BYSTANDER CPR, VENTRICULAR-FIBRILLATION, AND SURVIVAL IN WITNESSED, UNMONITORED OUT-OF-HOSPITAL CARDIAC-ARREST

Study objective: To assess whether bystander CPR (BCPR) on collapse af fects initial rhythm and outcome in patients with witnessed, unmonitor ed out-of-hospital cardiac arrest (OHCA). Design: Prospective cohort s tudy. Student's t test, the chi(2) test, and logistic regression were used for analysis. Setting: Suburban emergency medical service (EMS) s ystem. Participants: Patients 19 years or older with witnessed OHCA of presumed cardiac origin who experienced cardiac arrest before EMS arr ival between July 1989 and July 1993. Results: Of 722 patients who met the entry criteria, 153 received BCPR. Patients who received BCPR wer e 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 i nitially had ventricular fibrillation (VF) in the BCPR group: 80.9% ve rsus 61.4% (P<.01). The interval to definitive care for ventricular ta chycardia (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 ali ve who were initially in VT/VF was higher in the BCPR group: 18.3% ver sus 8.4% (P<.001). In a multivariate model, BCPR is a significant pred ictor for VT/VF and live discharge with adjusted ORs of 2.7 (95% Cl, 1 .7 to 4.4) and 2.4 (95% Cl, 1.5 to 4.0), respectively. For those patie nts in VT/VF, BCPR predicted live discharge from hospital with an adju sted OR of 2.1 (95% Cl, 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 inte rvals. For VT/VF patients, BCPR is associated with an increased rate o f live discharge.