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.

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.

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.

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.

The Head Injury Retrieval Trial (HIRT): a single-centre randomised controlled trial of physician prehospital management of severe blunt head injury compared with management by paramedics only.

BACKGROUND: Advanced prehospital interventions for severe brain injury remains controversial. No previous randomised trial has been conducted to evaluate additional physician intervention compared with paramedic only care. METHODS: Participants in this prospective, randomised controlled trial were adult patients with blunt trauma with either a scene GCS score <9 (original definition), or GCS<13 and an Abbreviated Injury Scale score for the head region ≥3 (modified definition). Patients were randomised to either standard ground paramedic treatment or standard treatment plus a physician arriving by helicopter. Patients were evaluated by 30-day mortality and 6-month Glasgow Outcome Scale (GOS) scores. Due to high non-compliance rates, both intention-to-treat and as-treated analyses were preplanned. RESULTS: 375 patients met the original definition, of which 197 was allocated to physician care. Differences in the 6-month GOS scores were not significant on intention-to-treat analysis (OR 1.11, 95% CI 0.74 to 1.66, p=0.62) nor was the 30-day mortality (OR 0.91, 95% CI 0.60 to 1.38, p=0.66). As-treated analysis showed a 16% reduction in 30-day mortality in those receiving additional physician care; 60/195 (29%) versus 81/180 (45%), p<0.01, Number needed to treat =6. 338 patients met the modified definition, of which 182 were allocated to physician care. The 6-month GOS scores were not significantly different on intention-to-treat analysis (OR 1.14, 95% CI 0.73 to 1.75, p=0.56) nor was the 30-day mortality (OR 1.05, 95% CI 0.66 to 1.66, p=0.84). As-treated analyses were also not significantly different. CONCLUSIONS: This trial suggests a potential mortality reduction in patients with blunt trauma with GCS<9 receiving additional physician care (original definition only). Confirmatory studies which also address non-compliance issues are needed. TRIAL REGISTRATION NUMBER: NCT00112398.

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.

Effect of case identification changes on pre-hospital intubation performance indicators in an Australian helicopter emergency medical service.

OBJECTIVE: A 45-min interval from injury to intubation has been proposed as a performance indicator for severe trauma patient management. In the Sydney pre-hospital system a previous change in case identification systems was associated with activation delay. We aimed to determine if this also decreased the proportion of patients intubated within this benchmark. METHODS: Retrospective cohort study of patients intubated by a helicopter emergency medical service (HEMS) over two time periods. Period 1 dispatch was via HEMS crew directly screening the computerised dispatch system, and period 2 was via paramedics in a central control room. Times from emergency call to intubation were compared. RESULTS: In the HEMS crew screening period 46/58 (79.31%) intubations met the target, compared with 137/314 (43.6%) in the central control period (P < 0.001). The median (interquartile range) time to intubation in the direct crew screening period was 33 (25-41) min, versus the central control period at 47 (38-60) min (P < 0.001). On multivariate modelling, distance to the scene was related to time to intubation (P < 0.001; Incident Rate Ratio = 1.018, 95% confidence interval 1.015-1.020) as was dispatch system, entrapment/access difficulty and indication for intubation (all P < 0.001). CONCLUSIONS: Time from emergency call to intubation was significantly shorter in the HEMS screening period where all non-trapped cases less than 50 km distant were intubated within the 45-min benchmark. There was no distance where intubation within 45 min could be assured for non-trapped patients in the central control period due to dispatch delays.

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.

Respiratory function in hoist rescue: comparing slings, stretcher, and rescue basket.

INTRODUCTION: Some types of equipment used in helicopter hoist rescue have the potential to cause respiratory embarrassment due to chest compression and/or body positioning. This study compared the respiratory effects of four commonly used devices. METHODS: A randomized crossover trial was undertaken in 27 healthy adults while suspended in single sling (SSling), double sling (DSling), supine in a rescue stretcher, and in a rescue basket (RB) of the type used by the U.S. Coast Guard. Primary variables measured were 1-s forced expiratory volume (FEVI), forced vital capacity (FVC), FEV1/FVC ratio, and inspiratory capacity (IC) in each modality versus control. Secondary measurements were peripheral oxygen saturation (SpO2), heart rate (HR), and respiratory rate (RR). RESULTS: Data meeting repeatability standards was obtained from at least 24 subjects in each position. The SSling was associated with significant mean decreases from control of 17% in FEV1, 19.8% in FVC, and 28.3% in IC, together with increases in HR and RR and a decrease in SpO2. The DSling and stretcher were associated with smaller decreases in expiratory spirometry; the DSling was associated with a >10% decrease in IC and the stretcher was associated with a >10% increase in IC. The values for RB did not vary from control for any outcome measure. There was no decrease in FEV1/FVC ratios in any modality. CONCLUSION: The RB was not associated with any change in measured outcomes. Other methods tested, especially SSling, have detrimental effects on respiratory function.

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.

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.

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.

Early post-tsunami disaster medical assistance to Banda Aceh: a personal account.

The south Asian tsunami on 26 December, 2004, saw Australia deploy civilian teams to an international disaster in large numbers for the first time. The logistics of supporting such teams in both a self sustainability capacity and medical equipment had not previously been planned for or tested. For the first Australian team deployed to Banda Aceh, which arrived on the fourth day after the tsunami, equipment sourced from the New South Wales Fire Brigades Urban Search and Rescue (US&R) cache supplied all food, water, tents, generators and sleeping equipment. The medical equipment was largely sourced from the CareFlight US&R medical cache. There were significant deficits in surgical equipment as the medical cache had not been designed to provide a stand alone surgical capability. This resulted in the need for substantial improvisation by the surgical teams during the deployment. Despite this, the team performed nearly 140 major procedures in austere circumstances and significantly contributed to the early international response to this major humanitarian disaster.