Nationwide status of aeromedical pre-hospital and retrieval medicine in Australia.

OBJECTIVE: To survey the current structure, capability and operational scope of pre-hospital and retrieval aeromedical teams across Australia. METHODS: The medical directors of all Australian civilian adult aeromedical retrieval organisations with pre-hospital teams and/or doctors for inter-hospital critical care patient transport were contacted in a survey to qualitatively assess capacity and team structure. RESULTS: All 17 organisations contacted completed the survey. While there is diversity in team structure with the pairing of doctors, paramedics and nurses, capacity for patient care is generally homogenous. A doctor/paramedic model is the more common team structure for rotary-wing missions, and doctor/nurse for fixed-wing. Differences are mostly due to state government controlled aspects of their health services. An advanced degree of intensive patient care occurs outside of the hospital. Land and sea rescue is an important aspect of Australian aeromedical work. CONCLUSION: Aeromedicine in Australia has many consistent elements, but variable contexts have resulted in a diversity of operational models.

The relationship between patient volume and mortality in NSW major trauma service hospitals.

INTRODUCTION: Conventional wisdom is that Major Trauma Services (MTS) treating larger volumes of severe trauma patients will have better outcomes than lower volume centres, but recent studies from Europe have questioned this relationship. We aimed to determine if there is a relationship between patient volume and outcome in New South Wales (NSW) MTS hospitals. MATERIALS AND METHODS: Retrospective observational study using data from the NSW State Trauma Registry from 2010 to 2019 inclusive. Adult patients with Injury Severity Score >15 transported directly to a NSW MTS were included. Outcome measures were mortality at hospital discharge, and intensive care unit and hospital length of stay. Generalised estimating equation models were created to determine the adjusted relationship between patient volume and the main outcome measures. RESULTS: The mean annual patient volume of the MTS ranged from 127.4 to 282.0 patients whilst the observed mortality rates p.a. ranged from 10.4 % to 17.19 %. Multivariate analysis, using low volume MTS as the reference, did not demonstrate a significant difference in mortality between high and low volume MTS (adjusted OR: 1.14 95 % CI: 0.98-1.25, P = 0.087). There was however a significant correlation between volume and length of hospital stay (adjusted ß; 0.024, 95 % CI, 0.182 - 1.089, P = 0.006). CONCLUSIONS: There was no mortality difference between high and low volume MTS demonstrated. Length of hospital stay significantly increased with increasing volume however.

Association between three prehospital thoracic decompression techniques by physicians and complications: a retrospective, multicentre study in adults.

INTRODUCTION: We sought to compare the complication rates of prehospital needle decompression, finger thoracostomy and three tube thoracostomy systems (Argyle, Frontline kits and endotracheal tubes) and to determine if finger thoracostomy is associated with shorter prehospital scene times compared with tube thoracostomy. METHODS: In this retrospective cohort study we abstracted data on adult trauma patients transported by three helicopter emergency medical services to five Major Trauma Service hospitals who underwent a prehospital thoracic decompression procedure over a 75-month period. Comparisons of complication rates for needle, finger and tube thoracostomy and between tube techniques were conducted. Multivariate models were constructed to determine the relative risk of complications and length of scene time by decompression technique. RESULTS: Two hundred and fifty-five patients underwent 383 decompression procedures. Fifty eight patients had one complication, and two patients had two complications. There was a weak association between decompression technique (finger vs tube) and adjusted risk of overall complication (RR 0.58, 95% CI: 0.33-1.03, P = 0.061). Recurrent tension physiology was more frequent in finger compared with tube thoracostomy (13.9 vs 3.2%, P < 0.001). Adjusted prolonged (80th percentile) scene time was not significantly shorter in patients undergoing finger vs tube thoracostomy (56 vs 63 min, P = 0.197), nor was the infection rate lower (2.7 vs 2.1%, P = 0.85). CONCLUSIONS: There was no clear evidence for benefit associated with finger thoracostomy in reducing overall complication rates, infection rates or scene times, but the rate of recurrent tension physiology was significantly higher. Therefore, tube placement is recommended as soon as practicable after thoracic decompression.

Australasian emergency ultrasound: A survey on the current status.

OBJECTIVE: Emergency ultrasound (EUS) has become an integral part of emergency medicine, and the core pillars of governance, infrastructure, administration, education and quality assurance (QA) are vital for its quality and continued growth. We aimed to assess the status of these vital pillars among Australasian EDs. METHODS: A survey among the clinical leads in ultrasound (CLUS) in Australasian EDs from November 2020 to April 2021. RESULTS: We analysed a total of 98 responses from CLUS representing 98 EDs. Most CLUS (85%) held EUS qualifications (CCPU 57%, DDU 18%, other 9%) but 15% had none. Only 66% of CLUS had dedicated clinical support time, and a mere 5% had administrative personnel support. Up to three ultrasound machines in 62% of EDs, but only 26% of EDs had secured image archiving facilities. In-house credentialing and the Australasian College for Emergency Medicine (ACEM) trainee special skills placement were available in 50% and 32% of EDs, respectively. Only 11% of EDs had regular EUS training for FACEMs, and only 66% of EDs had regular EUS education for emergency medicine trainees. Only 20 EDs had sonographer educators. Regarding EUS QA, only 33% of EDs provided formal EUS report, 23% of EDs conducted regular image reviews and 37% of EDs audited EUS performance. Only 35% of EDs had high-level disinfection equipment, and 56% of EDs had formal transducer disinfection protocols. CONCLUSION: Despite ACEM recommendations for the practice of EUS, Australasian EDs still lack vital governance, administrative support, infrastructure, education and QA processes. Prompt actions such as ACEM mandating these recommendations are required to improve resource allocation by health services.

External Aortic Compression in Noncompressible Truncal Hemorrhage and Traumatic Cardiac Arrest: A Scoping Review.

External aortic compression has been investigated as a treatment for non-compressible truncal haemorrhage in trauma patients. We sought to systematically gather and tabulate the available evidence around external aortic compression. We were specifically interested in its ability to achieve hemostasis and aid in resuscitation of traumatic arrest and severe shock and to consider physiological changes and adverse effects. A scoping review approach was chosen due to the highly variable existing literature. We were guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, using the specific extension for scoping reviews. Searches were done on PubMed and Scopus databases in October 2020. We found that a range of studies have investigated external aortic compression in a variety of settings, including case reports and small case series, porcine hemorrhage models and effects on healthy volunteers. External aortic compression for postpartum hemorrhage in a single center provided some evidence of effectiveness. Overall the level of evidence is limited, however, external aortic compression does appear able to achieve cessation of distal blood flow. Furthermore, it appears to improve many relevant physiological parameters in the setting of hypovolemic shock. Application for more than 60 minutes appears to cause increasingly problematic complications. In conclusion we find that the role of external aortic compression warrants further research. The intervention may have a role as a bridge to definitive treatment of noncompressible truncal haemorrahge.

First experience with the abdominal aortic and junctional tourniquet in prehospital traumatic cardiac arrest.

INTRODUCTION: The Abdominal Aortic and Junctional Tourniquet (AAJT) increased systemic vascular resistance, mean arterial pressure, carotid blood flow and rate of return of spontaneous circulation (ROSC) in animals with hypovolaemic traumatic cardiac arrest (TCA). The objective of this study was to report the first experience of the use of the AAJT as part of a pre-hospital TCA algorithm. METHODS: This is a descriptive case series of the use of the AAJT in patients with TCA in a civilian physician-led pre-hospital trauma service in Sydney, Australia between June 2015 to August 2019. Cases were identified and data sourced from routinely collected data sets within the retrieval service. RESULTS: During the study, 44 TCAs were attended, 22 with AAJT application. Mean time (standard deviation) to AAJT application since last signs of life was 16 (9) min. Eighteen (16 males, 2 females) patients, with median age (interquartile range) of 40 (25-58) years, were included for analysis. Seventeen patients (94%) had blunt trauma. Sixteen patients (89%) were in TCA at the time of service contact, 11 (61%) had a change in electrical activity, 4 (22%) had ROSC, and of the 6 with documented end-tidal carbon dioxide, the mean rise was 24.0 mmHg (95% CI 12.6-35.4) (P = 0.003). Three patients (17%) had sustained ROSC on arrival to the Emergency Department. No patients survived to hospital discharge. CONCLUSION: Physiological changes were demonstrated but there were no survivors. Further research focusing on faster application times may be associated with improved outcomes.

Success and complications by team composition for prehospital paediatric intubation: a systematic review and meta-analysis.

BACKGROUND: Clinical team composition for prehospital paediatric intubation may affect success and complication rates. We performed a systematic review and meta-analysis to determine the success and complication rates by type of clinical team. METHODS: We searched MEDLINE, EMBASE, and CINAHL for interventional and observational studies describing prehospital intubation attempts in children with overall success, first-pass success, and complication rates. Eligible studies, data extraction, and assessment of risk of bias were assessed independently by two reviewers. We performed a random-effects meta-analysis of proportions. RESULTS: Forty studies (1989 to 2019) described three types of clinical teams: non-physician teams with no relaxants (22 studies, n = 7602), non-physician teams with relaxants (12 studies, n = 2185), and physician teams with relaxants (12 studies, n = 1780). Twenty-two (n = 3747) and 18 (n = 7820) studies were at low and moderate risk of bias, respectively. Non-physician teams without relaxants had lower overall intubation success rate (72%, 95% CI 67-76%) than non-physician teams with relaxants (95%, 95% CI 93-98%) and physician teams (99%, 95% CI 97-100%). Physician teams had higher first-pass success rate (91%, 95% CI 86-95%) than non-physicians with (75%, 95% CI 69-81%) and without (55%, 95% CI 48-63%) relaxants. Overall airway complication rate was lower in physician teams (10%, 95% CI 3-22%) than non-physicians with (30%, 95% CI 23-38%) and without (39%, 95% CI 28-51%) relaxants. CONCLUSION: Physician teams had higher rates of intubation success and lower rates of overall airway complications than other team types. Physician prehospital teams should be utilised wherever practicable for critically ill children requiring prehospital intubation.

Near-infrared spectroscopy monitoring in a pre-hospital trauma patient cohort: An analysis of successful signal collection.

BACKGROUND: Noninvasive monitoring of cerebral physiology could potentially guide pre-hospital management of patients with traumatic injuries. Near-infrared spectroscopy (NIRS) is one such modality but the consistency of monitoring performance remains unclear. This study assessed the proportion of successful signal collection during pre-hospital care. METHODS: As part of a prospective observational study, an independent study observer placed three sensors for a Nonin 7610 NIRS device; two on the forehead and one on the forearm. NIRS records were analysed for time of adequate monitoring signal in each sensor (>70% of total pre-hospital time). We also compared pre-hospital scene and transport times for patients with or without NIRS monitoring. RESULTS: Sixty-three patients with monitoring sensors applied were compared to 255 patients where no study observer was on board and 97 without NIRS monitoring for various reasons within the same time period. The proportion of pre-hospital time with successful monitoring (>70%) was 71.4% (45 of 63) for all three sensors, with at least two sensors functional in 90.4% (57 of 63). The median (interquartile range) scene time was 19 (11-23) minutes in patients with NIRS monitoring compared to 18 (11-27) minutes without NIRS monitoring (P = .570). There was no difference in the median (interquartile range) total pre-hospital time between patients with or without monitoring sensors (72 [59-89] versus 72 [59-80] minutes; P = .605). CONCLUSIONS: In this pre-hospital observational feasibility study with dedicated personnel an acceptable proportion of measurement time was achieved in over 90% of monitored subjects. Addition of NIRS monitoring did not alter pre-hospital scene or transport times in this research setting.

Physician-staffed helicopter emergency medical services augment ground ambulance paediatric airway management in urban areas: a retrospective cohort study.

OBJECTIVES: Paediatric intubation is a high-risk procedure for ground emergency medical services (GEMS). Physician-staffed helicopter EMS (PS-HEMS) may bring additional skills, drugs and equipment to the scene including advanced airway management beyond the scope of GEMS even in urban areas with short transport times. This study aimed to evaluate prehospital paediatric intubation performed by a PS-HEMS when dispatched to assist GEMS in a large urban area and examine how often PS-HEMS provided airway intervention that was not or could not be provided by GEMS. METHODS: We performed a retrospective observational study from July 2011 to December 2016 of a PS-HEMS in a large urban area (Sydney, Australia), which responds in parallel to GEMS. GEMS intubate without adjuvant neuromuscular blockade, whereas the PS-HEMS use neuromuscular blockade and anaesthetic agents. We examined endotracheal intubation success rate, first-look success rate and complications for the PS-HEMS and contrasted this with the advanced airway interventions provided by GEMS prior to PS-HEMS arrival. RESULTS: Overall intubation success rate was 62/62 (100%) and first-look success was 59/62 (95%) in the PS-HEMS-treated group, whereas the overall success rate was 2/7 (29%) for the GEMS group. Peri-intubation hypoxia was documented in 5/65 (8%) of the PS-HEMS intubation attempts but no other complications were reported. However, 3/7 (43%) of the attempted intubations by GEMS were oesophageal intubations, two of which were unrecognised. CONCLUSIONS: PS-HEMS have high success with low complication rates in paediatric prehospital intubation. Even in urban areas with rapid GEMS response, PS-HEMS activated in parallel can provide safe and timely advanced prehospital airway management for seriously ill and injured children beyond the scope of GEMS practice. Review of GEMS airway management protocols and the PS-HEMS case identification and dispatch system in Sydney is warranted.

Two cases of penetrating left ventricular cardiac trauma: Pre-hospital ultrasound and direct to theatre.

Left ventricular (LV) Cardiac penetrating trauma is a rare and grave injury. In cases of penetrating cardiac trauma, pre-hospital Ultrasound by flight doctors can assist identify specific pathology. This pre-hospital triage has now been linked to a change in both pre-hospital and in-hospital management. There are minimal cases reported where Pre-Hospital ultrasound provided definitive diagnosis and, while providing Pre-Hospital blood transfusion, informed a direct to theatre approach. In 2017 in New South Wales, Australia, a new protocol "Code Crimson" has been introduced to formalise a system wide process where Pre-Hospital medical teams can expedite a straight to Theatre approach.

Predrawn prehospital medications are microbiologically safe for up to 48 hours.

BACKGROUND: Prehospital medical teams are commonly required to administer a range of medications for urgent stabilisation and treatment. The safe preparation of medications during resuscitation requires attention, time and resources, and can be a source of medication error. In our two road and HEMS (Helicopter Emergency Medical Service) prehospital services, medication errors are mitigated by predrawing commonly used medications to set concentrations daily (Hunter Retrieval Service, HRS) or second-daily (CareFlight Sydney, CFS). However, there are no published data confirming that such practice is microbiologically safe. METHODS: A convenience sample of 299 predrawn medication syringes with syringe dwell times up to 48 hours were collected at the end of their operational deployment. Predrawn medication syringes collected for culture were ketamine, midazolam, fentanyl, thiopentone, rocuronium, suxamethonium, metaraminol and normal saline. The samples were incubated and cultured at a tertiary hospital pathology laboratory using best-practice methodology for non-tissue samples. The samples were collected from June 2017 to February 2018. RESULTS: The mean dwell times ranged from 30.7 hours (fentanyl at HRS) to 48.5 hours (rocuronium at CFS). None of the 299 cultured samples yielded significant micro-organisms. One sample of suxamethonium with a syringe dwell time of 34 hours grew Bacillus cereus but was likely a contaminant introduced during sample collection. CONCLUSION: Predrawing of the eight studied medications for urgent prehospital procedures appears to be a microbiologically safe practice with syringe dwell times up to 48 hours.

A precise measurement of the magnetic field in the corona of the black hole binary V404 Cygni.

Observations of binary stars containing an accreting black hole or neutron star often show x-ray emission extending to high energies (>10 kilo--electron volts), which is ascribed to an accretion disk corona of energetic particles akin to those seen in the solar corona. Despite their ubiquity, the physical conditions in accretion disk coronae remain poorly constrained. Using simultaneous infrared, optical, x-ray, and radio observations of the Galactic black hole system V404 Cygni, showing a rapid synchrotron cooling event in its 2015 outburst, we present a precise 461 ± 12 gauss magnetic field measurement in the corona. This measurement is substantially lower than previous estimates for such systems, providing constraints on physical models of accretion physics in black hole and neutron star binary systems.

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

BACKGROUND: New 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. METHODS: We 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. RESULTS: Seven 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. CONCLUSIONS: HEMS 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.

Hemodynamic Deterioration in Lateral Compression Pelvic Fracture After Prehospital Pelvic Circumferential Compression Device Application.

Increased fracture displacement has previously been described with the application of pelvic circumferential compression devices (PCCDs) in patients with lateral compression-type pelvic fracture. We describe the first reported case of hemodynamic deterioration temporally associated with the prehospital application of a PCCD in a patient with a complex acetabular fracture with medial displacement of the femoral head. Active hemorrhage from a site adjacent to the acetabular fracture was subsequently demonstrated on angiography. Caution in the application of PCCDs to patients with lateral compression-type fractures is warranted.

Loss of Consciousness During Single Sling Helicopter Hoist Rescue Resulting in a Fatal Fall.

INTRODUCTION: Although harness suspension trauma has been documented since the 1960s, especially in the mountaineering setting, there is little robust medical research into the area. Helicopter hoist rescue shares similar risks and is reserved for those cases that cannot be accessed safely by other routes, where extrication may be hazardous or will take an unreasonable amount of time. The single sling or chest harness used for hoist rescue is a single harness around the upper torso and is easier and quicker to apply than a stretcher. However, the risks of a chest harness need to be balanced against the patient's condition, the environment, aircraft performance, and the urgency of the rescue. CASE REPORT: We report an adult male falling 80 ft to his death while being hoisted into a rescue helicopter for a likely fractured ankle. A single rescue sling harness technique was used, but the patient became unconscious, slipped out of the harness, and fell. He had significant comorbidities, including cardiomyopathy, obstructive sleep apnea, morbid obesity, and diabetes. DISCUSSION: A decrease in cardiac output secondary to thoracic compression was the presumed cause for his loss of consciousness and the potential physiological mechanisms and modifying factors are discussed. Further research into harness suspension trauma is required. Stretcher, double point harnesses, or rescue baskets are likely safer methods of hoisting, especially in a medically compromised patient. Biles J, Garner AA. Loss of consciousness during single sling helicopter hoist rescue resulting in a fatal fall. Aerosp Med Hum Perform. 2016; 87(9):821-824.

Physician staffed helicopter emergency medical service case identification - a before and after study in children.

BACKGROUND: Severely injured children may have better outcomes when transported directly to a Paediatric Trauma Centre (PTC). A case identification system using the crew of a physician staffed helicopter emergency medical service (P-HEMS) that identified severely injured children for P-HEMS dispatch was previously associated with high rates of direct transfer. It was theorised that discontinuation of this system may have resulted in deterioration of system performance. METHODS: Severe paediatric trauma cases were identified from a state based trauma registry over two time periods. In Period A the P-HEMS case identification system operated in parallel with a paramedic dispatcher (Rapid Launch Trauma Co-ordinator-RLTC) operating from a central control room (n = 71). In Period B the paramedic dispatcher operated in isolation (n = 126). Case identification and direct transfer rates were compared as was time to arrival at the PTC. RESULTS: After cessation of the P-HEMS system the rate of case identification fell from 62 to 31 % (P < 0.001), identification of fatal cases fell from 100 to 47 % (P < 0.001), the rate of direct transfer to a PTC fell from 66 to 53 % (P = 0.076) and the time to arrival in a PTC increased from a median 69 (interquartile range 52 - 104) mins to 97 (interquartile range 56 - 305) mins (P = 0.003). When analysing the rate of direct transfer to a PTC as a function of team composition, after adjusting for age and injury severity scores, there was no change in the rate between the physician and paramedic groups across the two time periods (relative risk 0.92, 95 % CI: 0.44 to 1.41). DISCUSSION: The parallel identification system improves case identification rates and decreases time to arrival at the PTC, whilst requiring RLTC authorisation preserves the safety and efficiency benefits of centralised dispatch. The model could be extended to adult patients with similar benefits. CONCLUSIONS: A case identification system relying solely on RLTC paramedics resulted in a significantly lower case identification rate and increased prehospital time with a non-significant fall in direct transfer rate to the PTC. The elimination of the P-HEMS input from the tasking system resulted in worse performance indicators and has the potential for poorer outcomes.

Performance comparison of improvised prehospital blood warming techniques and a commercial blood warmer.

INTRODUCTION: Prehospital transfusion of packed red blood cells (PRBC) may be life saving for hypovolaemic trauma patients. PRBCs should preferably be warmed prior to administration but practical prehospital devices have only recently become available. The effectiveness of purpose designed prehospital warmers compared with previously used improvised methods of warming has not previously been described. MATERIALS AND METHODS: Expired units of PRBCs were randomly assigned to a warming method in a bench study. Warming methods were exposure to body heat of an investigator, leaving the blood in direct sunlight on a dark material, wrapping the giving set around gel heat pads or a commercial fluid warmer (Belmont Buddy Lite). Methods were compared with control units that were run through the fluid circuit with no active warming strategy. RESULTS: The mean temperature was similar for all methods on removal from the fridge (4.5°C). The mean temperatures (degrees centigrade) for all methods were higher than the control group at the end of the circuit (all P≤0.001). For each method the mean (95% CI) temperature at the end of the circuit was; body heat 17.2 (16.4-18.0), exposure to sunlight 20.2 (19.4-21.0), gel heat pads 18.8 (18.0-19.6), Buddy Lite 35.2 (34.5-36.0) and control group 14.7 (13.9-15.5). CONCLUSIONS: All of the warming methods significantly warmed the blood but only the Buddy Lite reliably warmed the blood to a near normal physiological level. Improvised warming methods therefore cannot be recommended.