Pulseless electrical activity with witnessed arrest as a predictor of sudden death from massive pulmonary embolism in outpatients

Background: the objective was to determine clinical characteristics that ca n quickly distinguish sudden death from massive pulmonary embolism (MPE) fr om other causes of sudden death. Methods and results: all medical examiner reports from Charlotte, NC from 1992 to 1999 (n = 4926) were hand-searched for cases of sudden death which met the inclusion criteria: non-traumatic d eath, age 18-65 years, transported to an emergency department (ED), and aut opsy performed. Supplemental data from ED and prehospital records were retr ieved to complete documentation. Data were analyzed by univariate odds rati os (OR) followed by chi-square (chi (2)) recursive partitioning for decisio n tree construction. Three hundred eighty four cases met inclusion criteria ; MPE was the second most frequent cause of cardiac arrest in this cohort ( 37/384, 9.6%). The mean age of subjects with MPE (40.2 +/- 11.1 years) was significantly lower compared with non-PE subjects (46.5 +/- 9.9 years). Pul seless electrical activity was observed as the initial arrest rhythm (prima ry PEA) in 52/384 (13.5%) subjects. Out of 52 subjects with primary PEA, 28 (53%) died from MPE. Odds ratio data indicated significant association of MPE with female gender, arrest witnessed by medical providers, presence of primary PEA, and return of spontaneous circulation. The most accurate decis ion rule to recognize MPE consisted of witnessed arrest + primary PEA. This rule generated sensitivity = 67.6% and specificity = 94.5% and yielded a p osttest probability of MPE of 57%. Conclusions: outpatients with witnessed cardiac arrest and primary PEA carry a high probability of MPE. (C) 2001 El sevier Science Ireland Ltd. All rights reserved.