Analysis of multiple casualty incidents - a prospective cohort study.

BACKGROUND: Our aim was to report the rate and causes for multiple casualty incidents (MCI) to analyse the prehospital part of responding to MCIs, report mortality and find areas for improvement.
METHODS: A prospective cohort study conducted in an urban emergency medical service (EMS) between 1.3.1998 and 28.2.2004.
RESULTS: Fifty-nine MCIs involving 263 patients (167 walking, 96 non-walking) occurred. The incidence of MCIs was 1.8/100,000 inhabitants year(-1). Traffic accidents were the most common cause followed by residential fires, intoxications and stabbings or shootings. Early MCI alarm by the dispatching centre was performed in 18 MCIs. Deviations from standard emergency medical care occurred in 12% of patients. Lack of immobilization of the neck or back in trauma patients and lack of administration of 100% oxygen in suspected carbon monoxide intoxication were the most common deviations. Deviations were related to the lack of presence of on-scene medical command (P = 0.0013) and inadequate resources (P = 0.0342). One hundred and ninety-two patients were transported to emergency departments. Mortality during the prehospital phase was 4.9% (13/263) and during the next 28 days 2.3% (6/263). Adequate resources for safe and effective management of a MCI were related to an early MCI alarm by the dispatching centre (P = 0,022) and to the presence of on-scene medical command (P < 0,001).
CONCLUSIONS: Traffic accidents, residential fires and intoxications were the leading causes for MCIs. Emergency medical service could respond to most MCIs efficiently and safely. Majority of deviations from standard medical care seemed potentially preventable. Several areas for improvement were identified. From prehospital links, the dispatching centre and on-scene medical command had a vital role in the successful management of MCIs.