ONLINE TELEMETRY - PROSPECTIVE ASSESSMENT OF ACCURACY IN AN ALL-VOLUNTEER EMERGENCY MEDICAL-SERVICE SYSTEM

Objective: To evaluate the need for on-line telemetry control in an al l-volunteer, predominantly advanced emergency medical technician (A-EM T) ambulance system. Methods: Emergency medical service (EMS) advanced life support (ALS) providers were asked to transmit the ECG rhythms o f monitored patients over a six-month period in 1993. The ECG rhythm i nterpretations of volunteer EMS personnel were compared with those of the on-line medical control physician. All discordant readings were re viewed by a panel of physicians to decide whether the misdiagnosis wou ld have resulted in treatment aberrations had transmission been unavai lable. Results: Patients were monitored and rhythms were transmitted i n 1,825 cases. 1,642 of 1,825 rhythms were correctly interpreted by th e EMS providers (90%; 95% CI 89-91%). The accuracy of the EMS provider s was dependent on the patient's rhythm (chi-square, p < 0.00001), the chief complaint (chi-square, p = 0.0001), and the provider's level of training (chi-square, p = 0.02). Correct ECG rhythm interpretations w ere more common when the out-of-hospital interpretation was sinus rhyt hm (95%), ventricular fibrillation (87%), paced rhythm (94%), or agona l rhythm (96%). The EMS providers were frequently incorrect when the o ut-of-hospital rhythm interpretation was atrial fibrillation/flutter ( 71%), supraventricular tachycardia (46%), ventricular tachycardia (59% ), or atrioventricular block (50%). Of the 183 discordant cases, 124 ( 68%) involved missing a diagnosis of, or incorrectly diagnosing, atria l fibrillation/flutter. Review of the discordant readings identified 1 1 cases that could have resulted in treatment errors had the rhythms n ot been transmitted, one of which might have resulted in an adverse ou tcome. Conclusions: In this all-volunteer, predominantly A-EMT ALS sys tem, patients with a field interpretation of a sinus rhythm do not req uire ECG rhythm transmission. Field interpretations of atrial fibrilla tion/flutter, supraventricular tachycardia, ventricular tachycardia, a nd atrioventricular blocks are frequently incorrect and should continu e to be transmitted.