Raymond L. Fowler

Early versus Later Rhythm Analysis in Patients with Out-of-Hospital Cardiac Arrest

BACKGROUND In a departure from the previous strategy of immediate defibrillation, the 2005 resuscitation guidelines from the American Heart Association-International Liaison Committee on Resuscitation suggested that emergency medical service (EMS) personnel could provide 2 minutes of cardiopulmonary resuscitation (CPR) before the first analysis of cardiac rhythm. We compared the strategy of a brief period of CPR with early analysis of rhythm with the strategy of a longer period of CPR with delayed analysis of rhythm. METHODS We conducted a cluster-randomized trial involving adults with out-of-hospital cardiac arrest at 10 Resuscitation Outcomes Consortium sites in the United States and Canada. Patients in the early-analysis group were assigned to receive 30 to 60 seconds of EMS-administered CPR and those in the later-analysis group were assigned to receive 180 seconds of CPR, before the initial electrocardiographic analysis. The primary outcome was survival to hospital discharge with satisfactory functional status (a modified Rankin scale score of ≤3, on a scale of 0 to 6, with higher scores indicating greater disability). RESULTS We included 9933 patients, of whom 5290 were assigned to early analysis of cardiac rhythm and 4643 to later analysis. A total of 273 patients (5.9%) in the later-analysis group and 310 patients (5.9%) in the early-analysis group met the criteria for the primary outcome, with a cluster-adjusted difference of -0.2 percentage points (95% confidence interval, -1.1 to 0.7; P=0.59). Analyses of the data with adjustment for confounding factors, as well as subgroup analyses, also showed no survival benefit for either study group. CONCLUSIONS Among patients who had an out-of-hospital cardiac arrest, we found no difference in the outcomes with a brief period, as compared with a longer period, of EMS-administered CPR before the first analysis of cardiac rhythm. (Funded by the National Heart, Lung, and Blood Institute and others; ROC PRIMED ClinicalTrials.gov number, NCT00394706.).

A descriptive analysis of emergency medical service systems participating in the Resuscitation Outcomes Consortium (ROC) network

Background. The optimal Emergency Medical Services (EMS) system characteristics have not been defined, resulting in substantial variability across systems. The Resuscitation Outcomes Consortium (ROC) is a United States-Canada research network that organized EMS agencies from 11 different systems to perform controlled trials in cardiac arrest andlife-threatening trauma resuscitation. Objectives. To describe EMS systems participating in ROC using a novel framework. Methods. Standardized surveys were created by ROC investigators anddistributed to each site for completion. These included separate questions for individual hospitals, EMS agencies, anddispatch centers. Results were collated andanalyzed by using descriptive statistics. Results. A total of 264 EMS agencies, 287 hospitals, and154 dispatch centers were included. Agencies were described with respect to the type (fire-based, non-fire governmental, private), transport status (transport/non-transport), andtraining level (BLS/ALS). Hospitals were described with regard to their trauma designation andthe presence of electrophysiology andcardiac catheterization laboratories. Dispatch center characteristics, including primary versus secondary public safety answering point (PSAP) status andthe use of prearrival instructions, were also described. Differences in EMS system characteristics between ROC sites were observed with multiple intriguing patterns. Rural areas andfire-based agencies had more EMS units andproviders per capita. This may reflect longer response andtransport distances in rural areas andthe additional duties of most fire-based providers. In addition, hospitals in the United States typically had catheterization laboratories, whereas Canadian hospitals generally did not. The vast majority of both primary andsecondary PSAPs use computer-aided dispatch. Conclusions. Similarities anddifferences among EMS systems participating in the ROC network were described. The framework used in this analysis may serve as a template for future EMS research.

THE ROLE OF INTRAOSSEOUS VASCULAR ACCESS IN THE OUT-OF-HOSPITAL ENVIRONMENT (RESOURCE DOCUMENT TO NAEMSP POSITION STATEMENT)

Thousands of critically ill emergency patients are treated in the out-of-hospital setting in the United States every year. In many patients intravenous (IV) therapy cannot be initiated because of inadequate access to peripheral veins. In some cases, this lack of vascular access may limit benefit of medications because of late administration.[[1]] Both speed andoverall success of vascular access are important when evaluating potential methodologies for their use in the out-of-hospital environment. Insertion of an IV cannula has been reported to require substantial time in the prehospital environment, with a recent study reporting an average successful intravenous line placement time of 4.4 ± 2.8 minutes.[[2]] In critically ill pediatric patients, vascular access may present substantial difficulties to the provide.[[3]] Intraosseous access may provide a significant time saving which may benefit many critically ill patients, both by decreasing the time to achieve access andby decreasing the time to administration of indicated medications.[[4]] Achieving rapid administration of medications may facilitate the care of critically ill patients.[[1]] Devices are now available that permit rapid, accurate access to the intraosseous space. Recent changes in the American Heart Associations resuscitation guidelines state that the intraosseous route should be the first alternative to difficult or delayed intravenous access.[[5]] With these considerations, the role of intraosseous vascular access in the out-of-hospital environment should be reemphasized.

The detrimental effects of ventilation during low-blood-flow states.

Purpose of reviewIn recent years, it has become increasingly apparent that resuscitative ventilatory procedures, classically thought to be life saving, may have profound detrimental effects. Recent findingsMost assisted breathing techniques during resuscitation involve the provision of intermittent positive pressure ventilation to inflate lung zones for erythrocyte oxygenation and clearance of carbon dioxide. A growing number of studies involving low-flow states, however, have demonstrated that provision of overzealous (or even ‘normal’) ventilatory rates with intermittent positive pressure ventilation can significantly diminish both systemic and coronary circulation, most likely through inhibition of venous return. Recent laboratory studies of hemorrhage have shown not only a direct detrimental impact of each positive pressure ventilation breath on coronary perfusion, but also how dramatic improvements in blood flow can be achieved, without loss of oxygenation, by delivering breaths infrequently during such low-flow states. Likewise, in cardiac arrest models, studies have shown that interrupting chest compressions, even to provide breaths, can be extremely deleterious by abruptly (and continually) lowering the aortic pressure head to the coronary arteries, thus impairing restoration of spontaneous circulation. Even with endotracheal intubation and uninterrupted chest compressions, frequent positive pressure ventilation still inhibits circulation during cardiopulmonary resuscitation. Despite directed training, paramedics (and other rescuers) have been shown to still excessively ventilate during cardiac arrest resuscitations. SummaryVentilation can have profound detrimental hemodynamic effects in low-flow states, exacerbating the circulatory compromise. This underappreciated confounding variable may be one of the reasons many clinical trials of resuscitative interventions have failed despite dramatic successes in the laboratory.

Fluid resuscitation of the patient with major trauma.

Current reviews and consensus documents now recommend a more discriminating approach to the traditional practices of delivering liberal infusions of intravenous fluid to all major trauma patients with suspected or known major hemorrhage. The evolving evidence suggests that aggressive fluid resuscitation prior to hemostasis leads to additional bleeding through hydraulic acceleration of hemorrhage, soft clot dissolution, and dilution of clotting factors. Aggressive preoperative fluid infusion is still considered appropriate for unconscious patients without palpable blood pressure or for those with controllable hemorrhage (e.g. isolated extremity or head injury), However, the latest recommendations are to limit or delay intravenous fluid resuscitation preoperatively in those with uncontrollable hemorrhage (e.g. those with penetrating torso injuries), even if they are hypoperfusing. Although most clinicians still generally support fluid resuscitation for multisystem blunt trauma, particularly with head injury, the most recent experimental data have begun to challenge this traditional practice as well, suggesting a ‘slow infusion’ approach when there is risk for uncontrolled internal bleeding. By providing oxygen delivery with slow, limited infusion, new hemoglobin-based oxygen carriers might help to resolve the current dilemma of having to limit preoperative resuscitation when there is risk of uncontrolled hemorrhage.

Preoperative resuscitation of the trauma patient.

Purpose of review The traditional approach to trauma patients with presumed internal hemorrhage has been immediate, aggressive intravenous fluid resuscitation. Recent experimental and clinical data, however, suggest a more discriminating approach that first considers concurrent head injury, hemodynamic stability and the presence of potentially uncontrollable hemorrhage (e.g. deep truncal injury) versus a controllable source (e.g. distal extremity wound) as well as the use of new techniques to inhibit bleeding and better ways to monitor the patients condition. Recent findings Evolving data suggest that while aggressive fluid infusions could be used for patients with isolated extremity, thermal or head injury, they should be limited in conditions with potentially uncontrollable internal hemorrhage, and particularly in patients with penetrating truncal injury being transported immediately to a trauma center. Likewise, the minute volume of positive pressure ventilatory support should be limited with potential severe hemorrhage due to the secondary reductions in venous return. For trauma patients with severe bleeding there is growing evidence for the increased use of plasma and factor VIIa, as well as tourniquets, intraosseus devices and evolving monitoring techniques. Summary Owing to the growing societal threat of trauma, further research, including studies already under way, will be critical to delineate the timing and technique of infusing advantageous resuscitative fluids such as hypertonic saline and hemoglobin-based oxygen carriers as well as the use of hemostatic agents and special blood products.

Prehospital care delivery and triage of stroke with emergent large vessel occlusion (ELVO): report of the Standards and Guidelines Committee of the Society of Neurointerventional Surgery

Recent randomized clinical trials1–5 established the superiority of endovascular recanalization techniques, specifically mechanical embolectomy, compared with best medical therapy alone for the treatment of patients with emergent large vessel occlusion (ELVO) stroke. ELVO stroke is defined as a stroke secondary to anterior circulation large vessel occlusion (LVO) of the internal carotid, middle cerebral (M1 segments) arteries documented by imaging, without large completed infarct and presenting within 6 hours of symptom onset.6 Given the overwhelming clinical evidence provided by these trials, recent American Heart Association (AHA) guidelines concluded that “embolectomy needs to be performed as rapidly as possible for the greatest clinical benefit, and is best when performed within 6 h from onset of symptoms” (AHA class I, level of evidence A).6 In addition, cost modeling derived from trial outcomes data and claims databases in the USA strongly suggests that cost-effectiveness and an overall societal benefit is associated with investment in access to these endovascular techniques.7 Rapid access to endovascular services depends upon optimization of prehospital stroke care and transport within stroke systems of care, focusing on the unique needs of patients with ELVO through their diagnostic investigation and treatment pathway. The Society of NeuroInterventional Surgery (SNIS) proposed process time metrics for ELVO stroke treatment, including door to IV tissue plasminogen activator (t-PA) of <30 min, comprehensive stroke center (CSC) door to puncture of <60 min, CSC door to recanalization of <90 min and primary stroke certification (PSC) picture to CSC puncture of <90 min.8 Early team awareness of the patient with potential ELVO, coupled with efficient interdisciplinary communication, triage and transport assist in meeting these ideal time metrics, and also contribute to improved clinical outcomes through efficiency gains and maximization of endovascular care delivery. The Standards and Guidelines Committee of the SNIS, a multidisciplinary society representing leaders in the field of …

Role of rapid sequence induction for intubation in the prehospital setting: helpful or harmful?

Use of rapid sequence induction for intubation was introduced to the prehospital environment in the hope of enhancing patient outcome by improving early definitive airway management. Varying success has been achieved in both air and ground transport emergency medical services systems, but concern persists about the potential to cause patients harm. Individual emergency medical services systems must determine the need for rapid sequence induction for intubation and their ability to implement a rapid sequence induction for intubation protocol effectively with minimal adverse events. Therefore, the value of rapid sequence induction for intubation is dependent on each emergency medical services system design in their ability to establish personnel requirements and ongoing training, expertise in airway management skills, medical direction and supervision, and a quality assurance program. If these principles are strictly adhered to, rapid sequence induction for intubation may be safely used as an advanced airway management technique in the prehospital setting.

Prehospital endotracheal intubation: elemental or detrimental?

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2015 and co-published as a series in Critical Care. Other articles in the series can be found online at http://ccforum.com/series/annualupdate2015. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Developing an ST-elevation myocardial infarction system of care in Dallas County

BACKGROUND The American Heart Association Caruth Initiative (AHACI) is a multiyear project to increase the speed of coronary reperfusion and create an integrated system of care for patients with ST-elevation myocardial infarction (STEMI) in Dallas County, TX. The purpose of this study was to determine if the AHACI improved key performance metrics, that is, door-to-balloon (D2B) and symptom-onset-to-balloon times, for nontransfer patients with STEMI. METHODS Hospital patient data were obtained through the National Cardiovascular Data Registry Action Registry-Get With The Guidelines, and prehospital data came from emergency medical services (EMS) agencies through their electronic Patient Care Record systems. Initial D2B and symptom-onset-to-balloon times for nontransfer primary percutaneous coronary intervention (PCI) STEMI care were explored using descriptive statistics, generalized linear models, and logistic regression. RESULTS Data were collected by 15 PCI-capable Dallas hospitals and 24 EMS agencies. In the first 18 months, there were 3,853 cases of myocardial infarction, of which 926 (24%) were nontransfer patients with STEMI undergoing primary PCI. D2B time decreased significantly (P < .001), from a median time of 74 to 64 minutes. Symptom-onset-to-balloon time decreased significantly (P < .001), from a median time of 195 to 162 minutes. CONCLUSION The AHACI has improved the system of STEMI care for one of the largest counties in the United States, and it demonstrates the benefits of integrating EMS and hospital data, implementing standardized training and protocols, and providing benchmarking data to hospitals and EMS agencies.