In this study we assessed the effect of bystander type on 1-month outcomes (survival and favorable neurological status) among elderly OHCA patients. Our results revealed that OHCA patients with a non-family bystander were more likely to survive compared than those with a family bystander. The rate of bystander CPR increased with advancing age categories among patients with a non-family bystander, but seemed to be the same across all age categories in cases with a family bystander. Bystander chest compression only and conventional CPR had significant impacts and similar 1-month outcomes, and PAD also had a significant impact on 1-month outcomes.
Many previous reports have described outcomes among elderly patients with cardiopulmonary arrest
[17–21]. However, most studies were published in the 1980s and 1990s and had relatively small data sets. Over the past few decades, countries with increased life expectancies are having larger numbers of elderly people. The resuscitation techniques and equipment used by pre-hospital EMS and hospital physicians are advancing, and it is therefore important for these care providers to have up-to-date information about the characteristics and outcomes of OHCA cases among the elderly. Since some characteristics of OHCA patients such as their age may affect the decisions made by EMS regarding the provision of ACLS and the treatment decisions made by physicians after hospital arrival, the present study provides important information to support correct decision-making by EMS and physicians. Up-to-date information is an important consideration when developing effective policies to increase bystander CPR rates and improve outcomes.
Previous studies have reported that approximately half of OHCA patients did not receive bystander CPR before EMS arrival at the scene
[9, 22]. Hauff et al.
 reported that the physical limitations of bystanders were the major reason for lack of bystander CPR, even when a dispatcher provided CPR instructions via telephone. Lack of bystander CPR often appeared to be due to a combination of the bystander’s physical limitations and the position of the OHCA patient. Patient emesis and bystander concerns about disease transmission also appeared to impede bystander CPR.
Recently, several papers have reported on the outcomes of elderly OHCA patients
[23, 24]. Deasy et al.
 studied 30,006 OHCA patients attended by paramedics, of whom 32% were aged 65–79 years, 21% were 80–89 years, 5% were 90–99 years, and 0.1% were ≥100 years. The rate of attempted resuscitation decreased with advancing age, with overall survival rates to hospital discharge of patients aged 65–79 years, 80–89 years, and 90–99 years of 8%, 4%, and 2%, respectively. They also assessed information about the location of collapse and reported that the proportion of OHCA events occurring at nursing homes increased with advancing age. By comparison, the present study indicated a slightly higher survival rate, with an overall bystander CPR rate of <50% and an increasing bystander CPR rate with advancing age categories among non-family-witnessed OHCA patients. Surprisingly, the rate of bystander CPR was only 35.5% among cases with a family bystander, indicating that OHCA patients with family bystanders were less likely to receive bystander CPR than those with a non-family bystander, especially in the older age categories.
The relatively good 1-month outcomes in the present study could be explained by the selection of only witnessed OHCA cases. Most OHCA cases with a family bystander may occur at the patient’s home, whereas patients in the more advanced age groups may be more likely to be in a nursing home where OHCA could be witnessed by nursing home staff, which would increase the proportions of cases with a non-family bystander. Nursing home staff classified as non-family bystanders may have basic life support (BLS) training and may be accustomed to dealing with OHCA, resulting in a higher bystander CPR rate and earlier performance of bystander CPR, which could achieve a higher initial VF/VT rate and better outcomes. It is known that immediate bystander CPR maintains VF longer in OHCA patients, which is a strong predictor of survival
. Our results also indicate a shorter interval from the call to EMS to EMS arrival at the scene and from collapse to the call to EMS in the non-family bystander group compared to the family bystander group, which could also affect the rate of initial VF/VT and 1-month outcomes. As the difference in the interval from collapse to bystander CPR was more marked than the differences in intervals from the call to EMS to EMS arrival or from collapse to the call to EMS between the family and non-family groups, the interval from collapse to bystander CPR seemed to have the most impact on initial VF/VT rates and 1-month outcomes. Family bystanders may be elderly people such as the spouse of the OHCA patient and may have physical limitations that make it difficult to perform bystander CPR compared to a younger non-family bystander such as a colleague, passer-by, or facility staff member.
It has been reported that patients with known heart disease received bystander CPR in only 16% of cases
 and that older people are not very willing to learn CPR even when they have a family member with known heart disease
. Generally, a large proportion of OHCA events occurs at the patient’s home, and these have a poor prognosis
[9, 28]. Herlitz et al.
 reported the characteristics and outcomes of OHCA patients who collapsed at home compared with those who collapsed in other places. Those who collapsed at home were witnessed less often, received bystander CPR less often, were found to have VF less often, and had a longer interval between collapse and call to EMS, start of CPR, and first defibrillation. Furthermore, conventional bystander CPR (chest compression with ventilation) was performed less frequently when the collapse was in the patient’s home. While they concluded that OHCA occurring at home was a strong independent predictor of adverse outcome, they did not give reasons for this. Even though they identified the bystander as layperson, ambulance personnel, medical personnel, or police, they did not distinguish if a layperson was a family or non-family bystander. Jackson et al.
 reported that OHCA occurring outside the home was associated with improved outcomes. Patients with witnessed OHCA outside the home were more likely to receive bystander CPR and to survive. Our results showed a lower bystander CPR rate and a higher rate of adverse outcomes in cases with a family bystander compared to a non-family bystander.
It has been suggested that simplifying the CPR technique to include chest compression only may increase the rate of bystander CPR in elderly OHCA patients when a dispatcher provides telephone CPR instruction
. In the present study, both bystander chest compression only and bystander conventional CPR were associated with improved outcomes, with both having a similar level of impact on the rates of 1-month survival and favorable neurological status. The simpler procedure of chest compression only might therefore be appropriate for dispatcher-assisted telephone CPR for elderly OHCA patients when the bystander is an elderly person with physical limitations or emotional distress.
Several limitations of our study should be acknowledged. First, the database did not include detailed information about bystanders such as age and gender, the quality of bystander CPR, and whether the bystander had BLS or ACLS training. Therefore, we could not assess the influence of these factors on outcome. Second, PAD was implemented because early defibrillation using PAD has a significant impact on survival and favorable neurological outcome. Therefore, the accessibility of PAD in OHCA patients with family versus non-family bystanders should be evaluated. However, we could not assess the effects of OHCA location because the database did not include this information. The type of family bystander may be different depending on whether the OHCA occurs at home or elsewhere. Third, we did not have data regarding the medical histories or comorbidities of OHCA patients. Fourth, there is a possibility that family members may have been aware of patient preferences not to attempt resuscitation in the event of OHCA. However, the database did not include detailed information about this point.