Christopher H. Lee

Early Cardiac Catheterization Laboratory Activation by Paramedics for Patients with ST-segment Elevation Myocardial Infarction on Prehospital 12-Lead Electrocardiograms

Abstract Background. Prompt reperfusion in ST-segment elevation myocardial infarction (STEMI) saves lives. Although studies have shown that paramedics can reliably interpret STEMI on prehospital 12-lead electrocardiograms (p12ECGs), prehospital activation of the cardiac catheterization laboratory by emergency medical services (EMS) has not yet gained widespread acceptance. Objective. To quantify the potential reduction in time to percutaneous coronary intervention (PCI) by early prehospital activation of the cardiac catheterization laboratory in STEMI. Methods. This prospective, observational study enrolled all patients diagnosed with STEMI by paramedics in a mid-sized regional EMS system. Patients were enrolled if: 1) the paramedic interpreted STEMI on the p12ECG, 2) the Acute Cardiac Ischemia Time-Insensitive Predictive Instrument (ACI-TIPI) score was 75%% or greater, and 3) the patient was transported to either of two area PCI centers. Data recorded included the time of initial EMS “STEMI alert” from the scene, time of arrival at the emergency department (ED), and time of actual catheterization laboratory activation by the ED physician, all using synchronized clocks. The primary outcome measure was the time difference between the STEMI alert and the actual activation (i.e., potential time savings). The false-positive rate (patients incorrectly diagnosed with STEMI by paramedics) was also calculated and compared with a locally accepted false-positive rate of 10%%. Results. Twelve patients were enrolled prior to early termination of the study. The mean and median potential time reductions were 15 and 11 minutes, respectively (range 7–29 minutes). There was one false STEMI alert (8.3%% false-positive rate) for a patient with a right bundle branch block who subsequently had a non–ST-segment elevation myocardial infarction. The study was terminated when our cardiologists adopted a prehospital catheterization laboratory activation protocol based on our initial data. Conclusion. Important reductions in time to reperfusion seem possible by activation of the catheterization laboratory by EMS from the scene, with an acceptably low false-positive rate in this small sample. This type of clinical research can inform multidisciplinary policies and bring about meaningful clinical practice changes.

EMS Activation of the Cardiac Catheterization Laboratory Is Associated with Process Improvements in the Care of Myocardial Infarction Patients

Abstract Introduction. Prior data from our institution suggested that our paramedics can accurately interpret ST-segment elevation myocardial infarction (STEMI) on prehospital 12-lead electrocardiograms (ECGs), and that activation of the cardiac catheterization laboratory by paramedics immediately upon diagnosing STEMI at the scene could potentially decrease door-to-balloon (D2B) times. A “field activation” protocol was thus initiated in May 2010. This study examined D2B times and compliance with the national 90-minute D2B performance benchmark in the first 14 months. Hypothesis. We hypothesized that D2B times would be shorter, and 90-minute compliance better, when the catheterization laboratory was activated by emergency medical services (EMS), compared with when either EMS failed to activate the catheterization laboratory or when the STEMI patient arrived by means other than EMS. Methods. For this prospective, observational study, EMS and hospital data were reviewed for consecutive STEMI patients at a single hospital between May 2010 and July 2011. Patients were categorized as: 1) EMS field activations, 2) patients transported by EMS without EMS catheterization laboratory activation (e.g., ambulance from outside our area, paramedic missed STEMI/protocol violation), or 3) walk-in STEMI patient. Data were manipulated in Excel, means with standard deviations (SDs) and 95% confidence intervals (95% CIs) were determined, and analysis of variance (ANOVA) with Dunnetts correction was used to compare groups. Results. There were 38 EMS field activations, 47 nonactivation EMS STEMI arrivals, and 28 walk-in STEMI patients. The mean (±SD) D2B times were 37 (±17), 87 (±40), and 80 (±23) minutes, respectively. D2B time was better for the EMS field activations than for either nonactivation EMS transports (difference of means 35.3 min, 95% CI 22.3–48.3 min, p < 0.001) or walk-in patients (difference of means 37.0 min, 95% CI 21.8–52.2 min, p < 0.001). Compliance with the 90-minute D2B benchmark was 100%, 72%, and 68%, respectively, and was better for the EMS field activations than for either of the other groups (p < 0.001). Conclusions. In the system studied, EMS field activation of the catheterization laboratory for patients with STEMI is associated with shorter D2B times and better compliance with 90-minute benchmarks than ED activation for either walk-in STEMI patients or STEMI patients arriving by EMS without field activation. Improvements are needed in compliance with the field activation protocol to maximize these benefits. Key words: emergency medical services; emergency medical technicians; electrocardiography; myocardial infarction; heart catheterization

A Descriptive Study of the “Lift-Assist” Call

Abstract Introduction. Responses for “lift assists” (LAs) are common in many emergency medical services (EMS) systems, and result when a person dials 9-1-1 because of an inability to get up, is subsequently determined to be uninjured, and is not transported for further medical attention. Although LAs often involve recurrent calls and are generally not reimbursable, little is known of their operational effects on EMS systems. We hypothesized that LAs present an opportunity for earlier treatment of subtle-onset medical conditions and injury prevention interventions in a population at high risk for falls. Objectives. To quantify LA calls in one community, describe EMS returns to the same address within 30 days following an index LA call, and characterize utilization of EMS by LA patients. Methods. Data from the computer-aided dispatch (CAD) system of a suburban fire-based EMS system were retrospectively reviewed. All LAs from 2004 to 2009 were identified using “exit codes” transmitted by paramedics after each call. The number and nature of return visits to the same address within 30 days were examined. Results. From 2004 through 2009, there were 1,087 LA responses (4.8% of EMS incidents) to 535 different addresses. Two-thirds of the LA calls (726; 66.8%) were to one-third of these addresses (174 addresses; 32.5%); 563 of the return calls to the same address occurred within 30 days after the index LA. For 214 of these return visits, it was possible to compare patient age and sex with those associated with the initial LA, revealing that 85% of return visits were likely for the same patients. Of these, 38.5% were for another LA/refusal of transport, 8.2% for falls and other injuries, and 47.3% for medical complaints. Hospital transport was required in 55.5% of these return visits. The EMS crews averaged 21.5 minutes out of service per LA call. Conclusion. Lift-assist calls are associated with substantial subsequent utilization of EMS, and should trigger fall prevention and other safety interventions. Based on our data, these calls may be early indicators of medical problems that require more aggressive evaluation.

Prehospital Electronic Patient Care Report Systems: Early Experiences from Emergency Medical Services Agency Leaders

Background As the United States embraces electronic health records (EHRs), improved emergency medical services (EMS) information systems are also a priority; however, little is known about the experiences of EMS agencies as they adopt and implement electronic patient care report (e-PCR) systems. We sought to characterize motivations for adoption of e-PCR systems, challenges associated with adoption and implementation, and emerging implementation strategies. Methods We conducted a qualitative study using semi-structured in-depth interviews with EMS agency leaders. Participants were recruited through a web-based survey of National Association of EMS Physicians (NAEMSP) members, a didactic session at the 2010 NAEMSP Annual Meeting, and snowball sampling. Interviews lasted approximately 30 minutes, were recorded and professionally transcribed. Analysis was conducted by a five-person team, employing the constant comparative method to identify recurrent themes. Results Twenty-three interviewees represented 20 EMS agencies from the United States and Canada; 14 EMS agencies were currently using e-PCR systems. The primary reason for adoption was the potential for e-PCR systems to support quality assurance efforts. Challenges to e-PCR system adoption included those common to any health information technology project, as well as challenges unique to the prehospital setting, including: fear of increased ambulance run times leading to decreased ambulance availability, difficulty integrating with existing hospital information systems, and unfunded mandates requiring adoption of e-PCR systems. Three recurring strategies emerged to improve e-PCR system adoption and implementation: 1) identify creative funding sources; 2) leverage regional health information organizations; and 3) build internal information technology capacity. Conclusion EMS agencies are highly motivated to adopt e-PCR systems to support quality assurance efforts; however, adoption and implementation of e-PCR systems has been challenging for many. Emerging strategies from EMS agencies and others that have successfully implemented EHRs may be useful in expanding e-PCR system use and facilitating this transition for other EMS agencies.

Advanced Cardiac Life Support and Defibrillation in Severe Hypothermic Cardiac Arrest

The application of Advanced Cardiac Life Support (ACLS) in severe hypothermic cardiac arrest remains controversial. While the induction of mild hypothermia has been shown to improve outcomes in patients already resuscitated from cardiac arrest, it is unknown whether ACLS protocols are effective during the resuscitation of the severely hypothermic cardiac arrest patient. We describe a case of a 47-year-old man who was successfully resuscitated from a ventricular fibrillation (VF) arrest with a core body temperature of 26.4°C. The patient had been found unresponsive in a bathtub of cold water following an apparent suicide attempt. An incorrect pronouncement of death by the fire department delayed his transport to the hospital by more than four hours. Once in the emergency department (ED), the patient sustained a VF cardiac arrest and was successfully defibrillated using ACLS protocols. He ultimately survived his hospitalization with near-complete neurologic recovery. In this case report, we discuss the application of ACLS to the resuscitation of the hypothermic cardiac arrest patient as well as the issues involved in the prehospital determination of death.

Severe angioedema in myxedema coma: a difficult airway in a rare endocrine emergency.

Myxedema coma is the most lethal manifestation of hypothyroidism. It is a true medical emergency and can result in profound hemodynamic instability and airway compromise. Myxedema coma currently remains a diagnostic challenge due to the rarity of cases seen today, and failure to promptly initiate therapy with replacement thyroid hormone can be fatal. As thyroid hormone therapy can take days or weeks to reverse the manifestations of myxedema coma, interim supportive therapy is critical while awaiting clinical improvement. Some patients will require endotracheal intubation in the emergency department (ED), and physicians should be aware that unanticipated posterior pharyngeal edema in myxedema coma could severely complicate airway management. Although mechanical ventilation is a well-described adjunctive therapy for myxedema coma, reports of the potential difficulty in securing a definitive airway in these patients are rare. We describe a case of an unidentified woman who presented to the ED with myxedema coma requiring urgent endotracheal intubation and was found to have extensive posterior pharyngeal angioedema inconsistent with her relatively benign external examination. This case highlights the typical features of myxedema coma and discusses our necessity for a rescue device in definitive endotracheal tube placement. Emergency physicians should anticipate a potentially difficult airway in all myxedema coma patients regardless of the degree of external facial edema present.

Therapeutic Hypothermia for Survivors of Cardiac Arrest in a Community-Based Setting

Survival rates and neurologic outcomes from sudden outof-hospital cardiac arrest are poor. Although recent advances in cardiopulmonary resuscitation (CPR) techniques and advanced cardiac life support (ACLS) have resulted in somewhat improved survival rates over the past decade, ensuring good neurologic outcome in cardiac arrest survivors continues to be problematic. Even after successful resuscitation and return of spontaneous circulation (ROSC), debilitating anoxic brain injury has been reported in the majority of survivors. The recognition of the frequent problem of persistent neurologic injury after cardiac arrest was evidenced in the American Heart Association/International Liaison Committee on Resuscitation (AHA/ILCOR) “Guidelines 2000” for CPR and emergency cardiovascular care (ECC) where the term “cardiopulmonary-cerebral resuscitation” was introduced in the guideline literature. The extreme vulnerability of the brain to even limited amounts of ischemia can result in devastating neurologic injury and is a major cause of morbidity and mortality. Studies have demonstrated that the duration of cardiac arrest is highly correlated with the severity of subsequent global brain ischemia. Combined with the low-flow anoxic state of cardiac arrest, the mechanisms of neuronal injury are multifactorial and include the detrimental effects of cerebral edema and free radical formation, both of which can occur hours to days after cardiac arrest. Coupled with the systemic inflammatory response syndrome triggered by such an insult, these changes can also cause significant complications during the ischemicreperfusion phase of cardiac arrest resuscitation. Ultimately, these conditions can manifest themselves clinically in varying degrees of severity ranging from memory disorders and neurocognitive impairment, to coma and brain death, dependent at least in part on the patient’s pre-arrest state of health. Because of the devastating nature of postcardiac arrest brain injury, the identification and implementation of neurologic and cardioprotective modalities remains a priority in the field of resuscitation science. Of the many agents and techniques investigated over the past decade, induction of mild hypothermia has emerged as the only effective and proven treatment to improve neurologic outcome in survivors of cardiac arrest, with data first originating from two landmark studies published in 2002 by the New England Journal of Medicine. Hypothermia induction protocols have been recommended in cardiac arrest resuscitation guidelines since 2003. However, despite the consensus guidelines set forth by the AHA, the American College of Cardiology (ACC), and ILCOR, widespread implementation of therapeutic hypothermia protocols to survivors of cardiac arrest has been slow to develop, both internationally and in the United States. Why has the adoption of therapeutic hypothermia (TH) progressed so slowly? In recent publications examining this topic, several factors have been identified as potential barriers to widespread implementation. Physicians have cited insufficient evidence to support its use, the complexity of initiating hospital-wide protocols, fear of adverse events, and concerns that inducing hypothermia will be too labor-intensive or require expensive technology in order to implement. Because large academic medical centers have been slow to embrace hypothermia protocols, it is not surprising that smaller community hospitals have also lagged behind these therapeutic benchmarks. Although further research is certainly necessary to refine and optimize our current hypothermia protocols, the simple fact remains that hypothermia is the only intervention proven to improve neurologic outcome in patients who achieve ROSC after cardiac arrest. Therefore, it was with great interest that we read the article “Community-Based Application of Mild Therapeutic Hypothermia for Survivors of Cardiac Arrest,” in this issue of the Southern Medical Journal. Following AHA/ILCOR guidelines for hypothermia and using locally available resources, the authors were able to implement a successful protocol at three relatively small community hospitals. After initiating a hypothermia protocol that achieved goal temperatures within therapeutic guidelines the majority of the time, the authors found improved neurologic outcomes when compared with historical controls. As there is no universally accepted method for cooling these patients, the authors combined a commercially available cooling device with the very simple technique of placing ice packs on the groin, axilla, and neck. The authors successfully demonstrated that TH is not only technologically possible in smaller, community-based settings, but also that such facilities can achieve improved patient outcomes comparable with those of larger, tertiary care academic centers. The study methodology necessitates several cautions when interpreting these findings. First, the use of historical From the Department of Emergency Medicine, Section of Emergency Medical Services, Yale University School of Medicine, New Haven, CT.