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Paramedic Interpretation of Prehospital Lead-II ST-Segments

Published online by Cambridge University Press:  28 June 2012

Robert Hill
Affiliation:
St. Luke's Hospital, Bethlehem, Pennsylvania, USA
Michael Heller*
Affiliation:
Emergency Medicine Residency of the Lehigh Valley, Department of Emergency Medicine, St. Luke's Hospital, Bethlehem, Pennsylvania, USA
Alexander Rosenau
Affiliation:
Lehigh Valley Hospital, Allentown, Pennsylvania, USA
Scott Melanson
Affiliation:
St. Luke's Hospital, Bethlehem, Pennsylvania, USA
David Pronchik
Affiliation:
St. Luke's Hospital, Bethlehem, Pennsylvania, USA
John Patterson
Affiliation:
St. Luke's Hospital, Bethlehem, Pennsylvania, USA
H. Gulick
Affiliation:
Allentown EMS, Allentown, Pennsylvania, USA
*
Emergency Medicine Residency, 801 Ostrum Street, Bethlehem, PA 18015USA

Abstract

Objective:

To determine the reliability of ST-segment interpretation by paramedics from lead-II rhythm strips obtained in the prehospital setting.

Design:

Prospective, blinded study of 127 patients transported by an urban/rural emergency medical services system with complaints consistent with ischemic heart disease.

Methods:

Emergency department physicians asked emergency medical technician-paramedics (EMT-P) via radio to evaluate ST-segments for elevation or depression and grade it as “mild,” “moderate,” or “severe.” Then, this rhythm strip was interpreted blindly by emergency physicians who also interpreted the lead-II obtained from a 12-lead electrocardiogram (ECG) obtained in the emergency department (ED). The field interpretation was compared with the subsequent readings and the final in-patient diagnosis using positive predictive value (PPV), negative predictive value (NPV), and the Kappa statistic. Markedly discrepant interpretations were analyzed separately.

Results:

Using physician interpretation as the reference standard, paramedic interpretation of the lead-II ST-segments obtained in the prehospital setting was correct (within ±1 gradation) in 113 out of 127 total cases (89%). Of 105 patients for whom final hospital diagnosis was available, the ST-segment on the rhythm strip obtained in the prehospital setting, had a positive predictive value of 74% and a negative predictive value of 85% for myocardial ischemia or myocardial infarction (MI) (p <0.001, Kappa = 0.59). Discordant interpretations between the paramedics and emergency physicians often were related to a basic misunderstanding of rhythm strip morphology.

Conclusion:

Field interpretation of ST-segments by paramedics is fairly accurate as judged both by emergency physicians and correlation with final patient outcome, but its clinical utility is unproved. A small but clinically significant number of outliers, consisting of markedly discrepant false positives, reflects paramedic uncertainty in identifying the deviations of the ST-segment.

Type
Original Research
Copyright
Copyright © World Association for Disaster and Emergency Medicine 1997

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References

1. Gibler, WB, Aufderheide, T: Emergency Cardiac Care; Mosby-Yearbook Inc.; 1994: p 147.Google Scholar
2. Hargarten, KM, Aprahamian, C, Stueven, H et al. : Limitations of acute myocardial infarction and unstable angina. Ann Emerg Med 1987;16:13251329.CrossRefGoogle ScholarPubMed
3. Scarlovsky, S, Davidson, E, Lewin, R et al. : Acute myocardial infarction: Significance of ECG changes during chest pain. Amer Heart J 1986;112:459462.CrossRefGoogle Scholar
4. Pozen, MV, Fried, DD, Vbignt, G et al. : Studies of ambulance patients with ischemic heart disease. Amer J Public Health 1977;67:532535.CrossRefGoogle ScholarPubMed
5. McGuiness, JB, Begg, TB, Semple, T: First electrocardiogram in recent myocardiac infarction. BMJ 1976;2(6033):449451.CrossRefGoogle Scholar
6. Karagounis, L, Ipsen, SK, Jessop, MR: Impact of field-transmitted electrocardiograph on time to in-hospital thrombolytic therapy in acute myocardial infarction. Am Emergh Med 1990;60:786791.Google Scholar
7. Jacobs, , Luise, JA, Eisenscher, J: Congruency in physician-EMT assessment. Ann Emerg Med 1981;10:201208.CrossRefGoogle ScholarPubMed
8. Krucoff, M, Green, C, Satler, L et al. : Noninvasive detection of coronary, artery patency using continuous ST-segment monitoring. Am J Cardiol 1986;57:910922.CrossRefGoogle ScholarPubMed
9. Hog, K, Hornung, R, Howie, C et al. : Electrocardiographic prediction of coronary artery patency after thrombolytic treatment in acute myocardial infarction: Use of the ST-segment as a non-invasive marker. BMJ 1988;60:275280.Google Scholar
10. Gibler, W, Runyon, J, Levy, R et al. : A rapid diagnostic and treatment center for patients with chest pain in the emergency department. Ann Emerg Med 1995;25:18.CrossRefGoogle ScholarPubMed
11. Fasmire, F, Smith, E: Continuous 12-lead electrocardiograph monitoring in the emergency department. Am J Emerg Med 1993;11:5460.CrossRefGoogle Scholar
12. Jakobsson, J, Nyquist, O, Rehnquist, N et al. : Concise education of ambulance personnel in ECG interpretation and out of hospital defibrillation. Eur Heart J 1987;8:229333.CrossRefGoogle ScholarPubMed
13. Aufderheide, T, Herdley, G, Woo, J et al. : A prospective evaluation of prehospital 12-lead ECG application in chest patient patients. J Electrocardiol 1991;24:813.CrossRefGoogle Scholar