Defibrillation Strategies for Refractory Ventricular Fibrillation.

BACKGROUND: Despite advances in defibrillation technology, shock-refractory ventricular fibrillation remains common during out-of-hospital cardiac arrest. Double sequential external defibrillation (DSED; rapid sequential shocks from two defibrillators) and vector-change (VC) defibrillation (switching defibrillation pads to an anterior-posterior position) have been proposed as defibrillation strategies to improve outcomes in patients with refractory ventricular fibrillation. METHODS: We conducted a cluster-randomized trial with crossover among six Canadian paramedic services to evaluate DSED and VC defibrillation as compared with standard defibrillation in adult patients with refractory ventricular fibrillation during out-of-hospital cardiac arrest. Patients were treated with one of these three techniques according to the strategy that was randomly assigned to the paramedic service. The primary outcome was survival to hospital discharge. Secondary outcomes included termination of ventricular fibrillation, return of spontaneous circulation, and a good neurologic outcome, defined as a modified Rankin scale score of 2 or lower (indicating no symptoms to slight disability) at hospital discharge. RESULTS: A total of 405 patients were enrolled before the data and safety monitoring board stopped the trial because of the coronavirus disease 2019 pandemic. A total of 136 patients (33.6%) were assigned to receive standard defibrillation, 144 (35.6%) to receive VC defibrillation, and 125 (30.9%) to receive DSED. Survival to hospital discharge was more common in the DSED group than in the standard group (30.4% vs. 13.3%; relative risk, 2.21; 95% confidence interval [CI], 1.33 to 3.67) and more common in the VC group than in the standard group (21.7% vs. 13.3%; relative risk, 1.71; 95% CI, 1.01 to 2.88). DSED but not VC defibrillation was associated with a higher percentage of patients having a good neurologic outcome than standard defibrillation (relative risk, 2.21 [95% CI, 1.26 to 3.88] and 1.48 [95% CI, 0.81 to 2.71], respectively). CONCLUSIONS: Among patients with refractory ventricular fibrillation, survival to hospital discharge occurred more frequently among those who received DSED or VC defibrillation than among those who received standard defibrillation. (Funded by the Heart and Stroke Foundation of Canada; DOSE VF ClinicalTrials.gov number, NCT04080986.).

Protected 911: Development, Implementation, and Evaluation of a Prehospital COVID-19 High-Risk Response Team.

Patients with COVID-19 who require aerosol-generating medical procedures (such as endotracheal intubation) are challenging for paramedic services. Although potentially lifesaving for patients, aerosolizing procedures carry an increased risk of infection for paramedics, owing to the resource limitations and complexities of the pre-hospital setting. In this paper, we describe the development, implementation, and evaluation of a novel pre-hospital COVID-19 High-Risk Response Team (HRRT) in Peel Region in Ontario, Canada. The mandate of the HRRT was to attend calls for patients likely to require aerosolizing procedures, with the twofold goal of mitigating against COVID-19 infections in the service while continuing to provide skilled resuscitative care to patients. Modelled after in-hospital 'protected code blue' teams, operationalizing the HRRT required several significant changes to standard paramedic practice, including the use of a three-person crew configuration, dedicated safety officer, call-response checklists, multiple redundant safety procedures, and enhanced personal protective equipment. Less than three weeks after the mandate was given, the HRRT was operational for a 12-week period during the first wave of COVID-19 in Ontario. HRRT members attended ~70% of calls requiring high risk procedures and were associated with improved quality of care indicators. No paramedics in the service contracted COVID-19 during the program.

A Higher Antibody Response Is Generated With a 6- to 7-Week (vs Standard) Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Vaccine Dosing Interval.

The optimal dosing interval for severe acute respiratory syndrome coronavirus 2 vaccines remains controversial. In this prospective study, we compared serology results of paramedics vaccinated with mRNA vaccines at the recommended short (17-28 days) vs long (42-49 days) interval. We found that a long dosing interval resulted in higher spike, receptor binding domain, and spike N terminal domain antibody concentrations.

Early Observations During the COVID-19 Pandemic in Cardiac Catheterization Procedures for ST-Elevation Myocardial Infarction Across Ontario.

BACKGROUND: In response to the COVID-19 pandemic, Ontario issued a declaration of emergency, implementing public health interventions on March 16, 2020. METHODS: We compared cardiac catheterization procedures for ST-elevation myocardial infarction (STEMI) between January 1 and May 10, 2020 to the same time frame in 2019. RESULTS: From March 16 to May 10, 2020, after implementation of provincial directives, STEMI cases significantly decreased by up to 25%. The proportion of patients who achieved guideline targets for first medical contact balloon for primary percutaneous coronary intervention (PCI) decreased substantially to 28% (median, 101 minutes) for patients who presented directly to a PCI site and to 37% (median, 149 minutes) for patients transferred from a non-PCI site, compared with 2019. CONCLUSIONS: STEMI cases across Ontario have been substantially affected during the COVID-19 pandemic.

INTRODUCTION: En réponse à la pandémie de COVID-19, l'Ontario a déclaré l'état d'urgence et mis en place des interventions de santé publique le 16 mars 2020. MÉTHODES: Nous avons comparé les procédures de cathétérisme cardiaque lors d'infarctus du myocarde avec sus-décalage du segment ST (STEMI) du 1er janvier au 10 mai 2020 à la même période en 2019. RÉSULTATS: Du 16 mars au 10 mai 2020, après la mise en place des directives provinciales, les cas de STEMI ont connu une diminution significative pouvant atteindre jusqu'à 25 %. La proportion de patients qui ont atteint les objectifs prévus aux lignes directrices entre le premier contact médical et le ballonnet de l'intervention coronarienne percutanée (IPC) a connu une diminution considérable de 28 % (médiane, 101 minutes) pour ceux qui se présentaient directement dans un site d'IPC et de 37 % (médiane, 149 minutes) pour ceux qui étaient dirigés vers un site non-ICP, et ce, en comparaison à 2019. CONCLUSIONS: La pandémie de COVID-19 a considérablement nui aux cas de STEMI de l'Ontario.

Clinical considerations for out-of-hospital cardiac arrest management during COVID-19.

Managing out-of-hospital cardiac arrest requires paramedics to perform multiple aerosol generating medical procedures in an uncontrolled setting. This increases the risk of cross infection during the COVID-19 pandemic. Modifications to conventional protocols are required to balance paramedic safety with optimal patient care and potential stresses on the capacity of critical care resources. Despite this, little specific advice has been published to guide paramedic practice. In this commentary, we highlight challenges and controversies regarding critical decision making around initiation of resuscitation, airway management, mechanical chest compression, and termination of resuscitation. We also discuss suggested triggers for implementation and revocation of recommended protocol changes and present an accompanying paramedic-specific algorithm.