EVALUATION OF A PREHOSPITAL CHEST PAIN PROTOCOL

Study objectives: To evaluate the diagnostic accuracy and outcomes for patients treated by use of a prehospital chest pain protocol (CPP). Design: Consecutive case series for 1 year (1993) of prehospital nontrauma advanced life support (ALS) cases including hospital outcomes. Setting: Nonurban two-tiered emergency medical services system. Participants: Patients treated under the prehospital CPP or with hospital diagnoses of ischemic heart disease (IHD; ICD-9 between 410 and 414). Patients with cardiac arrest or dysrhythmias were excluded. Interventions: Patients were given, by standing orders, ECG monitoring, IV access, and sublingual nitroglycerin. Further therapy was guided by on-line medical direction. Results: Of 3,122 ALS nontrauma patients, 620 (20%) were treated with the CPP. All patients underwent ECG monitoring, IV access was started in 83%, and 62% received nitroglycerin. Only 55% of patients completed the entire CPP; patients who failed to complete the CPP had the same prevalence of IHD as those who completed it. When compared with hospital diagnosis of IHD, the CPP had a sensitivity of 69% (95% confidence interval [CI], 64% to 74%), a specificity of 87% (95% CI, 86% to 88%), and a positive predictive value of 42%. The positive likelihood ratio of CPP for IHD was 5.31, and the negative likelihood ratio was .36. The hospital mortality rate for all patients was 2.2%; for those with IHD, it was 1.6%. Conclusion: This prehospital ALS CPP had good diagnostic accuracy, but only half of patients completed it, and the hospital mortality rate was low. These data challenge the efficacy of the CPP.