Comparison of outcome of paramedic-witnessed cardiac arrest in patients younger and older than 70 years

Abstract

To obtain further information concerning differences in the mechanism of out-of-hospital cardiac arrest between elderly and younger patients, 381 consecutive patients who experienced out-of-hospital cardiac arrest, and whose arrest was witnessed by paramedics, were studied. In 91% of cases the arrest occurred at the time the patient's cardiac rhythm was monitored. Patients were divided into 2 age groups: elderly patients were >70 years (187) and younger patients were <70 years (194). Elderly patients more commonly had a past history of heart failure (25 vs 10%, p < 0.003) and were more commonly taking digoxin (40 vs 20%, p < 0.005) and diuretics (35 vs 25%, p < 0.0004). Before the cardiac arrest, elderly patients were more likely to be complaining of dyspnea (53 vs 40%, p < 0.009), whereas younger patients were more likely to complain of chest pain (27 vs 13%, p < 0.001). Forty-two percent of younger patients demonstrated ventricular fibrillation as the initial out-of-hospital rhythm associated with the arrest, compared to only 22% of elderly patients (p < 0.001). Besides patient age, initial cardiac rhythm varied according to the patient's complaint preceding the arrest. Sixty-eight percent of patients with chest pain demonstrated ventricular fibrillation, whereas only 21% of patients with dyspnea demonstrated ventricular fibrillation. Elderly patients could be as successfully resuscitated as younger patients; however, 24% of younger patients survived, compared to only 10% of elderly patients (p < 0.001). Survival was not only dependent on the patient's age, but was dependent on the patient's complaint preceding arrest and the initial cardiac rhythm associated with the arrest. Sixty-five percent of younger patients complaining of chest pain and demonstrating ventricular fibrillation survived. Even in the elderly patients, 58% survived if their complaint was chest pain and if ventricular fibrillation was their initial out-of-hospital rhythm associated with the cardiac arrest.