Carin M. Van Gelder

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

Pilot Test of the SALT Mass Casualty Triage System

Introduction. No existing mass casualty triage system has been scientifically scrutinized or validated. A recent work group sponsored by the Centers for Disease Control and Prevention, using a combination of expert opinion and the extremely limited research data available, created the SALT (sort–assess–lifesaving interventions–treat/transport) triage system to serve as a national model. An airport crash drill was used to pilot test the SALT system. Objective. To assess the accuracy and speed with which trained paramedics can triage victims using this new system. Methods. Investigators created 50 patient scenarios with a wide range of injuries and severities, and two additional uninjured victims were added at the time of the drill. Students wearing moulage and coached on how to portray their injuries served as “victims.” Assuming proper application of the SALT system, the patient scenarios were designed such that 16 patients would be triaged as T1/red/immediate, 12 as T2/yellow/delayed, 14 as T3/green/minimal, and 10 as T4/black/dead. Paramedics were trained to proficiency in the SALT system one week prior to the drill using a 90-minute didactic/practical session, and were given “flash cards” showing the triage algorithm to be used if needed during the drill. Observers blinded to the study purpose timed and recorded the triage process for each patient during the drill. Simple descriptive statistics were used to analyze the data. Results. The two paramedics assigned to the role of triage officers applied the SALT algorithm correctly to 41 of the 52 patients (78.8% accuracy). Seven patients intended to be T2 were triaged as T1, and two patients intended to be T3 were triaged as T2, for an overtriage rate of 13.5%. Two patients intended to be T2 were triaged as T3, for an undertriage rate of 3.8%. Triage times were recorded by the observers for 42 of the 52 patients, with a mean of 15 seconds per patient (range 5–57 seconds). Conclusions. The SALT mass casualty triage system can be applied quickly in the field and appears to be safe, as measured by a low undertriage rate. There was, however, significant overtriage. Further refinement is needed, and effect on patient outcomes needs to be evaluated.

Pilot test of a proposed chemical/biological/radiation/ nuclear-capable mass casualty triage system

Introduction. Existing mass casualty triage systems do not consider the possibility of chemical, biological, or radiologic/nuclear (CBRN) contamination of the injured patients. A system that can triage injured patients who are or may be contaminated by CBRN material, developed through expert opinion, was pilot-tested at an airport disaster drill. The study objective was to determine the systems speed andaccuracy. Methods. For a drill involving a plane crash with release of organophosphate material from the cargo hold, 56 patient scenarios were generated, with some involving signs andsymptoms of organophosphate toxicity in addition to physical trauma. Prior to the drill, the investigators examined each scenario to determine the “correct” triage categorization, assuming proper application of the proposed system, andtrained the paramedics who were expected to serve as triage officers at the drill. During the drill, the medics used the CBRN triage system to triage the 56 patients, with two observers timing andrecording the events of the triage process. The IRB deemed the study exempt from full review. Results. The two triage officers applied the CBRN system correctly to 49 of the 56 patients (87.5% accuracy). One patient intended to be T2 (yellow) was triaged as T1 (red), for an over-triage rate of 1.8%. Five patients intended to be T1 were triaged as T2, andone patient intended to be T2 was triaged as T3 (green), for an under-triage rate of 10.7%. All six under-triage cases were due to failure to recognize or account for signs of organophosphate toxidrome in applying the triage system. For the 27 patients for whom times were recorded, triage was accomplished in a mean of 19 seconds (range 4-37, median 17). Conclusions. The chemical algorithm of the proposed CBRN-capable mass casualty triage system can be applied rapidly by trained paramedics, but a significant under-triage rate (10.7%) was seen in this pilot test. Further refinement andtesting are needed, andeffect on outcome must be studied.

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.

An Open, Interoperable, and Scalable Prehospital Information Technology Network Architecture

Abstract Some of the most intractable challenges in prehospital medicine include response time optimization, inefficiencies at the emergency medical services (EMS)–emergency department (ED) interface, and the ability to correlate field interventions with patient outcomes. Information technology (IT) can address these and other concerns by ensuring that system and patient information is received when and where it is needed, is fully integrated with prior and subsequent patient information, and is securely archived. Some EMS agencies have begun adopting information technologies, such as wireless transmission of 12-lead electrocardiograms, but few agencies have developed a comprehensive plan for management of their prehospital information and integration with other electronic medical records. This perspective article highlights the challenges and limitations of integrating IT elements without a strategic plan, and proposes an open, interoperable, and scalable prehospital information technology (PHIT) architecture. The two core components of this PHIT architecture are 1) routers with broadband network connectivity to share data between ambulance devices and EMS system information services and 2) an electronic patient care report to organize and archive all electronic prehospital data. To successfully implement this comprehensive PHIT architecture, data and technology requirements must be based on best available evidence, and the system must adhere to health data standards as well as privacy and security regulations. Recent federal legislation prioritizing health information technology may position federal agencies to help design and fund PHIT architectures.

Noninvasive fireground assessment of carboxyhemoglobin levels in firefighters.

Objectives. Carboxyhemoglobin (COHb) levels can be estimated by chemical analysis of exhaled alveolar breath. Such noninvasive measurement could be used on the fireground to screen both firefighters (FFs) andvictims. The purpose of this study was to assess the feasibility of using a hand-held carbon monoxide (CO) monitoring device to screen for CO toxicity in FFs under field conditions. Methods. Informed consent was obtained from all participants. Using a hand-held breath CO detection device, COHb readings were collected at baseline, andthen as FFs exited burning buildings after performing interior fire attack andoverhaul with self-contained breathing apparatus (SCBA) during live-fire training. Ambient CO levels were occasionally measured in interior areas where the FFs were working to assess the degree of CO exposure. Results. Baseline COHb readings of 64 FFs ranged from 0% to 3% (mean 1%, median 1%). One hundred eighty-four COHb readings were collected during training exercises. The mean andmedian COHb levels were 1%. The maximum value in a FF wearing SCBA was 3%; values of 14%, 5%, and4% were measured in instructors who were not properly wearing SCBA. Ambient CO readings during fire attack ranged from 75 to 1,290 ppm, andthe ambient CO reading for overhaul ranged from 0 to 130 ppm. When the device was used for interior CO monitoring, washout time limited its utility for COHb monitoring in FFs. Conclusions. A hand-held CO monitoring device adapted for estimation of COHb levels by exhaled breath analysis can feasibly be deployed on the fireground to assess CO exposure in FFs.

Threats to Life in Residential Structure Fires

Introduction. Firefighters are taught that heat, oxygen deprivation, andcarbon monoxide (CO) are the primary threats to life in residential structure fires, andthey are taught to search for victims on the fire floor first, andthen floors above. The objective of this study was to gather data regarding oxygen, CO, andheat conditions inside a realistic house fire, to examine the validity of these teachings. Methods. During six live-burn training evolutions in a two-story wood-frame house, metering for oxygen levels, CO levels, andtemperature was conducted. Except where noted, all readings were taken 24 inches off the floor, to simulate the location of a crawling victim or firefighter. Readings were hand-recorded on a convenience basis by firefighters stationed outside the building, near the meters. Results. Of the 35 oxygen levels recorded, the lowest was 18.2%, with only 12 readings below 20%. Three of 16 first-floor readings were below 20%, whereas nine of 19 second-floor readings were below 20% (p = 0.07). First- andsecond-floor readings were comparable (mean 20.3% vs. 19.9%, p = 0.11). Except for one reading of 1,870 ppm, all CO readings at the ceiling exceeded the 2,000-ppm limit of the meters. Of the 34 CO levels recorded 24 inches off the floor, 29 (76%) exceeded the permissible exposure limit of 50 ppm, with the highest reading being 1,424 ppm, well above the “immediately dangerous to life andhealth” level of 1,200 ppm. None of the 20 CO levels recorded on the first floor exceeded the 30-minute exposure limit of 800 ppm, whereas seven of 14 second-floor readings exceeded this limit (p < 0.001). While ceiling temperatures frequently exceeded the 1,000°F limit of the meters, none of 16 readings taken 24 inches off the floor exceeded 137°F. First- andsecond-floor temperatures were comparable (mean 88.5°F vs. 90.1°F, p = 0.9). Conclusions. In residential structure fires, CO poses a greater threat to victims andfirefighters than does oxygen deprivation or heat. Emergency medical services personnel should consider CO toxicity in all fire victims. Conditions on the floor above a fire are at least as adverse as those on the fire floor.

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.

An Experimental Model of Heat Storage in Working Firefighters

Objective. Develop experimental models to study uncompensable heat stress (UCHS) in working firefighters (FFs). Methods. FFs ingested core temperature (Tc) capsules prior to performing sequential tasks in 40°C andpersonal protective ensemble (PPE), or 18°C andno PPE. Both trials were conducted in an environmental chamber with FFs using self-contained breathing apparatus (SCBA). Results. FFs exercising in heat andPPE reproduced UCHS conditions. For every FF in both trials for whom the capsules worked, Tc was elevated, andTcmax occurred after completion of study protocol. Trials with PPE resulted in a mean maximum temperature of 38.94°C (± 0.37°C); Tcmax reached 40.4°C. Without PPE, maximum Tc averaged 37.79°C (± 0.07°C). Heat storage values ranged from 131 to 1205 kJ, averaging 578 kJ (± 151.47kJ) with PPE and210.83 kJ (± 21.77kJ) without PPE. Conclusions. An experimental model has been developed that simulates the initial phases of an interior fire attack to study the physiology of UCHS in FF. The hot environment andPPE increase maximum Tc andheat storage over that due to the exertion required to perform the tasks andmay decrease time to volitional fatigue. This model will permit controlled studies to optimize work-rest cycles, rehab conditions, andphysical conditioning of FFs.