Effectiveness of a prehospital medical control system: an analysis of the interaction between emergency room physician and paramedic.

Medical control for paramedics by means of radio and ECG telemetry is costly, time consuming, and of unproved value. We assessed the interaction between emergency room physicians and paramedics during ambulance transport of "seriously ill" cardiac patients (cardiac arrest, acute myocardial infarction, or new onset of crescendo angina pectoris) with paramedics in service. Thirty-five percent of all arrhythmias and 35% of potentially life-threatening arrhythmias were misclassified. Correct treatment was rendered in 74% of the cases, although only 65% were correctly diagnosed (p < 0.01). The principal predictive variable for misdiagnosing or incorrectly treating a patient was the presence of a potentially life-threatening arrhythmia, precisely the condition for which medical control and the paramedic system has the most to offer. Only 39% of patients with life-threatening arrhythmias were correctly diagnosed and correctly treated, whereas 64% of patients without life-threatening arrhythmias were correctly diagnosed and correctly treated (p < 0.001). Mortality reflected correct diagnosis and treatment. In-hospital and overall mortalities were 12% and 33%, respectively, for patients who were correctly diagnosed and treated (p < 0.06), compared with 20% and 43%, respectively, for patients who were incorrectly diagnosed or incorrectly treated (p < 0.04). More rigorous medical control is needed to improve the quality of patient care and outcome and to further integrate the advanced life support program into the health care system.