Where do we need to improve resuscitation? Spatial analysis of out-of-hospital cardiac arrest incidence and mortality

Table 1 Characteristics of out-of-hospital cardiac arrests in the high-, neutral-, and low-survival areas

Variables	High-survival	Neutral-survival	Low-survival	Total	P
n	432	1907	562	2901
Median age (IQR)	63 (53–72)	66 (55–77)	70 (60–81)	67 (56–77)	< 0.001
Male	81.3% (of 432)	67.5% (of 1907)	64.1% (of 562)	68.9% (of 2901)	< 0.001
Public	58.8% (of 432)	24.0% (of 1906)	15.8% (of 562)	27.6% (of 2900)	< 0.001
Witnessed	79.2% (of 423 )	72.5% (of 1872)	70.1% (of 556)	73.0% (of 2851)	0.002
CPR before EMS	78.3% (of 414)	68.5% (of 1843)	66.4% (of 548)	69.6% (of 2805)	< 0.001
AED before EMS	52.3% (of 432)	47.1% (of 1906)	48.4% (of 562)	48.1% (of 2900)	0.25
Local AED	32.7% (of 206)	13.3% (of 897)	5.1% (of 272)	14.8% (of 1395)	< 0.001
Shockable initial rhythm	55.3% (of 409 )	38.5% (of 1828)	32.0% (of 544)	39.7% (of 2781)	< 0.001
30-day-survival	35.6% (of 432)	19.7% (of 1907)	9.1% (of 562)	20.0% (of 2901)	< 0.001
30-day-survival (Utstein)	59.5% (of 205)	45.8% (of 609)	25.9% (of 147)	45.7% (of 961)	< 0.001

Unknown or missing values were excluded for each variable separately and the numbers in parenthesis indicate the number of data points for each variable. CPR and AED rates reflect BLS and AED use before EMS arrival. Local AED refers to an on-site AED (instead of AEDs brought by first responders) and the corresponding value is defined only for the subgroup of cases where an AED is connected. 30-day survival is also given for the Utstein comparator group, i.e. witnessed arrests with shockable rhythm. All P-values except for age were obtained by a two proportion z-test comparing high and low-survival. P-value for age was obtained by a Kruskal-Wallis test. CPR: cardiopulmonary resuscitation, AED: automatic external defibrillator

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