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Date: October 18th, 2022

Reference: Moore et al. Head and thorax elevation during cardiopulmonary resuscitation using circulatory adjuncts is associated with improved survival. Resuscitation 2022

Guest Skeptic: Clay Odell is a Paramedic, Firefighter, and registered nurse (RN).

Case: You are the Chief of your local Fire and EMS Department, and an individual contacts you saying he saw a piece on TV about a “Heads Up” CPR device, and he wants to donate half the cost and has his checkbook out.

Background: We have covered Out of Hospital Cardiac Arrests (OHCAs) many, many times on the SGEM. This includes epinephrine for OHCA, target temperature management, mechanical CPR, supraglottic airways, steroids, hands on defibrillation and many more topics.

  • SGEM#50: Under Pressure Journal Club: Vasopressin, Steroids and Epinephrine in Cardiac Arrest
  • SGEM#54: Baby It’s Cold Outside: Pre-hospital Therapeutic Hypothermia in Out of Hospital Cardiac Arrest
  • SGEM#59: Can I Get a Witness: Family Members Present During CPR
  • SGEM#64: Classic EM Paper: OPALS Study
  • SGEM#107: Can’t Touch This: Hands on Defibrillation
  • SGEM#136: CPR – Man or Machine?
  • SGEM#143: Call Me Maybe for Bystander CPR
  • SGEM#152: Movin’ on Up – Higher Floors, Lower Survival for OHCA
  • SGEM#162: Not Stayin’ Alive More Often with Amiodarone or Lidocaine in OHCA
  • SGEM#189: Bring Me To Life in OHCA
  • SGEM#238: The Epi Don’t Work for OHCA
  • SGEM#247: Supraglottic Airways Gonna Save You for an OHCA?
  • SGEM#275: 10th Avenue Freeze Out – Therapeutic Hypothermia after Non-Shockable Cardiac Arrest
  • SGEM#306: Fire Brigade and the Staying Alive APP for OHCAs in Paris
  • SGEM#314: OHCA – Should you Take ‘em on the Run Baby if you Don’t get ROSC?
  • SGEM#329: Will Corticosteroids Help if…I Will Survive a Cardiac Arrest?
  • SGEM#336: You Can’t Always Get What You Want – TTM2 Trial
  • SGEM#344: We Will…We Will Cath You – But should We After An OHCA Without ST Elevations?
  • SGEM#353: At the COCA, COCA for OHCA

Overall, the success rate of resuscitation of out of hospital cardiac arrest – or OHCA’s – is pretty dismal and efforts to improve resuscitation rates are absolutely vital. Animal research has suggested that elevating the head during CPR improves success rates. The proposed physiology includes decreased intracranial pressure and improved return of venous blood from the head and neck to the thorax.

Pathophysiology has been used to justify practice many times in medicine. There are examples of medical reversal when properly conducted studies are performed to confirm the hypotheses. The time to accept a claim is when there is sufficient evidence.

This study is an attempt to confirm (or refute) the pathophysiology and the animal research into human subjects.

Clinical Question: Does the rapid use of an automated head up device as part of a CPR bundle improve survival from OHCA?

Reference: Moore et al. Head and thorax elevation during cardiopulmonary resuscitation using circulatory adjuncts is associated with improved survival. Resuscitation 2022

  • Population: Adults 18 years of age and older with OHCA (ventricular fibrillation [VF] or ventricular tachycardia [VT], pulseless electrical activity [PEA], or asystole; routine and consistent treatment with ACE-CPR within the participating pre-hospital system; and routine and consistent recording of the 911 call receipt to placement of the APPD [automated controlled head and thorax patient positioning device] time interval.
    • Excluded: Children, prisoners, women known to be pregnant, patients >175kg and patients without documentation of 911 call to start of EMS CPR time interval.
  • Intervention: Automated controlled elevation of the head and thorax CPR (ACE-CPR) with an impedance threshold device (ITD) and active compression decompression (ACD-CPR) or LUCAS manual compression device
  • Comparison: Conventional CPR (C-CPR) with or without ITD
  • Outcome:
    • Primary Outcome: Survival to hospital discharge
    • Secondary Outcomes: Return of spontaneous circulation (ROSC) at any time, “favorable neurological function” defined as a Cerebral Performance Category (CPC) of 1 or 2 or “neurologically favorable function” defined as a modified Rankin Scale (mRS) score ≤ 3
  • Type of Study: Multi-centre, prospective observational study

Authors’ Conclusions: “Compared with C-CPR controls, rapid initiation of ACE-CPR was associated with a higher likelihood of survival to hospital discharge after OHCA.”

Quality Checklist for Observational Study:

  1. Did the study address a clearly focused issue? Yes
  2. Did the authors use an appropriate method to answer their question? Yes
  3. Was the cohort recruited in an acceptable way? Yes
  4. Was the exposure accurately measured to minimize bias? Yes
  5. Was the outcome accurately measured to minimize bias? Yes
  6. Have the authors identified all-important confounding factors? Unsure
  7. Was the follow up of subjects complete enough? Yes
  8. How precise are the results? Not very
  9. Do you believe the results? Unsure
  10. Can the results be applied to the local population? Unsure
  11. Do the results of this study fit with other available evidence? Yes
  12. Funding of the Study: ACE-CPR device manufacturer “Advanced CPR Solutions”

Results: They included 227 patients from the ACE-CPR registry data who were propensity score matched to 860 C-CPR patients. The mean age was 64 years, 68% were male, 7% were EMS witness, 43% bystander CPR attempted, 17% in ventricular fibrillation or pulseless ventricular tachycardia.

Key Result: When all the patients in the study were considered, ACE-CPR was not associated with improved survival to discharge for the adult patients with OHCA.

  • Primary Outcome: Survival to hospital discharge
    • ACE-CPR 9.5% vs. C-CPR 6.7%, OR 1.44 (95% CI, 0.86 to 2.44)
    • Subgroup analysis of those treated from 911 call to ACE-CPR within 11 minutes and 18 minutes had an improved odds ratio of survival
  • Secondary Outcomes:
    • ROSC at any time (no statistical difference): ACE-CPR 33% vs. C-CPR 33%, OR 1.02 (95% CI, 0.75 to 1.49)
    • Survival to hospital discharge with favorable neurological status (no statistical difference): ACE-CPR vs C-CPR 9% vs 4.1%, OR, 1.47, 95% CI, 0.76–2.82),

 

1) Association Is Not Causation: It is good to remember that this study design (prospective observational) cannot be used to conclude causation. While it is interesting that there was an association between rapid ACE-CPR use and mortality, causation would need to be demonstrated in a properly designed RCT.

A search of ClinicalTrial.gov did not find any RCTs. However, there is another observational study (before-after design) currently underway in Europe called GRAVITY.

2) Propensity Score Matching: The authors compared their own data to patient data from other studies. Propensity score matching is a mathematical technique used in observational studies to try to minimize confounders. It can potentially improve the accuracy of minimizing some of the biases. However, it cannot address unmeasured confounders and get to the level of a randomized controlled trial. Peter C. Austin published a paper in 2011 that gives a reasonable introduction to propensity score matching.

3) Time to Treatment: We know that certain things can be important in patients with OHCA. This includes early high-quality CPR and having a shockable rhythm. Time is another important factor. This study showed that earlier ACE-CPR application from 911 dispatch had a greater odds ratio than those treated in a similar time frame with C-CPR. We must be careful not to over-interpret these results. It could also be that those using these fancy new devices were performing at a higher level for other important aspects correlated to survival. Of course, randomization to early vs. late CPR would be unethical.

They also highlighted <11min and <18min in a subgroup analysis. Why were these times picked and was it done a priori? We could not find that this study was registered or published their methodology in advance.

4) Generalizability: This study included six sites which were characterized as early adopters. Are there any differences between those locations that embraced this technology sooner compared to those that did not? Perhaps it is those traits that lead to faster care and ultimately better outcomes? And not necessarily the head elevation?

5) Conflicts of Interest: The study was funded by the manufacturer of the ACE-CPR device. Co-author Bayert Salverda received payment from AdvancedCPR Solutions on contract basis for data collection services. He was listed as “data curation”.

Another co-author, Keith Lurie, is a co-founder of AdvancedCPR Solutions, owns a significant equity position in this company and serves as its Chief Medical Officer. None of the other co-authors declared any relationship with industry or other relevant entities, financial or otherwise that might pose a conflict of interest with the publication.

As we have pointed out before, industry funding does not negate results, but it should make us more skeptical.

Comment on Authors’ Conclusion Compared to SGEM Conclusion: We agree that there was an association between rapid application of ACE-CPR and lower mortality.

SGEM Bottom Line: We cannot recommend the purchase of an ACE-CPR device at this time.

Case Resolution: The generous offer to help purchase an ACE-CPR device is declined.

Clay Odell

Clinical Application: Current research has not adequately shown a difference in outcomes between high-quality conventional CPR and ACE-CPR. There is a potential that earlier application of the ACE-CPR device, along with ITD and ACD-CPR or mechanical CPR may improve outcomes. However, it is too soon to adopt this technology. The authors mention further studies being conducted and we look forward to critically appraising those publications when available.

What Do I Tell the Donor? I would thank the individual for the generous offer but there lacks high-quality evidence the ACE-CPR device saves lives. Our suggestion would be for them to purchase something that has been proven to save lives like an automated external defibrillator for the local community center.

Keener Kontest: Last weeks winner was…there was no winner. The fastest growing racial/ethnic group in the US over the last 20 years is Asian Americans.

Listen to the SGEM podcast to hear this weeks’ question. If you know the answer, send and email to TheSGEM@Gmail.com with “keener” in the subject line. The first correct answer will win a cool skeptical prize.

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics’ Guide to Emergency Medicine.