BACKGROUND: In patients with out-of-hospital cardiac arrest who present with an initial shockable rhythm, a longer delay to the first shock decreases the probability of survival, often attributed to cerebral damage. The mechanisms of this decreased survival have not yet been elucidated. Estimating the probability of successful defibrillation and other factors in relation to the time to first shock may guide prehospital care systems to implement policies that improve patient survival by decreasing time to first shock. METHODS: Patients with a witnessed out-of-hospital cardiac arrest and ventricular fibrillation (VF) as an initial rhythm were included using the prospective ARREST registry (Amsterdam Resuscitation Studies). Patient and resuscitation data, including time-synchronized automated external defibrillator and manual defibrillator data, were analyzed to determine VF termination at 5 seconds after the first shock. Delay to first shock was defined as the time from initial emergency call until the first shock by any defibrillator. Outcomes were the proportion of VF termination, return of organized rhythm, and survival to discharge, all in relation to the delay to first shock. A Poisson regression model with robust standard errors was used to estimate the association between delay to first shock and outcomes. RESULTS: Among 3723 patients, the proportion of VF termination declined from 93% when the delay to first shock was 16 minutes ( P _trend <0.001). Every additional minute in VF from emergency call was associated with 6% higher probability of failure to terminate VF (adjusted relative risk, 1.06 [95% CI, 1.04–1.07]), 4% lower probability of return of organized rhythm (adjusted relative risk, 0.96 [95% CI, 0.95–0.98]), and 6% lower probability of surviving to discharge (adjusted relative risk, 0.94 [95% CI, 0.93–0.95]). CONCLUSIONS: Every minute of delay to first shock was associated with a significantly lower proportion of VF termination and return of organized rhythm. This may explain the worse outcomes in patients with a long delay to defibrillation. Reducing the time interval from emergency call to first shock to ≤6 minutes could be considered a key performance indicator of the chain of survival.

Ventilation during cardiopulmonary resuscitation is vital to achieve optimal oxygenation but continues to be a subject of ongoing debate. This narrative review aims to provide an overview of various components and challenges of ventilation during cardiopulmonary resuscitation, highlighting key areas of uncertainty in the current understanding of ventilation management. It addresses the pulmonary pathophysiology during cardiac arrest, the importance of adequate alveolar ventilation, recommendations concerning the maintenance of airway patency, tidal volumes and ventilation rates in both synchronous and asynchronous ventilation. Additionally, it discusses ventilation adjuncts such as the impedance threshold device, the role of positive end-expiratory pressure ventilation, and passive oxygenation. Finally, this review offers directions for future research.

Airway management and ventilation are essential components of cardiopulmonary resuscitation to achieve oxygen delivery in order to prevent hypoxic injury and increase the chance of survival. Weighing the relative benefits and downsides, the best approach is a staged strategy; start with a focus on high-quality chest compressions and defibrillation, then optimize mask ventilation while preparing for advanced airway management with a supraglottic airway device. Endotracheal intubation can still be indicated, but has the largest downsides of all advanced airway techniques. Whichever stage of airway management, ventilation and chest compression quality should be closely monitored. Capnography has many advantages and should be used routinely. Optimizing ventilation strategies, harmonizing ventilation with mechanical chest compression devices, and implementation in complex and stressful environments are challenges we need to face through collaborative innovation, research, and implementation.

In many European countries prehospital care by emergency medical services (EMS) is supplemented by physician-staffed services. There is ongoing controversy on the benefits of a prehospital physician. Possible advantages are additional competencies of the physician. Similarities and differences in competencies of EMS providers and physicians have however never been studied. This study aims to compare competencies of ambulance nurses and helicopter EMS physicians in the Netherlands to gain better insight into the controversy of the prehospital physician. In this descriptive study, a quantitative inventory was made of the diagnostic, therapeutic, and clinical judgment competencies of the ambulance nurse and physician, based on analysis of protocols, registration, equipment, and personal interviews. We identified 438 mutual competencies of the ambulance nurse and physician and 62 physician-specific competencies. The ambulance nurse masters 278 diagnostic, 131 therapeutic, and 29 clinical judgment competencies. The physician masters 285 diagnostic, 175 therapeutic, and 40 clinical judgment competencies. Seventy-one percent of the physician-specific competencies are therapeutic and related to advanced life support. The ambulance nurse and physician have various mutual competencies. In addition, the physician can provide specific competencies on the scene. Knowing the exact overlap and differences in competencies is the first step to understand the prehospital physician controversy. Our results can be used as a tool for the next step in research on prehospital care by EMS providers and physicians and to improve prehospital care.

Of patients with out-of-hospital cardiac arrest (OHCA) presenting in ventricular fibrillation (VF), the majority require multiple shocks.¹ Guidelines recommend chest compressions be resumed immediately after the shock without a rhythm check.² In current practice, when VF is present at consecutive rhythm checks, it is uncertain whether previous shocks repeatedly failed to terminate VF (refractory VF) or VF recurred after successful shocks. Alternative defibrillation strategies have been studied in patients found to be in VF at three consecutive rhythm checks.³ We studied the incidence of refractory and recurrent VF in patients receiving multiple consecutive standard shocks and the time to refibrillation in cases with recurrent VF.

Volunteer responder systems (VRSs) aim to decrease time to defibrillation by dispatching trained volunteers to automated external defibrillators (AEDs) and out-of-hospital cardiac arrest (OHCA) victims. AEDs are often underutilized due to poor placement. This study provides a cost-effectiveness analysis of adding AEDs at strategic locations to maximize quality-adjusted life years (QALYs). We simulated combined volunteer, police, firefighter, and emergency medical service response scenarios to OHCAs, and applied our methods to a case study of Amsterdam, the Netherlands. We compared the competing strategies of placing additional AEDs, using steps of 40 extra AEDs (0, 40, …, 1480), in addition to the existing 369 AEDs. Incremental cost-effectiveness ratios (ICERs) were calculated for each increase in additional AEDs, from a societal perspective. The effect of AED connection and time to connection on survival to hospital admission and neurological outcome at discharge was estimated using logistic regression, using OHCA data from Amsterdam from 2006 to 2018. Other model inputs were obtained from literature. Purchasing up to 1120 additional AEDs (ICER €75,669/QALY) was cost-effective at a willingness-to-pay threshold of €80,000/QALY, when positioned strategically. Compared to current practice, adding 1120 AEDs resulted in a gain of 0.111 QALYs (95% CI 0.110-0.112) at an increased cost of €3792 per OHCA (95% CI €3778-€3807). Health benefits per AED diminished as more AEDs were added. Our study identified cost-effective strategies to position AEDs at strategic locations in a VRS. The case study findings advocate for a substantial increase in the number of AEDs in Amsterdam.