EFFECTS OF PREHOSPITAL CARE ON OUTCOME IN PATIENTS WITH CARDIAC ILLNESS

To compare outcomes of patients with acute cardiac illness transported by ambulance for whom prehospital care was provided by emergency medi cal technician-paramedics (EMT-Ps) or EMTs trained in defibrillation ( EMT-Ds). Design: A prospective chart review carried out over 3.5 years . Setting: The Hamilton-Wentworth region of Ontario, Canada, which cov ers 1,136 km(2) and includes five receiving hospitals. Participants: W e prospectively identified 8,720 potentially eligible patients from ap proximately 30,000 who presented to the ambulance service. We reviewed hospital charts to confirm eligibility. The group of 8,720 patients y ielded 3,066 patients with acute cardiac illness who met all other eli gibility requirements. We excluded patients in cardiac arrest. Results : Incidence of myocardial infarction (MI), length of hospital stay, an d mortality were evaluated. Analysis was performed with chi(2) tests f or association, linear regression, and logistic regression. Of the eli gible patients who received prehospital EMS care, 783 sustained MIs. T he proportions of people discharged alive with the diagnosis of MI did not differ between crew types (P=.16). Average hospital slay was 13 d ays in both groups for patients with the discharge diagnosis of MI; ho spital stay ranged from 9 (EMT-D) to 11 days (EMT-P) for any patient w ith a discharge diagnosis other than MI. These values were statistical ly similar. The odds ratio of having had an MI after treatment by an E MT-D crew was 1.02 (95% confidence interval,.86 to 1.21) compared with that for treatment by an EMT-P crew. Conclusion: In an urban setting with short (less than 10 minutes) average transport times, the availab ility of prehospital paramedic care does not affect occurrence of MI, length of hospital stay, or mortality of patients presenting to the EM S system with cardiac illness.