A critical analysis of on-scene helicopter transport on survival in a statewide trauma system

Lives saved by helicopter emergency medical services: an overview of literature

INTRODUCTION

The objective of this review is to give an overview of literature on the survival benefits of Helicopter Emergency Medical Services (HEMS). The included studies were assessed by study design and statistical methodology.

METHODS

A literature search was performed in the National Library of Medicine's Medline database, extending from 1985 until April 2007. Manuscripts had to be written in English and describe effects of HEMS on survival expressed in number of lives saved. Moreover, analysis had to be performed using adequate adjustment for differences in case-mix.

RESULTS

Sixteen publications met the inclusion criteria. All indicated that HEMS assistance contributed to increased survival: Between 1.1 and 12.1 additional survivors were recorded for every 100 HEMS uses. A combination of four reliable studies shows overall mortality reduction of 2.7 additional lives saved per 100 HEMS deployments.

CONCLUSION

Literature shows a clear positive effect on survival associated with HEMS assistance. Efforts should be made to promote consistent methodology, including uniform outcome parameters, in order to provide sufficient scientific evidence to conclude the ongoing debate about the beneficial effects of HEMS.

Surgical trauma referrals from rural level III hospitals: should our community colleagues be doing more, or less?

BACKGROUND

Rural citizens die more frequently because of trauma than their urban counterparts. Skill maintenance is a potential issue among rural surgeons because of infrequent exposure to severely injured patients. The primary goal was to evaluate the outcomes of multiple injuries patients who required a laparotomy after referral from level III trauma centers.

METHODS

All severely injured patients (injury severity score >12) referred to a level I trauma center from level III hospitals, during a 48-month period were evaluated. Comparisons between referrals (level III and IV) as well as survivors and nonsurvivors used standard statistical methodology.

RESULTS

One thousand two hundred and thirty patients (35%) were transferred from level III (33%) and level IV (67%) centers (43% underwent an operative procedure). Only 13% required a laparotomy, whereas 87% needed procedures from other subspecialists. Referred patients had a mean injury severity score of 28, length of stay of 28 days, and mortality rate of 26%. More patients arrived hemodynamically unstable from level IV (55%) versus level III (35%) hospitals (p < 0.05). Nonsurvivors from level III centers were more likely to transfer via aircraft (100%) than from level IV hospitals (55%) (p < 0.05). Most (91%) definitive general surgery procedures could have been completed by surgeons at level III centers; however, 90% also had multisystem injuries requiring treatment by other subspecialists.

CONCLUSIONS

Most severely injured patient referrals from level III and IV trauma centers in Western Canada are appropriate. The lack of consistent subspecialty coverage mandates most transfers from level III hospitals. This data will be used to engage rural Alberta physicians in an educational outreach program.

Outcomes of Blunt Trauma Victims Transported by HEMS from Rural andUrban Scenes

OBJECTIVE

Mortality differences exist between victims of urban and rural trauma; however, it is unknown if these differences persist in those patients who survive to HEMS transport. This study examined the in-hospital mortality, length of hospital stay, and discharge status of adult blunt trauma victims transported by HEMS from rural and urban scenes to regional trauma centers.

METHODS

Retrospective review of all adult (age >/= 15) HEMS transports in 2001; 271 urban and 141 rural blunt trauma patients were identified from HEMS transport records and the trauma registries at three level one trauma centers. Demographic data, scene and hospital interventions, as well as discharge status of the two groups were examined.

RESULTS

Total mileage [27 +/- 12 vs. 119 +/- 64, p < 0.001], total flight times (minutes) [30 +/- 10 vs. 79 +/- 40, p < 0.001], and scene times (minutes) [16 +/- 8 vs. 21 +/- 14, p < 0.001] were significantly longer for rural flights. There were no significant differences between the groups with regard to age, gender, receiving hospital, and initial HEMS vitals. Injury Severity Score, ICU length of stay (LOS), total hospital LOS, and hospital mortality did not differ between the two groups. After controlling for age, gender, and ISS, there were no significant mortality differences between the two groups (p = 0.074).

CONCLUSIONS

Despite longer flight and scene times for rural patients, adjusted in-hospital mortality rates were similar for patients transported from urban and rural scenes. Factors prior to HEMS arrival may contribute to increased mortality rates of rural blunt trauma victims documented nationally.

Presentation of trauma at the National Orthopaedic Hospital Enugu: a pilot study

This prospective study spanning three months was undertaken to provide insight to trauma care including intervention times in this centre. Improved organization of trauma care is needed urgently for improved outcomes.

Air medical response to traumatic brain injury: a computer learning algorithm analysis

BACKGROUND

The role of air medicine in traumatic brain injury (TBI) has been studied extensively using trauma registries but remains unclear. Learning algorithms, such as artificial neural networks (ANN), support vector machines (SVM), and decision trees, can identify relationships between data set variables but are not empirically useful for hypothesis testing.

OBJECTIVE

To use ANN, SVM, and decision trees to explore the role of air medicine in TBI.

METHODS

Patients with Head Abbreviated Injury Score 3+ were identified from our county trauma registry. Predictive models were generated using ANN, SVM, and decision trees. The three best-performing ANN models were used to calculate differential survival values (actual and predicted outcome) for each patient. In addition, predicted survival values with transport mode artificially input as "air" or "ground" were calculated for each patient to identify those who benefit from air transport. For SVM analysis, chi was used to compare the ratio of unexpected survivors to unexpected deaths for air- and ground-transported patients. Finally, decision tree analysis was used to explore the indications for various transport modes in optimized survival algorithms.

RESULTS

A total of 11,961 patients were included. All three learning algorithms predicted a survival benefit with air transport across all patients, especially those with higher Head Abbreviated Injury Score or Injury Severity Score values, lower Glasgow Coma Scale scores, or hypotension.

CONCLUSION

Air medical response in TBI seems to confer a survival advantage, especially in more critically injured patients.

Outcomes of pediatric trauma patients transported from rural and urban scenes

OBJECTIVES

Mortality differences exist between victims of urban and rural trauma. It is unknown if these differences persist in those patients who survive to HEMS transport. This study examined the in-hospital mortality, hospital LOS, and discharge status of pediatric blunt trauma victims transported by HEMS from rural and urban scenes.

METHODS

Retrospective review of pediatric (< 17) transports between 1997 and 2001. 130 rural and 419 urban pediatric patients transported to area trauma centers were identified from HEMS and registry records.

RESULTS

Total mileage, flight times, and scene times were significantly longer for rural flights (P < 0.05). There were no significant differences between the groups with regard to age, gender, vitals, hospital/ICU days, and mortality. After controlling for ISS and mechanism of injury, urban patients were 9 times more likely to die compared to rural patients.

CONCLUSIONS

Pediatric patients injured in urban areas had shorter total flight and scene times than pediatric patients flown from rural scenes. Higher adjusted in-hospital mortality rates in the urban group were likely a result of faster EMS response and transport times, which minimized out-of-hospital deaths. Factors prior to HEMS arrival may have more impact on the increased mortality rates of rural blunt trauma victims documented nationally.

A prospective study of the impact of multiple patient transports on care provided during aeromedical transport

OBJECTIVES

The purpose of the current study was to determine reasons for multiple-patient transports using a helicopter emergency medical services (HEMS) and to observe for any negative impact on patient care caused by the presence of the second patient.

METHODS

The study was a prospective observational study of all two-patient trauma transports (doubles) over a 12-month period, from January 2004 through December 2004. The authors selected a sample of 20% of single-patient transports (singles) from the same time period for comparison. Flight crews completed a study form after the flight. Information requested included Glasgow Coma Scale (GCS) score, Revised Trauma Score (RTS), and negative impact on care of the primary patient caused by transporting the secondary patient. Data were analyzed using Mann-Whitney rank test and descriptive statistics.

RESULTS

There were a total of 59 double-trauma transports. A total of 269 single-trauma transports were identified for comparison. Although there was no statistically significant difference in GCS score or RTS (single vs. primary double), doubles never included the most severely injured trauma patients. The secondary patients from the doubles were the least severely injured. There were nine patients in whom the crew felt there was a negative impact from the second patient. Need for trauma center evaluation of the second patient and distance of transport were common reasons for double transports.

CONCLUSIONS

Patients transported as doubles do not include the most severely injured trauma patients. In only a small percentage of doubles did the second patient have a perceived impact on care of the primary patient.

Helicopter Emergency Ambulance Service (HEAS) transfer: an analysis of trauma patient case-mix, injury severity and outcome

INTRODUCTION

A retrospective review of all patients transferred by helicopter ambulance to the Great Western Hospital over a 20-month period between January 2003 and September 2004 was undertaken to establish the case-mix of patients (trauma and non-trauma) transferred and the outcome.

PATIENTS AND METHODS

Details of all Helicopter Emergency Ambulance Service (HEAS) transfers to this unit in the study time period were obtained from the three HEAS providers in the area and case notes were reviewed.

RESULTS

There were 156 trauma patients transferred (total 193) in the study period with 111 cases identified for analysis with a mean age of 33 years (range, 1-92 years). Average Injury Severity Score on admission was 12 (range, 1-36). Forty-five patients were discharged home from the emergency department, 24 cases had operation, 10 patients required ICU care and 2 were pronounced dead in the emergency department. Average hospital stay following HEAS transfer was 2.97 days (range, 0-18 days).

DISCUSSION

Helicopter ambulance transfer in the acute setting is of debated value. Triage criteria are at fault if as many as 41% of patients transferred are being discharged home from casualty having incurred the financial cost of helicopter transfer. We suggest that the triage criteria for helicopter emergency transfer should be reviewed.

[The influence of transportation mode on mortality in polytraumatized patients. An analysis based on the German Trauma Registry]

BACKGROUND

Thirty years after its introduction in Germany, the benefits of the helicopter emergency medical service (HEMS) compared to ground ambulances (GA) still remain unclear. The aim of this study was to evaluate the influence of helicopter transport on rescue time and mortality based on the data of the German Trauma Registry.

METHODS

Data from patients with multiple injuries were documented prospectively between 1993 and 2003 in different trauma centers in Germany, Switzerland, Austria and The Netherlands. From these data, patients with an injury severity score (ISS)<16 were excluded. Patients who were transported to the hospital without a physician were also excluded. The data from included patients were evaluated for time to hospital and influence of transportation service on mortality.

RESULTS

A total of 7,534 patients with multiple injuries were included. Of these, 3,870 patients were transported by HEMS and 3,664 reached the hospital by GA. There were 74.9% male patients in the HEMS group, and 71.3% male patients in the GA group. The mean ISS was higher in the HEMS group (31.4 vs 30.7; P<0.01); patients transported by GA were older (HEMS: 39.2; NEF:41.3; P<0.01). The GA arrived on the scene after 14.33 min, the HEMS after 18.18 min (P<0.01). Time at the scene was longer in the HEMS group (HEMS: 26:26 min; NEF: 22:29 min; P<0.01). Intubation rate in the HEMS group was about 80%, while patients transported by GA were intubated in 60% of cases. The overall mortality was 30.9%. Evaluation of the TRISS prediction of survival showed a benefit for patients transported with HEMS. In a multivariate analysis, intubated patients with ISS<or=60 had a lower mortality rate if transported with HEMS (NEF: 40.1%; HEMS 34.9%; P<0.01).

CONCLUSIONS

Only minor differences in age and ISS were found between the groups. The time between the accident and arrival of the physician was longer in the HEMS group. The HEMS group also remained on the scene for longer, but had a higher rate of intervention. According to our analysis of the German Trauma Registry, patients with multiple injuries benefit from HEMS transportation.

Helicopter trauma transport: an overview of recent outcomes and triage literature

PURPOSE OF REVIEW

The purpose of this review is to assess literature pertinent to outcomes benefits accrued by the use of helicopter emergency medical services for trauma transport. A previous annotated bibliography assessed literature published between 1980 and 2000. The goal of this paper is to address developments since fall 2001, and to cast recent studies in the light of earlier work in an attempt to provide a long-range overview of the relevant literature.

RECENT FINDINGS

In the year covered by this review, we identified four papers that directly assessed the association between the helicopter emergency medical services utilization and trauma outcome, and three that addressed the closely related issue of the helicopter emergency medical services triage appropriateness. An Italian study found no benefit associated with advanced prehospital care for patients with severe head injury. A US multicenter trial assessing blunt trauma transports found a substantial mortality reduction associated with helicopter use. Two other US studies, characterized by a similar 'natural experiment' design of assessing mortality changes on either side of a timepoint at which the helicopter emergency medical services availability ceased, reached opposite conclusions about the benefits of the service. Recent studies addressing the helicopter emergency medical services utilization in terms of triage were characterized by varying levels of agreement with the widely held belief that this service is characterized by overtriage.

SUMMARY

The preponderance of recent and previously extant evidence supports an argument that the helicopter emergency medical services transport is associated with significant benefit for some injured patients. The primary challenges at this time include the determination of which patients benefit and the elucidation of which aspects of the helicopter emergency medical services are responsible for any salutary effects of its utilization.

Medically appropriate use of helicopter EMS: the mission acceptance/triage process

INTRODUCTION

Appropriate use of helicopter emergency medical services (HEMS) ensures the maximum impact of a limited resource on improved health outcomes. Overtriage increases real and opportunity costs and may unjustifiably expose the program to small but inherent safety risks. The purpose of this study is to describe the mission acceptance process for an integrated, provincially based HEMS program and determine its utilization patterns.

METHODS

This is a retrospective review of patient care and administrative databases. All missions were reviewed to determine whether they were medically appropriate. "Appropriateness" was defined a priori as requiring admission to a critical care unit, death during transportation or in first 24 hours, or in the case of trauma, an injury severity scale (ISS) score > or = 12. Overtriage was defined as not meeting these a priori definitions.

RESULTS

Five hundred eighty-four missions were reviewed from March 31, 2003 through December 31, 2004. Our mission acceptance process consists of three distinct but complementary phases: ongoing outreach education, scanning by dispatchers in an integrated dispatch center, and a clinician to online physician discussion about each case. The overall overtriage rate was 13.1%.

CONCLUSION

The rate of medically appropriate missions in this system is relatively high. Prospective research is required to improve HEMS triage systems.

The Fastest Route Between Two Points is Not Always a Straight Line: An Analysis of Air and Land Transfer of Nonpenetrating Trauma Patients

BACKGROUND

The distance beyond which helicopter transport is faster than ground for interfacility transfer of trauma patients has not been established. Our objective was to determine whether such a threshold exists.

METHODS

A retrospective cohort study was conducted involving 243 patients transported by land and 139 patients by air from 13 sites during a 3-year period. Time intervals between critical events were compared for the two modes of transport at each site.

RESULTS

The time interval between the decision to transfer and the actual departure time was shorter for patients transferred by land from all sites studied (mean 41.3 versus 89.7 minutes, p < 0.001). The travel time was shorter by helicopter from all sites (mean 58.4 versus 78.9 minutes, p < 0.001). The time between the decision to transfer and the arrival at the trauma center was similar at most sites but faster by land overall (mean 120.3 versus 150.0 minutes, p = 0.014). No threshold was detected beyond which helicopter transport was superior.

CONCLUSIONS

Several factors other than the distance to be traveled determine the time required for interfacility transfer of trauma patients. A fixed distance threshold beyond which helicopter transport should be used does not exist. The decision as to which mode of transport to use for emergent trauma patient transfers should be based upon multiple factors including the distance traveled and ambulance availability, and must be individualized for each site that transfers patients.

Is air transport faster? A comparison of air versus ground transport times for interfacility transfers in a regional referral system

INTRODUCTION

Helicopter transport is often considered in an effort to minimize time to critical interventions, such as cardiac catheterization or arterial thrombolysis in stroke patients. However, for interfacility transports, the extra time considerations for helicopter preparation, takeoff, and time to get to the transferring hospital may not offset the slower transport times for local ground ambulances. The purpose of this study was to compare transport times for helicopter with traditional ground ambulance for interfacility transfers within a regional referral system.

METHODS

All patients transported from an outside hospital to the intensive care unit of the University of Wisconsin were eligible for this study. Equal numbers of patients transferred by ground and by helicopter from each facility were sequentially selected. The following intervals were compared: time from call to dispatch, time from dispatch to arrival at the referring hospital, time at the referring hospital, transport time to the receiving hospital, and total transport time.

RESULTS

One hundred forty-five patients were included in this study, transferred from 20 hospitals within the UW referral system. Dispatch times and time at the referring hospital were location independent, and each was shorter for ground transport. Ground dispatch times were 5+/-6 minutes, whereas for helicopter transport dispatch times were 17+/-8 (P<.001). Times at the referral hospital were on average longer for helicopter transport (31+/-11 minutes for air ambulance, 25+/-13 for ground; P=.008). Other intervals were location dependent. Arrivals were much more variable for ground transport, reflecting the fact that private ambulance services may have to travel some distance to reach the referring hospital (helicopter 18+/-8 minutes, ground 19+/-18 minutes). As expected, transport time from the referring hospital was shorter for helicopter transport. From each of the hospitals, average helicopter transport was as fast as the best ground transport.

CONCLUSION

Helicopter transport was faster than ground transport for interfacility transfer of patients from all hospitals studied in our referral system. Under optimal dispatch and transport conditions, the time difference from several hospitals was minimal. For stable patients for whom the only issue is time to critical procedure, it may be reasonable for those hospitals to try ground transport first if timely service is available to transport in that way. Even for those hospitals, helicopter transport should be considered for these patients if ground transport is not optimally available, as well as for patients in whom minimizing time outside of the hospital is a significant consideration, or when transport of such patients impacts emergency medical services availability to the community for a significant time.

Helicopter Scene Transport of Trauma Patients with Nonlife-Threatening Injuries: A Meta-Analysis

BACKGROUND

Helicopters have become a major part of the modern trauma care system and are frequently used to transport patients from the scene of their injury to a trauma center. While early studies reported decreased mortality for trauma patients transported by helicopters when compared with those transported by ground ambulances, more recent research has questioned the benefit of helicopter transport of trauma patients. The purpose of this study was to determine the percentage of patients transported by helicopter who have nonlife-threatening injuries.

METHODS

A meta-analysis was performed on peer-review research on helicopter utilization. The inclusion criteria were all studies that evaluated trauma patients transported by helicopter from the scene of their injury to a trauma center with baseline parameters defined by Injury Severity Score (ISS), Trauma Score (TS), Revised Trauma Score (RTS), and the likelihood of survival as determined via Trauma Score-Injury Severity Score (TRISS) methodology.

RESULTS

There were 22 studies comprising 37,350 patients that met the inclusion criteria. According to the ISS, 60.0% [99% confidence interval (CI): 54.5-64.8] of patients had minor injuries, According to the TS, 61.4% (99% CI: 60.8-62.0) of patients had minor injuries. According to TRISS methodology, 69.3% (99% CI: 58.5-80.2) of patients had a greater than 90% chance of survival and thus nonlife-threatening injuries. There were 25.8% (99% CI: -1.0-52.6) of patients discharged within 24 hours after arrival at the trauma center.

CONCLUSIONS

The majority of trauma patients transported from the scene by helicopter have nonlife-threatening injuries. Efforts to more accurately identify those patients who would benefit most from helicopter transport from the accident scene to the trauma center are needed to reduce helicopter overutilization.

The Impact of Aeromedical Response to Patients With Moderate to Severe Traumatic Brain Injury

STUDY OBJECTIVE

Aeromedical crews offer an advanced level of practice and rapid transport to definitive care; however, their efficacy remains unproven. Previous studies have used relatively small sample sizes or have been unable to adequately control for the effect of other potentially influential variables. Here we explore the impact of aeromedical response in patients with moderate to severe traumatic brain injury.

METHODS

This was a retrospective analysis using our county trauma registry. All patients with head Abbreviated Injury Score of 3 or greater were included; interfacility transfers were excluded. The impact of aeromedical response was determined using logistic regression, adjusting for age, sex, mechanism, preadmission Glasgow Coma Scale score, head Abbreviated Injury Score, Injury Severity Score, and the presence of preadmission hypotension. Propensity scores were used to account for variability in selection of patients to undergo air versus ground transport. Patients with moderate and severe traumatic brain injury, as defined by head Abbreviated Injury Score and Glasgow Coma Scale score, were compared. Finally, aeromedical patients undergoing field intubation were compared with ground patients undergoing emergency department (ED) intubation.

RESULTS

A total of 10,314 patients meeting all inclusion and exclusion criteria and with complete data sets were identified and included 3,017 transported by aeromedical crews. Overall mortality was 25% in the air- and ground-transported cohorts, but outcomes were significantly better for the aeromedical patients when adjusted for age, sex, mechanism of injury, hypotension, Glasgow Coma Scale score, head Abbreviated Injury Score, and Injury Severity Score (adjusted odds ratio [OR] 1.90; 95% confidence interval [CI] 1.60 to 2.25; P<.0001). Good outcomes (discharge to home, jail, psychiatric facility, rehabilitation, or leaving against medical advice) were also higher in aeromedical patients (adjusted OR 1.36; 95% CI 1.18 to 1.58; P<.0001). The primary benefit appeared to be in more severely injured patients, as reflected by head Abbreviated Injury Score and Glasgow Coma Scale score. Improved survival was also observed for air-transported patients intubated in the field versus ground-transported patients given emergency intubation in the ED (adjusted OR 1.42; 95% CI 1.13 to 1.78; P<.001).

CONCLUSION

Here we analyze a large database of patients with moderate to severe traumatic brain injury. Aeromedical response appears to result in improved outcomes after adjustment for multiple influential factors in patients with moderate to severe traumatic brain injury. In addition, out-of-hospital intubation among air-transported patients resulted in better outcomes than ED intubation among ground-transported patients. Patients with more severe injuries appeared to derive the greatest benefit from aeromedical transport.

Einfluss von Rettungsmittel und Zielklinik auf die Letalität nach Polytrauma

BACKGROUND

The aim of this study was to document the present knowledge from the medical literature on (1) efficacy of aeromedical evacuation (helicopter emergency medical service, HEMS) and (2) influence of the level of the first receiving hospital on mortality of patients.

METHODS

Systematic review of the literature between 1970 and 2003; identification of studies with an evidence level of at least III and included control group; own results.

RESULTS

(1) 17 studies concerning the efficacy of HEMS were included into the review. No single study yielded shorter rescue times with the use of HEMS. 11 of 17 studies showed a significantly higher survival rate (8.2 to 52%) with the employment of HEMS especially with mid-degree polytrauma. (2) All 6 relevant studies dealing with hospital level found a considerable lower mortality rate (19 to 42%) for patients treated primarily at a level 1 trauma center or comparable institution.

CONCLUSIONS

The analyzed studies showed a trend toward decreased mortality rates with the employment of HEMS. Considering the comparable hospital level and even longer rescue times with HEMS, these differences can be explained with higher quality of initial diagnosis and treatment of the HEMS rescue team. Furthermore, mortality rates can be lowered significantly through primary treatment at a level 1 trauma center. Thus, the more flexible choice of the first receiving hospital represents a specific, clinically relevant advantage of HEMS in emergency medicine.

When is the helicopter faster? A comparison of helicopter and ground ambulance transport times

BACKGROUND

A retrospective analysis of 7,854 ground ambulance and 1,075 helicopter transports was conducted.

METHODS

The 911-hospital arrival intervals for three transport methods were compared: ground, helicopter dispatched simultaneously with ground unit, and helicopter dispatched nonsimultaneously after ground unit response.

RESULTS

Compared with ground transports, simultaneously dispatched helicopter transports had significantly shorter 911-hospital arrival intervals at all distances greater than 10 miles from the hospital. Nonsimultaneously dispatched helicopter transport was significantly faster than ground at distances greater than 45 miles, and simultaneous helicopter dispatch was faster than nonsimultaneous at virtually all distances. Ground transport was significantly faster than either air transport modality at distances less than 10 miles from the hospital.

CONCLUSION

Ground ambulance transport provided the shortest 911-hospital arrival interval at distances less than 10 miles from the hospital. At distances greater than 10 miles, simultaneously dispatched air transport was faster. Nonsimultaneous dispatched helicopter transport was faster than ground if greater than 45 miles from the hospital.

Auto launch/early activation: a survey of AAMS members and literature review

BACKGROUND

Rapid access to definitive care is a fundamental tenet of trauma care and forms the basis for current emergency medical and trauma systems. Helicopters offer expedited transport to trauma centers and can deliver advanced practice personnel to the scene of injury, but many systems do not dispatch air medical crews until after assessment by ground providers.

OBJECTIVES

Here we report data from the AAMS Auto Launch Survey and perform a literature review.

METHODS

A 7-question survey was developed by the AAMS Research Committee and approved by the board. An invitation to participate in the survey was sent by electronic mail to all current members. A link to an online survey was included. Results were presented descriptively. Some respondents were willing to share auto launch protocols, which were categorized into patient-related factors, event-related factors, and geographic considerations.

RESULTS

A total of 86 usable responses were recorded, which represented about a third of the 240 total AAMS members. Of these, 38 respondents (44.2%) routinely use auto launch. Just over half of those using early activation reported using a combination of event- and patient-related considerations; most also incorporating geographic criteria. About one-third of respondents auto launch only at the request of ground personnel, and about one-quarter use geographic criteria alone. Threshold distances ranged from 20 to 25 miles or 20 to 30 minutes by ground.

CONCLUSIONS

About half of respondents routinely use auto launch, although protocols are not consistent. Auto launch appears to offer a mechanism for decreasing EMS response times, but additional research is needed to help define optimal dispatch criteria.

Beneficial effect of helicopter emergency medical services on survival of severely injured patients

Background

In Rotterdam, the Netherlands, a helicopter-transported medical team (HMT), staffed with a trauma physician, provides additional therapeutic options at the scene of injury. This study evaluated the influence of the HMT on the chance of survival of severely injured trauma victims.

Methods

This was a 2-year prospective observational study of consecutive adults who suffered multiple trauma (Injury Severity Score (ISS) 16 or more) and presented to the Erasmus Medical Centre emergency ward. The effect of the HMT was quantified by an odds ratio (OR), adjusted for confounding variables in logistic regression models.

Results

Complete data for a total of 346 patients were available for analysis. Two hundred and thirty-nine patients were treated by ambulance personnel alone and 107 received additional HMT assistance. Patients in the HMT group had significantly lower Glasgow Coma Scale scores (mean 8·9 versus 10·6; P = 0·001) and a higher ISS (mean 30·9 versus 25·3; P &lt; 0·001). The unadjusted OR for death was 1·7 in favour of the group treated by ambulance staff only (OR for survival 0·61 (95 per cent confidence interval (c.i.) 0·37 to 1·0, P = 0·048)). After adjustment, however, patients in the HMT group had an approximately twofold better chance of survival (all injuries: OR 2·2 (95 per cent c.i. 0·92 to 5·9), P = 0·076; blunt injuries: OR 2·8 (95 per cent c.i. 1·07 to 7·52), P = 0·036).

Conclusion

The presence of the HMT may increase chances of survival for patients suffering multiple trauma, especially for those with blunt trauma.

Pre-hospital trauma care: a proposal for more efficient evaluation

Although mortality is an important outcome parameter for pre-hospital trauma care, it is influenced by many factors other than pre-hospital trauma care alone. We therefore studied an alternative method to evaluate pre-hospital trauma care by calculating the change in probability of survival (Ps) according to the TRISS methodology, before and directly after the pre-hospital trauma care. Correlations between patient characteristics and a change in Ps were assessed. Further, required sample sizes were calculated for an 80% power to detect a hypothetical 3% reduction in mortality and the corresponding change in Ps. In 140 of 191 patients with an Injury Severity Score > or =16, the Ps did not change. In 36, the Ps increased and in 15 patients, the Ps decreased. Between these three groups, significant differences were found in Revised Trauma Score and age, but no clear differences in Injury Severity Score or mortality. A 3% difference in mortality would require 6800 patients, in contrast to 3500 when the change in Ps was the primary outcome parameter. A change in Ps is a promising outcome parameter for a more efficient evaluation of pre-hospital trauma care. A good collaboration is, however, required between ambulance services and the trauma center for reliable registration.

Regional Air Transport of Burn Patients: A Case for Telemedicine?

BACKGROUND

Air transport of burn patients is plagued by frequent "overtriage." We examined the use of air transport and the feasibility of using alternative methods such as telemedicine to assist in evaluation and treatment of burn patients within our region.

METHODS

We reviewed all burn patients transported by air during 2000 to 2001. Each patient was classified as being most appropriate for air, ground, or family transport. In addition, a decision was made regarding whether telemedicine evaluation of the patient before transport could have significantly altered initial treatment decisions.

RESULTS

Two hundred twenty-five acutely burned patients were transferred from referring hospitals in nine states, at a mean distance of 246 air miles. Mean burn size calculated by burn center physicians was 19.7% total body surface area, whereas referring physicians' mean estimate was 29% total body surface area. In 92 cases, over- or underestimation of burn size by referring physicians of as much as 560% or decisions regarding performance of endotracheal intubation suggested that telemedicine evaluation before transport might have significantly altered transport decisions or care. Air transport charges exceeded hospital charges in 21 cases.

CONCLUSION

Frequent discrepancies in burn assessment contribute to overuse of air transport. The ability to evaluate burn patients by telemedicine may have the potential to assist decisions regarding transfer, avoid errors in initial care, and reduce costs. We are currently attempting to develop and test such a system.

Medical Helicopter Accidents in the United States: A 10-Year Review

OBJECTIVE

There has been a significant proliferation of medical helicopters and medical helicopter operations in the United States over the last decade. The purpose of this study was to determine whether the proliferation of medical helicopter operations in the United States was associated with a subsequent increase in the number of accidents

METHODS

We used univariate descriptive analysis of all pertinent medical accident files obtained from United States aviation databases for a 10-year period (1993-2002).

RESULTS

There were 84 medical helicopter accidents involving 260 persons (passengers, patients, crew, and pilots) during the 10-year study period. Of these, there were 72 fatalities and 64 injuries. The incidence of fatalities was 0.86 fatalities per accident. The incidence of nonfatal injuries was 0.76 per accident. Fifty-two percent of all reported accidents occurred during the last 3 years of the study period (2000-2002).

CONCLUSION

There was a steady and marked increase in the number of medical helicopter accidents in the United States during the 10-year period (1993-2002). These findings are worrisome in light of recent research that has indicated use of medical helicopters may be excessive and nonbeneficial for most patients.

The 2003 Air Medical Leadership Congress: findings and recommendations

To address important concerns facing the air medical community, 149 air medical transport leaders, providers, consultants, and experts met September 4-6, 2003, in Salt Lake City, Utah, for a 3-day summit-the Air Medical Leadership Congress: Setting the Health Care Agenda for the Air Medical Community. Using data from a Web-based survey, top air medical transport issues were identified in four core areas: safety, medical care, cost/benefit, and regulatory/compliance. This report reviews the findings of previous congresses and summarizes the discussions, findings, recommendations, and proposed industry actions to address these issues as set forth by the 2003 congress participants.

Rapid response car as a supplement to the helicopter in a physician-based HEMS system

BACKGROUND

The purpose of this study was to describe the use of a rapid response car (RRC) as a supplement to the ambulance helicopter in a mixed urban/rural region in Norway.

METHODS

Data from all the requested missions were collected from standard flight records. Operational factors, patient characteristics, primary diagnosis, treatment and modes of transport were registered and analyzed retrospectively.

RESULTS

In 1999-2001, a total of 4777 requests were included in the study, resulting in the initiation of 3172 helicopter and 752 RRC missions. In the RRC missions, 224 patients received advanced medical treatment that would otherwise not have been provided. For 181 patients, the availability of the RRC was crucial for receiving the treatment of the helicopter emergency medical services (HEMS). The cost of equipping the base with the RRC increased the annual budget by less than one percent.

CONCLUSION

The RRC was essential for solving missions in periods of non-flying conditions. The RRC increased the availability of the advanced prehospital life support offered by the HEMS in this region. Taking the modest increase in cost into consideration, it seems reasonable that this HEMS, covering mixed urban and rural areas, is equipped with such a vehicle.

Combined external and internal hospital disaster: Impact and response in a Houston trauma center intensive care unit*

OBJECTIVE

To increase awareness of specific risks to healthcare systems during a natural or civil disaster. We describe the catastrophic disruption of essential services and the point-by-point response to the crisis in a major medical center.

DESIGN

Case report, review of the literature, and discussion.

SETTING

A 28-bed intensive care unit in a level I trauma center in the largest medical center in the world.

CASE

In June 2001, tropical storm Allison caused >3 feet of rainfall and catastrophic flooding in Houston, TX. Memorial Hermann Hospital, one of only two level I trauma centers in the community, lost electrical power, communications systems, running water, and internal transportation. All essential hospital services were rendered nonfunctional. Life-saving equipment such as ventilators, infusion pumps, and monitors became useless. Patients were triaged to other medical facilities based on acuity using ground and air ambulances. No patients died as result of the internal disaster.

CONCLUSION

Adequate training, teamwork, communication, coordination with other healthcare professionals, and strong leadership are essential during a crisis. Electricity is vital when delivering care in today's healthcare system, which depends on advanced technology. It is imperative that hospitals take the necessary measures to preserve electrical power at all times. Hospitals should have battery-operated internal and external communication systems readily available in the event of a widespread disaster and communication outage. Critical services such as pharmacy, laboratories, blood bank, and central supply rooms should be located at sites more secure than the ground floors, and these services should be prepared for more extensive performances. Contingency plans to maintain protected water supplies and available emergency kits with batteries, flashlights, two-way radios, and a nonelectronic emergency system for patient identification are also very important. Rapid adaptation to unexpected adverse conditions is critical to the successful implementation of any disaster plan.

Impact of helicopter transport and hospital level on mortality of polytrauma patients

BACKGROUND

Despite numerous studies analyzing this topic, specific advantages of helicopter transport of blunt polytrauma patients as compared with ground ambulances have not yet been identified unequivocally.

METHODS

Four possible pathways in 403 polytrauma patients (Injury Severity Score [ISS] > 16) who were in reach of the helicopter emergency medical service (HEMS) Dresden were analyzed as follows: HEMS-UNI group (n = 140), transfer by HEMS into a university hospital; AMB-REG group (n = 102), transfer by ground ambulance into a regional (Level II or III) hospital; AMB-UNI group (n = 70), transfer by ground ambulance into the university hospital; and INTER group (n = 91), transfer by ground ambulance into a regional hospital, followed by transfer to the university hospital. Scores used were the ISS and the TRISS. Tests used for statistical analysis included chi2 and Fisher's tests. Statistical significance was set at p > 0.05.

RESULTS

Age, gender, and mean ISS (range, 33.3-35.6) revealed extensive homogeneity of the groups. Mortality of the AMB-REG group was almost doubled (41.2%) compared with HEMS-UNI (22.1%) patients (p = 0.002). The AMB-UNI group displayed the lowest mortality (15.7%, p = not significant). TRISS analysis (PRE-Chart) revealed identical outcome for AMB-UNI and HEMS-UNI patients. Rescue time averaged 90 +/- 29 minutes for HEMS-UNI patients, 68 +/- 25 minutes for AMB-UNI patients, and 69 +/- 26 minutes for the AMB-REG group.

CONCLUSION

Primary transfer by HEMS into a Level I trauma center reduces mortality markedly. In principle, this benefit can be attributed to superior preclinical therapy, primary admission to a Level I trauma center, or both. However, the identical probability of survival of the AMB-UNI and HEMS-UNI groups in this and comparable studies does not confirm generally better survival rates on account of a more aggressive on-site approach.

Isolated prehospital hypotension after traumatic injuries: a predictor of mortality?

In patients with traumatic injuries, prehospital hypotension that resolves by Emergency Department (ED) arrival is of uncertain significance. We examined the impact of prehospital hypotension (PH) in normotensive ED patients with traumatic injuries on predicting mortality and chest/abdominal operative intervention. A retrospective cohort study was conducted of consecutive patients undergoing helicopter transport to two trauma centers between 1993 and 1997. Outcomes were mortality and chest or abdominal operative intervention. Of 545 scene transports, 55 (10.1%) patients were hypotensive on ED arrival, leaving 490 normotensive ED patients. Of 490 patients, 35 (7%) had PH and 455 (93%) had no PH. Multiple logistic regression showed the PH group to have a relative risk for death of 4.4 (95% CI: 1.2-16.6, p < 0.03) and for chest or abdominal operative intervention of 2.9 (1.1-7.6, p < 0.03). In this study of normotensive trauma center patients, prehospital hypotension was associated with increased risk of mortality and significant chest or abdominal injury.

The utility of helicopter transport of trauma patients from the injury scene in an urban trauma system

BACKGROUND

Continuing controversy surrounding the value of scene helicopter evacuation of urban trauma victims led to the present study.

METHODS

A retrospective review was performed of all patients brought to our trauma center from the injury scene by helicopter from 1990 to 2001.

RESULTS

The study included 947 consecutive patients, 911 with blunt trauma and 36 with penetrating injuries. The mean Injury Severity Score (ISS) was 8.9. Fifteen patients died in the emergency department, 312 patients (33.5%) were discharged home from the emergency department (mean ISS, 2.7), and 620 patients were hospitalized (mean ISS, 11.4). Three hundred thirty-nine of the hospitalized patients (54.7%) had an ISS < or = 9; 148 patients had an ISS > or = 16. Eighty-four patients (8.9%) required early operation, mostly for open extremity fractures; only 17 patients (1.8%) underwent surgery for immediately life-threatening injuries. For 54.7% of the patients, the helicopter was judged to be clearly faster than would have been possible by ground transport. In 140 additional patients (14.8%) with prolonged scene time, the helicopter was probably faster than ground ambulance. Considering faster transport time and either the need for early operation or hospitalization with an ISS > or = 9 as advantageous, a maximum of 22.8% of the study population possibly benefited from helicopter transport.

CONCLUSION

The helicopter is used excessively for scene transport of trauma victims in our metropolitan trauma system. New criteria should be developed for helicopter deployment in the urban trauma environment.

Helicopter transport of pediatric trauma patients in an urban emergency medical services system: a critical analysis

BACKGROUND

Helicopter transport of pediatric trauma patients in an urban Emergency Medical Services system remains controversial.

METHODS

A retrospective review of pediatric patients transported by helicopter to a pediatric trauma center in Los Angeles, California, was conducted over a 3-year period. Pediatric patients (age < 15 years) are transported by helicopter if ground transport to a pediatric trauma center would exceed 20 minutes. Emergency Medical Services reports and hospital records were reviewed for key prehospital and outcome indicators.

RESULTS

One hundred eighty-nine patients met the study inclusion criteria. The median age was 5 years (range, 0-14 years). The most common mechanisms of injury were falls and automobile versus pedestrian crashes. Eighty-two percent of patients had a Revised Trauma Score > 7. Of the 175 (93%) patients whose hospital records were available, 24 (14%) were intubated in the emergency department, 32 (18%) were admitted to the intensive care unit, and 7 (4%) were taken directly to the operating room. Injury Severity Scores (ISSs) were as follows: ISS 0 to 15, 146 (83%); ISS 16 to 30, 26 (15%); and ISS > 30, 3 (2%). Fifty-seven (33%) patients were discharged home from the emergency department.

CONCLUSION

The majority of pediatric trauma patients transported by helicopter in our study sustained minor injuries. A revised policy to better identify pediatric patients who might benefit from helicopter transport appears to be warranted.

Paramedic helicopter emergency service in rural Finland - do benefits justify the cost?

BACKGROUND

The benefit of the Helicopter Emergency Medical Service (HEMS) is not well documented. The aim of our study was to investigate the potential health benefits of HEMS, and their relation to cost of the service in a rural area in Finland. We also evaluated whether the patient benefit is due to early Advanced Life Support (ALS) procedures performed on-scene, or due to rapid transport of patients to definitive care.

METHODS

We reviewed all helicopter missions during 1 year (1999). Based on given prehospital care, we divided these missions into various categories. At the time of discharge, in-hospital records were reviewed for patients who received prehospital ALS care in order to estimate the potential benefit of HEMS.

RESULTS

There were 588 missions. In 40% (n = 233/588), the mission was aborted. ALS care was given on-scene to 206 patients. It was estimated that in this group lives of three patients (1.5%) were saved, and 42 (20%) patients, mostly with cardiovascular disease, otherwise benefited from the service. The majority (84%) of the patients benefited from on-scene ALS procedures only. The cost for beneficial mission was euro 28 444.

CONCLUSION

A minority of all patients did benefit from HEMS. Benefit was related to early ALS care and the cost per beneficial mission was 28 444.

Helicopter transport of pediatric versus adult trauma patients

OBJECTIVE

Conflicting reports exist regarding the appropriate utilization of helicopter transport for victims of trauma. It has been suggested that adult patients are more severely injured compared with pediatric patients when transported by helicopter. The purpose of this study was to determine whether injury severity and survival probability in pediatric trauma patients were similar to those for adults when helicopter transport was utilized at a suburban trauma center.

METHODS

The authors conducted a retrospective review of all trauma patients transported by helicopter from the accident scene. Patients were identified from the Christiana Care Health System trauma registry from January 1995 to November 1999. Pediatric patients were defined as those aged 15 years and younger. Data collected were utilized to determine injury severity score (ISS), revised trauma score (RTS), and survival probability.

RESULTS

Nine hundred sixty-nine patients were transported; 143 were pediatric. There was no statistical difference noted in ISS (14.21 adult, 12.76 pediatric; p = 0.1506) and RTS (7.23 adult, 7.31 pediatric; p = 0.1832). Mean length of stay was less for the pediatric group (7.5 days adult, 5.2 days pediatric; p = 0.008). Survival probabilities were likewise similar for the two groups, yet the difference met statistical significance (0.92 adult, 0.95 pediatric; p = 0.03).

CONCLUSION

Pediatric patients transported from the accident scene by helicopter have similar ISSs and RTSs compared with adults. These data suggest that prehospital selection criteria for the two groups are similar.

Impact of discontinuing a hospital-based air ambulance service on trauma patient outcomes

BACKGROUND

The clinical benefit of aeromedical transportation of injured patients in the civilian population has been debated. The purpose of this study was to examine the effects of discontinuing a hospital-based helicopter transport program on trauma patient outcomes, with the hypothesis that the loss of an air ambulance would result in increased transport time and increased mortality among severely injured patients.

METHODS

Data on injury severity and patient outcomes were collected prospectively for the 12 months immediately preceding and 24 months following discontinuation of the helicopter ambulance service. Transport time, mortality rate, and hospital length of stay was compared.

RESULTS

The number of trauma patient admissions decreased 12%, with a 17% decrease in admissions of severely injured patients. Transport time decreased, with no change in mortality.

CONCLUSION

Discontinuation of a hospital-based air ambulance service did not increase transport time or increase mortality for trauma patients.

Helicopter transportation of burn patients

Analysis of 437 consecutive acute burn patients transported to our burn center revealed 339 transported by ground and 98 by helicopter. There were 18 air transport patients from within a 25-mile-radius, and 80 flown further than 25 miles. Mean age was the same in all groups (P>0.05). Percent total body surface area (TBSA) burned was 8.26% in ground transport patients, significantly less than the 20.35% (within 25 miles) and 21.40% (greater than 25 miles) seen in helicopter transports (P<0.0001). Three percent of ground transport patients and 28% of helicopter patients had inhalation injury (P<0.0001). There was no difference in incidence of inhalation injury among helicopter groups (28 vs. 29%, P=0.8). In patients with coexistent inhalation injury, the mean TBSA burned was significantly larger when compared with the TBSA of burns without inhalation injury (P<0.001). Air transported groups contained patients whose status was not critical based upon lack of inhalation injury and small burn size, and who could have been transported by ground. Non clinical factors such as insurance status, desire to keep ground ambulances in their community, and competing helicopter services reluctant to refuse to transport a patient appears to be factors in choosing air ambulance transportation. Regional single helicopter services and regional cooperative ground ambulance services should reduce use of helicopter transport of burn patients when it is not clinically indicated.

Helicopter transport and blunt trauma mortality: a multicenter trial

BACKGROUND

Despite many studies addressing potential impact of helicopter transport on trauma mortality, debate as to the efficacy of air transport continues.

METHODS

This retrospective study combined trauma registry data from five urban Level I adult and pediatric centers. Logistic regression assessed effect of helicopter transport on mortality while adjusting for age, sex, transport year, receiving hospital, prehospital level of care (Advanced Life Support vs. Basic Life Support), ISS, and mission type (scene vs. interfacility).

RESULTS

The study database comprised 16,699 patients. Crude mortality for Air (9.4%) was 3.4 times (95% CI, 2.9-4.0, p < 0.001) that of Ground (3.0%) patients. In adjusted analysis, helicopter transport was found to be associated with a significant mortality reduction (odds ratio, 0.76; 95% CI, 0.59-0.98; p = 0.031).

CONCLUSION

The results of this study are consistent with an association between helicopter transport mode and increased survival in blunt trauma patients.

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.

Trauma systems--state of the art

Trauma is an inevitable consequence of the lives we lead. There are many approaches to dealing with it but an ideal system, universally applicable, probably does not exist because of the national variations in social, economic, cultural and geographical characteristics. Many countries are beginning to recognise that the 'systems' they have in place for dealing with the burden of trauma are seriously deficient and that this situation cannot be allowed to continue into the new millennium. However, it is highly unlikely that in the near future. governments will suddenly find substantial extra finance for trauma care or the implementation of new systems. Throughout many countries, the individual components of trauma care systems are in place but, for whatever reasons, there is a lack of integration, which results in suboptimal care. The system we all should be aiming for is one of closer communication and greater cooperation. By taking into account community and national needs, available resources, and adapting what is currently in place it should then be possible to create 'a set of things working together as parts of a trauma mechanism'.

Use of an ambulance-based helicopter retrieval service

BACKGROUND

John Hunter Hospital is the major trauma centre for a region covering more than 25,000 square kilometres. The helicopter primary retrieval service for trauma is paramedic staffed and protocol driven. The aim of the present study was to assess the overtriage rate created by such protocols, and to assess the benefit to patient outcomes that may be attributable to the service.

METHODS

The John Hunter Hospital trauma database was used to identify all cases arriving by helicopter in 1996, as well as their demographic details, injury severity score, details of the accident and outcome. An expert panel reviewed the medical records for the 184 primary retrievals. Using a consensus model, estimates of time delay or saving were calculated and likelihood of benefit, no benefit or harm was assessed.

RESULTS

A total of 3087 trauma patients were assessed at John Hunter Hospital in 1996, of which 8% arrived by helicopter. Of the primary retrievals, 67.6% had an injury severity score of 9 or less, with only 17.9% having a score of 16 or greater. Twelve patients were discharged from Emergency and 36% were discharged within 48 h. The overall mortality was 5.0%. Twenty-five per cent of patients were retrieved within 35 km of John Hunter Hospital with minimal attributable benefit. Overall 1.7% of patients were felt to have been potentially harmed, 17.3% to have benefited and 81.0% to have had no attributable benefit related to the helicopter use.

CONCLUSIONS

Although the majority of retrievals are for minor injuries, the service provides benefit for the region. There is potential for harm, however, where base hospitals are overflown in situations where patients have airway compromise, and where patient transfer is delayed due to helicopter activation. Primary helicopter tasking to trauma cases within 35 km of the major trauma centre is seldom beneficial.

Prehospital trauma care

Concepts regarding uniform reporting of data after trauma and regarding treatment of brain trauma patients at the scene have recently been agreed upon in consensus processes. Endotracheal intubation and alternatives are as controversially discussed as fluid resuscitation and helicopter transport of trauma victims. Long-term outcomes of trauma patients should more frequently be studied using the Quality of Wellbeing Scale.