Effects of Prehospital Care on Outcome in Patients With Cardiac Illness,☆☆,,★★

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Abstract

See related editorial, "What Is a Paramedic Worth?"

Study objective: To compare outcomes of patients with acute cardiac illness transported by ambulance for whom prehospital care was provided by emergency medical 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 covers 1,136 km2 and includes five receiving hospitals. Participants: We prospectively identified 8,720 potentially eligible patients from approximately 30,000 who presented to the ambulance service. We reviewed hospital charts to confirm eligibility. The group of 8,720 patients yielded 3,066 patients with acute cardiac illness who met all other eligibility requirements. We excluded patients in cardiac arrest. Results: Incidence of myocardial infarction (MI), length of hospital stay, and mortality were evaluated. Analysis was performed with χ2 tests for association, linear regression, and logistic regression. Of the eligible patients who received prehospital EMS care, 783 sustained MIs. The proportions of people discharged alive with the diagnosis of MI did not differ between crew types (P =.16). Average hospital stay was 13 days in both groups for patients with the discharge diagnosis of MI; hospital stay ranged from 9 (EMT-D) to 11 days (EMT-P) for any patient with a discharge diagnosis other than MI. These values were statistically similar. The odds ratio of having had an MI after treatment by an EMT-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 availability of prehospital paramedic care does not affect occurrence of MI, length of hospital stay, or mortality of patients presenting to the EMS system with cardiac illness. [Shuster M, Keller J, Shannon H: Effects of prehospital care on outcome in patients with cardiac illness. Ann Emerg Med August 1995;26:138-145.]

Section snippets

INTRODUCTION

Prehospital advanced life support (ALS) care is available in some Canadian communities but is not yet generally available across the country. Prehospital ALS care is assumed to provide a greater benefit than basic care, but little evidence supports this assumption.1, 2 The expansion of prehospital ALS services in North America has slowed, partly because proof of benefit is lacking.3

Early defibrillation is one ALS intervention that has been proved effective.4, 5, 6, 7, 8 The development of

MATERIALS AND METHODS

The H-W region covers 1,136 km2 (438 square miles) and has approximately 445,000 inhabitants. The H-W EMS system is activated by dialing 911. A 911 call requesting medical assistance is received by the H-W police operator and forwarded to the Central Ambulance Communication Centre (CACC). CACC handles 45,000 calls per year, of which 13,000 are dispatched as code 4, the highest emergency priority. More than 25,000 of the 45,000 calls are scheduled calls and routine transfers. All scheduled calls

RESULTS

We screened 8,720 patients and found 3,083 patients (35%) who were eligible for our study. Seventeen patients were then excluded because of incomplete data. In analyzing results, we separated eligible patients into two groups according to the skills of the ambulance crews that treated and transported them. Patients were treated and transported by (1) two EMT-Ps or by one EMT-P and one EMT-D; or (2) by two EMT-Ds. Patients in the first group received ALS care, whereas patients in the second

DISCUSSION

Paramedics have been introduced to more and more communities in Canada and the United States over the last two decades. In many parts of North America, prehospital ALS is considered the standard of care.30, 31 Communities that do not have ALS-trained prehospital care providers often consider themselves underserved. However, little scientific evidence exists to show that prehospital ALS care affects patient outcome.1, 2, 3

If ALS care provides a significant benefit to the prehospital patient, we

CONCLUSION

The results of our study suggest that prehospital ALS care does not affect the occurrence of MI, LOS, or mortality in patients who present to the EMS system with cardiac illness in a community where transport times average less than 10 minutes. In communities where prehospital ALS care is available, delay at scene to treat possible symptoms of acute MI should be minimized.

Acknowledgements

The authors thank all the EMTs in the H-W area for their efforts in recording data during this study; John Lane for his contributions to the preparation of the grant proposal; Brent Browett, clinical coordinator, for his support and assistance throughout the study; Wendy Fisher and David Tysdale for their commitment to quality data collection and data entry; and Kang-In (David) Lee for his assistance with the data analysis. They also acknowledge the help they received from the medical records

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    From the Chedoke-McMaster Hospitals, Hamilton Paramedic Base Hospital Program*; Division of Emergency Medicine, and Department of Clinical Epidemiology and Biostatistics§, McMaster University, Hamilton, Ontario; and Institute for Work and Health, Toronto, Ontario, Canada.

    ☆☆

    Funded by the Ontario Ministry of Health, Emergency Health Services Research Initiatives Fund Grant 01788N

    Reprint no. 47/1/66179

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    Reprints not available from the authors.

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