Air Ambulance and Emergency Retrieval Services in Western Australia: Caseload Analysis Over 5 Years.

OBJECTIVE: The Royal Flying Doctor Service Western Operations (RFDSWO) provides critical care transfer and retrieval services across 2.5 million km2 to a population of 2.58 million people, providing both primary and secondary retrievals across Western Australia. Flying on average 26 million km/y, retrievals are undertaken with the use of rotary and fixed wing aircraft. Our current fleet includes 16 Pilatus PC-12NGs turboprops, 2 Pilatus PC-24 jets, and access to 1 helicopter (Bell 412). A Hawker XP800 Jet was retired in 2019 after 10 years of service. Our retrieval teams are formed of either a doctor and a nurse or a nurse only on fixed wing missions and a doctor and critical care paramedic for helicopter emergency medical services missions. We present our experiences and caseload statistics over the past 5 years. METHODS: We performed an analysis of our retrieval database looking at the workload from January 1, 2012, to December 31, 2016. This included the number of patients, age, ethnicity, type of retrieval, priority, diagnosis, and distances covered. RESULTS: Forty-three thousand forty-one patients underwent Royal Flying Doctor Service air transfer over a 5-year period. Aboriginal patients comprise around 3.1% of the Western Australian population but accounted for 33% of RFDSWO retrieval missions. There was a mean transfer rate of 8,608 patients per year, which was relatively consistent across the study period. The modal age was 55 to 59 years, but Aboriginal patients were younger with a mean age of 36.5 years (Aboriginal) versus 49.7 years (non-Aboriginal). The types of retrieval undertaken were as follows: primary (17.3%), secondary (81%), and repatriation (1.7%). The urgency/priority of missions was as follows: immediate (7.3%), urgent (54.5%), and semiurgent (38.1%). The 3 most common diagnosis (International Statistical Classification of Diseases, 10th Revision) categories were trauma/injury (22.9%), cardiovascular (22.3%), and gastrointestinal (10.5%). The modal distance flown was 700 km per mission. CONCLUSION: RFDSWO has 1 of the largest retrieval workloads in the world, covering a landmass comparable with Western Europe. This brings with it a variety of challenging cases and complex logistics, often in extremely harsh and remote environments. We bring a wide breadth of experience in the area of retrieval medicine, and our aim is to share these experiences with other teams.

In-Flight Pharmacological Management of Patients with Acute Mental Health Disturbance.

OBJECTIVE: Patients can be transferred many hundreds of kilometers with acute mental health disturbance for specialist mental health services in Western Australia. METHODS: A retrospective notes review of Royal Flying Doctor Service Western Operations records was undertaken over a 4-month period. Patients were identified from the transfer database by mental health diagnosis. Benzodiazepine and antipsychotic doses were converted into a reference drug per class for comparison. RESULTS: One hundred ten patients underwent air transfer in a total of 130 flights. Over 80% of patients were involuntary patients being transferred for specialist psychiatric evaluation and management in an inpatient mental health unit. Over half of the patients required no in-flight sedation, and around 80% of patients were managed with standard doses of first-line agents (haloperidol, midazolam, and diazepam). A small number of patients required alternative agents for refractory sedation, most commonly ketamine and propofol. There were no statistically significant differences for in-flight medication by sex, ethnicity, or substance misuse status. CONCLUSIONS: The rate of in-flight incidents including violence remained low. Transfers of patients with acute mental health disturbance are challenging, and quality preflight assessment and in-flight care are required to minimize the associated risks.

The effect of age, severity, and mechanism of injury on risk of death from major trauma in Western Australia.

BACKGROUND: We examined the association between age, mechanism of injury, and Injury Severity Score (ISS) on mortality in major trauma. METHODS: We used 9 years of population-based linked major trauma (ISS >15) registry data for Western Australia (N = 4,411). These were categorized using the Sampalis classification of injury severity: survivable (ISS 16-24), probably survivable (ISS 25-49), and nonsurvivable (ISS 50+). Age was categorized as younger than 15 years, 15 to 64 years, and 65 years or older. Multivariable linear logistic regression analysis was used to examine the risk of death. RESULTS: Motor vehicle crashes (MVCs) were most prominent for those younger than 65 years, and falls dominated the 65 years and older group. The median ISS for the three age groups were 20, 25, and 24, respectively (p = 0.001). The proportion of deaths in the three groups were 7.2%, 11.5%, and 30.1%, respectively (p = 0.0001). Falls were the most common cause of death. The inflexion point, above which the risk of death increases exponentially, was age 47 years. For the potentially survivable ISS 25 to 49 group, the inflexion point was age 25 years. After adjusting for age and ISS, falls had the greatest risk for death (odds ratio, 1.62; 95% confidence interval, 1.21-2.18). A lower ISS had a disproportionate effect on the elderly. CONCLUSION: The risk for major trauma death increases as age increases, with the inflexion point at age 47 years. Those younger than 15 years have a significantly lower ISS. The elderly have an increased risk for death following falls. LEVEL OF EVIDENCE: Epidemiologic study, level II.

Aeromedical transfer of women at risk of preterm delivery in remote and rural Western Australia: why are there no births in flight?

OBJECTIVE: For more than three decades, women at imminent risk of preterm birth (PTB) in Western Australia have been transferred by small aircraft over long distances to the single tertiary level perinatal centre in Perth, with no known case of birth during the flight. We aimed to review recent experience to understand how aircraft travel may delay PTB. DESIGN AND SETTING: Retrospective observational study of 500 consecutive Royal Flying Doctor Service (RFDS) transfers of women at risk of preterm labour to the tertiary referral centre, from September 2007 to December 31, 2009. MAIN OUTCOME MEASURES: In-flight delivery, complications associated with transfer and factors associated with delay in preterm delivery. RESULTS: There were no in-flight deliveries or serious complications associated with the aeromedical transfer of these patients. In a multivariable Cox proportional hazards regression analysis, clinical factors in the presentation that were associated with a shorter time from landing to subsequent delivery included cervical dilatation ≥ 4 cm, ruptured membranes, gestational age > 32 weeks and nulliparity. The aircraft reaching an ambient altitude > 14,000 feet, or cabin altitude above zero (sea level), was associated with a delay in time from landing to delivery for women who were not in spontaneous preterm labour. CONCLUSIONS: Our findings add to a 30-year experience that women at risk of preterm labour do not deliver during aeromedical transfer. Ambient and cabin altitude of the aircraft were associated with an extension in the time to delivery after arrival. The mechanisms underpinning this effect warrant further investigation.

Major trauma patients transferred from rural and remote Western Australia by the Royal Flying Doctor Service.

BACKGROUND: The "golden hour" of trauma care is irrelevant in rural areas. We studied the effect of distance and remoteness on major trauma patients transferred by the Royal Flying Doctor Service from rural and remote Western Australia. METHODS: The Royal Flying Doctor Service retrieval and Trauma Registry databases were linked for the period of July 1, 1997, to June 30, 2006. Major trauma was defined as Injury Severity Score (ISS) >15. Remoteness was quantified using the Accessibility/Remoteness Index of Australia (ARIA) classes: inner regional, outer regional, remote, and very remote. The primary outcome was death. RESULTS: Among 1328 major trauma transfers to Perth, mean age was 34.2 years ± 18.3 years (range, 0-87 years) and 979 (73.7%) were male. Over half were motor vehicle crashes. Mean transfer time was 11.6 hours (95% confidence interval [CI], 11.2-12.1). The median ISS was 25 (interquartile range [IQR], 18-29), and there were no differences within the ARIA classes for cause and injury patterns. After adjusting for ISS, age, and time, the risk of death increases as remoteness increases: outer regional odds ratio (OR), 2.25 (95% CI, 0.58-8.79); remote, 4.03 (95% CI 1.04-15.62); and very remote, 4.69 (95% CI, 1.23-17.84). Risk increases by 87% for each 1,000 km (OR, 1.87; 95% CI, 1.007-3.48; p = 0.05) flown. Despite long retrieval times, there were no deaths in flight. CONCLUSION: There is an excess of a fourfold increase in the risk of major trauma death in patients transferred to Perth from remote and very remote Western Australia. Remoteness, as measured by the ARIA, is more important than distance, in the risk of death.

A comparison of metropolitan vs rural major trauma in Western Australia.

BACKGROUND: Metropolitan and rural Western Australia (WA) major trauma transport times are extremely different. We compared outcomes from these different systems of care. METHODS: Major trauma (Injury Severity Score, ISS>15) data from the Royal Flying Doctor Service (RFDS) and Trauma Registries, 1 July 1997-30 June 2006. Two groups were studied: Metro (metropolitan major trauma transported directly to a tertiary hospital), and Rural (rural major trauma transferred by the RFDS to a tertiary hospital in Perth). The primary endpoint was death. We used logistic regression and multiple imputation. RESULTS: 3333 major trauma patients were identified (mean age 40.1 ± 22.6 yrs; Metro=2005, Rural=1328). The rural patients were younger, had a larger proportion of motor vehicle crashes, and higher median ISS (25 vs 24, p<0.001). Mean times to definitive care were 59 min versus 11.6h, respectively (p<0.0001). After adjusting for age, injury severity and the effect of time with the initial rural deaths, there was a significantly increased risk of death (OR 2.60, 95% CI 1.05-6.53, p=0.039) in the Rural group. For those rural patients who reached Perth, the adjusted OR for death was 1.10 (95% CI 0.66-1.84, p=0.708). CONCLUSION: There is more than double the risk of major trauma death in rural and remote WA. However, if a major trauma patient survives to be retrieved to Perth by the RFDS, then mortality outcomes are equivalent to the metropolitan area.