Regional Emergency Medical Services Research Articles

A Markovian queueing model for ambulance offload delays

Ambulance offload delays are a growing concern for health care providers in many countries. Offload delays occur when ambulance paramedics arriving at a hospital Emergency Department (ED) cannot transfer patient care to staff in the ED immediately. This is typically caused by overcrowding in the ED. Using queueing theory, we model the interface between a regional Emergency Medical Services (EMS) provider and multiple EDs that serve both ambulance and walk-in patients. We introduce Markov chain models for the system and solve for the steady state probability distributions of queue lengths and waiting times using matrix-analytic methods. We develop several algorithms for computing performance measures for the system, particularly the offload delays for ambulance patients. Using these algorithms, we analyze several three-hospital systems and assess the impact of system resources on offload delays. In addition, simulation is used to validate model assumptions.

121 Analysis of Inter-facility Transfer Rates After Initiation of a Regional PCI System

Background: Regionalization of percutaneous cardiac intervention (PCI) ST-segment elevation myocardial infarction (STEMI) systems has become ubiquitous in emergency medical services. Patients identified as out-of-hospital STEMIs have been demonstrated to have shorter 911-to-balloon times based on the out-of-hospital electrocardiogram. Direct reception of STEMI patients to these centers for intervention is increasingly becoming standard of care. However, the overall impact of Emergency Medical Services STEMI system transfer rates from non-PCI centers is not well characterized.Study Objective: To evaluate the impact of an emergency medical services STEMI system on the disposition of emergent PCI patients.Methods: This is an institutional review board-approved cohort analysis of interfacility transfers in a closed system of regional hospitals. The hospital system consisted of 4 hospitals with one becoming designated as PCI receiving center. The study population included all emergent PCIs in this system before and after implementation, which included out-of-hospital ECG transmission capabilities. Descriptive statistics analysis of emergent interfacility transfers for PCI before and after was completed along with a sub-analysis on STEMI patients. 911-to-balloon times were also compared.Results: A total of 399 emergent cardiac catheterizations were recorded during the study period (195 pre, 204 post). Transfers for emergent PCI decreased following STEMI system implementation from 36.4% (71/195) to 26.5% (54/204) (OR 1.59, 1.03–2.44). The difference in percentage of transfers for emergent PCI in STEMI patients was not statistically significant (28% to 22%, OR 1.24, 0.70–2.19). Time to PCI from initial ED/ emergency medical services contact was dramatically reduced.Conclusion: A regional emergency medical services PCI system reduces the percentage of transfers as well as time to emergent PCI. Patients suspected of having STEMIs were diverted away from receiving facilities without emergent PCI capability though emergent transfers from non-PCI centers still occurred in this system. Background: Regionalization of percutaneous cardiac intervention (PCI) ST-segment elevation myocardial infarction (STEMI) systems has become ubiquitous in emergency medical services. Patients identified as out-of-hospital STEMIs have been demonstrated to have shorter 911-to-balloon times based on the out-of-hospital electrocardiogram. Direct reception of STEMI patients to these centers for intervention is increasingly becoming standard of care. However, the overall impact of Emergency Medical Services STEMI system transfer rates from non-PCI centers is not well characterized. Study Objective: To evaluate the impact of an emergency medical services STEMI system on the disposition of emergent PCI patients. Methods: This is an institutional review board-approved cohort analysis of interfacility transfers in a closed system of regional hospitals. The hospital system consisted of 4 hospitals with one becoming designated as PCI receiving center. The study population included all emergent PCIs in this system before and after implementation, which included out-of-hospital ECG transmission capabilities. Descriptive statistics analysis of emergent interfacility transfers for PCI before and after was completed along with a sub-analysis on STEMI patients. 911-to-balloon times were also compared. Results: A total of 399 emergent cardiac catheterizations were recorded during the study period (195 pre, 204 post). Transfers for emergent PCI decreased following STEMI system implementation from 36.4% (71/195) to 26.5% (54/204) (OR 1.59, 1.03–2.44). The difference in percentage of transfers for emergent PCI in STEMI patients was not statistically significant (28% to 22%, OR 1.24, 0.70–2.19). Time to PCI from initial ED/ emergency medical services contact was dramatically reduced. Conclusion: A regional emergency medical services PCI system reduces the percentage of transfers as well as time to emergent PCI. Patients suspected of having STEMIs were diverted away from receiving facilities without emergent PCI capability though emergent transfers from non-PCI centers still occurred in this system.

Early versus Later Rhythm Analysis in Patients with Out-of-hospital Cardiac Arrest: Stiell IG, Nichol G, Leroux BG, et al. N Engl J Med 2011;265:787–97.

This study compared the strategy of a brief period of cardiopulmonary resuscitation (CPR) with early analysis of rhythm and delivery of indicated defibrillatory shocks as soon as possible with the strategy of a longer period of CPR with a delayed analysis of rhythm. The study was a cluster-randomized trial comprising 10 United States and Canadian universities and their regional emergency medical service (EMS) systems. Most patients were enrolled simultaneously in the study described herein as well as a concurrent study comparing the use of an impedance threshold device (ITD) with use of a sham ITD.

EMS-physicians' self reported airway management training and expertise; a descriptive study from the Central Region of Denmark

BackgroundPrehospital advanced airway management, including prehospital endotracheal intubation is challenging and recent papers have addressed the need for proper training, skill maintenance and quality control for emergency medical service personnel. The aim of this study was to provide data regarding airway management-training and expertise from the regional physician-staffed emergency medical service (EMS).MethodsThe EMS in this part of The Central Region of Denmark is a two tiered system. The second tier comprises physician staffed Mobile Emergency Care Units. The medical directors of the programs supplied system data. A questionnaire addressing airway management experience, training and knowledge was sent to the EMS-physicians.ResultsThere are no specific guidelines, standard operating procedures or standardised program for obtaining and maintaining skills regarding prehospital advanced airway management in the schemes covered by this study. 53/67 physicians responded; 98,1% were specialists in anesthesiology, with an average of 17,6 years of experience in anesthesiology, and 7,2 years experience as EMS-physicians. 84,9% reported having attended life support course(s), 64,2% an advanced airway management course. 24,5% fulfilled the curriculum suggested for Danish EMS physicians. 47,2% had encountered a difficult or impossible PHETI, most commonly in a patient in cardiac arrest or a trauma patient. Only 20,8% of the physicians were completely familiar with what back-up devices were available for airway management.ConclusionsIn this, the first Danish study of prehospital advanced airway management, we found a high degree of experience, education and training among the EMS-physicians, but their equipment awareness was limited. Check-outs, guidelines, standard operating procedures and other quality control measures may be needed.

Citizens’ response to out-of-hospital cardiac arrests (OHCAS) in residences of a remote time distance from regional emergency medical service (EMS) system

Citizens’ response to out-of-hospital cardiac arrests (OHCAS) in residences of a remote time distance from regional emergency medical service (EMS) system

Improving Patient Outcomes from Acute Cardiovascular Events Through Regionalized Systems of Care

ST-segment elevation myocardial infarction (STEMI), cardiac arrest, and ischemic stroke are a diverse group of cardiovascular illnesses linked by the necessity for timely intervention in order to maximize patient outcomes. Despite the known efficacies of therapies, such as emergent percutaneous coronary intervention (PCI), rapid administration of tissue plasminogen activator, and induction of therapeutic hypothermia after cardiac arrest, translating these discoveries into standard practice nationwide has proven difficult to achieve. Significant regional variations in practice are commonplace, and facilities with higher patient volumes of STEMI, cardiac arrest, and ischemic stroke consistently have better outcomes compared with lower-volume facilities. Such disparities in emergency care led the Institute of Medicine in 2006 to describe the existing emergency care system as “at the breaking point,” and to call for “coordinated, regionalized, and accountable” systems of care. An effective and equitable regionalized emergency care system would resemble the existing US trauma system in some respects, with transparent and standard triage guidelines, cooperation between local and regional emergency medical service systems, and an integrated network of referring and receiving facilities. Emerging technologies, such as telemedicine, will likely play a significant role. Regionalized referral systems, such as designated PCI centers and designated stroke centers, are in existence, but have largely been reactive and local, and no mechanism is in place to ensure equitable distribution of such facilities across all geographic regions. As scientific advances in the treatment of these conditions continue to evolve, so too must the system of care that provides these therapies. Evidence suggests that regionalized systems of care for acute cardiovascular events may increase compliance with existing life-saving guidelines and improve patient outcomes.

Houston's Medical Disaster Response to Hurricane Katrina: Part 2: Transitioning From Emergency Evacuee Care to Community Health Care

After Hurricane Katrina hit the Gulf Coast on August 29, 2005, thousands of ill and injured evacuees were transported to Houston, TX. Houston's regional disaster plan was quickly implemented, leading to the activation of the Regional Hospital Preparedness Council's Catastrophic Medical Operations Center and the rapid construction of a 65-examination-room medical facility within the Reliant Center. A plan for triage of arriving evacuees was quickly developed and the Astrodome/Reliant Center Complex mega-shelter was created. Herein, we discuss major elements of the regional disaster response, including regional coordination, triage and emergency medical service transfers into the region's medical centers, medical care in population shelters, and community health challenges.

Houston's Medical Disaster Response to Hurricane Katrina: Part 1: The Initial Medical Response From Trauma Service Area Q

After Hurricane Katrina hit the Gulf Coast on August 29, 2005, thousands of ill and injured evacuees were transported to Houston, TX. Houston's regional disaster plan was quickly implemented, leading to the activation of the Regional Hospital Preparedness Council's Catastrophic Medical Operations Center and the rapid construction of a 65-examination-room medical facility within the Reliant Center. A plan for triage of arriving evacuees was quickly developed and the Astrodome/Reliant Center Complex mega-shelter was created. Herein, we discuss major elements of the regional disaster response, including regional coordination, triage and emergency medical service transfers into the region's medical centers, medical care in population shelters, and community health challenges.

Impact of a rapid access protocol on decreasing door-to-balloon time in acute ST elevation myocardial infarction

Ischemic cardiovascular disease is the leading cause of death in Canada. In ST elevation myocardial infarction (STEMI), time to reperfusion is a key determinant in reducing morbidity and mortality with percutaneous coronary intervention (PCI) being the preferred reperfusion strategy. Where PCI is available, delays to definitive care include times to electrocardiogram (ECG) diagnosis and cardiovascular laboratory access. In 2004, the Cardiac Care Network of Ontario recommended implementation of an emergency department (ED) protocol to reduce reperfusion time by transporting patients with STEMI directly to the nearest catheterization laboratory. The model was implemented in Frontenac County in April 2005. The objective of this study was to assess the effectiveness of a protocol for rapid access to PCI in reducing door-to-balloon times in STEMI. Two 1-year periods before and after implementation of a rapid access to PCI protocol (ending March 2005 and June 2006, respectively) were studied. Administrative databases were used to identify all subjects with STEMI who were transported by regional emergency medical services (EMS) and received emergent PCI. The primary outcome measure was time from ED arrival to first balloon inflation (door-to-balloon time). Times are presented as medians and interquartile ranges (IQRs). Statistical comparisons were made using the Mann-Whitney U test and presented graphically with Kaplan-Meier curves. Patients transported under the rapid access protocol (n = 39) were compared with historical controls (n = 42). Median door-to-balloon time was reduced from 87 minutes (IQR 67-108) preprotocol to 62 minutes (IQR 40-80) postprotocol (p < 0.001). In our region, implementation of an EMS protocol for rapid access to PCI significantly reduced time to reperfusion for patients with STEMI.

Emergency Medical Services Response to a Major Freeway Bridge Collapse

The Interstate 35W Bridge in Minneapolis collapsed into the Mississippi River on August 1, 2007, killing 13 people and injuring 127. This article describes the emergency medical services response to this incident. Complexities of the event included difficult patient access, multiple sectors of operation, and multiple mutual-aid agencies. Patient evacuation and transportation was rapid, with the collapse zone cleared of victims 95 minutes after the initial 9-1-1 call. A common regional emergency medical service incident management plan that was exercised was critical to the success of the response. Communication and patient tracking difficulties could be improved in future responses.

Binarization and cleanup of handwritten text from carbon copy medical form images

This paper presents a methodology for separating handwritten foreground pixels, from background pixels, in carbon copied medical forms. Comparisons between prior and proposed techniques are illustrated. This study involves the analysis of the New York State (NYS) Department of Health (DoH) Pre-Hospital Care Report (PCR) [Western Regional Emergency Medical Services, Bureau of Emergency Medical Services, New York State (NYS) Department of Health (DoH), Prehospital Care Report v4.] which is a standard form used in New York by all Basic and Advanced Life Support pre-hospital health care professionals to document patient status in the emergency environment. The forms suffer from extreme carbon mesh noise, varying handwriting pressure sensitivity issues, and smudging which are further complicated by the writing environment. Extraction of handwriting from these medical forms is a vital step in automating emergency medical health surveillance systems.

Sodium bicarbonate improves outcome in prolonged prehospital cardiac arrest

Objective This study evaluates the effect of early administration of an empirical (1 mEq/kg) sodium bicarbonate dose on survival from prehospital cardiac arrest within brief (<5 minutes), moderate (5-15 minutes), and prolonged (>15 minutes) down time. Methods Prospective randomized, double-blinded clinical intervention trial that enrolled 874 prehospital cardiopulmonary arrest patients managed by prehospital, suburban, and rural regional emergency medical services. Over a 4-year period, the randomized experimental group received an empirical dose of bicarbonate (1 mEq/kg) after standard advanced cardiac life support interventions. Outcome was measured as survival to emergency department, as this was a prehospital study. Results The overall survival rate was 13.9% (110/792) for prehospital arrest patients. There was no difference in the amount of sodium bicarbonate administered to nonsurvivors (0.859 ± 0.284 mEq/kg) and survivors (0.8683 ± 0.284 mEq/kg) ( P = .199). Overall, there was no difference in survival in those who received bicarbonate (7.4% [58/420]), compared with those who received placebo (6.7% [52/372]) ( P = .88; risk ratio, 1.0236; 0.142-0.1387). There was, however, a trend toward improved outcome with bicarbonate in prolonged (>15 minute) arrest with a 2-fold increase in survival (32.8% vs 15.4%; P = .007). Conclusion The empirical early administration of sodium bicarbonate (1 mEq/kg) has no effect on the overall outcome in prehospital cardiac arrest. However, a trend toward improvement in prolonged (>15 minutes) arrest outcome was noted.

The Effectiveness of Out-of-Hospital Use of Continuous End-Tidal Carbon Dioxide Monitoring on the Rate of Unrecognized Misplaced Intubation Within a Regional Emergency Medical Services System

We evaluate the association between out-of-hospital use of continuous end-tidal carbon dioxide (ETCO2) monitoring and unrecognized misplaced intubations within a regional emergency medical services (EMS) system. This was a prospective, observational study, conducted during a 10-month period, on all patients arriving at a regional Level I trauma center emergency department who underwent out-of-hospital endotracheal intubation. The regional EMS system that serves the trauma service area is composed of multiple countywide systems containing numerous EMS agencies. Some of the EMS agencies had independently implemented continuous ETCO2 monitoring before the start of the study. The main outcome measure was the unrecognized misplaced intubation rate with and without use of continuous ETCO2 monitoring. Two hundred forty-eight patients received out-of-hospital airway management, of whom 153 received intubation. Of the 153 patients, 93 (61%) had continuous ETCO2 monitoring, and 60 (39%) did not. Forty-nine (32%) were medical patients, 104 (68%) were trauma patients, and 51 (33%) were in cardiac arrest. The overall incidence of unrecognized misplaced intubations was 9%. The rate of unrecognized misplaced intubations in the group for whom continuous ETCO2 monitoring was used was zero, and the rate in the group for whom continuous ETCO2 monitoring was not used was 23.3% (95% confidence interval 13.4% to 36.0%). No unrecognized misplaced intubations were found in patients for whom paramedics used continuous ETCO2 monitoring. Failure to use continuous ETCO2 monitoring was associated with a 23% unrecognized misplaced intubation rate.

Association of obesity with worsened prehospital cardiac arrest

Background. This study evaluated a potential correlation between patient age, body weight and survival from prehospital cardiac arrest, as a secondary endpoint in a study evaluating the effect of bicarbonate on survival.Design. A prospective, randomized, double‐blinded clinical intervention trial.Methods. 874 prehospital cardiopulmonary arrest patients in a prehospital urban, suburban, and rural regional emergency medical service (EMS) area were used. This group underwent conventional Advanced Cardiac Life Support (ACLS) intervention followed by empiric early administration of sodium bicarbonate (1 mEq/L). Survival was measured as presence of vital signs on ED survival. Data was analyzed utilizing Student's t‐test, Fisher's exact test, Chi‐square with Pearson correlation and logistic regression (p<0.05).Results. The overall survival rate was 13.9% (110 of 793) of prehospital arrest patients. There was no significant difference between the control and bicarbonate groups for patient age (67.7 versus 67.4 years, p = 0.769) and body weight (87.9 versus 89.7 kg, p = 0.508). There was no difference in outcome associated with age for non‐survivors or survivors (67.3 versus 67.5 years, p = 0.943). However, a significant difference in total body weight (TBW) was noted between non‐survivors and survivors (84.9±27.3 kg versus 77.3±21.4 kg, p<0.002).Conclusion. There is a significant adverse association between body weight and outcome, but no association between advanced age and prehospital survival.

Rapid protocol changes in a regional emergency medical services system: Do providers comply?

Study objectives: Emergency medical services (EMS) directors are often forced to rapidly make protocol changes in response to events in an EMS system. These changes are expected to have an immediate impact on patient care. Success depends on the speed at which the protocol is adopted, its continued use rate, and the rate at which providers stop using the protocol as a defined end date approaches. No study has attempted to characterize compliance with rapid protocol changes. We characterize compliance by EMS providers when a 1-month protocol is introduced and then terminated. Methods: This is a descriptive study. To reduce individual emergency department crowding, a protocol instructing EMS providers to contact an EMS medical control staffed by attending EMS physicians was introduced into a regional EMS system. Providers were instructed to call for all patients inbound to a 2-hospital system to receive destination instructions. A high compliance would allow medical control to triage patients to the most appropriate hospital after consideration of patient needs, resource availability, and waiting times. Medical control physicians logged all calls prospectively. Registration records were reviewed to determine the total number of patients arriving by EMS. Compliance was defined as the daily percentage of EMS patients being called in to medical control. The protocol functioned for 31 days and was terminated on short notice. Results: Compliance rose from 56% on day 1 to 88% by day 4. Day 5 through day 30 compliance ranged from 59% to 93% (mean 72%). On the final day of the protocol's operation, after an announcement the previous day of its termination, compliance decreased from 68% to 39%. Conclusion: EMS providers will rapidly adopt and continue to comply with a protocol. Announcement of protocol termination causes an immediate drop in compliance even before a defined termination date. Medical directors should consider these factors when considering the results of the introduction of a protocol into an EMS system.

Improvement in Misplaced Endotracheal Tube Recognition within a Regional Emergency Medical Services System

Improvement in Misplaced Endotracheal Tube Recognition within a Regional Emergency Medical Services System

The evolution and current status of emergency medical services for children

Emergency physicians have come to believe that comprehensive pediatric emergency care should be integrated into an overall medical system and organized regionally to address the special needs of children. Since our emergency medical systems have evolved in the care of adult trauma victims, we must look to that development for the origin of our present emergency medical services for children. Not until the 1970s did it became obvious that children, just as adults, should be included in an comprehensive emergency medical system for the care of their life threatening injuries. Since there is considerable overlap in the basic principles of trauma resuscitation and management of shock in children and adults, most children's regional trauma program developed as a part of an overall emergency medical system. The sharing of trauma facilities made it possible to utilize the special expertise of a very small number of pediatric surgeons who had trauma experience and to incorporate their skills into the broader concept of comprehensive regional trauma centers for children and adults. With further experience we soon realized that such emergency medical services for children's systems should include the following components: A two way communication system, a transport system with special equipment for the management of small children, a training program for first responders at the trauma site, a designated pediatric trauma center, a pediatric intensive care unit at the regional trauma center, a neurology/neurosurgery intermediate care unit at the regional center, a pediatric trauma rehabilitation unit and finally a pediatric trauma longterm rehabilitation and management unit for those with residual disabilities. With the further development of this concept of trauma units for children, pediatric surgeons, general surgeons involved in trauma care and pediatric emergency physicians have offered leadership to expand the emergency medical system for children to include life-threatening illness, as well as injuries. Thus, the organization of regional emergency medical services for children permits the highest quality management of children with life-threatening injuries and illness. This then is the final product: an inclusive, comprehensive emergency medical system for children for all life threatening conditions, both trauma and serious illness.

Out-of-hospital cardiac arrests in an urban/rural area during 1991 and 1996: have emergency medical service changes improved outcome?

Survival after out-of-hospital cardiac arrest is influenced by pre-hospital emergency medical care. This study compares outcome of cardiac arrest victims presenting to an emergency department serving a mixed urban/rural area (Norfolk, UK) in 1991 with 1996. Between these years the regional emergency medical service (EMS) was extensively re-organized. We identified 113 such cases of out-of-hospital cardiac arrest in 1991 and 147 in 1996. The age distribution, proportion of witnessed arrests, and initial rhythms were similar for the 2 years. In 1996 EMS response time was significantly slower and the proportion of cases where the EMS arrived before arrest was significantly lower. Fewer patients who had a witnessed arrest received immediate bystander CPR in 1996. The number of patients discharged home decreased from 15 in 1991 to 11 in 1996, but this difference did not reach statistical significance. The majority of survivors had restoration of spontaneous circulation prior to arrival in the emergency department (14 in 1991 and ten in 1996). Survival was greatest in those arresting in the presence of the EMS (ten in 1991 and nine in 1996). In conclusion changes in EMS provision have resulted in an increase in the response time. This was associated with a decrease in the number of survivors although this was not statistically significant.

Stroke in a regional emergency medical services system; a case analysis in the Mainz EMS

Stroke in a regional emergency medical services system; a case analysis in the Mainz EMS

Stroke in a regional emergency medical services system; a case analysis in the Mainz EMS

Stroke in a regional emergency medical services system; a case analysis in the Mainz EMS