of these organizations), there is significant concern with this document.
Developing clinical practice guidelines
The evidence to support this intervention is inadequate to claim that it is clearly beneficial and grossly inadequate to claim it is the standard of care. In the world of evidence-based medicine, there is a specific process to be followed when developing clinical practice guidelines.
The GRADE methodology requires a systematic review and outlines a rigorous process undertaken by a publicly named expert panel without any conflicts of interest, in which all available evidence is systematically evaluated to determine the certainty in the evidence based on the established domains of risk of bias, inconsistency, indirectness, imprecision and publication bias . Based on the certainty of the evidence, as well as contextual considerations, a recommendation is developed and described in terms of strength. Thus, the panel may develop a strong recommendation based on high quality evidence demonstrating benefits clearly outweigh harms. or vice versa in a recommendation against.
Examining the evidence
This “standard of care,” akin to a strong recommendation in GRADE, does not appear to have gone through such a process. Based on the available evidence, it is likely that such a process would either make no recommendation based on insufficient evidence or, at best, offer a weak recommendation in favor, based on very low certainty of evidence due to a high risk of bias and indirect evidence. That is a far cry from a standard of care.
Most of the evidence supporting this intervention is animal based. The human evidence is observational and weak. The most often cited study that claims improved survival has several limitations . The largest problem with the paper is it claims benefit in the absence of supporting evidence. This is a cardinal sin in science and, frankly, I am surprised this paper got published with this overstated conclusion. Specifically, this paper’s stated purpose and primary outcome was to assess the association between head-up CPR and survival to hospital discharge. Despite inconclusive results showing no significant improvement, the paper claimed survival was improved. The authors make this claim supported by subgroup analysis based on time to application. This is what is called data-dredging and should be used only for generating hypotheses to be tested in future, more rigorous trials. A complete criticism of this paper is beyond the scope of this article, however, there have been several published [4,5].
Causality vs. association
Finally, it needs to be made clear that this intervention may be shown to have real benefit to patients. That would be wonderful indeed, and I truly hope this occurs. However, the available evidence suggests that while it may be beneficial, it is also possible it may not be beneficial. We just do not yet know.
There is clearly sufficient evidence to suggest further studies are needed, specifically well-designed, randomized controlled studies that are better able to control for confounding factors that can demonstrate causality rather than just association.
We are not there yet. And because of this, it is premature to declare this intervention as a standard of care.
1. First-In Responders Providing Neuroprotective (“Heads-Up”) CPR as the Standard of Care for Emergency Medical Services Systems. NFPA. Available at https://www.nfpa.org/-/media/Files/Membership/member-sections/Metro-Chiefs/Urban-Fire-Forum/2023/UFF23_NPCPR-Position-Statement.ashx.
2. Guyatt GH, Oxman AD, Vist GE, Kunz R, Falck-Ytter Y, Alonso-Coello P, Schünemann HJ: GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ. 2008;April 26;336(7650):924–6.
3. Moore JC, Pepe PE, Scheppke KA, Lick C, Duval S, Holley J, Salverda B, Jacobs M, Nystrom P, Quinn R, et al.: Head and thorax elevation during cardiopulmonary resuscitation using circulatory adjuncts is associated with improved survival. Resuscitation. 2022;October;179:9–17.
4. Swaminathan A: Heads Up! There is No Association with Improved Outcomes for Head Up CPR: Why We Must Read Past the Abstract.RebelEM. Available at https://rebelem.com/heads-up-there-is-no-association-with-improved-outcomes-for-head-up-cpr-why-we-must-read-past-the-abstract/.
5. Carley S: Head up, mechanical and impedance device assisted CPR – does it make a difference?St Emlyns. Available at https://www.stemlynsblog.org/jc-head-up-mechanical-and-impedance-device-assisted-cpr-does-it-make-a-difference-st-emlyns/.