The health benefit of thrombolysis in acute myocardial infarction is greatest when patients are treated soon after onset of symptoms. One approach to reducing treatment delay is to give thrombolysis before the patient reaches hospital. When an ambulance trust proposed a prehospital thrombolysis service, local commissioners requested an estimate of its possible health impact. Clinical audit and ambulance trust data were obtained for 165 patients who received thrombolysis for acute myocardial infarction in the coronary care unit of a local hospital in one year. This information was then used to estimate the health impact of prehospital thrombolysis in the local population in a mathematical model derived from the results of trials comparing prehospital and hospital thrombolysis.
The best predicted local health benefit from the proposed prehospital thrombolysis service is that, if 45 minutes can be cut off the call-to-needle time, 61 cases of acute myocardial infarction need to be treated to save one additional life at 35 days.
By use of published research data, the health benefits of prehospital thrombolysis can be estimated for a local population. Variables in the treatment population and ambulance service will influence the size of the health benefit that can be achieved.
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