Ventricular tachyarrhythmias after cardiac arrest in public versus at home.

BACKGROUND: The incidence of ventricular fibrillation or pulseless ventricular tachycardia as the first recorded rhythm after out-of-hospital cardiac arrest has unexpectedly declined. The success of bystander-deployed automated external defibrillators (AEDs) in public settings suggests that this may be the more common initial rhythm when out-of-hospital cardiac arrest occurs in public. We conducted a study to determine whether the location of the arrest, the type of arrhythmia, and the probability of survival are associated. METHODS: Between 2005 and 2007, we conducted a prospective cohort study of out-of-hospital cardiac arrest in adults in 10 North American communities. We assessed the frequencies of ventricular fibrillation or pulseless ventricular tachycardia and of survival to hospital discharge for arrests at home as compared with arrests in public. RESULTS: Of 12,930 evaluated out-of-hospital cardiac arrests, 2042 occurred in public and 9564 at home. For cardiac arrests at home, the incidence of ventricular fibrillation or pulseless ventricular tachycardia was 25% when the arrest was witnessed by emergency-medical-services (EMS) personnel, 35% when it was witnessed by a bystander, and 36% when a bystander applied an AED. For cardiac arrests in public, the corresponding rates were 38%, 60%, and 79%. The adjusted odds ratio for initial ventricular fibrillation or pulseless ventricular tachycardia in public versus at home was 2.28 (95% confidence interval [CI], 1.96 to 2.66; P < 0.001) for bystander-witnessed arrests and 4.48 (95% CI, 2.23 to 8.97; P<0.001) for arrests in which bystanders applied AEDs. The rate of survival to hospital discharge was 34% for arrests in public settings with AEDs applied by bystanders versus 12% for arrests at home (adjusted odds ratio, 2.49; 95% CI, 1.03 to 5.99; P = 0.04). CONCLUSIONS: Regardless of whether out-of-hospital cardiac arrests are witnessed by EMS personnel or bystanders and whether AEDs are applied by bystanders, the proportion of arrests with initial ventricular fibrillation or pulseless ventricular tachycardia is much greater in public settings than at home. The incremental value of resuscitation strategies, such as the ready availability of an AED, may be related to the place where the arrest occurs.

Amiodarone for sustained stable ventricular tachycardia in the prehospital setting.

OBJECTIVE: Amiodarone is commonly used in the treatment of stable ventricular tachycardia (VT), but its efficacy has not been empirically examined in the prehospital setting. The objective of this study was to examine the safety and efficacy of amiodarone administered by paramedics to patients with stable VT. METHODS: Patient records from Victoria, Australia between 1 May 2007 and 30 June 2017 were examined retrospectively. Patients attended by Ambulance Victoria with stable sustained VT who were administered amiodarone by paramedics as the initial treatment were included. Data were used to determine the prevalence of treatment with amiodarone, the incidence of VT termination prior to transfer of care, and the incidence of progression to electrical cardioversion. RESULTS: Sixty-one patients were identified who met the inclusion criteria. The mean age was 72 years (standard deviation = 14) with 77% (n = 47) being male. Of the patients treated with amiodarone, 52% (n = 32) reverted successfully during paramedic care while 48% (n = 29) did not. Two patients required cardioversion for haemodynamic instability after amiodarone administration. One patient experienced cardiac arrest after receiving amiodarone and was successfully resuscitated by paramedics. CONCLUSIONS: Approximately half of the patients treated with amiodarone reverted from VT while under paramedic care. Patient deterioration was rare, with cardiac arrest or requirement for cardioversion occurring very infrequently. Amiodarone was relatively safe and moderately effective for the treatment of sustained stable VT. However, given recent evidence of increased efficacy of procainamide for stable VT, further studies are required in the prehospital setting to compare these two drugs.

A survey of front-line paramedics examining the professional relationship between paramedics and physician medical oversight.

OBJECTIVE: Paramedicine is often dependent on physician medical directors and their associated programs for direction and oversight. A positive relationship between paramedics and their oversight physicians promotes safety and quality care while a strained or ineffective one may threaten these goals. The objective of this study was to explore and understand the professional relationship between paramedics and physician medical oversight as viewed by front-line paramedics. METHODS: All active front-line paramedics from four municipal paramedic services involving three medical oversight groups in Ontario were invited to complete an online survey. RESULTS: Five hundred and four paramedics were invited to participate in the study, with 242 completing the survey (48% response rate); 66% male, 76% primary care paramedics with an average of 13 (SD=9) years of experience. Paramedics had neutral or positive perceptions regarding their autonomy, opportunities to interact with their medical director, and medical director understanding of the prehospital setting. Paramedics perceived medical directives as rigid and ambiguous. A significant amount of respondents reported a perception of having provided suboptimal patient care due to fear of legal or disciplinary consequences. Issues of a lack of support for critical thinking and a lack of trust between paramedics and medical oversight groups were often raised. CONCLUSIONS: Paramedic perceptions of physician medical oversight were mixed. Concerning areas identified were perceptions of ambiguous written directives and concerns related to the level of trust and support for critical thinking. These perceptions may have implications for the system of care and should be explored further.