Defining the outcome measures for out-of-hospital trials in acute pulmonary edema.

Abstract

Comparing studies of the effectiveness of out-of-hospital interventions in acute pulmonary edema (APE) is difficult due to the diversity of outcome measures used in the literature. The objective of this study was to define a set of clinically relevant outcome measures for future out-of-hospital trials in APE. A Medline search and hand-search of bibliographies was undertaken to develop a list of APE outcome measures. A survey was mailed to a sample of 227 Canadian emergency physicians using the Dillman methodology, requesting that respondents select clinically relevant outcome measures from this list and rank them by importance. A selection frequency of >or=70% and a median ranking score were used to determine relevant outcome measures. The Medline and bibliography search identified 21 APE outcome measures. The survey response rate was 71%. Outcome measures selected most frequently were heart rate, respiratory rate, respiratory distress scale, subjective dyspnea scale, out-of-hospital intubation, emergency department (ED) intubation, survival to discharge, and out-of-hospital mortality. The median ranking score identified a similar set of measures: heart rate, respiratory rate, respiratory distress scale, subjective dyspnea scale, out-of-hospital intubation rate, and ED intubation rate. There was no significant difference in outcome selection between physicians who worked in communities with and without advanced out-of-hospital care. Clinically relevant out-of-hospital APE outcome measures were identified and endorsed by a representative survey of Canadian emergency physicians. Clinicians appear to favor short-term and non-mortality outcomes for out-of-hospital interventions. The use of this set of APE outcome measures may improve the design and comparability of future out-of-hospital trials.