Reference: Kragholm K, Wissenberg M, Mortensen RN, et al. Bystander Efforts and 1-Year Outcomes in Out-of-Hospital Cardiac Arrest. N Engl J Med. 2017;376(18):1737-1747. [PMID: 2846789]
Background & Objectives:
Bystander CPR and defibrillation has been associated with increased survival in patients with out-of-hospital cardiac arrest (OHCA). It is well studied that many patients who survive cardiac arrest have long term neurological deficits secondary to anoxic brain injury. Many of these patients require assistance with activities of daily living in the form of nursing home care. However, there is little known whether there is any improvement in functional outcomes for patients with OHCA in the setting of bystander CPR and defibrillation. The authors of this study hypothesized that bystander CPR in addition to use of an automated external defibrillator would potentially augment cerebral perfusion and reduce the extent of neurological insult by decreasing the amount of time to acquisition of ROSC. The authors sought to examine whether bystander CPR and bystander defibrillation would affect long term risk of anoxic brain damage or nursing home admission among 30 day survivors of OHCA over a 1 year period.
Danish investigators evaluated all 30 day survivors for OHCA aged 18 and older who were listed in the Danish Cardiac Arrest Registry from 2001 to 2012. Using nationwide registries, 1 year risk of anoxic brain injury, nursing home admission and all cause mortality was examined. Survivors of cardiac arrest were divided into four groups: 1) no bystander resuscitation 2) bystander CPR but no bystander defibrillation 3) bystander debrillation (regardless of bystander CPR status) and 4) EMS witnessed cardiac arrest. In addition, temporal changes in bystander interventions were studied (i.e. outcomes in relationship to increasing rates of bystander interventions in Denmark over the study period).
Of the 34,459 individuals eligible for the study, 2,855 patients were 30 day survivors of OHCA during the 2001-2012 study period. The key findings were as follows:
- 10.5% of patients had anoxic brain injury or were admitted to a nursing home. 9.7% of patients died within 1 year.
- Percentage of 30 day survivors increased from 3.9% to 12.4% over the course of the study
- Percentage of bystander CPR in OHCA unwitnessed by EMS (n=2084) increased from 66.7% to 80.6% (p<0.001) over the course of the study. Percentage of bystander defibrillation increased from 2.1% to 16.8% (p<0.001). In concert, the rate of brain damage or nursing home admission decreased from 10.0% to 7.6% (p<0.001). All cause mortality decreased from 18.0% to 7.9% (p=0.002).
- Bystander CPR was associated with lower risk of brain damage or nursing home admission compared to no bystander resuscitation (adjusted hazard ratio 0.62 95% CI 0.47-0.82). Similar findings were observed with bystander defibrillation compared to no bystander resuscitation (adjusted hazard ratio 0.45 95% CI 0.24-0.84)
- There is lower risk of anoxic brain damage, nursing home admission or death from any cause in 30 day survivors of OHCA who undergo bystander CPR or bystander defibrillation compared to those who do not receive bystander intervention.
- Increasing rates of bystander interventions in Denmark during the course of the study period was associated with decreased rates of anoxic brain injury, nursing home admission, and all-cause mortality
What this means for EMS:
Denmark has instituted widespread initiatives including mandatory and voluntary CPR training, dissemination of automated external defibrillators throughout the country, health care professionals at emergency dispatch centers and dispatcher-assisted CPR. System wide measures and efforts to educate the lay public on BLS skills including high quality CPR and use of automated external defibrillation, is a critical step in both increasing survival rates from OHCA and improving functional outcomes for patients.