Helicopter Emergency Medical Services Services Research Articles

Comparative Study on the Outcome of Trauma Patients Transferred by Doctor Helicopters and Ground Ambulance in South Korea.

The purpose of this study was to analyze the cost-effectiveness of helicopter emergency medical services (HEMS) for its economic operations in South Korea. This study targeted trauma patients that were transported by either HEMS or ground emergency medical services (GEMS) from the scene of an accident to a regional emergency medical center. From this patient population, severe trauma patients (injury severity score ISS ≥ 16 points) with a distance travelled from the scene of the injury to the hospital that was 30 km or longer and with analyzable outcome data were extracted and included in this study. Cost-effectiveness was analyzed from survival and efficiency based on medical costs incurred from the pre-hospital setting to hospital discharge. This study included a total of 34 HEMS and 105 GEMS patients with an Injury Severity Score (ISS) ≥ 16 points from a pool of 357 potential patients. The survival-to-discharge rate of HEMS was 29 of 34 patients (85.3%) and was significantly higher than that of GEMS, where only 66 of 105 patients (62.8%) survived to discharge (P = 0.024). The expected and the actual mortality was higher in HEMS than it was in GEMS. Statistical significant difference in cost was found between the 2 groups (P = 0.002). The results of the present study indicate the increased discharge rate, survival rate and reduced in hospital mortality of HEMS with reduced admission time. This result association leads to reasonable cost effectiveness and efficient estimates overall.

Incidence of hyperoxia in trauma patients receiving pre-hospital emergency anaesthesia: results of a 5-year retrospective analysis

BackgroundPrevious studies have demonstrated an association between hyperoxia and increased mortality in various patient groups. Critically unwell and injured patients are routinely given high concentration oxygen in the pre-hospital phase of care. We aim to investigate the incidence of hyperoxia in major trauma patients receiving pre-hospital emergency anesthesia (PHEA) in the pre-hospital setting and determine factors that may help guide clinicians with pre-hospital oxygen administration in these patients.MethodsA retrospective cohort study was performed of all patients who received PHEA by a single helicopter emergency medical service (HEMS) between 1 October 2014 and 1 May 2019 and who were subsequently transferred to one major trauma centre (MTC). Patient and treatment factors were collected from the electronic patient records of the HEMS service and the MTC. Hyperoxia was defined as a PaO2 > 16 kPA on the first arterial blood gas analysis upon arrival in the MTC.ResultsOn arrival in the MTC, the majority of the patients (90/147, 61.2%) had severe hyperoxia, whereas 30 patients (20.4%) had mild hyperoxia and 26 patients (19.7%) had normoxia. Only 1 patient (0.7%) had hypoxia. The median PaO2 on the first arterial blood gas analysis (ABGA) after HEMS handover was 36.7 [IQR 18.5–52.2] kPa, with a range of 7.0–86.0 kPa. SpO2 pulse oximetry readings before handover were independently associated with the presence of hyperoxia. An SpO2 ≥ 97% was associated with a significantly increased odds of hyperoxia (OR 3.99 [1.58–10.08]), and had a sensitivity of 86.7% [79.1–92.4], a specificity of 37.9% [20.7–57.8], a positive predictive value of 84.5% [70.2–87.9] and a negative predictive value of 42.3% [27.4–58.7] for the presence of hyperoxemia.ConclusionTrauma patients who have undergone PHEA often have profound hyperoxemia upon arrival at hospital. In the pre-hospital setting, where arterial blood gas analysis is not readily available a titrated approach to oxygen therapy should be considered to reduce the incidence of potentially harmful tissue hyperoxia.

Prehospital Whole Blood Transfusion Programs in Norway

Background: Prehospital management of severe hemorrhage has evolved significantly in Norwegian medical emergency services in the last 10 years. Treatment algorithms for severe bleeding were previously focused on restoration of the blood volume by administration of crystalloids and colloids, but now the national trauma system guidelines recommend early balanced transfusion therapy according to remote damage control resuscitation principles. Materials and Methods: This survey describes the implementation, utilization, and experience of the use of low titer group O whole blood (LTOWB) and blood components in air ambulance services in Norway. Medical directors from all air ambulance bases in Norway as well as the blood banks that support LTOWB were invited to participate. Results: Medical directors from all 13 helicopter emergency medical services (HEMS) bases, the 7 search and rescue (SAR) helicopter bases, and the 4 blood banks that support HEMS with LTOWB responded to the survey. All HEMS and SAR helicopter services carry LTOWB or blood components. Four of 20 (20%) HEMS bases have implemented LTOWB. A majority of services (18/20, 90%) have a preference for LTOWB, primarily because LTOWB enables early balanced transfusion and has logistical benefits in time-critical emergencies and during prolonged evacuations. Conclusion: HEMS services and blood banks report favorable experiences in the implementation and utilization of LTOWB. Prehospital balanced blood transfusion using whole blood is feasible in Norway.

Oxygenation strategies prior to and during prehospital emergency anaesthesia in UK HEMS practice (PREOXY survey)

BackgroundMaintaining effective oxygenation throughout the process of Pre-Hospital Emergency Anaesthesia (PHEA) is critical. There are multiple strategies available to clinicians to oxygenate patients both prior to and during PHEA. The optimal pre-oxygenation technique remains unclear, and it is unknown what techniques are being used by United Kingdom Helicopter Emergency Medical Services (HEMS). This study aimed to determine the current pre- and peri-PHEA oxygenation strategies used by UK HEMS services.MethodsAn electronic questionnaire survey was delivered to all UK HEMS services between 05 July and 26 December 2019. Questions investigated service standard operating procedures (SOPs) and individual clinician practice regarding oxygenation strategies prior to airway instrumentation (pre-oxygenation) and oxygenation strategies during airway instrumentation (apnoeic oxygenation). Service SOPs were obtained to corroborate questionnaire replies.ResultsReplies were received from all UK HEMS services (n = 21) and 40 individual clinicians. All services specified oxygenation strategies within their PHEA/RSI SOP and most referred to pre-oxygenation as mandatory (81%), whilst apnoeic oxygenation was mandatory in eight (38%) SOPs. The most commonly identified pre-oxygenation strategies were bag-valve-mask without PEEP (95%), non-rebreathable face mask (81%), and nasal cannula at high flow (81%). Seven (33%) services used Mapleson C circuits, whilst there were eight services (38%) that did not carry bag-valve-masks with PEEP valve nor Mapleson C circuits. All clinicians frequently used pre-oxygenation, however there was variability in clinician use of apnoeic oxygenation by nasal cannula. Nearly all clinicians (95%) reported manually ventilating patients during the apnoeic phase, with over half (58%) stating this was their routine practice. Differences in clinician pre-hospital and in-hospital practice related to availability of humidified high flow nasal oxygenation and Mapleson C circuits.ConclusionsPre-oxygenation is universal amongst UK HEMS services and is most frequently delivered by bag-valve-mask without PEEP or non-rebreathable face masks, whereas apnoeic oxygenation by nasal cannula is highly variable. Multiple services carry Mapleson C circuits, however many services are unable to deliver PEEP due to the equipment they carry. Clinicians are regularly manually ventilating patients during the apnoeic phase of PHEA. The identified variability in clinical practice may indicate uncertainty and further research is warranted to assess the impact of different strategies on clinical outcomes.

Feasibility of Prehospital Rapid Sequence Intubation in the Cabin of an AW169 Helicopter

ObjectivePrehospital rapid sequence intubation (RSI) is an important aspect of prehospital care for helicopter emergency medical services (HEMS). This study examines the feasibility of in-aircraft (aircraft on the ground) RSI in different simulated settings. MethodsUsing an AW169 aircraft cabin simulator at Air Ambulance Kent Surrey Sussex, 3 clinical scenarios were devised. All required RSI in a “can intubate, can ventilate” (easy variant) and a “can't intubate, can't ventilate” scenario (difficult variant). Doctor-paramedic HEMS teams were video recorded, and elapsed times for prespecified end points were analyzed. ResultsEndotracheal intubation (ETI) was achieved fastest outside the simulator for the easy variant (median = 231 seconds, interquartile range = 28 seconds). Time to ETI was not significantly longer for in-aircraft RSI compared with RSI outside the aircraft, both in the easy (p = .14) and difficult variant (p = .50). Wearing helmets with noise distraction did not impact the time to intubation when compared with standard in-aircraft RSI, both in the easy (p = .28) and difficult variant (p = .24). ConclusionIn-aircraft, on-the-ground RSI had no significant impact on the time to successful completion of ETI. Future studies should prospectively examine in-cabin RSI and explore the possibilities of in-flight RSI in civilian HEMS services.

Decision support tool and suggestions for the development of guidelines for the helicopter transport of patients with COVID-19

The novel coronavirus SARS-CoV2 emerged in December 2019 and is now pandemic. Initial analysis suggests that 5% of infected patients will require critical care, and that respiratory failure requiring intubation is associated with high mortality.Sick patients are geographically dispersed: most patients will remain in situ until they are in need of critical care. Additionally, there are likely to be patients who require retrieval for other reasons but who are co-incidentally infected with SARS-CoV-2 or shedding virus.The COVID-19 pandemic therefore poses a challenge to critical care retrieval systems, which often depend on small teams of specialists who live and work together closely. The infection or quarantining of a small absolute number of these staff could catastrophically compromise service delivery.Avoiding occupational exposure to COVID-19, and thereby ensuring service continuity, is the primary objective of aeromedical retrieval services during the pandemic. In this discussion paper we collaborated with helicopter emergency medical services(HEMS) worldwide to identify risks in retrieving COVID-19 patients, and develop strategies to mitigate these.Simulation involving the whole aeromedical retrieval team ensures that safety concerns can be addressed during the development of a standard operating procedure. Some services tested personal protective equipment and protocols in the aeromedical environment with simulation. We also incorporated experiences, standard operating procedures and approaches across several HEMS services internationally.As a result of this collaboration, we outline an approach to the safe aeromedical retrieval of a COVID-19 patient, and describe how this framework can be used to develop a local standard operating procedure.

A Spatial Analysis of Incident Location and Prehospital Mortality for Two United Kingdom Helicopter Emergency Medical Services (HEMS)

Most trauma and out of hospital cardiac arrest (OHCA) deaths occur prior to arrival at hospital, with increased risk for rural compared to urban patients. Essex and Hertfordshire Air Ambulance Trust (EHAAT) and Kent Surrey Sussex Air Ambulance Trust (KSS) provide a physician-paramedic Helicopter Emergency Medical Service (HEMS) in two regions of the United Kingdom. We investigated whether an association exists between prehospital mortality and distance from care in HEMS patients. We performed a retrospective study using spatial statistics to investigate the geographic distribution of scene outcome (alive versus deceased). We also performed multiple logistic regression of outcome against quartiles of distance from base to scene and a relative risk (RR) estimation over the operational areas. Organisations were analysed separately to assess consistency of spatial relationships. 2680 EHAAT and 4213 KSS patients met the inclusion criteria. Ripley’s K and Cross K functions indicated that outcomes (death and leaving the scene alive) cluster together. For KSS distance was not associated with outcome, for EHAAT distance was a significant predictor of mortality at furthest distance (41 to 95 km; OR 5.82, 95%CI 1.63 to 37.18, p = 0.019). Only one area of KSS and no areas of EHAAT had an increased RR of mortality. In contrast to previous research of pre-hospital patients, we found little evidence of geographic difference in scene outcome for trauma patients attended by the two HEMS services. Increased mortality risk for OHCA at the furthest distance from helicopter base was found in one organisation; a single area of increased RR of mortality was found for the other organisation.

Defining a mission-based method to determine a HEMS unit\u2019s actual service area

BackgroundGeographical service areas are used as descriptive system indicators in Emergency Medical Service (EMS) related studies and reporting templates. The actual service area may differ significantly from administrative areas; this may lead to inaccuracy in determining indicator values, such as population or mission density, thus making it biased when comparing results between different areas and organizations.The aim of this study was to introduce a univocal, repeatable and easily adaptable method to determine the actual service area of a helicopter emergency medical service (HEMS) unit for statistical, quality measurement and research purposes using widely available geographical information (GIS) and statistical analysis tools.MethodsThe method was first tested with Tampere HEMS unit. All accepted missions in 2017 were extracted from FinnHEMS database (FHDB). We calculated distance from HEMS base to each accepted mission location. Missions were reordered based on the distance and 99th and 95th percentiles were calculated for mission distances. Convex hulls including 100, 99 and 95% of the missions, and the population and area covered by these missions, were then calculated. The method was repeated for all Finnish HEMS bases.ResultsApproximately 90% of Tampere HEMS unit’s accepted missions took place within 100 km from the base. 10.9% of the missions occurred outside of the administrative service area. 95% convex hull areas are most in line with the everyday experience of where the units actually operate. In Tampere, the 95% convex hull area corresponds to 76,5% of the administrative area’s population and to 89,8% of its area. Calculating the 95% convex hull areas for all Finnish HEMS units results in service areas that overlap at some points, and some areas of the country fall outside of all HEMS service areas.ConclusionsAdministrative areas do not correspond to the actual service areas of HEMS units. The service area of a HEMS unit defined by administrative boundaries may differ significantly from actual operations. Using historical mission data to create a convex hull that incorporates mission locations could offer a standardized and comparable solution for determining actual HEMS unit service areas, which can be used for statistical comparison, quality measurement and system development.

Search and Rescue and Remote Medical Evacuation in a Norwegian Setting: Comparison of Two Systems

Helicopter emergency medical services (HEMS) contribute to and complement other specialized search and rescue (SAR) services. Conversely, traditional SAR services perform medical evacuation (medevac), depending on crew, training, medical equipment, and procedures for interdisciplinary cooperation. We aim to describe and compare SAR and remote medevac mission characteristics in a military SAR helicopter system to a civilian HEMS operating in the same region. Retrospective, observational study of SAR and remote medevac missions performed at a Norwegian military SAR helicopter and civilian HEMS base in the 5-y period from January 1, 2013 to December 31, 2017. Descriptive statistics and median values with interquartile range (IQR) were applied where appropriate. Comparisons were performed with the Mann-Whitney U test. We included 721 missions. The SAR service performed 359 (50%) missions, of which 237 (33%) were SAR and 122 (17%) were remote medevac missions. The HEMS service performed 85 (12%) SAR and 277 (38%) remote medevac missions. Median mission time for SAR missions was 152 (IQR 100-235) min for the SAR service and 57 (IQR 34-89) min for the HEMS service. Trauma was the dominating mechanism in 48% of patients, followed by medical conditions (21%) and psychiatric disorders (9%). Medevac patients in both services had a higher median National Advisory Committee for Aeronautics score of 3 (IQR 2-4) compared to 1 (IQR 0-3) in SAR missions (P<0.05). Both SAR and HEMS services perform SAR and remote medevac missions extensively and mission profiles vary.

Air Versus Ground Transportation in Isolated Severe Head Trauma: A National Trauma Data Bank Study

BackgroundThe effect of prehospital helicopter emergency medical services (HEMS) on mortality has been analyzed previously in polytrauma patients with discordant results. ObjectiveOur aim was to compare outcomes in patients with isolated severe blunt traumatic brain injuries (TBIs) transported by HEMS or ground emergency medical services (GEMS). MethodsWe conducted a National Trauma Data Bank study (2007–2014). All adult patients (≥16 years old) who sustained an isolated severe blunt TBI and were transported by HEMS or GEMS were included in the study. ResultsThere were 145,559 patients who met the inclusion criteria. Overall, 116,391 (80%) patients were transported via GEMS and 29,168 (20%) via HEMS. Median transportation time was longer for HEMS patients (41 vs. 25 min; p < 0.001). HEMS patients were more likely to have hypotension (2.7% vs. 1.5%; p < 0.001), Glasgow Coma Scale (GCS) score < 9 (38.2% vs. 10.9%; p < 0.001), and head Abbreviation Injury Scale (AIS) score of 5 (20.1% vs. 9.7%; p < 0.001). Stepwise logistic regression analysis identified age ≥ 65 years old, male sex, hypotension, GCS score < 9, prehospital intubation, and head AIS scores 4 and 5 as independent predictors of mortality. Helicopter transportation was independently associated with improved survival (odds ratio [OR] 0.55; 95% confidence interval [CI] 0.47–0.67; p < 0.001). Admission to a Level I trauma center was an independent predictor of survival (OR 0.64; 95% CI 0.53–0.82; p = 0.001). Regardless of head AIS, helicopter transport was an independent predictor of survival (AIS 3: OR 0.35; p < 0.001; AIS 4: OR 0.44; p < 0.001; AIS 5: OR 0.76; p < 0.001). A prolonged transport time was not an independent predictor of mortality. ConclusionsHelicopter transport, in adult patients with isolated severe TBI, is associated with improved survival.

Locating helicopter emergency medical service bases to optimise population coverage versus average response time

BackgroundNew South Wales (NSW), Australia has a network of multirole retrieval physician staffed helicopter emergency medical services (HEMS) with seven bases servicing a jurisdiction with population concentrated along the eastern seaboard. The aim of this study was to estimate optimal HEMS base locations within NSW using advanced mathematical modelling techniques.MethodsWe used high resolution census population data for NSW from 2011 which divides the state into areas containing 200–800 people. Optimal HEMS base locations were estimated using the maximal covering location problem facility location optimization model and the average response time model, exploring the number of bases needed to cover various fractions of the population for a 45 min response time threshold or minimizing the overall average response time to all persons, both in green field scenarios and conditioning on the current base structure. We also developed a hybrid mathematical model where average response time was optimised based on minimum population coverage thresholds.ResultsSeven bases could cover 98% of the population within 45mins when optimised for coverage or reach the entire population of the state within an average of 21mins if optimised for response time. Given the existing bases, adding two bases could either increase the 45 min coverage from 91% to 97% or decrease the average response time from 21mins to 19mins. Adding a single specialist prehospital rapid response HEMS to the area of greatest population concentration decreased the average state wide response time by 4mins. The optimum seven base hybrid model that was able to cover 97.75% of the population within 45mins, and all of the population in an average response time of 18 mins included the rapid response HEMS model.ConclusionsHEMS base locations can be optimised based on either percentage of the population covered, or average response time to the entire population. We have also demonstrated a hybrid technique that optimizes response time for a given number of bases and minimum defined threshold of population coverage. Addition of specialized rapid response HEMS services to a system of multirole retrieval HEMS may reduce overall average response times by improving access in large urban areas.

The Impact of Helicopter Emergency Medical Service Night Operations in South East England

ObjectiveThis study sought to assess the impact of a helicopter emergency medical service (HEMS) capable of night operations. MethodsThis is a retrospective case review of all night HEMS missions attended by a charity air ambulance service in South East England over a 2-year period (October 1, 2013, to October 1, 2015). ResultsDuring the 2-year trial period, the HEMS service undertook a total of 5,004 missions and attended to 3,728 patients. Of these, 1,373 missions, or 27.4% of the total HEMS activity, were night missions. Night missions increased from year 1 (n = 617) to year 2 (n = 756). A mean of 1.9 missions per night were conducted, resulting in the treatment of 1.3 patients per night. A higher proportion of patients were transported to a major trauma center at night (64% vs. 51%, χ2 = 41.8, P < .0001). Weather conditions prevented HEMS from responding at night via air for 15% of the night operational hours. ConclusionA 2-year trial period of a night HEMS service in South East England showed the predicted activation rate, with a mean of 1.3 patients attended to per night. Patients transported to a major trauma center had a mean Injury Severity Score of 23. Further research is warranted to determine if the night HEMS service conveys a patient outcome benefit.

Ambulance helicopter contribution to search and rescue in North Norway.

BackgroundSearch and rescue (SAR) operations constitute a significant proportion of Norwegian ambulance helicopter missions, and they may limit the service’s capacity for medical operations. We compared the relative contribution of the different helicopter resources using a common definition of SAR-operation in order to investigate how the SAR workload had changed over the last years.MethodsWe searched the mission databases at the relevant SAR and helicopter emergency medical service (HEMS) bases and the Joint Rescue Coordination Centre (North) for helicopter-supported SAR operations within the potential operation area of the Tromsø HEMS base in 2000–2010. We defined SAR operations as missions over land or sea within 10 nautical miles from the coast with an initial search phase, missions with use of rescue hoist or static rope, and avalanche operations.ResultsThere were 769 requests in 639 different SAR operations, and 600 missions were completed. The number increased during the study period, from 46 in 2000 to 77 in 2010. The Tromsø HEMS contributed with the highest number of missions and experienced the largest increase, from 10 % of the operations in 2000 to 50 % in 2010. Simple terrain and sea operations dominated, and avalanches accounted for as many as 12 % of all missions. The helicopter crews used static rope or rescue hoist in 141 operations.DiscussionWe have described all helicopter supported SAR operations in our area by combining databases. The Tromsø HEMS service had taken over one half of the missions by 2010. Increased availability for SAR work is one potential explanation.ConclusionsThe number of SAR missions increased during 2000-2010, and the Tromsø HEMS experienced the greatest increase in workload.

In-Hospital Outcome Based on the Mode of EMS Transportation in a High-Income Rapidly Developing Middle Eastern Country

&lt;p&gt;&lt;strong&gt;BACKGROUND:&lt;/strong&gt; Helicopter emergency medical services (HEMS) are considered as a standard component of advanced pre-hospital emergency care system. We assessed the clinical presentation and outcomes of trauma patients transported by HEMS versus ground emergency medical services (GEMS).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;METHODS:&lt;/strong&gt; A retrospective analysis of prospectively collected trauma registry data at a level I trauma center was conducted for patients transported by GEMS and HEMS between 2011 and 2013. Patients’ data were categorized and analyzed based on the mode of transportation (MOT).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;RESULTS:&lt;/strong&gt; A total of 4596 trauma patients were admitted to the hospital with a mean age of 31±15 years. Injured patients were transported to the trauma centre by GEMS (93.3%) and HEMS (6.7%). The common mechanisms of injury were motor vehicle crash (37%) and fall (25%). MVC victims were transported to the hospital by HEMS, whereas, patients with fall and pedestrian injuries (P=0.001 for all) were more likely to be transported by GEMS. Moreover, patients in the HEMS group had a higher frequency of head (p=0.001) and chest (p=0.001) injuries and required prolonged ICU and overall hospital stay (p=0.001). When compared with GEMS, HEMS group were more likely to sustain severe injuries (ISS&amp;gt;15; p=0.001) and needed frequent on-scene intubation (P=0.001). Hospital mortality was grater in HEMS patients (10% vs 4%, p=0.001) in comparison to GEMS. Multivariate analysis, after adjusting for the confounding factors demonstrated that polytrauma and lower scene GCS were the independent predictors of mortality.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;CONCLUSIONS: &lt;/strong&gt;Patients transported by HEMS are characterized by greater injury severity, traumatic brain injury and on-scene intubation. Moreover, the mortality is 2.5 fold greater in patients transported by GEMS, however, the impact of MOT on mortality disappear after adjusting for potential confounders. Institutional guidelines that focus on clinical triage criteria, key environmental factors and reducing transport time may be informed by this study. Further investigations are needed to better quantifyestimate the pre-hospital time intervals and to identify the sub-groups of trauma patients who will clearly benefit from the use of HEMS.&lt;/p&gt;

‘Interception’: a model for specialist prehospital care provision when helicopters are not available

The deployment of specialist teams to incident scenes by helicopter and the delivery of critical care interventions such as Rapid Sequence Induction of anaesthesia to patients are becoming well-established components...

The effect of Helicopter Emergency Medical Services on trauma patient mortality in the Netherlands

IntroductionObject of this study was to evaluate the effect of the Helicopter Emergency Medical Services (HEMS) on trauma patient mortality and the effect of prehospital time on the association between HEMS and mortality. Materials and methodsTrauma patients admitted to a level 1 trauma centre and treated on-scene by the HEMS and Emergency Medical Services (EMS) between 2003 and 2008 were included (n=186). A control group treated by EMS only (n=186) was created by matching on ISS, age and severe traumatic brain injury (TBI). Mortality was compared by calculating odds ratios (OR) and numbers needed to treat (NNT), with adjustment for prehospital coded Revised Trauma Score. The effect of prehospital time mortality was tested by a logistic regression. Analyses were made for patients with and without TBI. ResultsThe OR of early trauma fatality for the HEMS/EMS versus EMS-only groups was 0.8 for patients both with TBI (95% CI 0.4–1.7; NNT: 22) and without TBI (95% CI 0.2–3.3; NNT: 273). The risk of in-hospital mortality was non-significantly higher for patients with TBI in the HEMS/EMS group (OR=1.3; 95% CI 0.6–2.7; NNT: −15) compared to the EMS-only group and non-significantly lower for patients without TBI (OR=0.9; 95% CI 0.3–2.5; NNT: 129). After adjustment for prehospital time, the risk of early trauma fatality for patients with TBI treated by the HEMS decreased (OR=0.6; 95% CI 0.3–1.6). The risk of in-hospital mortality for these patients decreased from 1.3 to 0.8 (95% CI 0.4–2.0). The effect of the HEMS on patients without TBI did not change after adjustment for prehospital time. DiscussionHEMS treatment is associated with a non-significantly higher risk of in-hospital mortality for patients with TBI and a non-significantly lower risk for patients without TBI. This increased risk of mortality in TBI patients is attributable to the increased prehospital time. These results indicate that HEMS does not have a positive impact on survival.

Physician staffed helicopter emergency medical service dispatch via centralised control or directly by crew – case identification rates and effect on the Sydney paediatric trauma system

BackgroundSevere paediatric trauma patients benefit from direct transport to dedicated Paediatric Trauma Centres (PTC). Parallel case identification systems utilising paramedics from a centralised dispatch centre versus the crew of a physician staffed Helicopter Emergency Medical Service (HEMS) allowed comparison of the two systems for case identification rates and subsequent timeliness of direct transfer to a PTC.MethodsPaediatric trauma patients over a two year period from the Sydney region with an Injury Severity Score (ISS) > 15 were retrospectively identified from a state wide trauma registry. Overall paediatric trauma system performance was assessed by comparisons of the availability of the physician staffed HEMS for patient characteristics, transport mode (direct versus indirect) and the times required for the patient to arrive at the paediatric trauma centre. The proportion of patients transported directly to a PTC was compared between the times that the HEMS service was available versus the time that it was unavailable to determine if the HEMS system altered the rate of direct transport to a PTC. Analysis of variance was used to compare the identifying systems for various patient characteristics when the HEMS was available.ResultsNinety nine cases met the inclusion criteria, 44 when the HEMS system was operational. Patients identified for physician response by the HEMS system were significantly different to those that were not identified with higher median ISS (25 vs 18, p = 0.011), and shorter times to PTC (67 vs 261mins, p = 0.015) and length of intensive care unit stays (2 vs 0 days, p = 0.045). Of the 44 cases, 21 were not identified, 3 were identified by the paramedic system and 20 were identified by the HEMS system, (P < 0.001). Direct transport to a PTC was more likely to occur when the HEMS dispatch system was available (RR 1.81, 95% CI 1.20-2.73). The median time (minutes) to arrival at the PTC was shorter when HEMS available (HEMS available 92, IQR 50-261 versus HEMS unavailable 296, IQR 84-583, P < 0.01).ConclusionsPhysician staffed HEMS crew dispatch is significantly more likely to identify cases of severe paediatric trauma and is associated with a greater proportion of transports directly to a PTC and with faster times to arrival.