Seven years' experience with early defibrillation by police and paramedics in an emergency medical services system.

PRIMARY OBJECTIVE: To assess the outcome of patients with out-of-hospital cardiac arrest with ventricular fibrillation as the presenting rhythm in an emergency medical services system utilizing a combined police/paramedic response to provide early defibrillation. MATERIALS AND METHODS: Police and paramedics were dispatched from law enforcement and ambulance communications centers, respectively. First-arriving personnel delivered initial shocks, all using automated external defibrillators. Patients were classified according to response to initial shocks: restoration of pulses with shocks only or in need of advanced life support, including epinephrine. Discharge survival was defined as return to home without disabling neurologic injury. RESULTS: Over the 7-year period of study 131 patients presented with ventricular fibrillation: 58 were first treated by police and 73 by paramedics. Restoration of pulses with shocks only and discharge survival were not different in police and paramedic groups, with overall survival of 40% (53 of 131 patients). Among the survivors, 19% (18/95 patients) obtained a spontaneous circulation only after administration of epinephrine and other ALS interventions. CONCLUSION: Both restoration of a functional circulation, without need for advanced life support interventions, and discharge survival without neurologic disability are very dependent upon the rapidity with which defibrillation is accomplished, regardless of who delivers the shocks. In addition, a smaller but significant number of patients who require ALS interventions, including epinephrine, for restoration of a spontaneous circulation survive to discharge. Short time differences, on the order of 1 min, are significant determinants of both immediate response to shocks and discharge survival.

High discharge survival rate after out-of-hospital ventricular fibrillation with rapid defibrillation by police and paramedics.

STUDY OBJECTIVE: To assess outcome in patients with ventricular fibrillation (VF) treated by defibrillator-equipped police and emergency medical technician-paramedics in an advanced life support (ALS) emergency medical services (EMS) system. METHODS: We carried out a retrospective observational outcome study of all consecutive adult patients with atraumatic cardiac arrest treated from November 1990 through July 1995. The study was carried out in a city with a population of 76,865 in an area of 32.6 square miles. Central 911 dispatched police and an ALS ambulance simultaneously. Accurate intervals were obtained with the synchronization of all defibrillator clocks with the 911 dispatch clock. The personnel who arrived first delivered the initial shock. After shocks delivered by police, paramedics provided additional treatment if needed. Main outcome measures were time elapsed before delivery of the first shock, restoration of spontaneous circulation (ROSC), and survival to discharge home. RESULTS: Of 84 patients, 31 (37%) were first shocked by police. Thirteen of the 31 demonstrated ROSC, without need for ALS treatment. All 13 survived to discharge. The other 18 patients required ALS; 5 (27.7%) survived. Among the 53 patients first shocked by paramedics, 15 had ROSC after shocks only, and 14 survived. The other 38 needed ALS treatment; 9 survived. Call-to-shock time for all patients was less in the police group than in the paramedic group (5.6 versus 6.3 minutes, P = .038). For all patients, call-to-shock time was less in those with ROSC after shocks only than in those who needed ALS (5.4 versus 6.3 minutes, P = .011). Survival to discharge was 49% (41 of 84), with 18 of 31 (58%) in the police group and 23 of 53 (43%) in the paramedic group. Call-to-shock time for survivors was 5.8 minutes; it was 6.4 minutes for the nonsurvivors (P = .020). Neither ROSC nor discharge survival was significantly different between police and paramedic-shocked patients. ROSC after initial shock and call-to-shock time were major determinants of survival, whether the first shocks were administered by police or by paramedics. With ROSC after shocks only, 27 of 28 (96%) survived, whereas 14 of 56 (25%) needing ALS survived (P < .001). CONCLUSION: A high discharge-to-home survival rate was obtained with early defibrillation by both police and paramedics. When shocks resulted in ROSC, the overwhelming majority of patients survived (96%). Even brief time decreases (eg. 1 minute) in call-to-shock time increase the likelihood of ROSC from shocks only, with a consequent decrease in the need for ALS intervention. Short call-to-shock time and ROSC response to shocks only are major determinants of a high rate of survival after VF.

Early defibrillation by police: initial experience with measurement of critical time intervals and patient outcome.

STUDY OBJECTIVE: To assess the feasibility of consistent acquisition of precise and clinically important time intervals in a city police department defibrillation study. DESIGN: On a daily basis, clocks at 911 dispatch were synchronized with those at ambulance dispatch, and all clocks on all defibrillators were synchronized to this time. Times were obtained from recordings at dispatch centers and from defibrillator memory modules. SETTING: City with a population of 70,745 and an area of 30 square miles. PARTICIPANTS: All patients in ventricular fibrillation (VF) treated by police officers using semiautomated defibrillators. INTERVENTIONS: On receipt of a call at 911 dispatch, the nearest squad car was dispatched. If police arrived before the ambulance and a cardiac arrest was confirmed, the closest squad car with a defibrillator was dispatched. Police delivered up to three shocks before ambulance arrival. RESULTS: Of 44 patients in VF, 14 were initially treated by police. Seven of 14 regained a spontaneous circulation with police shocks and seven required additional advanced life support care for restoration of pulses. Ten of the 14 were discharged home. The 911 call-to-shock time interval was 4.9 +/- 1.3 minutes for the seven who regained a spontaneous circulation with police shocks and 6.1 +/- 0.7 minutes for the seven without restoration of pulses by police (P = .035, one-sided, two-sample t-test). CONCLUSION: Acquisition of precise times for determination of time intervals is feasible with a concerted effort to synchronize all clocks from which times are derived. Even small differences in call-to-shock time intervals appear to be critical determinants of restoration of a spontaneous circulation.

Acute abdominal pain in the elderly.

STUDY OBJECTIVES: To determine the incidences of both specific diagnosis and surgical diseases in patients more than 65 years old who present to the emergency department with nontraumatic abdominal pain of less than one week's duration, and to determine the ED staff's ability to diagnose and triage elderly patients with acute abdominal pain. DESIGN: A 12-month retrospective review of all elderly patients who presented to the ED with acute, nontraumatic abdominal pain. SETTING: A regional trauma center serving a predominately rural population in the Midwest. The ED has 55,000 patient visits yearly. MEASUREMENTS AND MAIN RESULTS: Of the 127 patients enrolled, 30 (24%) had no specific diagnosis made in the ED. Biliary tract disease (12%) and small bowel obstruction (12%) were the two most common specific diagnoses. Overall, 53 patients (42%) required surgery, usually during the initial hospitalization. In four cases, the postoperative diagnosis differed significantly from the ED diagnosis. Of the 74 patients (58%) who did not undergo surgery, 51 had follow-up information available. In 14 patients, the follow-up diagnosis differed from the original diagnosis, but most of these changes did not appreciably alter the treatment and outcome. CONCLUSIONS: The incidence of surgical disease is high in elderly patients with acute abdominal pain, and ED staff are able to diagnose and triage these patients accurately.

Cholelitholysis using methyl tertiary butyl ether.

We tested methyl tertiary butyl ether both in vitro and in vivo to evaluate its efficacy as a potential cholesterol gallstone solvent for direct instillation into the human gallbladder or bile duct. Like diethyl ether, methyl tertiary butyl ether is an aliphatic ether with an excellent cholesterol-solubilizing capacity. However, unlike diethyl ether which vaporizes at body temperature, methyl tertiary butyl ether remains a liquid having a boiling point of 55.2 degrees C. In vitro, methyl tertiary butyl ether dissolved human gallstones (40%-94% cholesterol) within 60-100 min. In contrast, monooctanoin, an established gallstone solvent, required greater than 50 h to dissolve similar stones. By direct catheter instillation in 6 dogs, methyl tertiary butyl ether required only 4-16 h to dissolve gallstones surgically implanted in the gallbladder. The dogs tolerated methyl tertiary butyl ether with only minor clinical, biochemical, or histologic effects. We conclude that further evaluation of methyl tertiary butyl ether for dissolution of human gallbladder and biliary duct cholesterol stones is warranted.