The Ontario Prehospital Advanced Life Support (OPALS) study Part II: Rationale and methodology for trauma and respiratory distress patients. OPALS Study Group

Association of Statewide Implementation of the Prehospital Traumatic Brain Injury Treatment Guidelines With Patient Survival Following Traumatic Brain Injury: The Excellence in Prehospital Injury Care (EPIC) Study

Importance

Traumatic brain injury (TBI) is a massive public health problem. While evidence-based guidelines directing the prehospital treatment of TBI have been promulgated, to our knowledge, no studies have assessed their association with survival.

Objective

To evaluate the association of implementing the nationally vetted, evidence-based, prehospital treatment guidelines with outcomes in moderate, severe, and critical TBI.

Design, Setting, and Participants

The Excellence in Prehospital Injury Care (EPIC) Study included more than 130 emergency medical services systems/agencies throughout Arizona. This was a statewide, multisystem, intention-to-treat study using a before/after controlled design with patients with moderate to critically severe TBI (US Centers for Disease Control and Prevention Barell Matrix-Type 1 and/or Abbreviated Injury Scale Head region severity ≥3) transported to trauma centers between January 1, 2007, and June 30, 2015. Data were analyzed between October 25, 2017, and February 22, 2019.

Interventions

Implementation of the prehospital TBI guidelines emphasizing avoidance/treatment of hypoxia, prevention/correction of hyperventilation, and avoidance/treatment of hypotension.

Main Outcomes and Measures

Primary: survival to hospital discharge; secondary: survival to hospital admission.

Results

Of the included patients, the median age was 45 years, 14 666 (67.1%) were men, 7181 (32.9%) were women; 16 408 (75.1% ) were white, 1400 (6.4%) were Native American, 743 (3.4% ) were Black, 237 (1.1%) were Asian, and 2791 (12.8%) were other race/ethnicity. Of the included patients, 21 852 met inclusion criteria for analysis (preimplementation phase [P1]: 15 228; postimplementation [P3]: 6624). The primary analysis (P3 vs P1) revealed an adjusted odds ratio (aOR) of 1.06 (95% CI, 0.93-1.21; P = .40) for survival to hospital discharge. The aOR was 1.70 (95% CI, 1.38-2.09; P < .001) for survival to hospital admission. Among the severe injury cohorts (but not moderate or critical), guideline implementation was significantly associated with survival to discharge (Regional Severity Score-Head 3-4: aOR, 2.03; 95% CI, 1.52-2.72; P < .001; Injury Severity Score 16-24: aOR, 1.61; 95% CI, 1.07-2.48; P = .02). This was also true for survival to discharge among the severe, intubated subgroups (Regional Severity Score-Head 3-4: aOR, 3.14; 95% CI, 1.65-5.98; P < .001; Injury Severity Score 16-24: aOR, 3.28; 95% CI, 1.19-11.34; P = .02).

Conclusions and Relevance

Statewide implementation of the prehospital TBI guidelines was not associated with significant improvement in overall survival to hospital discharge (across the entire, combined moderate to critical injury spectrum). However, adjusted survival doubled among patients with severe TBI and tripled in the severe, intubated cohort. Furthermore, guideline implementation was significantly associated with survival to hospital admission. These findings support the widespread implementation of the prehospital TBI treatment guidelines.

Trial Registration

ClinicalTrials.gov identifier: NCT01339702.

Out-of-Hospital Cardiac Arrest in a Teaching Hospital in Hong Kong: Descriptive Study Using the Utstein Style

Objective

To describe, using the Utstein template, the characteristics of patients presenting with out-of-hospital cardiac arrest to a university teaching hospital in the New Territories of Hong Kong, and to evaluate survival.

Design

Prospective study.

Setting

The emergency department of a teaching hospital in the New Territories, Hong Kong.

Participants

Patients older than 12 years with non-traumatic out-of-hospital cardiac arrest who were transported to the hospital between 1 July 2002 and 31 December 2002.

Main outcome measures

Demographic data, characteristics of cardiac arrest and response time intervals of the emergency medical service presented according to the Utstein style, and also survival to hospital discharge rate.

Results

A total of 124 patients were included (49.2% male; mean age 71.9 years). The majority of cardiac arrests occurred in patients' home. The overall bystander cardiopulmonary resuscitation (CPR) rate was 15.3% (19/124). The most common electrocardiographic rhythm at scene was asystole, whilst pulseless ventricular tachycardia (VT)/ventricular fibrillation (VF) was found in 18.0%. The overall survival was 0.8% (1/124), and survival to hospital discharge was significantly higher for patients with VF or pulseless VT than those patients with other rhythms of cardiac arrest (11.1% versus 0%). The median witnessed/recognised collapse to defibrillation time was 14 minutes. The median prehospital time interval from collapse/recognition to arrival at hospital was 33 minutes.

Conclusion

The prognosis of out-of-hospital cardiac arrest in Hong Kong was poor. Major improvements in every component of the chain of survival are necessary.

The impact of prehospital resuscitation research on in-hospital care

Since their introduction over 40 years ago, paramedics have been trained to deliver select advanced life support interventions in the community with the goal of reducing morbidity and mortality from cardiovascular disease and trauma. The ensuing decades witnessed a great deal of interest in paramedic care, with an exponential growth in prehospital resuscitation research. As part of the CJEM series on emergency medical services (EMS), we review recent prehospital research in out-of-hospital cardiac arrest and discuss how, in a novel departure from the origins of EMS, prehospital research is beginning to influence in-hospital care. We discuss emerging areas of study related to cardiopulmonary resuscitation (CPR) quality, therapeutic hypothermia, termination of resuscitation, and the use of end-tidal carbon dioxide measurement, as well as the subtle ripple effects that prehospital research is having on the broader understanding of the management of these critically ill patients.

The scene time interval and basic life support termination of resuscitation rule in adult out-of-hospital cardiac arrest

We validated the basic life support termination of resuscitation (BLS TOR) rule retrospectively using Out-of-Hospital Cardiac Arrest (OHCA) data of metropolitan emergency medical service (EMS) in Korea. We also tested it by investigating the scene time interval for supplementing the BLS TOR rule. OHCA database of Seoul (January 2011 to December 2012) was used, which is composed of ambulance data and hospital medical record review. EMS-treated OHCA and 19 yr or older victims were enrolled, after excluding cases occurred in the ambulance and with incomplete information. The primary and secondary outcomes were hospital mortality and poor neurologic outcome. After calculating the sensitivity (SS), specificity (SP), and the positive and negative predictive values (PPV and NPV), tested the rule according to the scene time interval group for sensitivity analysis. Of total 4,835 analyzed patients, 3,361 (69.5%) cases met all 3 criteria of the BLS TOR rule. Of these, 3,224 (95.9%) were dead at discharge (SS,73.5%; SP,69.6%; PPV,95.9%; NPV, 21.3%) and 3,342 (99.4%) showed poor neurologic outcome at discharge (SS, 75.2%; SP, 89.9%; PPV, 99.4%; NPV, 11.5%). The cut-off scene time intervals for 100% SS and PPV were more than 20 min for survival to discharge and more than 14 min for good neurological recovery. The BLS TOR rule showed relatively lower SS and PPV in OHCA data in Seoul, Korea.

Advanced trauma life support training for hospital staff

BACKGROUND

Injury is responsible for an increasing global burden of death and disability. As a result, new models of trauma care have been developed. Many of these, though initially developed in high-income countries (HICs), are now being adopted in low and middle-income countries (LMICs). One such trauma care model is advanced trauma life support (ATLS) training in hospitals, which is being promoted in LMICs as a strategy for improving outcomes for victims of trauma. The impact of this health service intervention, however, has not been rigorously tested by means of a systematic review in either HIC or LMIC settings.

OBJECTIVES

To quantify the impact of ATLS training for hospital staff on injury mortality and morbidity in hospitals with and without such a training program.

SEARCH METHODS

The search for studies was run on the 16th May 2014. We searched the Cochrane Injuries Group's Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), Ovid MEDLINE(R), Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily and Ovid OLDMEDLINE(R), Embase Classic+Embase (Ovid), ISI WOS (SCI-EXPANDED, SSCI, CPCI-S & CPSI-SSH), CINAHL Plus (EBSCO), PubMed and screened reference lists.

SELECTION CRITERIA

Randomised controlled trials, controlled trials and controlled before-and-after studies comparing the impact of ATLS-trained hospital staff versus non-ATLS trained hospital staff on injury mortality and morbidity.

DATA COLLECTION AND ANALYSIS

Three authors applied the eligibility criteria to trial reports for inclusion, and extracted data.

MAIN RESULTS

None of the studies identified by the search met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

There is no evidence from controlled trials that ATLS or similar programs impact the outcome for victims of injury, although there is some evidence that educational initiatives improve knowledge of hospital staff of available emergency interventions. Furthermore, there is no evidence that trauma management systems that incorporate ATLS training impact positively on outcome. Future research should concentrate on the evaluation of trauma systems incorporating ATLS, both within hospitals and at the health system level, by using more rigorous research designs.

Evaluation of the impact of implementing the emergency medical services traumatic brain injury guidelines in Arizona: the Excellence in Prehospital Injury Care (EPIC) study methodology

Traumatic brain injury (TBI) exacts a great toll on society. Fortunately, there is growing evidence that the management of TBI in the early minutes after injury may significantly reduce morbidity and mortality. In response, evidence-based prehospital and in-hospital TBI treatment guidelines have been established by authoritative bodies. However, no large studies have yet evaluated the effectiveness of implementing these guidelines in the prehospital setting. This article describes the background, design, implementation, emergency medical services (EMS) treatment protocols, and statistical analysis of a prospective, controlled (before/after), statewide study designed to evaluate the effect of implementing the EMS TBI guidelines-the Excellence in Prehospital Injury Care (EPIC) study (NIH/NINDS R01NS071049, "EPIC"; and 3R01NS071049-S1, "EPIC4Kids"). The specific aim of the study is to test the hypothesis that statewide implementation of the international adult and pediatric EMS TBI guidelines will significantly reduce mortality and improve nonmortality outcomes in patients with moderate or severe TBI. Furthermore, it will specifically evaluate the effect of guideline implementation on outcomes in the subgroup of patients who are intubated in the field. Over the course of the entire study (~9 years), it is estimated that approximately 25,000 patients will be enrolled.

Prehospital non-drug assisted intubation for adult trauma patients with a Glasgow Coma Score less than 9

OBJECTIVES

Prehospital airway management for adult trauma patients remains controversial. We sought to review the frequency that paramedic non-drug assisted intubation or attempted intubation is performed for trauma patients in Ontario, Canada, and determine its association with mortality.

METHODS

We conducted a retrospective cohort study using the Ontario Trauma Registry's Comprehensive Data Set for 2002-2009. Eligible patients were greater than 16 years of age, had an initial Glasgow Coma Score of less than 9 and were cared for by ground-based non-critical care paramedics. The primary outcome was mortality. Outcomes were compared between patients undergoing prehospital intubation versus basic airway management. Logistic regression analyses were used to quantify the association between prehospital intubation and mortality.

RESULTS

Of the 2229 patients included in the analysis, 671 (30.1%) underwent prehospital intubation. Annual rates of prehospital intubation declined from 33.7% to 14.0% (ptrend<0.0001) over the study period. Unadjusted death rates were 66.0% versus 34.8% in the intubation and basic airway groups, respectively (p<0.0001). Intubation in the prehospital setting was associated with a heightened risk of mortality (adjusted OR 2.8, 95% CI 1.1 to 7.6).

CONCLUSIONS

Prehospital non-drug assisted intubation for trauma is being performed less frequently in Ontario, Canada. Within our study population, paramedic non-drug assisted intubation or attempted intubation was associated with a heightened risk of mortality.

Risk adjustment measures and outcome measures for prehospital trauma research: recommendations from the emergency medical services outcomes project (EMSOP)

OBJECTIVES

The objectives were to conduct a comprehensive, systematic review of the literature for risk adjustment measures (RAMs) and outcome measures (OMs) for prehospital trauma research and to use a structured expert panel process to recommend measures for use in future emergency medical services (EMS) trauma outcomes research.

METHODS

A systematic literature search and review was performed identifying the published studies evaluating RAMs and OMs for prehospital injury research. An explicit structured review of all articles pertaining to each measure was conducted using the previously established methodology developed by the Canadian Physiotherapy Association ("Physical Rehabilitation Outcome Measures").

RESULTS

Among the 4,885 articles reviewed, 96 RAMs and/or OMs were identified from the existing literature (January 1958 to February 2010). Only one measure, the Glasgow Coma Scale (GCS), currently meets Level 1 quality of evidence status and a Category 1 (strong) recommendation for use in EMS trauma research. Twelve RAMs or OMs received Category 2 status (promising, but not sufficient current evidence to strongly recommend), including the motor component of GCS, simplified motor score (SMS), the simplified verbal score (SVS), the revised trauma score (RTS), the prehospital index (PHI), EMS provider judgment, the revised trauma index (RTI), the rapid acute physiology score (RAPS), the rapid emergency medicine score (REMS), the field trauma triage (FTT), the pediatric triage rule, and the out-of-hospital decision rule for pediatrics.

CONCLUSIONS

Using a previously published process, a structured literature review, and consensus expert panel opinion, only the GCS can currently be firmly recommended as a specific RAM or OM for prehospital trauma research (along with core measures that have already been established and published). This effort highlights the paucity of reliable, validated RAMs and OMs currently available for outcomes research in the prehospital setting and hopefully will encourage additional, methodologically sound evaluations of the promising, Category 2 RAMs and OMs, as well as the development of new measures.

Advanced trauma life support training for hospital staff

BACKGROUND

Injury is responsible for an increasing global burden of death and disability. As a result, new models of trauma care have been developed. Many of these, though initially developed in high-income countries (HICs), are now being adopted in low and middle-income countries (LMICs). One such trauma care model is advanced trauma life support (ATLS) training in hospitals, which is being promoted in LMICs as a strategy for improving outcomes for victims of trauma. The impact of this health service intervention, however, has not been rigorously tested by means of a systematic review in either HIC or LMIC settings.

OBJECTIVES

To quantify the impact of ATLS training for hospital staff on injury mortality and morbidity in hospitals with and without such a training program.

SEARCH STRATEGY

We searched the CENTRAL, MEDLINE, EMBASE, PUBMED, CINAHL and ZETOC databases and the Cochrane Injuries Group's Specialised Register. For this update, the search strategy was expanded to include more parameters on research methodology and was run for all years to September 2008.

SELECTION CRITERIA

Randomised controlled trials, controlled trials and controlled before-and-after studies comparing the impact of ATLS-trained hospital staff versus non-ATLS trained hospital staff on injury mortality and morbidity.

DATA COLLECTION AND ANALYSIS

One author applied the eligibility criteria to trial reports for inclusion, and extracted data.

MAIN RESULTS

There is a limited amount of literature about this topic. None of the studies identified by the search met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

There is no clear evidence that ATLS or similar programs impact the outcome for victims of injury, although there is some evidence that educational initiatives improve knowledge of hospital staff of available emergency interventions. Furthermore, there is no evidence that trauma management systems that incorporate ATLS training impact positively on outcome. Future research should concentrate on the evaluation of trauma systems incorporating ATLS, both within hospitals and at the health system level, by using more rigorous research designs.

Aspects on the increase in bystander CPR in Sweden and its association with outcome

AIM

To describe changes in the proportion of bystanders performing cardiopulmonary resuscitation (CPR) in out of hospital cardiac arrest (OHCA) in Sweden and to study the impact of bystander CPR on ventricular fibrillation and on survival during various times.

PATIENTS AND METHODS

All patients who suffered from OHCA in Sweden in whom CPR was attempted and who were included in the Swedish cardiac arrest register (SCAR) between 1992 and 2005. Crew witnessed cases were excluded.

RESULTS

In all 34,125 patients were included in the survey. Among witnessed OHCA the proportion of patients receiving bystander CPR increased from 40% in 1992 to 55% in 2005 (p<0.0001). In non-witnessed OHCA the corresponding proportion increased from 22% to 44% (p<0.0001). There was a significant increase in bystander CPR regardless of age, sex and place. The increase was only found when CPR was performed by lay persons (21% in 1992 to 40% in 2005; p<0.0001). Bystander CPR was associated with an increased proportion of patients found in a shockable rhythm and a lower number of shocks to receive return of spontaneous circulation. Bystander CPR was associated with a similar increase in survival early and late in the evaluation.

CONCLUSION

There was a marked increase in bystander CPR in OHCA, when performed by lay persons, during the last 14 years in Sweden. Bystander CPR was associated with positive effects both on ventricular fibrillation and survival.

Comparison of the Cerebral Performance Category score and the Health Utilities Index for survivors of cardiac arrest

STUDY OBJECTIVE

The Cerebral Performance Category score is an easy to use but unvalidated measure of functional outcome after cardiac arrest. We evaluate the comparability of results from the Cerebral Performance Category scale versus those of the validated but more complex Health Utilities Index scale for health-related quality of life.

METHODS

This prospective substudy of the Ontario Prehospital Advanced Life Support (OPALS) Study included adult out-of-hospital cardiac arrest patients treated in 20 cities. This prospective cohort study included all survivors of out-of-hospital adult cardiac arrest enrolled in phase II (rapid basic life support with defibrillation) and phase III (advanced life support) of the OPALS Study, as well as the intervening run-in phase. Survivors were interviewed at 12 months for Cerebral Performance Category Score and the Health Utilities Index Mark 3 (Health Utilities Index).

RESULTS

Of 8,196 eligible out-of-hospital cardiac arrest patients between 1995 and 2002, 418 (5.1%) survived to discharge, and 305 (3.7%) completed the Health Utilities Index interview and had Cerebral Performance Category scored at 12 months. The 305 patients had the following data: mean age 63.9 years; male 78.0%; paramedic-witnessed arrest 25.6%; bystander cardiopulmonary resuscitation 32.1%; initial rhythm ventricular fibrillation/ventricular tachycardia 86.9%, Cerebral Performance Category 1 267, Cerebral Performance Category 2 26, Cerebral Performance Category 3 12. Overall, the median scores (interquartile range) were Cerebral Performance Category 1 (1 to 1) and Health Utilities Index 0.84 (0.61 to 0.97). The Cerebral Performance Category score ruled out good quality of life (Health Utilities Index >0.80), with a sensitivity of 100% (95% confidence interval [CI] 98% to 100%) and specificity 27.1% (95% CI 20% to 35%); thus, when the Cerebral Performance Category score was 2 or 3, it was unlikely that the Health Utilities Index score would be good. The Cerebral Performance Category score had sensitivity 55.6% (95% CI 42% to 67%) and specificity 96.8% (95% CI 94% to 98%) for predicting poor quality of life (Health Utilities Index >0.40); ie, when Cerebral Performance Category was 1, it was highly unlikely that the Health Utilities Index score would be poor. The weighted kappa was 0.39 and the interclass correlation was 0.51.

CONCLUSION

This represents the largest study yet conducted of the performance of the Cerebral Performance Category score in 1-year survivors of out-of-hospital cardiac arrest. Overall, the Cerebral Performance Category score classified patients well for their quality of life, ruling out a good Health Utilities Index score with high sensitivity and ruling in poor Health Utilities Index score with high specificity. The Cerebral Performance Category is an important tool in that it indicates broad functional outcome categories that are useful for a number of key clinical and research applications but should not be considered a substitute for the Health Utilities Index.

The OPALS Major Trauma Study: impact of advanced life-support on survival and morbidity

BACKGROUND

To date, the benefit of prehospital advanced life-support programs on trauma-related mortality and morbidity has not been established

METHODS

The Ontario Prehospital Advanced Life Support (OPALS) Major Trauma Study was a before-after systemwide controlled clinical trial conducted in 17 cities. We enrolled adult patients who had experienced major trauma in a basic life-support phase and a subsequent advanced life-support phase (during which paramedics were able to perform endotracheal intubation and administer fluids and drugs intravenously). The primary outcome was survival to hospital discharge.

RESULTS

Among the 2867 patients enrolled in the basic life-support (n = 1373) and advanced life-support (n = 1494) phases, characteristics were similar, including mean age (44.8 v. 47.5 years), frequency of blunt injury (92.0% v. 91.4%), median injury severity score (24 v. 22) and percentage of patients with Glasgow Coma Scale score less than 9 (27.2% v. 22.1%). Survival did not differ overall (81.1% among patients in the advanced life-support phase v. 81.8% among those in the basic life-support phase; p = 0.65). Among patients with Glasgow Coma Scale score less than 9, survival was lower among those in the advanced life-support phase (50.9% v. 60.0%; p = 0.02). The adjusted odds of death for the advanced life-support v. basic life-support phases were nonsignificant (1.2, 95% confidence interval 0.9-1.7; p = 0.16).

INTERPRETATION

The OPALS Major Trauma Study showed that systemwide implementation of full advanced life-support programs did not decrease mortality or morbidity for major trauma patients. We also found that during the advanced life-support phase, mortality was greater among patients with Glasgow Coma Scale scores less than 9. We believe that emergency medical services should carefully re-evaluate the indications for and application of prehospital advanced life-support measures for patients who have experienced major trauma.

Advanced life support for out-of-hospital respiratory distress

BACKGROUND

Respiratory distress is a common symptom of patients transported to hospitals by emergency medical services (EMS) personnel. The benefit of advanced life support for such patients has not been established.

METHODS

The Ontario Prehospital Advanced Life Support (OPALS) Study was a controlled clinical trial that was conducted in 15 cities before and after the implementation of a program to provide advanced life support for patients with out-of-hospital respiratory distress. Paramedics were trained in standard advanced life support, including endotracheal intubation and the administration of intravenous drugs.

RESULTS

The clinical characteristics of the 8138 patients in the two phases of the study were similar. During the first phase, no patients were treated by paramedics trained in advanced life support; during the second phase, 56.6% of patients received this treatment. Endotracheal intubation was performed in 1.4% of the patients, and intravenous drugs were administered to 15.0% during the second phase. This phase of the study was also marked by a substantial increase in the use of nebulized salbutamol and sublingual nitroglycerin for the relief of symptoms. The rate of death among all patients decreased significantly, from 14.3% to 12.4% (absolute difference, 1.9%; 95% confidence interval [CI], 0.4 to 3.4; P=0.01) from the basic-life-support phase to the advanced-life-support phase (adjusted odds ratio, 1.3; 95% CI, 1.1 to 1.5).

CONCLUSIONS

The addition of a specific regimen of out-of-hospital advanced-life-support interventions to an existing EMS system that provides basic life support was associated with a decrease in the rate of death of 1.9 percentage points among patients with respiratory distress.

Pediatric Fall Injuries in Agricultural Settings: A New Look at a Common Injury Control Problem

OBJECTIVES

Children on farms experience high risks for fall injuries. This study characterized the causes and consequences of fall injuries in this pediatric population.

METHODS

A retrospective case series was assembled from registries in Canada and the United States. A new matrix was used to classify each fall according to initiating mechanisms and injuries sustained on impact.

RESULTS

Fall injuries accounted for 41% (484/1193) of the case series. Twenty percent of the fall injuries were into the path of a moving hazard (complex falls), and 91% of complex falls were related to farm production. Sixty-one percent of complex falls from heights occurred while children were not working. Fatalities and hospitalized injuries were overrepresented in the complex falls.

CONCLUSIONS

Pediatric fall injuries were common. This analysis provides a novel look at this occupational injury control problem.

A Comprehensive Framework for Determining the Cost of an Emergency Medical Services System

To determine the cost of an emergency medical services (EMS) system, researchers, policymakers, and EMS providers need a framework with which to identify the components of the system that must be included in any cost calculations. Such a framework will allow for cost comparisons across studies, communities, and interventions. The objective of this article is to present an EMS cost framework. This framework was developed by a consensus panel after analysis of existing peer-reviewed and non-peer-reviewed resources, as well as independent expert input. The components of the framework include administrative overhead, bystander response, communications, equipment, human resources, information systems, medical oversight, physical plant, training, and vehicles. There is no hierarchical rank to these components; they are all necessary. Within each component, there are subcomponents that must be considered. This framework can be used to standardize the calculation of EMS system costs to a community. Standardizing the calculation of EMS cost will allow for comparisons of costs between studies, communities, and interventions.

Design and implementation of resuscitation research: special challenges and potential solutions

Evaluation of the effectiveness of resuscitation interventions is challenging. We describe these challenges, which include design, enrolment and analysis issues. Randomized trials establish if interventions work in predefined populations. "Efficacy" trials determine whether interventions work under ideal conditions. "Effectiveness" trials determine whether interventions work under usual practice conditions. These trials represent a trade-off between internal validity versus external validity. Randomized trials use random allocation of participants to interventions to produce study groups that are similar with respect to known and unknown risk factors, reduce bias in the allocation of participants, and assure that statistical tests have valid significance levels. In the emergency setting, there is a risk that treatment offered to control patients will be contaminated by providers' experiences of applying the intervention to patients receiving the experimental intervention. Frequently there is not time to obtain consent from a patient in an emergency setting. Exception from consent can be applied if certain conditions are met. Enrolment in a research study must be initiated quickly in an emergency setting or the patient will die or become disabled. In any trial, data can be used to explore different aspects of response to treatment: multiple treatments, subgroups, events; and interim analyses. We propose solutions to these challenges to help potential investigators through the myriad of difficulties in initiating trials in a complex environment. Design of simple trials that have adequate power enhances their external validity. Allocating groups of episodes to interventions by randomizing by clusters, rather than by individual patients reduces provider noncompliance. Waiver from consent for emergency research and use of novel technologies could facilitate enrolment despite time constraints. Rigorous statistical methods can be used to analyze multiple data without an excessive increase in the chance of a false-positive result.

Comparing pre-hospital clinical diagnosis of pediatric out-of-hospital cardiac arrest with etiology by coroner's diagnosis

OBJECTIVES

Making an accurate clinical diagnosis in the field can be a great challenge with pediatric out-of-hospital cardiac arrest (OHCA). We aimed to compare the etiology of pediatric OHCA by pre-hospital clinical diagnosis with etiology by coroner's diagnosis and autopsy.

DESIGN

As part of the Ontario Pre-hospital Advanced Life Support (OPALS) study, we conducted a prospective cohort study including children below age 19 with OHCA during an 11-year period. Prehospital clinical diagnosis was determined by blinded review and deaths were then matched with provincial coroner's office records. The agreement between prehospital clinical diagnosis and autopsy diagnosis was derived by consensus review. Inter-observer agreement was evaluated using kappa values.

RESULTS

For the period 1992-2002, there were 414 cardiac arrests in children <19 years of age that matched coroner's records. Mean age was 5.9 years (S.D. 6.4 years) with 39.4% of cases under 1 year of age. Etiology by clinical diagnosis was medical 49.5%, trauma 36.0% and undetermined 14.5%. The overall kappa for clinical diagnosis compared to coroner's diagnosis was 0.62. The kappa for medical cases was 0.53, trauma was 0.93 and 'undetermined' was -0.01. Medical clinical diagnosis had a lower agreement with the coroner's diagnosis (62.4%) compared with trauma (96.0%), RR 0.65, 95% CI [0.58, 0.73]. The poorest kappas by diagnosis were for neurological (0.39), respiratory (0.42), 'other' medical (0.56), SIDS (0.58) and cardiac (0.63). The commonest coroner's diagnoses in the 'undetermined' clinical diagnosis category were: pneumonia (17.6%), seizure or post-seizure (11.8%), arrhythmia (9.8%) and aspiration (5.9%).

CONCLUSION

Even in an ideal situation, a clinician in the field might be unable to determine the etiology of pediatric cardiac arrest in 14.5% of cases. There is poorer agreement for 'medical' compared to 'trauma' cases. This is the largest study to date comparing clinical diagnosis of the causes of OHCA in children to the 'gold-standard' of coroner's diagnosis.

Validation of a rule for termination of resuscitation in out-of-hospital cardiac arrest

BACKGROUND

We prospectively evaluated a clinical prediction rule to be used by emergency medical technicians (EMTs) trained in the use of an automated external defibrillator for the termination of basic life support resuscitative efforts during out-of-hospital cardiac arrest. The rule recommends termination when there is no return of spontaneous circulation, no shocks are administered, and the arrest is not witnessed by emergency medical-services personnel. Otherwise, the rule recommends transportation to the hospital, in accordance with routine practice.

METHODS

The study included 24 emergency medical systems in Ontario, Canada. All patients 18 years of age or older who had an arrest of presumed cardiac cause and who were treated by EMTs trained in the use of an automated external defibrillator were included. The patients were treated according to standard guidelines. Characteristics of diagnostic tests for the prediction rule were calculated. These characteristics include sensitivity, specificity, and positive and negative predictive values.

RESULTS

Follow-up data were obtained for all 1240 patients. Of 776 patients with cardiac arrest for whom the rule recommended termination, 4 survived (0.5 percent). The rule had a specificity of 90.2 percent for recommending transport of survivors to the emergency department and had a positive predictive value for death of 99.5 percent when termination was recommended. Implementation of this rule would result in a decrease in the rate of transportation from 100 percent of patients to 37.4 percent. The addition of other criteria (a response interval greater than eight minutes or a cardiac arrest not witnessed by a bystander) would further improve both the specificity and positive predictive value of the rule but would result in the transportation of a larger proportion of patients.

CONCLUSIONS

The use of a clinical prediction rule for the termination of resuscitation may help clinicians decide whether to terminate basic life support resuscitative efforts in patients having an out-of-hospital cardiac arrest.

What are the etiology and epidemiology of out-of-hospital pediatric cardiopulmonary arrest in Ontario, Canada?

BACKGROUND

Pediatric cardiopulmonary arrest (CPA) outside of the hospital has a very high mortality rate.

OBJECTIVES

To evaluate the etiology and initial compromise of pediatric CPA cases in hopes of developing strategies to improve out-of-hospital resuscitation.

METHODS

The Ontario Prehospital Advanced Life Support (OPALS) study was a large multicenter initiative to evaluate the impact of emergency medical services (EMS) programs on 17 communities with 40,000 critically ill and injured patients who were older than 11 years. As part of this study, the authors conducted a retrospective observational cohort study that included all children younger than 18 years of age with out-of-hospital CPA, during an 11-year period from 1991-2002. CPA was defined as patient being pulseless, apneic, and requiring chest compressions. Data were collected from ambulance call reports and centralized dispatch data and were reviewed by two independent investigators.

RESULTS

There were 503 children with CPA in the sample. Mean age was 5.6 years (range, 0-17 yr); 58.4% of patients were male, and 37.8% were younger than 1 year of age. Cardiopulmonary resuscitation (CPR) first was started by a bystander in 32.4% of cases, whereas 66.0% were unwitnessed arrests. Initial rhythms were asystole 77.2% of the time, pulseless electrical activity 16.4% of the time, and ventricular fibrillation or ventricular tachycardia 4% of the time. Annual incidence was 9.1/100,000 children. CPA was witnessed in 34.0% of cases; 80.7% of these were bystander-witnessed, and 18.1% were EMS-witnessed. Primary pathogenic cause of arrest was medical in 61.2% of cases, trauma in 37.2% of cases, and indeterminate in 1.6% of cases. Initial underlying physiologic compromise of witnessed arrests was judged to be respiratory in 39.8% of cases, sudden collapse (presumed electrical) in 16.4% of cases, progressive shock in 1.2% of cases, and indeterminate in 42.6% of cases. Presumed etiology was trauma, 37.6%; sudden infant death syndrome (SIDS), 20.3%; and respiratory disease, 11.6%, most commonly. Survival to hospital discharge was 2.0%.

CONCLUSIONS

This is one of the largest population-based, prospective cohorts of pediatric CPA reported to date, and it reveals that most pediatric arrests are unwitnessed and receive no bystander CPR. Those that are witnessed most often are caused by respiratory arrests or trauma. Trauma, SIDS, and respiratory disease are the most common etiologies overall. These data are vital to planning large resuscitation trials looking at specific interventions (i.e., increasing bystander CPR) and highlight the need for better strategies for prevention and early recognition.

Economic value of out-of-hospital emergency care: a structured literature review

STUDY OBJECTIVE

The evaluation of the impact of out-of-hospital emergency care is a relatively new research focus. As such, there is a compelling need to determine how finite health care resources should be used in this setting. The objective of this study is to conduct a structured review of published economic evaluations of out-of-hospital emergency care to assess its economic value.

METHODS

A structured literature search and structured review of articles pertaining to the economic value of out-of-hospital care was performed. The bibliographic database MEDLINE was searched for pertinent English-language articles published between 1966 and 2003. The search used the medical subject headings "emergency medical services" and "emergency medical technician" and was limited to the subheading "economics" and crossed with the medical subject heading "economics." The titles generated by this search were systematically reviewed and limited by topic. Abstracts from the identified titles were reviewed to select a final set of pertinent articles. These articles were further limited based on explicit inclusion and exclusion criteria. Authors used a previously published structured evaluation tool to review the final set of identified articles for quality and content.

RESULTS

The initial MEDLINE search identified 3,533 citations. From this set, 535 potentially relevant abstracts were reviewed. From the abstract review, 46 articles were identified, along with an additional 14 from searching the secondary references. Of these 60 articles, 32 met the review inclusion criteria and were subjected to a full structured review. These studies predominantly addressed the cost of cardiac arrest (n=13, 41%), major trauma (n=8, 25%), and emergency medical services treatment in general (n=8, 25%). Only 14 studies considered the costs and consequences of competing alternatives. Of these, 2 were cost-benefit and 12 were cost-effectiveness evaluations. Two of the 14 studies met all 10 criteria for high-quality economic evaluation, whereas 2 others met none.

CONCLUSION

There is a paucity of out-of-hospital care literature that addresses cost and economic value. The extant literature is limited in scope, poor in quality, and evaluates small subsets of out-of-hospital emergency care costs. Favorable cost-effectiveness has not been firmly established for most aspects of out-of-hospital emergency care.

Etiology of pediatric out-of-hospital cardiac arrest by coroner's diagnosis

OBJECTIVES

To determine etiology of pediatric OHCA in a population-based sample from autopsy and coroner's diagnosis.

DESIGN

As part of the Ontario Pre-hospital Advanced Life Support (OPALS) study, we conducted a prospective cohort study including children below age 19 years with OHCA in an 11-year period. Deaths were matched with provincial coroner's office records and autopsies and investigation notes were reviewed.

RESULTS

From 1992 to 2002, there were 474 cardiac arrests in children below 19 years of age giving an annual incidence of 59.7 per million children. Mean age was 5.8 (S.D. 6.3), 43.0% were <1 year of age, males were 59.1%. 25.1% were bystander witnessed and 20.3% received bystander CPR. 1.9% survived to discharge. Four hundred and thirty nine matched to coroner's office records. Annual incidence rates per million by age groups were: 175.0 (age 1-4 years), 33.0 (age 5-14 years) and 61.6 (age 15-18). Annual incidence rates per million according to coroner's cause of death were: natural (26.2), accidental (17.4), suicide (3.7) and homicide (1.9). Post-mortem rate was 84.3% and Mean Injury Severity Score was 31.4 (S.D. 16.5). The commonest causes of natural death were SIDS (30.3%), cardiovascular (19.2) and respiratory (18.3%). The commonest causes of accidental death were drowning (27.5%), residential accidents (18.8%), fire (13.0%) and motor vehicle collisions (12.3%).

CONCLUSION

The highest mortality rates were among children age <4 years. 52.6% of deaths were from 'unnatural' causes (accidental, suicide, homicide, undetermined). Our findings will be useful for planning prevention, treatment and future research of pediatric OHCA.

Methodological design for economic evaluation in Public Access Defibrillation (PAD) trial

OBJECTIVE

Our objective is to describe the rationale and methods for the economic analysis of the PAD trial. The objective of this analysis is to assess whether automated external defibrillators (AEDs) use by lay responders is good value for money.

METHODS

Design. This economic evaluation is being conducted concurrently with a randomized trial of (a) control--training to recognize arrest, access 911, and administer cardiopulmonary resuscitation (CPR) while awaiting arrival of emergency medical services providers versus (b) intervention--training to recognize arrest, access 911, administer CPR, and use an AED while awaiting emergency medical services providers. Lay responders in either group were trained to deliver the study intervention. Population. Participating sites identified distinct units with a population of at least 250 people aged > or = 50 years. Outcome. The primary economic outcome is the incremental cost-effectiveness ratio of intervention versus control.

RESULTS

Nine hundred ninety-three units including 1260 public and residential locations were randomized. There were 30 survivors in the intervention group and 15 in the control group (P = .03). Sampling will identify program and health care costs. A societal perspective will be adopted. Incremental cost effectiveness will be estimated by using bootstrapping and decision analytic modeling.

CONCLUSION

The study will demonstrate whether defibrillation by lay responders improves outcomes at reasonable cost. If so, then the thousands of lives will be improved annually. If not, then limited resources can be invested in other interventions. Our methods also provide a framework for economic evaluations of other interventions for acute cardiovascular events.

Emergency medical services in Japan: An opportunity for the rational development of pre-hospital care and research

Japan is at a crossroads in the development of its Emergency Medical Services (EMS). At present, Japan has an essentially pure scoop-and-run, defibrillation system. However, there is a strong movement toward expanding the scope of paramedic practice to include more complex, Advanced Life Support (ALS) and trauma protocols to its nationally standardized pre-hospital protocols. The implications of introducing complex pre-hospital protocols guided by the use of existing scientific evidence to support such action is discussed in the context of Japan's unique opportunity to test many fundamental questions in pre-hospital medical care and the public's understanding and acceptance of these practices. Japan, a technologically advanced country that is not encumbered by entrenched "standards of care," has the opportunity to develop an efficient and rational EMS system.

Nontraumatic out-of-hospital hypotension predicts inhospital mortality

STUDY OBJECTIVE

Out-of-hospital hypotension may signify need for intensive resuscitation and rapid diagnosis on emergency department (ED) arrival. We hypothesized that nontraumatic out-of-hospital hypotension confers risk of inhospital mortality.

METHODS

This was a multicenter study of ambulance-transported, nontrauma, non-cardiopulmonary resuscitation patients conducted at 2 venues: (1) a cross-sectional risk assessment study of high-priority medical transports at a US metropolitan county; and (2) a Canadian prospective multicenter cohort study of patients with respiratory distress. Data at both venues were extracted from prospectively recorded, standardized run sheets by either a physician or a paramedic. Data extraction and analysis at each venue were conducted independently. Exposures to hypotension were defined as age older than 17 years old, systolic blood pressure less than 100 mm Hg during transport, and 1 or more of 10 predefined symptoms of circulatory insufficiency. Nonexposures to hypotension had the same definition as exposures, except the systolic blood pressure had to be more than 100 mm Hg during the entire out-of-hospital transport. The main outcome variable was inhospital mortality.

RESULTS

At venue 1, of 3,128 transports, 395 (13%) exposures and 395 nonexposures were identified. Inhospital mortality of exposures was 26% versus 8% for nonexposures (adjusted odds ratio [OR] 4.6; 95% confidence interval [CI] 2.0 to 5.9). At venue 2, of 7,679 transports, 532 exposures (7%) and 7,147 nonexposures were identified. Out-of-hospital exposure to hypotension conferred a mortality rate of 32% versus 11% for nonexposures (OR 3.0; 95% CI 2.4 to 3.7), representing a sensitivity of 18% and a specificity of 95%.

CONCLUSION

The inhospital mortality rate after out-of-hospital, nontraumatic hypotension is high and reproducible. Future research should focus on ED clinical protocols to ensure appropriate resuscitation and investigation of etiology of out-of-hospital hypotension.

Advanced trauma life support training for hospital staff

BACKGROUND

Injury is responsible for an increasing global burden of death and disability. As a result, new models of trauma care have been developed. Many of these, though initially developed in high-income countries, are now being adopted in low and middle-income countries (LMICs). One such trauma care model is advanced trauma life support (ATLS) training in hospitals, which is being promoted in LMICs as a strategy for improving outcomes for victims of trauma. However, the evidence of effectiveness for this health service intervention, in either HIC or LMIC settings, has not been rigorously tested using methodology such as a systematic review.

OBJECTIVES

To quantify the effectiveness of hospitals with an ATLS-trained trauma response system versus hospitals without such a response system in reducing mortality and morbidity following trauma.

SEARCH STRATEGY

We searched the Cochrane Injuries Group Specialised Register (CIGSR), the Cochrane Controlled Trials Register (CCTR), MEDLINE & PubMed, EMBASE, CINAHL, Science Citation Index, National Research Register, and web-based trials databases such as Current Controlled Trials. We checked references of background papers and contacted authors to identify additional published or unpublished data.

SELECTION CRITERIA

Randomised controlled trials, controlled trials, controlled before- and- after studies comparing effectiveness of hospitals with an ATLS-trained trauma response system versus hospitals without such a response system in reducing mortality and morbidity following trauma.

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied eligibility criteria to trial reports for inclusion and to extract data.

MAIN RESULTS

There is a limited literature relating to this topic but none of the studies identified met the inclusion criteria for this review.

REVIEWERS' CONCLUSIONS

There is no clear evidence that ATLS training (or similar) impacts on the outcome for victims of trauma, although there is some evidence that educational initiatives improve knowledge of what to do in emergency situations. Further, there is no evidence that trauma management systems incorporating ATLS training impact positively on outcome. Future research should concentrate on the evaluation of trauma systems incorporating ATLS, both within hospitals and at the health system level, by using rigorous research designs.

Health-Related Quality of Life Is Better for Cardiac Arrest Survivors Who Received Citizen Cardiopulmonary Resuscitation

Background— This study evaluated the prehospital factors associated with better health-related quality of life for survivors of out-of-hospital cardiac arrest.

Methods and Results— This prospective, 20-community, cohort study involved consecutive, adult out-of-hospital cardiac arrest patients who survived to 1 year. Patients were contacted by telephone and evaluated for the Health Utilities Index Mark III (HUI3), which describes health as a utility score on a scale from 0 (dead) to 1.0 (perfect health). The 8091 cardiac arrest patients had overall survival rates of 5.2% to hospital discharge and 4.0% to 1 year. We successfully contacted and evaluated 268 of 316 (84.8%) of known 1-year survivors. The median HUI3 score was 0.80 (interquartile range, 0.50 to 0.97), which compares well with age-adjusted values for the general population (0.83). Logistic regression identified 2 factors independently associated with very good quality of life (HUI3 >0.90) and their odds ratios (95% CIs), as follows: age 80 years or older, 0.3 (0.1 to 0.84), and citizen-initiated cardiopulmonary resuscitation (CPR), 2.0 (1.2 to 3.4) (Hosmer-Lemeshow goodness-of-fit statistic, 0.74).

Conclusions— This study is the largest ever conducted for out-of-hospital cardiac arrest survivors, clearly shows that these patients have good quality of life, and is the first to demonstrate that citizen-initiated CPR is strongly and independently associated with better quality of life. These results emphasize the importance of optimizing community citizen CPR readiness. Given the low rate of citizen-initiated CPR in many communities, we believe that local and national initiatives should vigorously promote the practice of bystander CPR.

Optimal defibrillation response intervals for maximum out-of-hospital cardiac arrest survival rates

STUDY OBJECTIVE

Many centers optimize their emergency medical services (EMS) systems to achieve a target defibrillation response interval of "call received by dispatch" to "arrival at scene by responder with defibrillator" in 8 minutes or less for at least 90% of cardiac arrest cases. The objective of this study was to analyze survival as a function of time to test the evidence for this standard.

METHODS

This prospective cohort study included all adult, cardiac etiology, out-of-hospital cardiac arrest cases from phases I and II of the Ontario Prehospital Advanced Life Support (OPALS) study. Patients in the 21 Ontario study communities received a basic life support level of care with defibrillation by ambulance and firefighters but no advanced life support. Survival was plotted as a function of the defibrillation response interval. The equation of the curve, generated by means of logistic regression, was used to estimate survival at various defibrillation response interval cutoff points.

RESULTS

From January 1, 1991, to December 31, 1997, there were 392 (4.2%) survivors overall among the 9,273 patients treated. The defibrillation response interval mean was 6.2 minutes, and the 90th percentile was 9.3 minutes. There was a steep decrease in the first 5 minutes of the survival curve, beyond which the slope gradually leveled off. Controlling for known covariates, the decrement in the odds of survival with increasing response interval was 0.77 per minute (95% confidence interval 0.74 to 0.83). The survival function predicts, for successive 90th percentile cutoff points, both survival rates and additional lives saved per year in the OPALS communities compared with the 8-minute standard: 9 minutes (4.6%; -18 lives), 8 minutes (5.9%; 0 lives), 7 minutes (7.5%; 23 lives), 6 minutes (9.5%; 51 lives), and 5 minutes (12.0%; 86 lives).

CONCLUSION

The 8-minute target established in many communities is not supported by our data as the optimal EMS defibrillation response interval for cardiac arrest. EMS system leaders should consider the effect of decreasing the 90th percentile defibrillation response interval to less than 8 minutes.

CPR-only survivors of out-of-hospital cardiac arrest: implications for out-of-hospital care and cardiac arrest research methodology

STUDY OBJECTIVE

There is little evidence that cardiopulmonary resuscitation (CPR) alone may lead to the resuscitation of cardiac arrest victims with other than respiratory causes (eg, pediatric arrest, drowning, drug overdose). The objective of this study was to identify out-of-hospital cardiac arrest survivors resuscitated without defibrillation or advanced cardiac life support.

METHODS

This observational cohort included all adult survivors of out-of-hospital cardiac arrest of a cardiac cause from phases I and II of the Ontario Prehospital Advanced Life Support Study. During the study period, the system provided a basic life support/defibrillation level of care but no advanced life support. CPR-only patients were patients determined to be without vital signs by EMS personnel who regained a palpable pulse in the field with precordial thump or CPR only and then were admitted alive to the hospital. Six members of a 7-member expert review panel had to rate the patient as either probably or definitely having an out-of-hospital cardiac arrest, and a rhythm strip consistent with a cardiac arrest rhythm had to be present to be considered a patient. Criteria considered were witness status, citizen or first responder CPR, CPR duration, arrest rhythm and rate, and performance of precordial thump.

RESULTS

From January 1, 1991, to June 30, 1997, 9,667 patients with out-of-hospital cardiac arrest were treated. The overall survival rate to hospital discharge was 4.6%. There were 97 apparent CPR-only patients admitted to the hospital. Application of the inclusion criteria yielded 24 CPR-only patients who had true out-of-hospital cardiac arrest and 73 patients judged not to have cardiac arrest. Of the 24 true CPR-only patients admitted to the hospital, 15 patients were discharged alive, 10 patients were witnessed by bystanders, and 7 patients were witnessed by EMS personnel. The initial arrest rhythm was pulseless electrical activity in 9 patients, asystole in 12 patients, and ventricular tachycardia in 3 patients. One patient with ventricular tachycardia converted to sinus tachycardia with a single precordial thump.

CONCLUSION

CPR-only survivors of true out-of-hospital cardiac arrest do exist; some victims of out-of-hospital cardiac arrest of primary cardiac cause can survive after provision of out-of-hospital basic life support care only. However, many patients found to be pulseless by means of out-of-hospital evaluation likely did not have a true cardiac arrest. This has implications for the survival rates of most, if not all, previous cardiac arrest reports. Survival rates from cardiac arrest may actually be lower if one excludes survivors who never had a true arrest. The absence of vital signs by out-of-hospital assessment alone is not adequate to include patients in research reports or quality evaluations for cardiac arrest.

Emergency Medical Services Outcomes Project (EMSOP) II: developing the foundation and conceptual models for out-of-hospital outcomes research

Development of methodologically acceptable outcomes models for emergency medical services (EMS) is long overdue. In this article, the Emergency Medical Services Outcomes Project proposes a conceptual framework that will provide a foundation for future EMS outcomes research. The "Episode of Care Model" and the "Out-of-Hospital Unit of Service Model" are presented. The Episode of Care Model is useful in conditions in which interventions and outcomes, especially survival and major physiologic dysfunction, are linked in a time-dependent manner. Conditions such as severe trauma, anaphylaxis, airway obstruction, respiratory arrest, and nontraumatic cardiac arrest are amenable to this methodology. The Out-of-Hospital Unit of Service Model is essentially a subunit of the Episode of Care Model. It is valuable for evaluating conditions that have minimal-to-moderate therapeutic time dependency. This model should be used when studying outcomes limited to the out-of-hospital interval. An example of this is pain management for injuries sustained in motor vehicle crashes. These models can be applied to a wide spectrum of conditions and interventions. With the scrutiny of health care expenditures ever increasing, the identification of clinical interventions that objectively improve patient outcome takes on growing importance. Therefore, the development, dissemination, and use of meaningful methodologies for EMS outcomes research is key to the future of EMS system development and maintenance.

Trauma systems

Trauma is one of the major causes of death and disability in modern society, particularly for the young. Organized trauma systems reduce mortality and morbidity from trauma. An effective trauma system addresses all aspects of trauma care, from prevention to rehabilitation. Well-developed trauma systems are currently available only to a minority of the world's population. Trauma systems in developed nations have much potential for improvement.