Scientific Background
Survival for out-of-hospital cardiac arrest (OHCA) is 2-25%.

Objectives
To study OHCA in the Jerusalem district and identify predictors of survival.

Methodology
Data on patient demographics, arrest details, resuscitation activities, survival and neurological status at discharge were collected prolectively on all OHCAs (4/2005-12/2008), excluding trauma cases and minors. Patients were followed to hospital discharge. Paramedics underwent post–event interviews.

Findings
Of 1816 patients; age 73.8±15.9yrs, 56% male, 72.9% collapsed at home, 45% were unwitnessed. Lay-BLS was attempted in 13.6% of witnessed arrests. First on-location were volunteers in 18.5% (tier 1, time of arrival not recorded), white ambulances (tier 2) in 28.1%, median call-to-curb time 6.09 min (IQR 4:18-8:54) and MICUs (tier 3) in 53.4% of cases (median arrival time 8:01 min, IQR 5:47-11:22). Presenting rhythms recorded by MICAs which attend all OHCAs were asystole in 78.2% and VT/VF in 8.8% of cases. Automatic defibrillation was attempted in 75 cases (4.2%); successful conversion occurred in 6. 64.1% of cases, mostly asystolic (66.6%), received ALS. ROSC was achieved in 46.4% of ALS patients. 92 patients survived to hospital discharge (of the 540 arrivals to hospital); 48 neurologically intact (2.6% of all patients, 4.1% following ALS). Variables predicting neurologically-intact survival were VT/VF, witnessed arrest and younger age (p<0.01 for all). No inequalities of care were found, but survival among women was lower than for men. Paramedic interviews (n=304) revealed valuable information on knowledge and attitudes to resuscitation and futility.

Conclusions
Lay CPR was rarely undertaken. Presenting rhythms of VT/VF (i.e. potentially salvageable patients) were uncommon. Automatic defibrillation (tier 1/2) was not frequently performed and was largely unsuccessful. Although two thirds of the OHCA patients received ALS and in half of them ROSC was achieved, survival to hospital discharge was low (~1/25 of those who received ALS; but did not diverge from studies elsewhere) and only half of the survivors were neurologically intact (~1/40 of those who received ALS). Pre-hospital resuscitation appears overzealous at times, particularly in light of little data supporting successful hospital outcomes in such patients (e.g. unwitnessed asystoles), leading to an unnecessary burden on admitting hospitals and chronic care facilities.

Policy Implications / recommendations
These findings require corroboration in other districts in Israel. A reassessment of policy should be considered.

(1) Epidemiology Unit, Hadassah Medical Organization
(2) Director of Surgical Intensive Care, Shaare Zedek Medical Centre

Research number: A/69/2003