Prehospital advanced life support: benefits in trauma

Advanced or basic life support for trauma: meta-analysis and critical review of the literature

BACKGROUND

The question of whether to use advanced life support (ALS) or basic life support (BLS) for trauma patients in the prehospital setting has been much debated and still lacks a clear answer. The purpose of this study was to conduct a comprehensive critical review of the literature regarding this controversy

METHODS

A total of 174 articles on prehospital ALS or BLS for trauma were reviewed. Fifteen of these studies were found to involve mortality statistics for both ALS- and BLS-treated patients. Odds ratios were calculated for survival in ALS versus BLS and summarized across studies on the basis of multivariate scoring systems that incorporated both design and methodological assessment. Overall odds ratios for all studies were calculated on the basis of both raw data from the papers, and weighted odds ratios were calculated from the scoring systems.

RESULTS

Six studies were scored as being methodologically average (5 favoring BLS and 1 favoring ALS), two were scored as good (1 favoring BLS and 1 favoring ALS), seven as excellent (6 favoring BLS and 1 favoring ALS). Ten studies had an average study design score (6 favoring BLS and 4 favoring ALS) and seven had a good study design score (6 favoring BLS and 1 favoring ALS). Weighted odds ratio for dying was 2.59 for patients receiving ALS compared with those receiving BLS. The crude odds ratio was 2.92.

CONCLUSION

The aggregated data in the literature have failed to demonstrate a benefit for on-site ALS provided to trauma patients and support the scoop and run approach.

Evaluation of the acute cervical spine: a management algorithm

BACKGROUND

Safe, efficient, and cost-effective evaluation of the spine is the goal in the trauma setting. At our Level I trauma facility, the trauma service, emergency medicine, radiology, anesthesia, and the spine service combined individual concerns into one agreed-upon clearance protocol. Here, we present the effectiveness of a new cervical spine clearance protocol.

METHODS

A retrospective review was initiated of all trauma patients evaluated in a Level I trauma center the year before and after implementation of a new cervical spine protocol to determine the incidence of missed cervical injuries. An additional 6 months were reviewed to detect any missed injuries late in the study period.

RESULTS

During the 2-year study period, 4,460 patients presented to the emergency room with some form of cervical spine precautions. Blunt trauma comprised 90% of the study population. According to the protocol, approximately 45% required further cervical radiographs after presentation. In the preprotocol year, 77 of 2,217 (3.4%) patients were diagnosed with cervical spine injuries, 16 of 77 (21%) with multiple level of injuries, and 25 of 77 (32%) with neurologic compromise. Three of 2,217 patients had missed cervical spine injuries on their initial evaluations. In the postprotocol year, 84 of 2,243 (3.4%) patients had cervical injuries, 25 of 84 (30%) with multiple levels of injuries and 28 of 84 (28%) with neurologic compromise. No patient evaluated during the protocol year was missed. All statistics between the two groups were not significant.

CONCLUSION

The current protocol by risk stratifying patients on presentation is effective in assessing patients for cervical spine injuries.

History and development of trauma care in the United States

Until recently the development of systems for trauma care in the United States has been inextricably linked to wars. During the Revolutionary War trauma care was based on European trauma principles particularly those espoused by the Hunter brothers. Surgical procedures were limited mostly to soft tissue injuries and amputations. The American Civil War was remarkable because of the contributions that were made to the development of systems for trauma care. The shear magnitude of casualties required extensive infrastructure to support the surgeons at the battlefield and to care for the wounded. For the first time in an armed conflict, anaesthetics were used on a routine basis. Despite these major contributions, hospital gangrene was a terrible problem and was the cause of many mortalities. World War I and World War II were noteworthy because of the contributions made by surgeons in the use of blood. One of the major lessons of World War II was the reemphasis of how frequently lessons have to be relearned regarding the treatment and care of wounds. Between the Korean Conflict and the Vietnam War the discovery was made of the tremendous fluid shifts into the cell after severe hemorrhagic shock. As a consequence, the treatment of patients with shock was altered during the Vietnam Conflict, which resulted in better outcomes and less renal failure. The first trauma centers for civilians were started in the United States in 1966. Since 1988 the number of states with mature trauma systems has expanded from two to 35. During the same period, many studies have documented the efficacy of trauma systems in reducing unnecessary mortality and disability.

Survival after emergency department thoracotomy: review of published data from the past 25 years

BACKGROUND

Emergency department thoracotomy (EDT) has become standard therapy for patients who acutely arrest after injury. Patient selection is vitally important to achieve optimal outcomes without wasting valuable resources. The aim of this study was to determine the main factors that most influence survival after EDT.

STUDY DESIGN

Twenty-four studies that included 4,620 cases from institutions that reported EDT for both blunt and penetrating trauma during the past 25 years were reviewed. The primary outcomes analyzed were in-hospital survival rates.

RESULTS

EDT had an overall survival rate of 7.4%. Normal neurologic outcomes were noted in 92.4% of surviving patients. Factors reported as influencing outcomes were the mechanism of injury (MOI), location of major injury (LOMI), and signs of life (SOL). Survival rates for MOI were 8.8% for penetrating injuries and 1.4% for blunt injuries. When penetrating injuries were further separated, the survival rates were 16.8% for stab wounds and 4.3% for gunshot wounds. For the LOMI, survival rates were 10.7% for thoracic injuries, 4.5% for abdominal injuries, and 0.7% for multiple injuries. If the LOMI was the heart, the survival rate was the highest at 19.4%. The third factor influencing outcomes was SOL. If SOL were present on arrival at the hospital, survival rate was 11.5% in contrast to 2.6% if none were present. SOL present during transport resulted in a survival rate of 8.9%. Absence of SOL in the field yielded a survival rate of 1.2%. There was no clear single independent preoperative factor that could uniformly predict death.

CONCLUSIONS

The best survival results are seen in patients who undergo EDT for thoracic stab injuries and who arrive with SOL in the emergency department. All three factors-MOI, LOMI, and SOL-should be taken into account when deciding whether to perform EDT. Uniform reporting guidelines are needed to further elucidate the role of EDT taking into account the combination of MOI, LOMI, and SOL.

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

The Ontario Prehospital Advanced Life Support (OPALS) Study represents the largest prehospital study yet conducted, worldwide. This study will involve more than 25,000 cardiac arrest, trauma, and critically ill patients over an 8-year period (1994-2002). The current article, Part II, describes in detail the rationale and methodology for major trauma and respiratory distress patients and for an economic evaluation of Advanced Life Support (ALS) programs in the OPALS Study. The OPALS Study, using a rigorous controlled methodology and a large sample size, should clearly indicate the benefit in trauma and respiratory distress patient survival and morbidity that results from the widespread introduction of prehospital ALS programs to communities of many different sizes. [Stiell IG, Wells GA, Spaite DW, Nichol G, O'Brien B, Munkley DP, Field BJ, Lyver MB, Luinstra LG, Dagnone E, Campeau T, Ward R, Anderson S, for the OPALS Study Group: The Ontario Prehospital Advanced Life Support (OPALS) Study Part II: Rationale and methodology for trauma and respiratory distress patients.

The facilitated pediatric resuscitation room

Pediatric resuscitation is challenging for the emergency physician because the diverse range in the age and size of the patients encountered complicates the appropriate selection of medications, equipment, and supplies. The following enhancements in the pediatric resuscitation room were made to facilitate effective management of critically ill neonates and children: 1) expanding the concept of the Broselow tape as the central color theme of organization of all medication doses and equipment; 2) use of a large, simplified, color-coded wall chart to define patient parameters; 3) color-coded equipment; 4) adjustable "break-away" resuscitation stretcher; and 5) equipment suspended from the ceiling: a) radiant warmer; b) suction, oxygen, and electricity; c) cardiac monitor and fluid controller; d) X-ray unit. These changes give the resuscitation team greater accessibility to both the patient and the needed resuscitation supplies.

The effects of varying fluid volume and rate of resuscitation during uncontrolled hemorrhage

BACKGROUND

The role of rate and volume of infusion in survival from experimental uncontrolled hemorrhage was evaluated.

METHODS

Hemorrhage was initiated using tail resection in 43 female rats assigned to the following five groups: nonresuscitated; resuscitated with moderate volume, slower rate; resuscitated with moderate volume, faster rate; resuscitated with high volume, slower rate; and resuscitated with high volume, faster rate.

RESULTS

A trend toward improved survival was noted with faster rate of infusion (60 vs. 33.3% survival rate with moderate volume and 28.6 vs. 12.5% with high volume, compared with 16.7% in the nonresuscitated animals).

CONCLUSION

Rapid infusion of moderate volume of isotonic saline improved survival in uncontrolled hemorrhage. Extreme volumes, infused rapidly, also resulted in higher survival rates compared with those observed in nonresuscitated rats.

Outcome assessment of physiologic and clinical predictors of survival in patients after traumatic injury with a trauma score less than 5

OBJECTIVE

To define those physiologic and clinical variables that have a positive or negative predictive value in discriminating survivors from nonsurvivors with traumatic injuries and a Trauma Score of 5 or less.

METHODS

A retrospective review of 2,622 trauma patients transported by an air medical service from the scene of injury to a Level I trauma center was performed. Demographic, physiologic, and clinical variables were evaluated.

RESULTS

One hundred thirty-six patients were studied; 14 patients survived trauma resuscitation. Survivors had statistically significant improvement in the Glasgow Coma Scale from the field to arrival in the emergency room. Revised Trauma Score, probability of survival, pulse, respiratory rate, cardiac rhythm, central nervous system activity, and signs of life were statistically more favorable in survivors.

CONCLUSION

In patients who survived to discharge, signs of central nervous system activity in the field was a positive predictor of survival, and severe head injury served as a negative predictor of survival.

Prehospital advanced life support for major trauma: critical need for clinical trials

A widely diverse body of information exists on the use of Advanced Life Support procedures by prehospital personnel. We compared and contrasted the literature that currently exists on this topic. We examined methodologies, results, and conclusions for each article. We also stress the need for critical clinical evaluations in this arena.

Prehospital care and survival of pediatric patients with blunt trauma

BACKGROUND

The aim of this study was to compare the outcome of severe blunt trauma in children receiving prehospital care from either physician-staffed advanced life support (ALS) units, or from basic life support (BLS) units staffed by emergency medical technicians.

METHODS

The records of 288 children with severe blunt trauma who required intensive care in the regional level 1 trauma center or who died from their injuries were analyzed retrospectively. Patients were excluded if resuscitation at the scene was not attempted, if the level of prehospital care was unspecified, or if arrival at the level 1 trauma center was delayed beyond 150 minutes. Seventy-two patients met the inclusion criteria of BLS-, and 49 the criteria of ALS-prehospital care.

RESULTS

A reduced mortality rate (22.4% v 31.9%) was seen in the ALS group, which was more apparent in a "salvageable but high-risk" subgroup, characterized by Glasgow Coma of Scale 4 through 8, Pediatric Trauma Score of 0 through 5, and Injury Severity Score (ISS) of 25 through 49. However, a statistically significant difference was only seen when trauma severity was evaluated by the ISS.

CONCLUSION

An improved outcome in children with severe blunt trauma has been demonstrated when prehospital care is provided by physician-staffed ALS units compared with BLS units.

The use of TRISS methodology to validate prehospital intubation by urban EMS providers

The purpose of this study was to determine the impact of field orotracheal intubation (OI) by urban emergency medical technician-paramedics (EMT-Ps) on outcome compared with trauma score and injury severity score (TRISS) expectations. The records of all trauma patients intubated by EMT-Ps or hospital personnel were abstracted for OI attempts/ successes, use of neuromuscular blockade (NMB), scene time, discharge neurological status, and hospital survival compared with TRISS. EMT-Ps attempted 43% of all intubations; 81% were successful versus 98% by hospital staff (P < .05). NMB was used by 76% of hospital intubations versus none by EMS (P < .05). Scene time was 10.3 +/- 3.2 minutes versus 11.6 +/- 2.1 for patients intubated by emergency medical services (EMS) and hospital staff (P < .05). Sixty percent of patients intubated by EMS versus 68% by hospital staff had good/moderate discharge neurological status. Survival for patients intubated by EMS versus hospital staff was 11% and 40%, respectively, compared with 2% and 45% expected by TRISS. Field OI by urban EMT-Ps has a favorable impact on survival with good neurological outcome (P < .05).

Ineffectiveness of on-site intravenous lines: is prehospital time the culprit?

The purpose of the present study was to test the association between on-site intravenous fluid replacement and mortality in patients with severe trauma. The effect of prehospital time on this association was also evaluated. The design was that of an observational quasi-experimental study comparing 217 patients who had on-site intravenous fluid replacement (IV group) with an equal number of matched patients for whom this intervention was not performed (no-IV group). The patients were individually matched on their Prehospital Index obtained at the scene and were included in the study if they had an on-site Prehospital Index score > 3 and were transported alive to the hospital. The outcome measure of interest was mortality because of injury. The patients in the IV group had a significantly lower mean age (37 vs. 45 years; p < 0.001) and higher incidence of injuries to the head or neck (46 vs. 32%; p = 0.004), chest (34 vs. 17%; p < 0.001), and abdomen (28 vs. 12%; p < 0.001). The IV group also had a higher proportion of patients injured by motor vehicle crashes (41 vs. 27%; p = 0.003), firearms (9 vs. 2%; p = 0.001), and stabbing (20 vs. 9%; p = 0.001). The rate of extremity injuries (38 vs. 59%; p < 0.001) and falls (12 vs. 40%; p < 0.001) was lower for the IV group. In addition, the mean Injury Severity Score was significantly higher for the IV group (15 vs. 9; p < 0.001). The mortality rates for the IV and no-IV groups were 23 and 6% (p < 0.001). Logistic regression analysis showed that after adjusting for patient age, gender, Injury Severity Score, mechanism of injury, and prehospital time, the use of on-site intravenous fluid replacement was associated with a significant increase in the risk of mortality (adjusted odds ratio = 2.3; 95% confidence interval = 1.02-5.28; p = 0.04). To further evaluate the effect of prehospital time on the association between on-site IV use and mortality, the analysis was repeated separately for the following time strata: 0 to 30 minutes, 31 to 60 minutes, and >60 minutes. The adjusted odds ratios (95% confidence interval) for these strata were 1.05 (0.08-14.53; p = 0.97), 3.38 (0.84-13.62; p = 0.08), and 8.40 (1.27-54.69; p = 0.03). These results show that for prehospital times of less than 30 minutes, the use of on-site intravenous fluid replacement provides no benefit, and that for longer times, this intervention is associated with significant increases in the risk of mortality. The results of this observational study have shown that the use of on-site intravenous fluid replacement is associated with an increase in mortality risk and that this association is exacerbated by, but is not solely the result of, increased prehospital times. Our findings are consistent with the hypothesis that early intravenous fluid replacement is harmful because it disrupts the normal physiologic response to severe bleeding. Although this evidence is against the implementation of on-site intravenous fluid replacement for severely injured patients, further studies including randomized controlled trials are required to provide a definitive answer to this question.

'Clearing' cervical spine injuries in polytrauma patients: is it really safe to remove the collar?

Polytrauma patients are at increased risk for occult cervical spine injuries. Those unable to provide clinical clues to injury either remain in hard collars until they are able to cooperate with the physical examination or are deemed "clear of cervical injury" if the emergency room screening radiographs are without obvious bony abnormality. Cervical immobilization for a lengthy period of time is not without morbidity. Missed ligamentous injuries can lead to cervical instability, which in turn can result in permanent neurologic sequelae. This article reviews the current methodologies to "clear the cervical spine" and highlights the inadequacies.

On-scene times for trauma patients in West Yorkshire

OBJECTIVE

To assess whether length of time on-scene in patients with major injury was associated with severity of injury or with abnormal on-scene physiology.

METHODS

A retrospective analysis of a convenience sample of patients in whom prehospital on-scene times were entered onto the regional major trauma database. On-scene times of patients were analysed to assess whether ultimate injury severity score or on scene physiology measurements affected times. This was undertaken by examining subgroups of patients with similar injury severity or physiological measurements by Wilcoxon-Mann-Whitney testing and comparing 95% confidence intervals of the mean on-scene times.

RESULTS

The mean on-scene time for 111 non-entrapped patients was 26 minutes (95% confidence interval 23.5 to 28.6). Patients with injury severity score of > 15, with a Glasgow coma scale of < 13, and with an abnormal pulse spent significantly less time on-scene than less severely injured or physiologically deranged patients.

CONCLUSIONS

Paramedics have the ability to recognise patients with severe injury and reduce on-scene times. On-scene times were consistently long throughout all subgroups of major trauma patients.

Helicopter emergency medical services: their role in integrated trauma care

The role of helicopters in trauma management must be considered in the context of the provision of sophisticated, high-quality trauma care. The present review examines the evolution of systems of trauma care, the value of advanced life support (ALS), and the role of the Helicopter Emergency Medical Service (HEMS) in improving outcomes. Comparison is made of outcomes of patients managed by HEMS and road ambulances, and important aspects of HEMS including staffing and safety are discussed. There is a role for HEMS as part of a modern trauma system, in particular in bringing ALS skills and access to expert medical care to the rural accident scene or hospital at distances of up to 160 km. It is of greatest value when it is integrated into a well-organized ambulance service and emergency system with good triage and close medical supervision.

Trauma patient outcome after the Prehospital Trauma Life Support program

BACKGROUND

We have previously demonstrated a significant improvement in trauma patient outcome after the Advanced Trauma Life Support (ATLS) program in Trinidad and Tobago. In January of 1992, a Prehospital Trauma Life Support (PHTLS) program was also instituted. This study assessed trauma patient outcome after the PHTLS program.

METHODS

Morbidity (length of stay and degree of disability), mortality, injury severity score, mechanism of injury, age, and sex among all adult trauma patients transported by ambulance to the major trauma hospital were assessed between July of 1990 to December of 1991 (pre-PHTLS, n = 332) and January of 1994 to June of 1995 (post-PHTLS, n = 350).

RESULTS

Age, sex distribution, percentage blunt injury, and injury severity score were similar for both groups. Mortality pre-PHTLS (15.7%) was greater than post-PHTLS (10.6%). Length of stay and disability were statistically significantly decreased post-PHTLS. Age, injury severity score, and mechanism of injury were positively correlated with mortality in both periods. The previously reported post-ATLS mortality was similar to the pre-PHTLS mortality.

CONCLUSIONS

Post-PHTLS mortality and morbidity were significantly decreased, suggesting a positive impact of the PHTLS program on trauma patient outcome.

Effect of the prehospital trauma life support program (PHTLS) on prehospital trauma care

BACKGROUND

Improvement in trauma patient outcome has been demonstrated after the implementation of the Prehospital Trauma Life Support (PHTLS) program in Trinidad and Tobago. This study was aimed at identifying prehospital care factors that may explain this improvement.

METHODS

All patients transferred by ambulance to the major trauma referral hospital had assessment of airway control, oxygen use, cervical (C)-spine control, and hemorrhage control, as well as splinting of extremities during pre-PHTLS (July of 1990 to December of 1991; n = 332) and post-PHTLS periods (January of 1994 to June of 1995; n = 350). Pre-PHTLS data were compared with post-PHTLS data by chi 2 analysis with a p value < or = 0.05 being considered statistically significant.

RESULTS

The frequency (%) increased in the post-PHTLS period for airway control (10 vs. 99.7%), C-spine control (2.1 vs. 89.4%), splinting of extremities (22 vs. 60.6%), hemorrhage control (16 vs. 96.9%), and oxygen use (6.6 vs. 89.5%) when no specific problem was identified. When a specific problem was identified in these areas, the post-PHTLS percentage also increased for airway control (16.2 vs. 100%), C-spine control (25 vs. 100%), splinting of extremities (33.9 vs. 100%), hemorrhage control (18 vs. 100%), and oxygen use (43.2 vs. 98.9%).

CONCLUSIONS

Prehospital trauma care has changed after the introduction of the PHTLS program as indicated by more frequent airway control, use of oxygen, control of cervical (C)-spine and hemorrhage, as well as splinting of fractures. This finding was evident not only as a routine but particularly when a specific related problem was identified. This change in prehospital care could be responsible for the improved trauma patient outcome after PHTLS.

Does basic life support in a rural EMS system influence the outcome of patients with respiratory distress?

PURPOSE

The purpose of this study was to determine whether basic life support, prehospital emergency medical care in a rural area affects the hospital course of patients with respiratory distress.

METHODS

Medical records for patients admitted from the emergency department with a discharge diagnosis related to respiratory disease were reviewed. Data collected included: 1) mode of arrival; 2) initial symptom; 3) vital signs; 4) prehospital interventions applied; 5) hospital days; 6) discharge status; and 7) principal diagnosis. Multiple logistic regression analysis was used to predict length of hospital stay.

RESULTS

Charts for 603 patients were reviewed. Complete data for all variables included in the logistic regression analysis were available for 471 patients (78.1%). Because 55 patients died, only 416 (69.0%) were included in the multiple regression analysis conducted to predict length of hospital stay. Logistic regression analysis demonstrated that patients who arrived by ambulance and older patients were more likely to die; patients with higher systolic blood pressures were more likely to survive. Only patient age predicted length of hospital stay, with older patients having longer stays.

CONCLUSIONS

Basic life support prehospital care in this rural emergency medical services system does not result in a lower mortality rate or a shorter hospital stay for a broad group of patients with respiratory distress who require hospital admission. Although this study is limited to a single population and a single emergency medical services system, it is one of only a few studies of outcome in basic life support systems.

Preventable death evaluation of the appropriateness of the on-site trauma care provided by Urgences-Santé physicians

The study is based on 44 preventable deaths occurring in a cohort of 360 patients with major trauma. These cases were reviewed by a committee of nine experts. The mean Injury Severity Score (ISS) was 28, and most cases had injuries to the head/neck (68%) and chest (64%). The mean (+/- SD) observed prehospital times, and those considered the maximum allowable by the committee, were 40.6 +/- 12.0 minutes for head/neck injuries and 23.9 +/- 12.2 minutes for chest injuries (p < 0.05). Intravenous (i.v.) lines were started in 38 (86%) of the patients. The committee classified this procedure as harmful for 16 (42%) and neutral for 19 (50%). Among the 18 (46%) that were intubated, this intervention was considered harmful for 17% and neutral for 39%. In two of the three patients for whom a pneumatic antishock garment was applied, this procedure was considered harmful. Of the 34 patients that required direct transport at a level I trauma center, 50% were transferred to such a hospital. These results show significant prehospital delays and high rates of inappropriate IV line initiation and intubation in trauma patients receiving on-site care by physicians. We conclude that prehospital care protocols for trauma patients should emphasize prompt transport and specific on-site care algorithms.

Comparison of ambulance dispatch protocols for nontraumatic abdominal pain

STUDY OBJECTIVE

To compare rates of undertriage and overtriage of six ambulance dispatch protocols for the presenting complaint of nontraumatic abdominal pain, and to identify the optimal protocol.

DESIGN

Retrospective prehospital and emergency department chart review to classify patients' conditions as "emergency" or "nonemergency." Utility analysis was used to identify the preferred protocol and monetary cost-effectiveness analysis to identify the least expensive protocol.

SETTING

County emergency medical services (EMS) system with five receiving hospitals serving a mainly urban population of approximately 350,000.

PARTICIPANTS

Records of 902 patients who called 911 for nontraumatic abdominal pain were reviewed; patients not transported were excluded. Twenty-seven county EMS medical directors completed questionnaires.

RESULTS

Six ambulance dispatch protocols for nontraumatic abdominal pain were developed: indiscriminate-dispatch, four selective protocols, and no-dispatch. A dichotomous classification system was derived prospectively from the prehospital and medical records of patients who had activated the EMS system before the study period to define "emergency" and "nonemergency" conditions associated with nontraumatic abdominal pain. Emergency criteria identified patients with conditions requiring medical treatment within 1 hour. Reviewers determined, for each patient, whether an ambulance would have been dispatched by each of the protocols. Undertriage and overtriage rates were calculated for each protocol. County EMS medical directors assigned utility values to four potential outcomes of ambulance dispatch by the direct scaling method. The outcomes comprised correct and incorrect decisions to dispatch ambulances to patients with and without emergencies. The protocols were compared by decision analysis. A cost analysis was also performed, using an estimated marginal cost per transport of $302. Sensitivity analysis demonstrated the effect of varying the cost of an undertriage error and the cost per response. Of the 788 patients included in the study, 7.8% had conditions defined as emergencies. The four selective ambulance dispatch protocols had overtriage rates ranging from 10% to 51% and undertriage rates of 4% to 7%. None of the protocols was proven superior on the basis of the medical directors' assignment of utility values. The marginal cost of dispatching advanced life support ambulances to all patients with this complaint was $3,838 per emergency.

CONCLUSION

The majority of patients with nontraumatic abdominal pain who requested ambulance transport during the study period did not have conditions that were classified as emergencies. In the study model, if an undertriage error costs more than $3,674, indiscriminate ambulance dispatch is the least expensive protocol, and if an undertriage error costs less than $3,674, no ambulance dispatch is the least expensive strategy.

Emergency medical service systems research: problems of the past, challenges of the future

Out-of-hospital emergency care was designed around the concept of a system of interrelated events that combine to offer a patient the best care possible outside the hospital. However, in contrast to the actual operations of emergency medical service (EMS) systems, research has not typically used systems-based models as the method for evaluation. In this discussion we outline the weaknesses of component-based research models in EMS evaluation and attempt to provide a "systems-analysis" framework that can be used for future research. Incorporation of this multidiscipline approach into EMS research is essential if there is to be any hope of finding answers to many of the important questions that remain in the arena of out-of-hospital health care.

The effect of prehospital transport time on the mortality from traumatic injury

OBJECTIVE

To test the hypothesis that a prehospital time threshold (PhTT) exists that when exceeded, significantly increases the mortality of trauma patients transported directly from the scene of injury to a trauma center rather than to the closest hospital.

DESIGN

Review of data contained within the Illinois Trauma Registry encompassing the period from fall 1989 through spring 1991.

PARTICIPANTS

A total of 5,215 injured persons with an Injury Severity Score (ISS) > 10, cared for in an Illinois level-I or -II trauma center outside of the city of Chicago.

MEASUREMENTS

Injury severity expressed as ISS, scene time (ST), transport time (TrT), total emergency medical services time (TEMST), and outcome were determined for each patient. Patients were stratified into groups on the basis of ISS.

RESULTS

Patient outcomes were significantly different statistically between ISS groups (p < 0.001, chi 2). Mean ST and TEMST, but not TrT, were significantly different statistically between ISS groups (p < 0.001, analysis of variance). Lower ISS was associated with longer times. Mean ST, TrT, and TEMST were significantly different statistically between survivors and nonsurvivors (p < 0.001, two-sample t-tests). Survival was associated with longer times. Each of the mean times remained significantly different between survivors and nonsurvivors after controlling for severity of injury (p < 0.001, two-way analysis of variance).

CONCLUSION

No PhTT beyond which time patient transport to the closest hospital would have decreased mortality was identifiable, because no prehospital time < 90 minutes exerted a significant adverse effect upon survival.

AB or ABC: pre-hospital fluid management in major trauma

Pre-hospital trauma care in the United Kingdom is a neglected field with little consideration being given to this phase. Of the 14,500 annual fatalities from road traffic accidents in this country, 60% die before reaching hospital and it has been estimated that one-third of these fatalities are due to hypovolaemia. The pre-hospital fluid resuscitation of trauma patients is a controversial area and although it would seem sensible to commence intravenous (i.v.) fluids at the roadside, several large studies have failed to show any benefit from this intervention. By delaying departure to hospital, initiation of i.v. fluid replacement may actually worsen outcome. This paper reviews recent studies and discusses current thought on pre-hospital fluid replacement in major trauma.

A prospective in-field comparison of intravenous line placement by urban and nonurban emergency medical services personnel

STUDY HYPOTHESIS

Emergency medical services personnel are highly proficient at rapid i.v. line placement in the prehospital setting, with little difference between urban and nonurban areas in a geographically diverse state.

DESIGN

Prospective evaluation by an in-field observer of timing, sequence, success rates, and patient characteristics for IV line placement by prehospital personnel for 1 year.

SETTING

Twenty advanced life support agencies from all four emergency medical service regions of Arizona.

PARTICIPANTS

Fifty-eight patients encountered by participating emergency medical service agencies who had at least one i.v. line placement attempt in the prehospital setting.

RESULTS

Urban agencies encountered 24 patients (41.4%), and nonurban agencies encountered 34 (58.6%). Fifty-seven of 58 patients (98.3%) had at least one successful i.v. line started before arrival at a hospital. All 24 urban patients and 33 of 34 nonurban patients (97.1%) had a successful i.v. line attempt (P = .586, power = .09). In the urban setting, 24 of 31 attempts (77.4%) were successful, and in the nonurban setting 35 of 52 attempts (67.3%) were successful (P = .464, power = .28). Mean i.v. line procedure intervals were 1.6 minutes in urban and 1.4 minutes in nonurban settings (P = .408, power = .7). Thirty of 31 i.v. line attempts (96.7%) were completed in less than 4 minutes in urban systems, and 49 of 52 IV line attempts (94.2%) were completed in less than 4 minutes in nonurban systems (P = .520, power = .13). Mean i.v. line procedure intervals were 1.3 minutes for successful attempts and 2.1 minutes for unsuccessful ones (P = .015). Mean i.v. line procedure intervals for on-scene attempts were 1.3 minutes compared with 2.0 minutes for attempts during transport (P = .005). On average, i.v. line attempts in trauma patients took only 1.0 minutes compared with 1.7 in medical patients (P = .017).

CONCLUSION

Personnel in the 20 advanced life support agencies studied were extremely adept (rate of 98.3%) at obtaining i.v. line access in the prehospital setting. The time required to complete i.v. line placement was very short, and little difference was noted between urban and nonurban providers. I.v. procedure intervals were shorter for successful attempts, on-scene attempts, and attempts in trauma patients compared with their counterparts.

Determinants of on-scene time in injured patients treated by physicians at the site

INTRODUCTION

The controversy surrounding the use of advanced life support (ALS) for the pre-hospital management of trauma pivots on the fact that these procedures could cause significant and life-threatening delays to definitive in-hospital care. In Montreal, Québec, on-site ALS to injured patients is provided by physicians only. The purpose of this study was to identify parameters associated with the duration of scene time for patients with moderate to severe injuries treated by physicians at the scene.

HYPOTHESIS

The use of on-site ALS by physicians is associated with a significant increase in scene time.

METHODS

A total of 576 patients with moderate to severe injuries are included in the analysis. This group was part of a larger cohort used in the prospective evaluation of trauma care in Montreal. Descriptive statistics, analysis of variance, multiple linear regression, and multiple logistic regression techniques were used to analyze the data.

RESULTS

Use of ALS in general was associated with a statistically significant increase in the mean scene time of 6.5 min. (p = .0001). Significant increases in mean scene time were observed for initiation of an intravenous route (mean = 6.6 min., p = .0001), medication administration (mean = 5.7 min., p = .0001), and pneumatic antishock garment (PASG) application (mean = 9.3 min., p = .03). Similar differences were observed for total prehospital time. A significant increase in the relative odds for having long scene times (> 20 min.) also was associated with the use of ALS. This level of scene time was associated with a significant increase in the odds of dying (OR = 2.6, p = .009).

CONCLUSION

This study shows that physician-provided, on-site ALS causes significant increase in scene time and total prehospital time. These delays are associated with an increase in the risk for death in patients with severe injuries.

Saline locks in prehospital care

OBJECTIVES

1) To determine if paramedics could select appropriate patients for use of the saline lock; 2) to evaluate saline-lock patency upon arrival at the emergency department (ED); and 3) to define any cost-savings associated with the use of the saline lock.

POPULATION

Patients in the prehospital setting who required intravenous (IV) access, but did not require fluid resuscitation. Patients with hypotension or multiple traumatic injuries were excluded.

METHODS

Paramedics were given the option for the use of either the saline lock or a routine IV set-up. Initially, the reservoir was flushed with 1 ml 0.9 N saline solution and the flush was repeated only if medications subsequently were completed for each patient. Information collected included: 1) demographics; 2) reason for selection; 3) need for fluid infusion; 4) conversion of the lock to a routine IV set-up; and 5) administration of medications through the lock. Failures included inability to flush after arrival to the ED, or local infiltration detected on flush while in the ED. Costs associated with the use of the saline locks were compared with those associated with the use of traditional IV set-ups. Cost-savings were calculated as the cost of a traditional IV set-up minus costs of the lock set-up.

RESULTS

A total of 58 male and 42 female patients was enrolled. All patients were assigned appropriately. The most commonly used indications included chest pain, possible stroke, and shortness of breath. Two locks were occluded, and two had infiltrated when flushed following arrival of the patient to the ED. Five patients had IV fluid loads initiated through the locks. Cumulative cost-saving were [U.S.]$130 to the hospitals and $1,710 to the patients or their carriers. Most paramedics were pleased with the performance and utility of the locks.

CONCLUSIONS

The use of saline locks is an alternative to the use of traditional IVs in certain patients in the prehospital setting.

Design of an intraosseous infusion system

To reduce the emergency treatment time of shock victims, resuscitation fluids can be infused into a patient via their sternum rather than through a peripheral vein. Successful use of this method requires manual infusion because available medical equipment is not capable of infusing the preferred resuscitation fluids into the sternum at the required flow rates. This article describes the process and results of the design of a high pressure infusion system specifically intended for automating emergency sternal infusions. Infusion requirements for the human sternum were clearly defined, and were followed by the development and evaluation of many infusion system ideas, including numerous commercially available pump designs. The options were narrowed down to five schemes that were studied in depth. Finally, two schemes were picked, a compressed gas bag-within-a-bag design and a peristaltic design.

The golden hour and prehospital trauma care

A 1-year prospective study of 12 hospitals, and approximately 1 million people, was carried out to predict the effectiveness of prehospital advanced life support (ALS) for major trauma in Northern Ireland. Inclusion criteria were an Injury Severity Score (ISS) > 15 and reaching hospital alive. Two hundred and thirty-nine patients had mean prehospital times of 24 and 35 min for urban and rural hospitals, respectively. Most patients (75 per cent, N = 179) were within 10 minutes of a hospital. Of the other patients (25 per cent, N = 60), only 1/2 would have benefitted from prehospital ALS. Fifteen patients aspirated (for a mean time of 7 minutes) before ambulance arrival and eventually died. Seventy per cent of patients who died and who either aspirated or were apnoeic had severe primary brain injuries; the other 30 per cent were considered unsalvageable by both TRISS and peer review. ALS for major trauma will be appropriate for less than 50 patients with ISS > 15 per annum in Northern Ireland. Skill maintenance will be difficult for paramedics.

Are pre-hospital deaths from accidental injury preventable?

OBJECTIVE

To determine what proportion of pre-hospital deaths from accidental injury--deaths at the scene of the accident and those that occur before the person has reached hospital--are preventable.

DESIGN

Retrospective study of all deaths from accidental injury that occurred between 1 January 1987 and 31 December 1990 and were reported to the coroner.

SETTING

North Staffordshire.

MAIN OUTCOME MEASURES

Injury severity score, probability of survival (probit analysis), and airway obstruction.

RESULTS

There were 152 pre-hospital deaths from accidental injury (110 males and 42 females). In the same period there were 257 deaths in hospital from accidental injury (136 males and 121 females). The average age at death was 41.9 years for those who died before reaching hospital, and their average injury severity score was 29.3. In contrast, those who died in hospital were older and equally likely to be males or females. Important neurological injury occurred in 113 pre-hospital deaths, and evidence of airway obstruction in 59. Eighty six pre-hospital deaths were due to road traffic accidents, and 37 of these were occupants in cars. On the basis of the injury severity score and age, death was found to have been inevitable or highly likely in 92 cases. In the remaining 60 cases death had not been inevitable and airway obstruction was present in up to 51 patients with injuries that they might have survived.

CONCLUSION

Death was potentially preventable in at least 39% of those who died from accidental injury before they reached hospital. Training in first aid should be available more widely, and particularly to motorists as many pre-hospital deaths that could be prevented are due to road accidents.

Contribution of air medical personnel to the airway management of injured patients

INTRODUCTION

Air medical services are being pressured to demonstrate their value. Airway management is the first priority of care when treating injured patients in the prehospital setting. Injured patients with decreased Glasgow Coma Scale (GCS) are candidates for advanced airway procedures and air medical transport.

RESEARCH QUESTION

The purpose of this study was to determine the extent of air medical crews' contributions to the airway management of the injured patient in the prehospital setting.

METHOD

A study of adult (age > 12 years) injured patients encountered in a field setting, whose GCS on the arrival of the air medical crew was < or = 8, was conducted for 21 months (Feb. 1, 1991-Oct. 31, 1992).

RESULTS

During the study period, 174 patients who met the criteria were transported by the air medical crew. All but one received advanced airways including oral tracheal intubation, nasal tracheal intubation or cricothyrotomy. Of those, 68 (39%) of these procedures were completed by ground personnel (ground group), and 105 (61%) were completed by the air medical personnel (air group). The mean GCS for the ground group was 3.69 and for the air group was 4.69. The distributions were significantly different (Wilcoxon Rank Test p = 0.0002). Nineteen percent (13/68) of the patients whose airways were successfully managed by the ground personnel had a GCS of 5 to 8, as did 44% (46/105) of the air group's patients. The groups' patients were not significantly different in age or sex distribution.

CONCLUSION

Properly trained air medical personnel positively contribute to the prehospital care of injured patients by establishing definitive airways in patients with higher GCSs.

Physician in-field observation of prehospital advanced life support personnel: a statewide evaluation

STUDY HYPOTHESIS

Direct physician observation of advanced life support (ALS) personnel is rare in a demographically diverse state.

STUDY POPULATION

Twenty ALS agencies from throughout Arizona.

METHODS

A board-certified emergency physician performed on-site interviews with the emergency medical services (EMS) supervisor of each agency to approximate the number of days per year that physicians observe ALS personnel in the field.

RESULTS

Only 11 agencies (55%) reported that physicians ever observed ALS personnel. Among all agencies, an estimated total of 84 observer-days occurred per year. The agencies staffed a total of 86 ALS units, resulting in an estimated 0.98 observer-days/unit/year (84/86). On the average, it took 3.4 ALS personnel to staff a given unit over time and the probability that an ALS provider would be on a unit on any given day was 0.29 (1/3.4). The probability of a given provider being observed during one year was approximately 0.29 (0.98 x 0.29). Thus, on the average, an ALS provider would be observed by a physician approximately once every 3.5 years (1/0.29). Among urban agencies, the "average" ALS provider would be observed once every 2.9 years. This compared to a likelihood of in-field observation of only once every 6.7 years for non-urban providers (p = .036).

CONCLUSIONS

The skills of ALS providers in Arizona are observed by a physician in the field very infrequently. Although an uncommon occurrence in urban agencies, observation of non-urban ALS personnel occurs even less frequently. In addition, nearly one-half of the agencies surveyed never had a physician-observer. Although a variety of skills evaluation methods exist, it remains unclear whether any method is as useful as direct observation. Future investigations are needed to evaluate whether in-field physician observation impacts skills, patient care, or outcome in EMS systems.

Delays in care of the critically injured

Prehospital and resuscitation periods and times to emergency surgery were studied in major trauma victims over two 12-month periods to identify factors causing delay in emergency care. Eighteen patients required emergency surgery in the first group and 13 in the second. The mean presurgery time (i.e. time from arrival in the accident and emergency department to surgery) was 117 min in the first group and 111 min in the second. Causes of delay included a sequential approach to resuscitation and investigation, limited staff and theatre availability, and failure to call the trauma team. Times for resuscitation and times to surgery could be reduced by earlier decision-making, alerting key personnel promptly and performing tasks in parallel.

An optically scanned EMS reporting form and analysis system for statewide use: development and five years' experience

Analysis of emergency medical services (EMS) systems data is crucial to planning, education, research, and quality assurance programs. Currently, comparative analysis of EMS data between regions or states is virtually impossible due to wide variations in data collection and analysis methods. To devise a practical and uniform EMS reporting system, we referenced the minimum data set (MDS) established by the federal government in 1974 and surveyed 22 states known to be using uniform reporting systems. In developing our final data set, elements were added based on inclusion in the MDS, national survey results, a review of current EMS literature, and consensus of local EMS providers. This set of 48 elements then was incorporated into a reporting form using narrative and optically scanned formats, allowing automated data collection for computer analysis. After a pilot study, the system was improved to allow high-speed ink reading and large volume data storage and analysis using a microcomputer. This system has subsequently been adopted by seven states. The combined data base exceeds 250,000 cases. Error screening algorithms ensure data integrity and are also used for quality assurance. Customized output reports can be generated within minutes and have assisted in EMS quality assurance, planning, and research. We believe that the successful performance of this system supports the use of the suggested data elements as well as optical scanning and microcomputer analysis of EMS data.

The impact of injury severity and prehospital procedures on scene time in victims of major trauma

STUDY OBJECTIVE

To evaluate the relationship among injury severity, prehospital procedures, and time spent at the scene by paramedics for victims of major trauma.

DESIGN

Retrospective study of 98 consecutive patients with an Injury Severity Score of more than 15 who were brought to a trauma center by fire department paramedics.

SETTING

A medium-sized metropolitan emergency medical services (EMS) system and a Level I trauma center.

RESULTS

There were 66 male and 32 female patients with a mean age of 34 years. Thirty-two patients (32.6%) died. Blunt and penetrating trauma accounted for 68.4% and 31.6% of cases, respectively. Thirty-three patients (33.7%) had successful advanced airway procedures, and 81 (82.7%) had at least one IV line started in the field. Analysis of scene time, prehospital procedures, and injury severity parameters revealed that more procedures were performed in the field on the more severely injured cases; that despite this, there was a trend toward shorter scene time for more severely injured patients; and that there was a mean scene time of 8.1 minutes. This is the shortest scene time reported to date for prehospital trauma care in an EMS system.

CONCLUSION

Extremely short scene times can be attained without foregoing potentially life-saving advanced life support interventions in an urban EMS system with strong medical control. In such a system, the most severely injured victims may spend less time at the scene although more procedures are performed on them.

Effect of standing orders on paramedic scene time for trauma patients

STUDY OBJECTIVE

To determine if a protocol change that allowed paramedics to perform certain procedures before base station contact (standing orders) would decrease scene time in trauma patients.

DESIGN

Retrospective review of case series.

SETTING

A single-tiered, all advanced life support emergency medical services system.

INTERVENTION

Implementation with standing orders for invasive procedures.

TYPE OF PARTICIPANTS

All physiologically unstable trauma patients transported to a Level I trauma center by ambulance.

MEASUREMENTS AND MAIN RESULTS

One hundred ninety-seven patients met the inclusion criteria--87 before and 110 after the initiation of standing orders. Mean scene times for the control group (15.3 +/- 8.4 minutes) and for the standing orders group (15.1 +/- 7.6 minutes) were similar (P = .18). The power of the study to detect a two-minute difference in scene time was .92. Scene time was not influenced by mechanism of injury, and the number of procedures performed on patients was similar between the two groups.

CONCLUSION

Standing orders did not decrease scene time in physiologically unstable trauma patients. Further study is necessary to delineate the factors that actually contribute to on-scene time and the factors that are important in determining whether standing orders or on-line medical contact should be used.

Study design in prehospital trauma advanced life support-basic life support research: a critical review

The best method of prehospital care for the trauma victim remains controversial. Nine studies that compare advanced life support to basic life support for prehospital trauma care are reviewed. Limitations in the study designs are noted, and suggestions are made for more uniform reporting in prehospital trauma research.

A comparison of prehospital estimated time of arrival and actual time of arrival to an emergency department

The accuracy of the paramedic's estimated time until arrival (ETA) to an emergency department has never been studied. Two hundred and eighty paramedic runs were prospectively studied in a suburban, residency-affiliated emergency department. The average ETA was 7.39 +/- 3.72 minutes. The average actual time until arrival, as clocked by the directing emergency physician was 10.29 +/- 3.95 minutes. Two hundred and twenty-seven (81%) patients arrived later than their ETA. There were 24 (8.5%) cases where the physician's prehospital management would have been different had the ETA been more accurate.

The Three Rivers Regatta accident: an EMS perspective

The Three Rivers Regatta accident occurred on August 7, 1988 when a Formula I racing craft collided with shore, injuring 24 spectators. The authors retrospectively examined the prehospital-based response for this multiple-casualty incident that used emergency medical service (EMS) physicians and 32 paramedics stationed at water and land-based posts to triage and evacuate 24 patients in 32 minutes. Patients were transported to 5 hospitals including 4 Level I trauma centers; this was accomplished in 53 minutes. The EMS response was unique in a number of respects. This was a prehospital-based rescue with the entire triage and stabilization phase accomplished by River Rescue units that transported paramedic divers, EMS physicians, and trauma supplies for 30 patients. Also of significance was the inordinate proportion of pediatric patients that accounted for 50% (12/24) of the cases. Successful medical care was the result of planning based on "Daily Routine Doctrine" or escalation of existing treatment protocol; adequate supplies, personnel and transport adapted to local geography and patient population; communications, including all services--EMS, police, and fire; and prehospital physician input to ensure correct triage order and patient disposition.

Computer modeling of emergency medical system performance

Emergency medical services (EMS) system managers face difficult problems when determining the need for system expansion and unit deployment. Information relevant to the decision is often limited and frequently not in a usable format. This lack of usable information often results in decisions that create less-than-optimal EMS systems. A constant search for greater efficiency prompted the development of a computer simulation model to analyze the current EMS system operated by the Tucson Fire Department and to provide statistical information on the effects of potential vehicle base locations on system performance. The simulation model generates data that reflect a variety of parameters necessary in base location analysis. Included in the performance statistics for each unit and for the entire system are indicators of unit use rates, minimum and maximum response times, and proportion of calls reached within the critical response time of eight minutes or less. The model has been carefully validated and used in unit redeployment and unit activation in Tucson, Arizona.

Success rates for initiation of intravenous therapy en route by prehospital care providers

The optimal extent of prehospital care, including intravenous (IV) therapy for critically ill patients, remains unclear. The authors evaluated the success rate for IV cannulation in a moving ambulance by trained emergency medical technicians and paramedics in 641 adult medical- and trauma-related cases. At least one IV line was started in 80% of medical patients and 92% of trauma patients, regardless of blood pressure. In hypotensive patients, the success rates for at least one IV in medical and trauma patients were 80% and 95%, respectively. These data suggest that IV lines can be secured with a high degree of success en route to the hospital by trained personnel, and that prompt transport of unstable patients should not be delayed solely to obtain IV access.

Emergency department deaths

This study reviews 186 deaths resulting from trauma in a 2-year period in the Charity Hospital of Louisiana at New Orleans Accident Room in order to evaluate problems in prehospital and hospital resuscitative care. All subjects underwent autopsy, and only six were found to have injuries compatible with survival. Three of these were late arrivals (by transfer or self-imposed delay) and died of protracted hemorrhage. Only three deaths occurring in the Emergency Department itself were found to have been potentially preventable. The important factors in maximizing survival of trauma patients remain rapid transport; immediate, appropriate, rapid evaluation; and quick diagnosis, resuscitation, and definitive therapy. These require a well-trained emergency medical ambulance service delivering patients quickly to a hospital designed to handle trauma patients. One person, preferably a general surgeon with trauma experience, should supervise and monitor the patient continually until the resuscitation phase and all diagnostic tests are completed and definitive therapy is initiated.

Prehospital advanced trauma life support for penetrating cardiac wounds

Prehospital advanced trauma life support (ATLS) is controversial because the risks, benefits, and time required to accomplish it remain unknown. We studied 70 consecutive patients with penetrating cardiac injuries to determine the relationships among prehospital procedures, time consumed in the field, and ultimate patient outcome. Thirty-one patients sustained gunshot wounds, and 39 had stab wounds. The mean Revised Trauma Score was 2.8 +/- 0.5. Paramedics spent an average of 10.7 +/- 0.5 minutes at the scene. Seventy-one percent of the patients underwent endotracheal intubation; 93% had at least one IV line inserted; and 57% had two IV lines inserted. Twenty-one (30%) survived. There was no correlation between on-scene time and either the total number of procedures performed (r = .17, P = .17) or IV lines established (r = .06, P = .6). On-scene times did not differ regardless of whether endotracheal intubation or pneumatic antishock garment applications occurred. We conclude that well-trained urban paramedics can perform multiple life-support procedures with very short on-scene times and a high rate of patient survival and that prehospital trauma systems require a minimum obligatory on-scene time to locate patients and prepare them for transport.