The Efficacy of Advanced Life Support: A Review of the Liter

[Ace844]

Hi All,

I was wondering after reading this 'article' about how we can find out if EMS and ALS is actually efficacious in the timely response, treatment and transport of the public which we all serve?? IF not how do we change this? If so, how do we improve it and let others know that what we do works?? So post your data, and opinions here!!

Hope this Helps,

ACE844

http://www.pcrf.mednet.ucla.edu/pdf1.pdf

http://secure9.rolet.com/naemsp/naemsppres...ermay-jun05.pdf

(Anasthesiol Intensivmed Notfallmed Schmerzther. 2003 Oct;38(10):630-42. Related Articles @ Links

[Comparison of the emergency medical services systems of Birmingham and Bonn: process efficacy and cost effectiveness)

[Article in German]

Fischer M, Krep H, Wierich D, Heister U, Hoeft A, Edwards S, Castrillo-Riesgo LG, Krafft T.

Klinik und Poliklinik fur Anasthesiologie und Spezielle Intensivmedizin des Universitatsklinikum Bonn. Matthias.Fischer@ukb.uni-bonn.de]OBJECTIVE: Due to rising health care costs there is a need to verify that the treatment by Emergency Medical Services (EMS) systems is efficient and cost effective. The integration of emergency physicians is inherent part of out-of-hospital emergency care and regulated by law in Germany but not in England and the United States of America. Aim of this study therefore was to conduct a cost performance analysis by evaluating the underlying structure, the costs incurred and the achieved performance in two EMS systems with paramedics or emergency physicians on scene. METHODS: The study was carried out in West-Birmingham, a part of the West-Midlands-Ambulance-Service (WMAS), and the EMS of Bonn. Pre defined questionnaires, EMS protocols, calculations of purchasing power parity and recent publications concerning out-of-hospital resuscitation (CPR) were used to evaluate the operating costs, to describe the structure and to measure the quality of performance. Significance was assumed at p < 0.01 for CHI(2)- or t-test, respectively. RESULTS: Birmingham used state of the art technology for dispatch and logistics whereas Bonn trusted in high qualified personnel. In the 1st quarter 1997 the Mainz-Emergency-Evaluation Score could be achieved before (MEES A) and after preclinical treatment (MEES in 3502 and 3422 patients in Birmingham and Bonn, respectively. In Birmingham 7.5 % and in Bonn 17 % of all patients could be improved by the EMS treatment, respectively (p < 0.01). Looking at severely ill patients (MEES A < 22) the EMS in West-Birmingham achieved an improvement in 27.9 % of these patients with an averaged change in MEES of 0.9 +/- 1.7 points in all of them. In contrast the Bonn EMS improved the status in 47.8 % of these patients and MEES A could be improved considerably by 2.3 +/- 3.4 points (p < 0.01). Pharmacological treatment was less frequently used in Birmingham than in Bonn (12.9 % vs. 32.4 %, respectively; p < 0.01). At equal incidences of CPR attempts discharge rate after CPR was only 4 % in WMAS compared to 14.7 % in Bonn-North (p < 0.01). Per inhabitant and year total costs amounted to 10.43 euro for the EMS system in Birmingham, which is 42 % less than in Bonn. Unit hour utilisation reached 0.6 in Birmingham and only 0.33 in Bonn. In severely ill patients the improvement of MEES A by 0.1 points cost per inhabitant and year 1.16 euro in Birmingham and only 0.65 euro in Bonn. The survival of one patient after CPR was calculated to 0.7 euro in Birmingham and 0.17 euro in Bonn. CONCLUSIONS: The provider of the EMS in West-Birmingham--WMAS--organised a reliable system with high efficiency concerning unit hour utilisation and response time reliability. In the EMS of Bonn, in contrast, the complex therapy by the emergency physicians improved MEES considerably and increased probability of survival after CPR at a higher level of efficiency. Further investigations however are necessary to evaluate the presented parameter of efficiency.

http://pdm.medicine.wisc.edu/bissell.htm Prehospital and Disaster Medicine

Complete Paper

Volume 13, Number 1

COLLECTIVE REVIEW

The Efficacy of Advanced Life Support: A Review of the Literature

Richard A. Bissell, PhD;1 Dawn Gyory Eslinger, MS;2 Lynn Zimmerman, MS, BSN3]

Abstract

Introduction: Jurisdictions throughout the United States and some other parts of the world have invested substantial time and resources into creating and sustaining a prehospital advanced life support (ALS) system without knowing whether the efficacy of ALS-level care had been validated scientifically. In recent years, it has become fashionable for speakers before large audiences to declare that there is no scientific evidence for the clinical effectiveness of ALS-level care in the out-of-hospital setting. This study was undertaken to evaluate the evidence that pertains to the efficacy of ALS-level care in the current scientific literature.

Methods: An extensive review of the available literature was accomplished using computerized and manual means to identify all applicable articles from 1966 to October, 1995. Selected articles were read, abstracted, analyzed, and compiled. Each article also was categorized as presenting evidence supporting or refuting the clinical efficacy of ALS-level care, and a list was constructed that pointed to where the preponderance of the evidence lies.

Results: Research in this field differs widely in terms of methodological sophistication. Of the 51 articles reviewed, eight concluded that ALS-level care is not any more effective than is basic life support, seven concluded that it is effective in some applications but not for others, and the remainder demonstrated effectiveness. The strongest support for ALS-level care was in the area of responses to victims of cardiac arrest, whereas somewhat more divergent findings related to trauma or non condition-specific studies.

Conclusions: While not unanimous, the predominant finding of recent research into the clinical effectiveness of advanced life support demonstrates improved effectiveness over basic life support for patients with certain pathologies. More outcomes-based research is needed.

Bissell RA, Eslinger DG, Zimmerman L: Advanced life support: A review of the literature. Prehospital and Disaster Medicine 1998;13(1):69-79.

Introduction

Over the last 25 years of organized EMS, many speakers in lecture halls, grand rounds, and policy debates on three continents have declared that there is no evidence that prehospital advanced life support (ALS) is more effective clinically than is basic life support (BLS). The enthusiasm for this viewpoint recently reached new heights on emergency medical services (EMS) bulletin boards on the Internet. These declarations have been put forth by individuals with an international reputation for leadership in emergency health services who presumably are credible on this subject. When offered in meetings where policy makers, many of whom are unfamiliar with the literature, are engaged in resource allocation decisions, such knowledgeable-sounding comments have had a powerful effect on the outcome of the meetings. Thus, it seemed clear that a compendium of ALS-related research was needed, so that opinions can be based on the published literature rather than upon anecdotes and reports.

In the spring of 1994, the American Ambulance Association (AAA) asked the authors to compile the available literature relative to the effectiveness of advanced life support-levels of care. The objective was to identify documented research that addressed a list of key questions provided by the American Ambulance Association as a first step in examining the dynamics, effectiveness, and financial stability of the provision of ALS-level services compared to the provision of BLS-level services. The research questions were: 1) What is the correlation between ALS and survival after a medical or traumatic emergency?; and 2) Which diseases, injuries, or medical conditions are impacted by the provision of ALS?

The work was completed in Baltimore at the University of Maryland's National Study Center for Trauma and Emergency Medical Systems in late spring and summer of 1994. Since then, the search was updated to October 1995.

Methods

On-line computer files available through the University of Maryland Health Sciences Library, the National Library of Medicine, the Colorado Association of Research Libraries, and several other sources available through the Internet were searched. All articles deemed appropriate were obtained through local library or inter-library loan services. After reviewing the articles, the process of tying the literature to the research questions was initiated.

One of the obstacles facing research in emergency medical services (EMS) is that there is no centralized repository of EMS-related publications. Work that appears in peer-reviewed, scientific journals generally is available through the use of standard search channels. However, much of the work in this field has appeared in trade journals (e.g., Journal of Emergency Medical Services) or in industry sources (e.g., Ambulance Industry Journal, the journal published by the American Ambulance Association), and it was difficult to find references to such sources.

A second obstacle is the difficulty of conducting research in EMS, given the poor state of data sources and the short time in which the patients actually is in the care of EMS personnel.1 Additionally, often the research models used have limited power, given the task at hand.2 This literature review includes citations from research based on widely varying methods and data sources; we do not vouch for the methodologic soundness of each quoted source, although we have chosen from reputable publications and information sources.

Findings

Findings are presented using clinical groups: 1) cardiac arrest; 2) other cardiac emergencies; 3) trauma; 4) seizure management; and 5) findings that are not condition-specific.

Cardiac Arrest

Cardiac arrest and the related chance of reversing a particular rhythm (ventricular fibrillation), formed one of the two primary foci for the development of prehospital advanced life support. The 1966-1967 work of Pantridge3 using physician- and nurse-staffed mobile intensive care units in Belfast, stimulated work in several parts of the United States to create a method of delivering life-saving cardiac care only minutes after arrest or symptom onset. Instead of attempting to use scarce and expensive physicians in the prehospital setting, the emergency medical technician-basic (EMT) was created the United States to provide basic cardiac and injury life support, and the emergency medical technician-paramedic (EMT-P) to provide advanced life support measures.

By the late 1970s, Eisenberg4,5 and others were beginning to demonstrate higher successful resuscitation rates for ALS-level providers than for BLS-level providers. In a study in King County, Washington, Eisenberg¸et al described the cardiac arrest survival rate in a suburban population of 304,000 before and after the addition of paramedic-level ALS services. Paramedic-level services improved the rate of admissions to intensive care units or coronary care units of successfully resuscitated patients from 19% to 34% (p <0.001) and the rate of discharge of these patients improved from 7% to 17% (p <0.01). In addition, paramedic services decreased the time from arrest to the delivery of advanced care from an average of 27.5 minutes to 7.7 minutes.

Eisenberg et al¸6 further demonstrated, in a tiered-response system, the effectiveness of early defibrillation followed by paramedic-level care compared with BLS-level care followed by paramedic care. For randomized cases, when the time interval between EMT and paramedic arrival was more than four minutes, improved survival resulted when EMT defibrillation was followed by paramedic care (42%) compared with BLS-level care followed by paramedic care (19%). Thus, the authors demonstrated the value of providing at least limited ALS skills immediately following cardiac arrest, especially when followed by full paramedic-level care.

In 1991, Cummins et al,7 based largely on work done by Eisenberg8 and others, established methods of improving survival for victims of sudden cardiac arrest. "More people can survive sudden cardiac arrest when a particular sequence of events occurs as rapidly as possible. This sequence is 1) recognition of early warning signs; 2) activation of the emergency medical system; 3) basic cardiopulmonary resuscitation; 4) defibrillation; 5) intubation; and 6) intravenous administration of medications." These steps define the "chain of survival". If any one of these links is flawed, the chance of survival is attenuated and the efforts of the EMS system are condemned to poor results.7

Cummins et al¸7 compiled data from 31 locations for patients who suffered a cardiac arrest to determine the range of rates of survival to hospital discharge for all cardiac-arrest rhythms by system type (Table 1). Systems that employed emergency medical technicians trained to use defibrillators (EMT-Ds) had an average survival rate from cardiac arrest of patients of 16% compared with 29% for the systems employing the services of EMT-Ds and paramedics combined. This rate included those patients in witnessed cardiac arrest who presented with ventricular fibrillation]. The paramedic-only system showed a 17% average survival rate, almost identical to the rate obtained by the EMT-D-only system. This was explained by the observation that, in the paramedic-only systems, all advanced cardiac life support (ACLS) interventions were performed, but late in the course of the cardiac arrest. In the EMT-D systems, only basic CPR and defibrillation were performed, but much earlier. These studies demonstrated the strength of the first two links in the chain of survival: early defibrillation and early advanced care.

A six-year study of-patients suffering cardiac arrest in the out-of-hospital setting conducted in York and Adams Counties, Pennsylvania, found that 18% of patients who received early CPR (within four minutes) and early ALS-level care (within 10 minutes) survived to hospital discharge.9 The percentage dropped to 7% (p <0.001) when CPR was started early, but when the addition of ALS-level care was delayed (beginning after 10 minutes). Again, an early link to ALS appeared to be crucial.

Kellerman et al¸ studied the effects of adding first-responder defibrillation to an urban EMS system served by paramedics.10 Half of the participating fire-engine companies were given automatic external defibrillators (AEDs) and the staff was instructed to defibrillate patients immediately in the event of a cardiac arrest. The personnel staffing the other half of the participating engine companies were instructed to initiate CPR immediately in the event of a cardiac arrest. The average response time of the engine companies was 2.5 minutes faster than was the response time for the simultaneously dispatched paramedics. During the 39-month study, patients initially treated using an AED were no more likely to be resuscitated nor to survive to hospital discharge than were patients treated only using BLS-level procedures. They concluded that, even in a rapidly responding EMS system (including paramedics), first-responder defibrillation has a relatively minimal impact. "Early defibrillation alone cannot overcome low community rates of bystander CPR." Kellerman et al¸ thus, placed emphasis on another link in the cardiac survival chain: "early bystander CPR".

A prospective study of 566 patients examined the effectiveness of newly established EMT-D programs in rural Wisconsin.11 During the 18-month study, 6.4% of victims survived primary cardiac arrest with EMT-D intervention; however, prior to EMT-D implementation, only 3.6% had survived (p <0.02). One of the interesting outcomes of this study was the documentation of a linear relationship between time from arrest to defibrillation and survival: short times present a substantial challenge in rural areas.

A 1993 study by Larsen et al¸ used sophisticated mathematical formulas to analyze the relationship between cardiac arrest survival, time, and specific interventional strategies.12 Linear relationships with time and survival rates were established for strategies that included EMTs only, EMT-Ds only, paramedics, EMT/paramedic teams, EMT-D/paramedic teams, and the King County (Washington) EMT-D/paramedic teams. The mathematical model predicted that the highest survival rates would be obtained through the paramedic-only model and the EMT-D/paramedic model. The results reinforced earlier studies that showed the time to definitive care is the best predictor of success.

In another study by Kellerman et al¸ the Memphis Fire Department treated 1,068 victims of out-of-hospital cardiac arrest during a 39-month study period.13 Of these patients, 300 (29%) regained spontaneous circulation as a result of ACLS interventions and 26.5% were discharged from the hospital. They also concluded that rapid transport of adult patients who do not respond to ACLS yields dismal survival rates; therefore, on-line [direct] medical control should authorize the paramedics to cease resuscitation efforts in the field.

Several other studies emphasized the value of early defibrillation. Stults et al¸14 studied the issue in 30 rural communities with an average population of 10,400. The EMTs within specific communities attended a 16-hour training course to evaluate and defibrillate specific cases of patients with ventricular fibrillation. When early defibrillation was available, 19% of the patients were resuscitated and discharged from the hospital whereas only 3% were discharged alive from the hospital in those communities in which defibrillation was not available (p <0.05).

In Perth, Australia, a retrospective cohort study reviewed 231 cases with ventricular fibrillation that occurred between 01 January, 1987 and 31 December, 1988. Of the 231 patients treated with defibrillation by ambulance officers without full paramedic skills, 40 (22.7%) survived through 28 days after discharge from the hospital. "The proportion of survivors in this study is similar to that receiving full paramedic services."15 The authors concluded that when time to defibrillation is short, the chance of survival from cardiac arrest due to ventricular fibrillation increases; therefore, rapid initiation of defibrillation is the key component in survival from ventricular fibrillation that occurs outside of the hospital.

In 1990, the state of Delaware established a statewide paramedic system. Cardiac arrests occurring in one county between 01 October, 1990 and 30 September, 1991, were evaluated.16 Data obtained from paramedic records included age, gender, initial cardiac rhythm, time from dispatch to arrival of ALS-level care, and outcome. The definition of a successful prehospital resuscitation was "restoration of a detectable blood pressure and pulse." Seventy-three (19%) of 377 patients who experienced cardiac arrest were resuscitated successfully; however, when the population was grouped according to the initial electrocardiographic rhythm, the ventricular fibrillation/tachycardia group had a higher rate of resuscitation (30% versus 17%). The successful resuscitations were achieved within paramedic response times averaging between 5.6 and 6.5 minutes.

In the mid 1970s, advanced cardiac life support (ACLS) was introduced into the EMS systems of the cities of Minneapolis and St. Paul. A statistically significant improvement in the survival rates from out-of-hospital cardiac arrests became evident during the subsequent 10-year study period.17 Between 1972 and 1982, cardiac arrest survival rates improved for both men and women. Survival to hospital discharge increased from 4.9% to 13.1% for men and 1.1% to 3.5% for women. One-year survival post-cardiac arrest also improved from 1.8% to 11.7% for men and 0.5% to 3.5% for women.

Investigators in Monroe County, New York, evaluated 463 cases with prehospital cardiac arrest to which ALS-level units responded. The 48 patients who were found to be in ventricular fibrillation or ventricular tachycardia and who received CPR within four minutes and were treated according to ACLS protocols within 10 minutes by ALS-level providers, had a survival rate of 33%. In comparison, similar patients who received CPR within four minutes, but for whom ALS-level care was delayed beyond 10 minutes, had a survival rate only of 20%.18

During a six-month study, Pepe et al collected data from 200 cases with ventricular fibrillation; 13 (6.5%) were witnessed by paramedics.19 Eight (62%) of these 13 cases were resuscitated successfully and all survived to hospital discharge.

The same investigators also implemented an 18-month study to monitor survival rates of patients with ventricular fibrillation or tachycardia (VF/VT) following the conversion of an all-paramedic service to a tiered, priority dispatch system utilizing BLS-level and ALS-level units.20 For the six months of the transition period, 32 dual-response (1 EMT and 1 paramedic) units were formed. Six months prior to the transition, the VF/VT save rate for successful hospital discharges by the system was 11.3%. After the introduction of the tiered system, the save rate rose to 17.4% during the six-month transition period and remained at 17.0% six months after final activation of the new system. Side benefits of this conversion included improved paramedic morale and reductions in staffing shortages.20 In more recent work, Pepe et al21 examined the effectiveness of ACLS, and, while questioning some of its components, concluded that ACLS is effective enough clinically to be considered the current standard of care.

Another research group,22 took a different approach to examining the effectiveness of the use of ALS in managing victims of cardiac arrest. They trained prehospital ALS providers to use and interpret 12-lead electrocardiograms (ECGs). They concluded that paramedics are capable of operating effectively at this level and that the increased diagnostic power "...may allow for consideration of altering and improving prehospital and hospital-based management of this patient population."

While it is not the intent of this paper to examine economic issues, Valenzuela et al demonstrated that paramedic responses to out-of-hospital cardiac arrest is more cost-effective per-life-saved, than are many other common life-saving procedures.23

In an editorial, Ornato et al (1990) argued that evidence supporting the efficacy of ALS related to cardiac arrest is sufficiently strong to make ALS provision a moral imperative.24 They argued that the all-ALS system is most effective clinically and costs little more than does a tiered BLS-ALS system.

In summary, numerous studies have shown that the use of ALS-level care contributes to survival of victims of cardiac arrest, particularly when ventricular fibrillation is the primary presenting cardiac rhythm. Basic life support services are effective deterrents to sudden cardiac death only when backed-up by rapid implementation of advanced life support measures. Emergency medical technicians trained to defibrillate (EMT-Ds) have the most positive effect among BLS providers. Results from these studies are not identical, yet the preponderance of evidence strongly supports the need for prehospital ALS in order to obtain positive outcomes for patients in cardiac arrest. Debate continues on exactly which configuration of ALS delivery system produces the best outcomes for victims of cardiac arrest.

Other Cardiac Emergencies

At the time of this review, the most recent study of out-of-hospital (non-arrest) cardiac emergencies was conducted in the Hamilton-Wentworth area of Ontario, Canada. Shuster et al25 selected from 30,000 ambulance patients 3,066 with cardiac illness who called 9-1-1 for emergency medical assistance. Patients with a cardiac arrest were excluded from the study. Hamilton-Wentworth operates a two-tiered system with a limited number of ALS providers who are assigned only to emergency calls. Because of the lack of ALS providers, chances were roughly 50% that a given emergency request would be provided by BLS (EMT-D) personnel, thus, creating an almost random selection of cardiac patients treated either by ALS- or BLS-level personnel. While the patients who received ALS-level care seemed somewhat sicker than were those treated by the BLS crews (not statistically significant), the authors identified no statistically significant differences in outcome between the two groups. They concluded: "In an urban setting with short (<10 minutes) average transport times, the availability of prehospital paramedic care does not affect occurrence of MI, length of stay, or mortality of patients presenting to the EMS system with cardiac illness." They added: "We are disappointed at not being able to show a benefit of prehospital ALS care because we believe, along with all of the care providers in our EMS system, that ALS care is beneficial. Perhaps our outcome measures are too crude or the effect too small to demonstrate benefit."

In contrast, a prospective, longitudinal study conducted in South Carolina, found significant differences in rates of survival for victims of myocardial infarction with hypotension. Pressley et al26 demonstrated a decrease in the mortality rate from 69% in a BLS-only system to 10% following the introduction of paramedics into the system for those patients who, following a myocardial infarction, were hypotensive. The mortality rate for hypotensive patients with sinus bradycardia or atrioventricular (AV) block decreased from 71% to 0%; for those with normal sinus rhythm, the mortality rate decreased from 60% to 0%; and for those with sinus tachycardia or supraventricular tachycardia (SVT), the mortality rate fell from 100% to 33%. Among post-infarct patients with normotension, the mortality rate actually increased slightly (but not significantly), but for those with hypertension the mortality rate decreased from 16% to 9%. The authors concluded:

This study demonstrated a significant decrease in the mortality of patients with hypotension and acute myocardial infarction after the introduction of paramedic level treatment with an aggressive hypotensive protocol. The dramatic decline of mortality in patients with hypotension resulted in the emergence of the normotensive group with tachycardia as the new "high risk" population [p 1561].

In a study conducted in Pennsylvania, a retrospective record review of 493 patients suffering from congestive heart failure (identified by hospital discharge diagnosis) evaluated the effects on the mortality rate and length of stay of ALS medications administered in the prehospital setting.27 Of the 493 patients in this study, 54 died (10.9%). The treated and untreated groups were similar in age, gender, cardiac rhythms, previous use of medications, response times, and on-scene times. The mortality rate for the treated group was less than it was for the untreated group (odds ratio for improved survival, 2.51; 95% confidence interval, 1.37 to 4.55; p <0.01). Wuerz and Meador concluded that the use of "prehospital medications improve survival in congestive heart failure, especially in critical patients. More than one combination of medications seems effective, and early treatment is associated with improved survival. Basic life support (BLS) providers cannot provide the diagnoses and treatment found helpful for congestive heart failure in this study."

A two-year, prospective study examined the effects of mobile paramedic units on the outcome of patients who experienced an acute myocardial infarction (AMI) of whom 9.4% experienced a cardiac arrest prior to a coronary care unit (CCU) admission.28 The overall mortality rate was 20.9%. The study compared the outcome of patients who received prehospital care from a mobile paramedic unit versus a control group who selected another means of transportation to the hospital. Patient outcome did not improve with the use of the mobile paramedic unit. Further, the unit produced a 29-minute delay in hospital arrival. However, among the patients who arrested prior to CCU admission, six of 11 paramedic-assisted patients survived to hospital discharge, while only one of 11 in the "control" group survived. Differences in post-discharge deficits were not measured. The authors noted that one explanation for the results may have been in the potential bias introduced by the method of assigning patients to the study or control group. The study group self-selected by calling for paramedic services (and may have had a higher acuity level), while the control group chose other methods of transport.

Tresch et al, in a 1983 study,29 found that paramedics were able to diagnose out-of-hospital pulmonary edema of cardiac origin correctly 89% of the time. Sixty percent of patients in this study who demonstrated cardiac arrest prior to hospitalization were resuscitated successfully. The authors concluded:

Trained paramedic units are capable of quickly diagnosing and treating cardiac pulmonary edema during the prehospital period. Therapy administered by paramedics prior to the patient's arrival in the hospital appears to be beneficial and may prevent serious complications, including cardiac arrest [p 536].

An early multi-year study in Virginia compared the rates of survival from acute myocardial infarction (AMI) prior to and after the introduction of paramedic advanced life support services. The investigators found that the use of ALS-level services cut in half the number of AMI fatalities.30

In summary, studies of the effects of prehospital care on outcome from cardiac conditions other than cardiac arrest have produced differing results. Some identified found positive effects of paramedic care on the outcomes of patients with congestive heart failure and pulmonary edema of cardiac origin. Others found paramedic-level surveys significantly beneficial to hypotensive AMI patients, while others noted a positive contribution to outcome only for those patients with an AMI who also arrested.

Trauma

Traumatic injuries provided the second major impetus for creating and implementing advanced life support-level (ALS) services in the United States. In addition to the basic life support-level (BLS) trauma management skills, ALS providers added enhanced airway management, chest decompression, the potential use of paralytic agents, fluid replacement therapy, and important pharmacologic modalities.

Fortner et al examined survival rates for 180 people who jumped from a bridge (height: 50 meters) in Seattle since 1932.31 The effects of ALS-level care, which became available in Seattle in 1970, also were studied. Forty-nine people jumped between 1932 and 1949, and only one, a stunt man, survived. Between 1950 and 1969, 36 of the 45 jumpers landed in the water; between 1970 and 1981, 71 of 86 fell into water. During the middle period, BLS-level units treated 15 of the 36 people who initially survived the fall (42%). Advanced life support-level care was administered to 30 of the 70 initial survivors (42%) during the most recent period. With only BLS care, 10 of the 15 patients died en route; however, under ALS-level care, only one patient died. The survival rate for BLS care in this study was 27% versus the survival rate of 73% when ALS-level care was provided even though the injury severity score for ALS patients was 108% greater than was that for the BLS-treated patients.

A second retrospective study examined 112 patients with major, open, intra-abdominal vascular injuries and compared the mortality rates for four years of ALS-level care and eight years of BLS experience.32 When the patients' systolic blood pressure was critical (<60 mmHg), the addition of ALS-level care was associated with an increased survival rate from 14% to 50% even though in-field time extended from 22 to 38 minutes.

A controlled trial of the outcomes of 472 trauma patients who received prehospital ALS-level care and 589 trauma patients who received prehospital BLS-level care was conducted by Potter et al33 The hypothesis of this study was that "ALS had a favorable impact on mortality and morbidity." The study compared the outcomes for trauma patients in two cities: one in which prehospital ALS-level care was available and one where it was not. Within the first 24 hours of injury, 17 of the 37 (46%) ALS-treated patients died compared with 24 of 33 (73%) of the BLS-treated patients (p <0.05). In the BLS group, 26 (79%) of the patients died prior to admission to the intensive care unit (ICU) versus 16 (46%) in the ALS group (p <0.01). The incidence of respiratory failure for ALS-treated patients was 5% (5 of 93) versus 19% (14 of 74) for those who had received BLS-level care (p <0.025). Potter et al¸ concluded that "ALS for trauma is only resuscitative and not definitive therapy. If any group is amenable to ALS, it is the intermediate severity of injury group (i.e., neither overwhelmingly fatal, nor mild injuries); injury severity, age, response time, treatment time on scene, transport time, time to definitive care, type of trauma, and quality of hospital care all affect outcome." The study did not confirm the hypothesis that ALS care would reduce the case fatality rate; however, it demonstrated that 54% of deaths in the ALS group occurred at least 24 hours after the injury (27% of the patients treated with BLS procedures died after that period). Possible explanations were that the BLS group may have been more severely injured than were the ALS-treated patients or that the ALS group may have received a higher standard of care upon arrival at the hospital. Potter states that "researchers have found an association between ALS care and improved vital signs on hospital arrival." The authors concluded that ALS-level care reduces early mortality, but has little impact on long-term clinical outcomes.33

Cayten and colleagues compared BLS-level and ALS-level services that transported patients to the same receiving facilities. The study was controlled for severity of injury and compared age, initial trauma score (TS) in the field, injury severity score, response time, scene time, transport time, change in TS from field to hospital, and mortality rate (Table 2). The ALS-level units treated more seriously injured patients than did the BLS-level units. "The ALS units show almost precisely the same effect of TS change as do the BLS units and have a greater mortality rate." The additional eight minutes on scene may have contributed to this finding.34

In 1993, Cayten et al¸ continued the comparison of ALS- and BLS-levels of care through a retrospective review of the records of 781 patients involved in motor vehicle crashes (ISS >10) and 219 hypotensive patients.35 Data were collected from eight hospitals over a 24-month period. Initial, prehospital, Revised Trauma Scores (RTSs) were compared with initial emergency department RTSs. The scores improved between the two phases of care for ALS-treated patients, but not for BLS-treated patients. In addition, patients who received ALS-level care had significantly greater changes in blood pressure and in the percentage of patients with improved blood pressure. Advanced life support-levels of care also were associated with increased use of pneumatic antishock garments and intravenous fluids. Despite improvements in physiologic variables, the ALS group of patients did not have a higher survival rate when it was compared with the BLS group or when mortality rates were compared with predicted rates. These investigators did not document benefit from the use of ALS-level care for trauma patients with total prehospital times of <35 minutes.

Gold asked if advanced life support for trauma patients in the field has been proven to be beneficial or if it is a costly exercise in futility. The answer was pursued through assessment of the merit of prehospital ALS by defining a sub-population in which ALS-level of care significantly influenced outcomes.36 Gold recognized that several ALS procedures were controversial. Two schools of thought emerged: 1) ALS personnel should administer treatment as quickly as possible, noting that early resuscitation is the key to sustaining life; and 2) that the critical factor influencing outcome is the time to definitive medical or surgical treatment. The major concern was that ineffective prehospital interventions cause long delays in transportation, and thus, may harm the patient by delaying time to restorative care. This debate led to two important questions: 1) What procedures, if any, are useful in the prehospital setting? and 2) What is the trade-off between time spent in the field versus benefit of the procedure?

In airway management procedures, Gold maintained thatit is difficult to determine the optimal technique, because so few data exist on this subject. Gold then cited a study by Smith et al¸37 related to establishing an intravenous (IV) route for fluid administration: "In all cases, the time for IV initiation was longer than [was] the transportation time". Once the IV fluid infusion was started, Gold maintains that the amount of fluid had little effect on final patient outcome. She concluded that each situation must be assessed independently with consideration of transport time, IV access time, infusion volume, and severity of injuries. Gold felt that there are insufficient data to allow comparison of the efficacy of ALS-level and BLS-level of care for trauma patients. Studies existing at the time of her work (1987) were "...largely subject to criticism of their retrospective design, highly selective patient groups, lack of proper controls, and inability to separate the effects of ALS from other elements of medical care." According to Gold, if an incident occurs at a site within five minutes from the receiving facility, ALS may be harmful if it results in undue delays in transport. However, she did not address cases in which transport time is longer than five minutes or in which scene time is prolonged due to entrapment or other barriers.

In the 1985 article cited by Gold, Smith reported on prehospital stabilization of critically injured patients.37 Fifty-two ALS-treated trauma patients with systolic blood pressure <100 mm Hg on scene or at hospital arrival were evaluated. Fourteen of these patients died. According to Smith, five of those deaths could have been prevented with timely surgical therapy; concluding that placement of IV fluids can cause life-threatening delays. This study concluded that critically injured patients should be transported as soon as possible, limiting field maneuvers in order to decrease mortality.

In 1990, the effect of prehospital IV fluid therapy was examined in 6,855 trauma patients.38 Intravenous fluid therapy was used in 56%. There were no statistically significant differences between the volume of fluid administered in the group who survived versus those who died. The study findings suggest that "the mortality rate following trauma is not influenced by the prehospital administration of intravenous fluids, but is related to the severity of underlying injuries."

Bickell et al studied 598 adult patients in urban Houston with hypotension secondary to severe penetrating torso injuries.39 Those patients whose incidents happened on even-numbered days of the calendar were assigned to the study group that received aggressive prehospital fluid resuscitation according to ALS protocols. Patients who sustained their injuries on odd-numbered days were assigned to the "experimental" group, receiving no pre-operative fluid resuscitation. All other aspects of treatment were equal for both groups. The delayed resuscitation group had a significantly higher survival rate than did the immediate resuscitation group (70% vs. 62%, p = 0.04). The authors speculated that aggressive, early fluid resuscitation may interfere with the body's own mechanisms for reducing hemorrhage and maintaining cell oxygenation. They noted that the patients who had received aggressive, immediate resuscitation had significantly lower hemoglobin concentration than did those patients in the delayed group. They cautioned against extrapolating their findings to a rural setting or to patients with other kinds of trauma.

Delays in transport caused by paramedic interventions were found to be responsible for a decrease in the survival rate among patients with penetrating heart wounds.40 On the other hand, a prospective review of hypotensive victims of penetrating trauma could not confirm any adverse effects of time spent in the prehospital realm in relation to patient outcome. All of the patients evaluated for this study were transported within the "golden hour" after injury.41

In an excellent 1991 review of then current and future EMS problems and potentials, Johnson reported that the U.S. Department of Transportation disclosed that "the application of EMS care to highway injuries from 1966 through 1981 resulted in a decrease in mortality by 5.1 per 100 injuries with an EMS plan and BLS service and an additional 1.85 per 100 injuries with ALS."42 Readers should access Johnson's article and the more recent EMS Agenda for the Future43 for well-rounded reviews of current dynamics, including significant focus on the effectiveness of ALS. Both publications call for increased research.

The effects of dual-response runs in prehospital trauma care were examined in the state of New York.44 Outcome measures studied included changes in physiologic measurements between scene and receiving facility and survival through hospital discharge of those patients cared for by either BLS, ALS, or dual-response runs. Revised trauma scores (RTS) were used to quantify the stability/instability of victims being transported. The RTSs for patients transported by dual runs or ALS were higher than were those transported by BLS units. These data suggest that ALS-level care is crucial for improving RTS values. Advanced life support-level of care also was found to be associated positively with survival from blunt trauma.

The South Carolina Department of Transportation sponsored a grant to examine the possible advantages of ALS-level care for victims of motor vehicle crashes.45 In this study involving 538 cases, 435 patients were treated by ALS-level units and 102 were treated by BLS-level units. There was no difference in total on-scene time in relationship to survival rate; however, there was a statistically significant difference between ALS and BLS on-scene times (mean values = 24.8 minutes vs. 18.9 minutes). Thirty-two percent of the ALS-treated patients had improved systolic blood pressure versus only 12% of the BLS-treated cases. The trauma review committee felt that ALS procedures were essential in 85% of the cases studied.

North Carolina recognizes four levels of EMS care.46 Any North Carolina county that offers emergency medical services above the EMT-Basic level is considered a provider of ALS-level of care. Of the 100 counties in North Carolina, 24 provide BLS-level care and 76 provide ALS-level care. The ALS and BLS counties were compared for causes and frequency of injury, mortality, rurality, and other variables by the use of Student's t-test. The BLS counties were more rural, less wealthy, and had fewer medical resources than did the ALS counties. In the BLS counties, the mean trauma death rate was 8.2 per 100,000 compared with the ALS counties with a mean trauma death rate of 6.1. Because of the significant difference between the ALS and BLS counties, multivariate analysis was performed to control for confounding factors. Using stepwise forward discriminate analysis, the single most significant independent predictor of county death rates proved to be the ALS versus BLS factor (p = 0.0001).

In summary, several early studies focused on potentially negative effects of delayed transport of trauma patients caused by longer ALS on-scene times. However, more recent studies agree that ALS interventions significantly improve patient trauma scores and outcome, although there remains disagreement regarding the value of prehospital fluid resuscitation in severe trauma cases with short-to-moderate transport times. Studies that examine physiologic indicators report signs of improvement in ALS-managed patients compared with their BLS-managed equivalents when measured at hospital arrival. However, the value of these short-term physiologic improvements in terms of their contribution to eventual patient outcome is unknown. The few large statewide studies that have been completed are in substantial agreement regarding the positive value of ALS-level care for victims of life-threatening injuries.

Seizure Management

Responses to patients experiencing seizures consistently are reported among the top five reasons for EMS responses. Given the low seizure-related mortality rate, seizures present a situation that facilitates the assessment of morbidity. In 1977, in New York City alone, more than 4,000 persons received prehospital care for seizures. Abarbanell et al47 established ALS versus non-ALS triage criteria for use by prehospital personnel when treating a patient with seizure conditions. A retrospective review of 4,062 paramedic run reports indicated that "seizure" was the chief complaint in only 230 (5.6%). Advanced life support-level interventions were initiated during 25% of those runs. Those interventions were established during the initial patient assessment for all but one of these patients. Only one patient who did not initially require ALS care, later developed complications that dictated the use of an ALS-level intervention. This study concluded that, given similar field times, after ALS-level personnel initially assessed the patient, "it is reasonable and safe to triage seizure patients who do not require ALS intervention to non-ALS rescue teams for continuation of care and transportation."

Non-Condition-Specific Findings

Several studies have examined the efficacy of ALS-level care related to several or numerous medical conditions. As noted in the previously cited studies, a major controversy revolves around the relationship between time and access to definitive care. In 1976, an analysis of 3,200 critically ill, prehospital cases identified an inverse linear relationship between survival and time.48 By 1981, the "scoop and run" approach prevailed after observing specific time-critical patients for whom restorative therapy could not be administered in the field.49

If the impact of on-scene time remains controversial, the question of ALS-level versus BLS-level care adds to the dilemma. An extreme example was identified by a study in which physicians were dispatched to the scene to provide ALS care. The study concluded that this kind of ALS care was not associated with improved survival.50 Hospital arrival times exceeding 60 minutes were frequent with prehospital physician care, and were statistically significantly associated with increased mortality, (further supporting Cowley's "golden hour" concept that severely injured patients must reach definitive care within 60 minutes of injury to improve their chance of survival).51,52 Timely treatment at a Level-I-comparable hospital reduced the odds of death 38% for patients. Thus, there was a concern that this type of ALS-level care (physician provided) may delay transport, and may not be beneficial to patient outcome.

In an audit of an ambulance service, 682 cases were evaluated to determine the impact of ALS-level care.53 The authors concluded that there was no significant difference in the type or severity of the patients' conditions assessed by ALS or BLS providers. The ALS-crews did spend significantly more time on-scene (11.0 minutes) than did the BLS providers (8.3 minutes). The ALS crew utilized advanced skills in 23.6% of these cases, the majority being medically related (versus trauma). They concluded that the presence of a paramedic greatly increases on-scene time and extends advanced skills to patients in need; however, the benefits of time spent on scene for advanced skills must be evaluated carefully and compared with the possible detrimental effect of delayed hospital admission.

When the city of Boston revamped its EMS system, it conducted a prospective study regarding the effectiveness of ALS-level care. The study indicated that ALS-level interventions significantly improved patient trauma scores and outcomes.54

In an urban region of Ontario, Canada, investigators conducted a retrospective review of 10,291 patients who were treated by either EMT-Ds or EMT-Ps.55 Patients' conditions were categorized as: 1) cardiopulmonary; 2) other medical or surgical; and 3) trauma. In all categories, in the lower severity ratings, the difference in status change between patients treated by EMT-Ps and by EMT-Ds was not statistically significant; however, for seriously ill patients in the categories of cardiorespiratory and other medical or surgical, a difference was observed (Table 3). In all cases, a statistically significant difference between the two types of care was documented. For trauma victims, the differences were not as strong statistically as they were for cardiorespiratory section; however, a statistically significant difference was demonstrated between the two different crew types.

A retrospective review of an all-ALS provider service examined unexpected ALS procedures on non-emergency ambulance calls in Kansas City.56 The data reviewed included all transports within a one-year period that necessitated the use of an ALS procedure. During the study period, 6,362 calls were identified as non-emergent; however, 309 of these calls were upgraded to emergency while the unit was en route to the call. "Of the 6,053 non-emergency calls remaining, 710 (11.7%) involved the provision of one or more ALS interventions." These authors concluded that 11.7% of the patients who were classified by initial patient presentation as non-emergent cases actually required ALS interventions, thus supporting the use of a single-tier, all-ALS system.

Conclusions

The evidence for the value of advanced life support-level care in the management of victims of traumatic injuries or of cardiac is similar and though not unanimous, it is weighted heavily toward the positive side. With the exception of certain time-sensitive cases, such as penetrating heart wounds, the preponderance of collected evidence demonstrates that ALS-level care makes a positive contribution to patient outcome. Furthermore, there is evidence from an all-ALS system indicating that more than 10% of the cases originally thought to be BLS required ALS care in order to manage unexpected patient needs. All-ALS systems would be more capable of responding to the needs of such patients without delay. However, evidence suggests that physician-provided ALS-care that delays transport and hospital treatment can have a detrimental effect on patient outcome.

The state of research in EMS is poor both in quality and quantity, but gradually is improving. There are numerous barriers to good EMS research that include a lack of conceptual clarity regarding the research questions asked and the methods used. In this article, we have not attempted to critique or improve the methods in current use; Spaite et al¸2 Jones and Brenneis,1 and Maio and Spaite57 made significant contributions in this direction. Rather, we have demonstrated where the preponderance of evidence lies regarding the question of ALS effectiveness given the current limitations (Table 4). We encourage readers to review the literature. This work is not a final answer to the question; to the contrary, we hope it will stimulate future multidisciplinary studies that are well-conceived and well-executed.

One of the inevitable conclusions readers will reach is that our field is woefully under-researched and far too dependent on examining outcome in terms of death or survival. Much of what we do affects morbidity and the human experience; we make virtually no attempts to scientifically measure these impacts.

--------------------------------------------------------------------------------

References

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[AZCEP]

I will hold to my opinion of success depending on the situation.

Critical trauma with short transport times, BLS should be able to manage just fine.

Critical medical that lacks definitive care prehospital, BLS can manage reasonably well.

The longer transport times and the sicker patients tend to do better when ALS is utilized.

I will also admit that I am not familiar with the systems that were discussed, but I noticed that they were focused in the eastern US and Europe.

Interesting reading, but I don't think system changing decisions can be made just yet.

[Ace844]

I will hold to my opinion of success depending on the situation.

Critical trauma with short transport times, BLS should be able to manage just fine.

Critical medical that lacks definitive care prehospital, BLS can manage reasonably well.

The longer transport times and the sicker patients tend to do better when ALS is utilized.

I will also admit that I am not familiar with the systems that were discussed, but I noticed that they were focused in the eastern US and Europe.

Interesting reading, but I don't think system changing decisions can be made just yet.

"AZCEP,"

Here's another study which makes an interesting point as well similar to what you mention above.

(Role of the physician in prehospital management of trauma: European perspective.

Trauma

Current Opinion in Critical Care. 8(6):559-565 @ December 2002.

Ummenhofer, Wolfgang MD; Scheidegger, Daniel MD)

Abstract:

Advanced prehospital trauma life support is challenged as a whole. Formerly well-accepted basic principles for stabilizing vital functions of the severely injured patient like volume resuscitation, airway protection, and immobilization have been questioned. In prehospital management of trauma, the role of not only the physician but also the paramedic must be redefined. In the absence of evidence about the effectiveness of advanced trauma life support training for paramedic crews, the needs of trauma victims and capacities of emergency medical systems must be re-evaluated. Assessment of patients' conditions, including mechanism of trauma (blunt vs penetrating), source of hypovolemic shock (controlled vs ongoing hemorrhage), concomitant disease (as in elderly patients), and identification of therapeutic goals (such as for cerebral perfusion pressure or secondary brain damage caused by hypoxia in severe head injury), is a subject of increasing importance. Invasive airway management techniques require skills, expertise, and daily routines available only to experienced in-hospital personnel. The controversial issue of paramedic vs physician-based systems should be abandoned. It is the skill, the technique, the awareness of pitfalls, and the capability to handle complications that makes the difference, not the person in possession of the skill.

Lets hear from everyone..!!

Out here,

ACE844

[timdog88]

Thats great work, where did you find it? thats about the only time ive seen a study or review that was positive toward ALS. The fact that it was commisioned by the AAA hopefully doesnt have any bearing on the results, because they really sound very positive for ems as a whole. The last line of the article says something that I have thought about before; the only measure I ever seem to see in these studies is survival to discharge, but so much of what we do, and medicine in general, does not deal with life or death but relieving suffering and improving quality of life. How do we measure that?

[AZCEP]

"It is the skill, the technique, the awareness of pitfalls, and the capability to handle complications that makes the difference, not the person in possession of the skill."

If more providers took this profession more seriously, and understood the quote above, maybe we wouldn't have quite so many people telling us that our abilities need to be limited.

[madmedic8522]

ace, am i reading this correctly? did the article in your last post state "in the absence of evidence about the effectiveness" of ALS.

I'm questioning the article, and just want to make sure of what I'm reading before i respond to it.

otherwise so far interesting!

madmedic

[madmedic8522]

azcep, i do agree with that statement, and i believe that is the biggest issue with MY med con. it is a constant battle where I'm at, because we have so many cowboys who want to save the world, but don't want to put in the time when it comes to education. i work in a small county in MO that has 2 hospitals, so use of helicopters is important, due to the fact that both hospitals are level 3 trauma centers. every time that a decision to "fly" is made we get torn apart by med con, and the biggest problem is our EMS Liaison. however it comes back to the medics and emts in this area not taking the time to further their education as you stated

that's my opinion about where i'm at, and i'm sticking to it!

madmedic

[AZCEP]

This is actually a pretty common tactic of researchers.

They will discover that there is a lack of evidence in support of, or a lack of evidence against a particular item, then expand on it to say that because of the lack, the opposite must hold true.

A bit of a fallacy. On occasion, you will find that the authors will mention that the lack of conflicting evidence does not mean that something has been proven good or bad.

[madmedic8522]

OK that's what i thought, politicians, LOL!

so this was written by a bunch of PhDs that sit in a little office and compile a bunch of incomplete info, then through their opinion out there!

still the topic makes for a good discussion!

madmedic

[Ace844]

ace, am i reading this correctly? did the article in your last post state "in the absence of evidence about the effectiveness" of ALS.

I'm questioning the article, and just want to make sure of what I'm reading before i respond to it.

otherwise so far interesting!

madmedic

"mad,"

Yes you are reading it correctly, here's the quote;

"Role of the physician in prehospital management of trauma: European perspective. Trauma::In prehospital management of trauma, the role of not only the physician but also the paramedic must be redefined. In the absence of evidence about the effectiveness of advanced trauma life support training for paramedic crews, the needs of trauma victims and capacities of emergency medical systems must be re-evaluated."

It should be noted though that this was a european study from a country which uses both MD's, and medics in the pre-hospital setting.

Hope this helps,

ACE844