Bystander CPR, ventricular fibrillation, and survival in witnessed, unmonitored out-of-hospital cardiac arrest.

STUDY OBJECTIVE: To assess whether bystander CPR (BCPR) on collapse affects initial rhythm and outcome in patients with witnessed, unmonitored out-of-hospital cardiac arrest (OHCA). DESIGN: Prospective cohort study. Student's t test, the chi 2 test, and logistic regression were used for analysis. SETTING: Suburban emergency medical service (EMS) system. PARTICIPANTS: Patients 19 years or older with witnessed OHCA of presumed cardiac origin who experienced cardiac arrest before EMS arrival between July 1989 and July 1993. RESULTS: Of 722 patients who met the entry criteria, 153 received BCPR. Patients who received BCPR were younger than those who did not: 62.5 +/- 15.4 years versus 66.8 +/- 15.1 years (P < .01). We found no differences in basic or advanced life support response intervals or in frequency of AED use. More patients initially had ventricular fibrillation (VF) in the BCPR group: 80.9% versus 61.4% (P < .01). The interval to definitive care for ventricular tachycardia (VT)/VF was longer for the BCPR group (8.59 +/- 5.3 versus 7.45 +/- 4.7 minutes; P < .05). The percentage of patients discharged alive who were initially in VT/VF was higher in the BCPR group: 18.3% versus 8.4% (P < .001). In a multivariate model, BCPR is a significant predictor for VT/VF and live discharge with adjusted ORs of 2.7 (95% CI, 1.7 to 4.4) and 2.4 (95% CI, 1.5 to 4.0), respectively. For those patients in VT/VF, BCPR predicted live discharge from hospital with an adjusted OR of 2.1 (95% CI, 1.2 to 3.6). CONCLUSION: Patients who receive BCPR are more often found in VT/VF and have an increased rate of live discharge, with controls for age and response and definitive care intervals. For VT/VF patients, BCPR is associated with an increased rate of live discharge.

Bystander vs EMS first-responder CPR: initial rhythm and outcome in witnessed nonmonitored out-of-hospital cardiac arrest.

OBJECTIVES: To assess whether outcome and first-monitored rhythm for patients who sustain a witnessed, nonmonitored, out-of-hospital cardiac arrest are associated with on-scene CPR provider group. METHODS: A retrospective, cohort analysis was conducted in a suburban, heterogeneous EMS system. Patients studied were > or = 19 years of age, had had an arrest of presumed cardiac origin between July 1989 and January 1993, had gone into cardiac arrest prior to ALS arrival, and had received CPR on collapse. First-monitored rhythms and survival rates were compared for two patient groups who on collapse either: 1) had received CPR by nonprofessional bystanders (BCPR) or 2) had received CPR by on-scene EMS system first responders (FRCPR). RESULTS: Of 217 cardiac arrest victims, 153 (71%) had received BCPR and 64 (29%) had received FRCPR. The BCPR patients were slightly younger (62.4 vs 68.4 years, p = 0.01) and had slightly shorter ALS response intervals (6.4 vs 7.7 minutes, p = 0.02). There was no difference in BLS response time intervals or automatic external defibrillator (AED) use rates. The percentage of patients with a first-monitored rhythm of pulseless ventricular tachycardia/ventricular fibrillation (VT/VF) and the percentage of patients grouped by CPR provider who survived to hospital admission or to hospital discharge were: [see text]