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Two studies find bystander CPR, defibrillation linked to improved outcomes
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When the rates of bystander-initiated CPR and defibrillation increased, outcomes improved for people with out-of-hospital cardiac arrest, according to results from two studies published in JAMA.
A study conducted in Japan found that an increased rate of bystander CPR and defibrillation between 2005 and 2012 was associated with greater likelihood of neurologically intact survival, while results from a study conducted in North Carolina indicated that an increase in bystander CPR and defibrillation between 2010 and 2013 was associated with improved odds of survival and an increase in bystander CPR was associated with increased odds of survival with favorable neurological outcome.
Japan study
Shinji Nakahara, MD, PhD, and colleagues estimated the associations between bystander interventions and changes in neurologically intact survival among patients in Japan with out-of-hospital cardiac arrest. They conducted a retrospective descriptive study of 167,912 patients with bystander-witnessed out-of-hospital cardiac arrest of presumed cardiac origin between 2005 and 2012. Patient data was collected from Japan’s national out-of-hospital cardiac arrest registry.
Nakahara, from the department of emergency medicine at Teikyo University School of Medicine, Tokyo, and colleagues evaluated the incidence of bystander prehospital intervention, neurologically intact survival (defined as Glasgow-Pittsburgh cerebral performance category score of 1 or 2 and overall performance category score of 1 or 2 at 1 month or at discharge) and the potential association between them.
The number of bystander-witnessed out-of-hospital cardiac arrests of presumed cardiac origin increased from 14 per 100,000 persons (95% CI, 13.8-14.2) in 2005 to 18.7 per 100,000 persons (95% CI, 18.4-18.9) in 2012, and the age-adjusted proportion of neurologically intact survival increased from 3.3% (95% CI, 3-3.5) to 8.2% (95% CI, 7.8-8.6).
During the study period, they wrote, rates of bystander CPR increased from 38.6% to 50.9%, rates of bystander-only defibrillation increased from 0.1% to 2.3%, and rates of combined bystander and emergency medical services defibrillation increased from 0.1% to 1.4%, whereas rates of EMS-only defibrillation decreased from 26.6% to 23.5%.
Compared with no bystander chest compression, bystander chest compression was associated with increased neurologically intact survival (8.4% vs. 4.1%; OR = 1.52; 95% CI, 1.45-1.6). Compared with EMS-only defibrillation, bystander-only defibrillation (40.7% vs. 15%; OR = 2.24; 95% CI, 1.93-2.61) and combined bystander and EMS defibrillation (30.5% vs. 15%; OR = 1.5; 95% CI, 1.31-1.71) were associated with increased neurologically intact survival, according to the researchers.
They also found that compared with EMS-only defibrillation, no defibrillation was associated with reduced survival (2% vs. 15%; OR = 0.43; 95% CI, 0.39-0.48).
North Carolina study
Carolina Malta Hansen, MD, and colleagues examined temporal changes in resuscitation performed by bystanders and first-responder prior to EMS arrival following statewide initiatives to improve resuscitation efforts in North Carolina between 2010 and 2013. These initiatives included training members of the general population in CPR and the use of automated external defibrillators, training first responders in team-based CPR including AED use and high-performance CPR, and training dispatch centers to recognize cardiac arrest.
They also examined the association between bystander and first-responder resuscitation efforts and survival and neurological outcome. The researchers defined survival with favorable neurological outcome as cerebral performance category 1 or 2.
The study included 4,961 patients with out-of-hospital cardiac arrest identified in the Cardiac Arrest Registry to Enhance Survival between 2010 and 2013.
Malta Hansen, from Duke Clinical Research Institute, and colleagues found that the administration of bystander CPR and first-responder defibrillation in combination increased from 14.1% (95% CI, 10.9-18.1) in 2010 to 23.1% (95% CI, 19.4-27.2) in 2013 (P < .01). Survival with favorable neurological outcome increased from 7.1% (95% CI, 5.8-8.8) in 2010 to 9.7% (95% CI, 8.2-11.4) in 2013 (P = .02) and was associated with bystander-initiated CPR, they wrote.
After adjustment for age and sex, bystander and first-responder interventions were associated with higher rates of survival to hospital discharge.
Compared with survival following EMS-initiated CPR and defibrillation (15.2%; 95% CI, 10.8-20.9), survival following bystander-initiated CPR and defibrillation (33.6%; 95% CI, 25.5-42.9; OR = 3.12; 95% CI, 1.78-5.46), survival following bystander CPR and first-responder defibrillation (24.2%; 95% CI, 20-29; OR = 1.7; 95% CI, 1.06-2.71) and survival following first-responder CPR and defibrillation (25.2%; 95% CI, 21.4-29.6; OR = 1.77; 95% CI, 1.13-2.77) were higher, Malta Hansen and colleagues wrote.
Ongoing efforts needed
“Despite increased knowledge and use of bystander CPR as well as improved survival over time, ongoing efforts are needed to improve outcomes after [out-of-hospital cardiac arrest],” Graham Nichol, MD, MPH, FRCP, and Francis Kim, MD, both from the University of Washington, Seattle, wrote in a related editorial. “Mortality after resuscitation from cardiac arrest continues to be high in many communities. Further improvements in outcomes will require additional coordinated efforts to improve resuscitation care.”
Francis Kim
They noted that the Institute of Medicine has released a report with recommendations to improve outcomes after cardiac arrest, and that the present studies “demonstrate the potential benefit these changes can have on resuscitation outcomes. Lay persons can improve outcomes after cardiac arrest in their community by participating in their system of care as well as supporting increased measurement and resuscitation research.” – by Erik Swain
References:
Malta Hansen C, et al. JAMA. 2015;doi:10.1001/jama.2015.7938.
Nakahara S, et al. JAMA. 2015;doi:10.1001/jama.2015.8068.
Nichol G, Kim F. JAMA. 2015;doi:10.1001/jama.2015.7519.
Disclosures: The researchers from the Japan study report no relevant financial disclosures. Malta Hansen reports receiving grants from Helsefonden, Laerdal and TrygFonden. Three other researchers from the North Carolina study report financial ties with Laerdal and the Medtronic Foundation. Nichol reports receiving grants from Cardiac Science, HeartSine Technologies, Philips Healthcare, Physio-Control and Zoll and other support from Abiomed and Velomedix. Kim reports receiving support for scientific advisory from Mallinckrodt Pharmaceuticals.
Perspective
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Venu Menon, MD
A strength of these studies is their ability to measure outcomes with cardiac arrest over time. Without measurement, improvement is difficult to achieve. Despite the resources devoted to out-of-hospital cardiac arrest response and treatment, neurologically intact survival rates are suboptimal. We know what matters: restoring circulation as quickly as possible by starting CPR and then quickly defibrillating the heart to get it back to regular rhythm. The sooner this is done, the better the prognosis.
These papers validate the fact that if bystanders initiate CPR promptly as well as defibrillate when they have a chance, then when EMS personnel arrive and perform their tasks, there’s a likelihood of improved prognosis. Bystander CPR was associated with improved outcomes in these studies. As we advocate for public participation in cardiac arrest in terms of performing bystander CPR awareness of how and when to use an AED, this is a most important message.
There are variations in outcomes of out-of-hospital cardiac arrest in the United States. For example, if you live in Kings County, Washington, as opposed to another part of the country, your odds of neurologically intact survival after out-of-hospital cardiac arrest are greater than in most other locations. What differentiates Kings County is that they have a fantastic EMS system with exceedingly small response times, and they have a lot of bystander CPR. This is worth emulating, because without higher rates of bystander CPR participation and faster EMS response times, there will not be dramatic improvements. When EMS comes in and does CPR and defibrillates, the outcome in that population is much worse than when a bystander starts CPR and defibrillates or when a bystander starts CPR and the EMS takes over. If a bystander performs CPR effectively, it restores cardiac output and prevents anoxic end-organ injury and anoxic brain injury that is a feared consequence. The studies provided very important information from that standpoint.
Even with the strides that have been made, the likelihood of surviving neurologically intact still remains quite small. That’s a clarion call for us to do even more activities such as advocating for public training and participation, so we can make the numbers better. Although the improvements shown in the studies are small, these are real lives saved, and that’s important.
We should try to replicate these studies in other areas, including in urban, rural and semi-urban environments. We should also try to show that as you continue to improve public participation, you continue to improve prognoses. These studies should motivate every community to increase basic cardiac life support and access to AEDs, because these truly have the ability to save lives. Physicians and EMS technicians can’t change this too much; the power is truly in the hands of the people.
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