BACKGROUND: Accurate haemodynamic monitoring in the prehospital setting is essential. Non-invasive blood pressure measurement is susceptible to vibration and motion artefact, especially at extremes of hypotension and hypertension: invasive arterial blood pressure (IABP) monitoring is a potential solution. This study describes the largest series to date of cases of IABP monitoring being initiated prehospital.
METHODS: This retrospective observational study was conducted at East Anglian Air Ambulance (EAAA), a UK helicopter emergency medical service (HEMS). It included all patients attended by EAAA who underwent arterial catheterisation and initiation of IABP monitoring between 1st February 2015 and 20th April 2023. The following data were retrieved for all patients: sex; age; aetiology (medical cardiac arrest, other medical emergency, trauma); site of arterial cannulation; operator role (doctor/paramedic); time of insertion and, where applicable, times of pre-hospital emergency anaesthesia, and return of spontaneous circulation following cardiac arrest. Descriptive analyses were performed to characterise the sample.
RESULTS: 13,556 patients were attended: IABP monitoring was initiated in 1083 (8.0%) cases, with a median age 59 years, of which 70.8% were male. 546 cases were of medical cardiac arrest: in 22.4% of these IABP monitoring was initiated during cardiopulmonary resuscitation. 322 were trauma cases, and the remaining 215 were medical emergencies. The patients were critically unwell: 981 required intubation, of which 789 underwent prehospital emergency anaesthesia; 609 received vasoactive medication. In 424 cases IABP monitoring was instituted en route to hospital.
CONCLUSIONS: This study describes over 1000 cases of prehospital arterial catheterisation and IABP monitoring in a UK HEMS system and has demonstrated feasibility at scale. The high-fidelity of invasive arterial blood pressure monitoring with the additional benefit of arterial blood gas analysis presents an attractive translation of in-hospital critical care to the prehospital setting.

OBJECTIVE: Ruptured abdominal aortic aneurysms (rAAAs) are highly morbid emergencies. Not all hospitals are equipped to repair them, and an air ambulance network may aid in regionalising specialty care to quaternary referral centres. The association between travel distance by air ambulance and rAAA mortality in patients transferred as an emergency for repair was examined.
METHODS: A retrospective review of institutional data. Adults with rAAA (2002 - 2019) transferred from an outside hospital (OSH) to a single quaternary referral centre for repair via air ambulance were identified. Patients who arrived via ground transport or post-repair at an OSH for continued critical care were excluded. Patients were divided into near and far groups based on the 75th percentile of the straight line travel distance (> 72 miles) between hospitals. The primary outcome was 30 day mortality. Multivariable logistic regression was used to assess the association between distance and mortality after adjusting for age, sex, ethnicity, cardiovascular comorbidities, and repair type.
RESULTS: A total of 290 patients with rAAA were transported a median distance of 40.4 miles (interquartile range 25.5, 72.7) with 215 (74.1%) near and 75 (25.9%) far patients. Both the near and far groups had similar ages, sex, and ethnicity. There was no difference in pre-operative loss of consciousness, intubation, or cardiac arrest between groups. Endovascular aneurysm repair utilisation and intra-operative aortic occlusion balloon use were also similar. Neither the observed (26.8% vs. 23.9%, p = .61) nor the adjusted odds ratio (0.70, 95% confidence interval 0.36 - 1.39, p = .32) 30 day mortality rate differed significantly between the near and far groups.
CONCLUSIONS: Increasing distance travelled during transfer by air ambulance was not associated with worse outcomes in patients with rAAA. The findings support the regionalisation of rAAA repair to large quaternary centres via an integrated and robust air ambulance network.

BACKGROUND: Use of bystander video livestreaming from scene to Emergency Medical Services (EMS) is becoming increasingly common to aid decision making about the resources required. Possible benefits include earlier, more appropriate dispatch and clinical and financial gains, but evidence is sparse.
METHODS: A feasibility randomised controlled trial with an embedded process evaluation and exploratory economic evaluation where working shifts during six trial weeks were randomised 1:1 to use video livestreaming during eligible trauma incidents (using GoodSAM Instant-On-Scene) or standard care only. Pre-defined progression criteria were: (1) ≥ 70% callers (bystanders) with smartphones agreeing and able to activate live stream; (2) ≥ 50% requests to activate resulting in footage being viewed; (3) Helicopter Emergency Medical Services (HEMS) stand-down rate reducing by ≥ 10% as a result of live footage; (4) no evidence of psychological harm in callers or staff/dispatchers. Observational sub-studies included (i) an inner-city EMS who routinely use video livestreaming to explore acceptability in a diverse population; and (ii) staff wellbeing in an EMS not using video livestreaming for comparison to the trial site.
RESULTS: Sixty-two shifts were randomised, including 240 incidents (132 control; 108 intervention). Livestreaming was successful in 53 incidents in the intervention arm. Patient recruitment (to determine appropriateness of dispatch), and caller recruitment (to measure potential harm) were low (58/269, 22% of patients; 4/244, 2% of callers). Two progression criteria were met: (1) 86% of callers with smartphones agreed and were able to activate livestreaming; (2) 85% of requests to activate livestreaming resulted in footage being obtained; and two were indeterminate due to insufficient data: (3) 2/6 (33%) HEMS stand down due to livestreaming; (4) no evidence of psychological harm from survey, observations or interviews, but insufficient survey data from callers or comparison EMS site to be confident. Language barriers and older age were reported in interviews as potential challenges to video livestreaming by dispatchers in the inner-city EMS.
CONCLUSIONS: Progression to a definitive RCT is supported by these findings. Bystander video livestreaming from scene is feasible to implement, acceptable to both 999 callers and dispatchers, and may aid dispatch decision-making. Further assessment of unintended consequences, benefits and harm is required.
BACKGROUND: ISRCTN 11449333 (22 March 2022). https://www.isrctn.com/ISRCTN11449333.

BACKGROUND: Critical hypertension in major trauma patients is associated with increased mortality. Prehospital emergency anaesthesia (PHEA) is performed for 10% of the most seriously injured patients. Optimising oxygenation, ventilation, and cerebral perfusion, whilst avoiding extreme haemodynamic fluctuations are the cornerstones of reducing secondary brain injury. The aim of this study was to report the differential determinants of post-PHEA critical hypertension in a large regional dataset of trauma patients across three Helicopter Emergency Medical Service (HEMS) organisations.
METHODS: A multi-centre retrospective observational study of consecutive adult trauma patients undergoing PHEA across three HEMS in the United Kingdom; 2015-2022. Critical hypertension was defined as a new systolic blood pressure (SBP) > 180mmHg within 10 min of induction of anaesthesia, or > 10% increase if the baseline SBP was > 180mmHg prior to induction. Purposeful logistical regression was used to explore variables associated with post-PHEA critical hypertension in a multivariable model. Data are reported as number (percentage), and odds ratio (OR) with 95% confidence interval (95%CI).
RESULTS: 30,744 patients were attended by HEMS during the study period; 2161 received PHEA and 1355 patients were included in the final analysis. 161 (11.9%) patients had one or more new episode(s) of critical hypertension ≤ 10 min post-PHEA. Increasing age (compared with 16-34 years): 35-54 years (OR 1.76, 95%CI 1.03-3.06); 55-74 years (OR 2.00, 95%CI 1.19-3.44); ≥75 years (OR 2.38, 95%CI 1.31-4.35), pre-PHEA Glasgow Coma Scale (GCS) motor score four (OR 2.17, 95%CI 1.19-4.01) and five (OR 2.82, 95%CI 1.60-7.09), patients with a pre-PHEA SBP > 140mmHg (OR 6.72, 95%CI 4.38-10.54), and more than one intubation attempt (OR 1.75, 95%CI 1.01-2.96) were associated with post-PHEA critical hypertension.
CONCLUSIONS: Delivery of PHEA to seriously injured trauma patients risks haemodynamic fluctuation. In adult trauma patients undergoing PHEA, 11.9% of patients experienced post-PHEA critical hypertension. Increasing age, pre-PHEA GCS motor score four and five, patients with a pre-PHEA SBP > 140mmHg, and more than intubation attempt were independently associated with post-PHEA critical hypertension.

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BACKGROUND: In Europe, ambulances are increasingly being equipped with blood products for prehospital use. Available evidence on the early administration of blood products comes from military medicine and the Anglo-American medical literature; the evidence cannot be easily transferred to European countries.
OBJECTIVE: This study assesses the incidence of patients with massive haemorrhage after trauma and the potential need for prehospital blood transfusions.
METHODS: Data reported by 37 German air rescue stations between 2015 and 2020 were retrospectively analysed to predict the need for massive transfusion.
RESULTS: A total of 320,347 helicopter emergency medical service (HEMS) missions were performed and involved 2982 patients with potential need for massive transfusion after trauma (approximately 13 transfusions per helicopter per year). Men were most affected (73%). The median age of patients was 38 years. Traffic accidents accounted for 59% of the cases. Most patients sustained multiple injuries including traumatic brain injuries (62%), as well as thoracic (54%), abdominal (39%), and extremity injuries (41%). The median \"rSIG\" (reversed shock index multiplied with the Glasgow Coma Scale) decreased from 4.31 to 3.78.
CONCLUSIONS: Although the incidence of haemorrhagic trauma patients is low, the prehospital administration of blood products might be useful as a potentially life-saving bridging treatment until hospital admission.

Many popular tourist attractions and trekking routes in Bhutan and Nepal are situated between 3000 and 6000 m in elevation. High-altitude emergencies are becoming more common and medical providers must be aware of the practical and medical issues in managing these disorders. We reflect on the challenges in providing high-altitude emergency medical services in Bhutan and Nepal.

BACKGROUND: The work of Helicopter Emergency Medical Services (HEMS) teams crosses the boundaries of several high-risk occupations including medicine, aviation, and transport. Working conditions can be challenging and operational demands requires a 24-h rota, resulting in disruption of the normal circadian rhythm. HEMS crews are therefore prone to both mental and physical fatigue. As fatigue in medical providers is linked to poor cognitive performance, degradation of psychomotor skills and error, this study aimed to explore the existence of predictable patterns of crew-fatigue in a HEMS service.
METHODS: HEMS medical crew members working a 3-on 3-off forward rotating rota with a 5-week shift cycle were asked to do psychomotor vigilance tests (PVT) as an objective measure of fatigue. PVT testing was undertaken at the start, mid- and at the end of every shift during a full 5-week shift cycle. In addition, they were asked to score subjective tiredness with the Samn-Perelli Fatigue Scale (SPFS), and to keep a Transport Fatigue Assessment shift log, wherein they noted shift characteristics potentially related to fatigue. Primary outcome of interest was defined as the change in PVT and SPFS scores over time.
RESULTS: Mean baseline resting PVT in milliseconds at the start of the study period was 427 [390-464]. There was an overall trend towards higher PVT-scores with shift progression mean [95% CI] PVT at the start of shifts 447 [433-460]; halfway through the shift 452 [440-463]; end of the shift 459 [444-475], p = 0.10), whereas SPFS scores remained constant. Within a 5 week forward-rotating cycle, an overall trend towards a gradual increase in both average PVT (from 436 [238-454] to 460 [371-527, p = 0.68] ms;) and SPFS (from 2.9 [2.6-3.2] to 3.6 [3.1-4.0], p = 0.38) was observed, although significant interindividual variation was present. Reported SPFS scores ≥ 4 (moderate fatigue) were mainly related to workload (number of jobs) and transport mode (car-based shifts).
CONCLUSIONS: An overall trend towards a decline in psychomotor vigilance and an increase in self-reported tiredness was found for HEMS crew over a 5-week shift cycle. Using a bespoke predictive fatigue tool on a day-to-day basis could increase fatigue awareness and provide a framework to which relevant mitigating options can be applied.

BACKGROUND: Fixed-wing air ambulances play an important role in healthcare in rural Iceland. More frequent use of helicopter ambulances has been suggested to shorten response times and increase equity in access to advanced emergency care. In finding optimal base locations, the objective is often efficiency-maximizing the number of individuals who can be reached within a given time. This approach benefits people in densely populated areas more than people living in remote areas and the solution is not necessarily fair. This study aimed to find efficient and fair helicopter ambulance base locations in Iceland.
METHODS: We used high-resolution population and incident location data to estimate the service demand for helicopter ambulances, with possible base locations limited to twenty-one airports and landing strips around the country. Base locations were estimated using both the maximal covering location problem (MCLP) optimization model, which aimed for maximal coverage of demand, and the fringe sensitive location problem (FSLP) model, which also considered uncovered demand (i.e., beyond the response time threshold). We explored the percentage of the population and incidents covered by one to three helicopter bases within 45-, 60-, and 75-min response time thresholds, conditioned or not, on the single existing base located at Reykjavík Airport. This resulted in a total of eighteen combinations of conditions for each model. The models were implemented in R and solved using Gurobi.
RESULTS: Model solutions for base locations differed between the demand datasets for two out of eighteen combinations, both with the lowest service standard. Base locations differed between the MCLP and FSLP models for one combination involving a single base, and for two combinations involving two bases. Three bases covered all or almost all demand with longer response time thresholds, and the models differed in four of six combinations. The two helicopter ambulance bases can possibly obtain 97% coverage within 60 min, with bases in Húsafell and Grímsstaðir. Bases at Reykjavík Airport and Akureyri would cover 94.2%, whereas bases at Reykjavík Airport and Egilsstaðir would cover 88.5% of demand.
CONCLUSIONS: An efficient and fair solution would be to locate bases at Reykjavík Airport and in Akureyri or Egilsstaðir.

In cases of critical injury or illness abroad, fixed-wing air ambulance aircraft is employed to repatriate children to their home country. Air ambulance aircraft also transport children to foreign countries for treatment not locally available and newborns back home that have been born prematurely abroad. In this retrospective observational study, we investigated demographics, feasibility, and safety and outcomes of long-distance and international aeromedical transport of neonates and children. The study included 167 pediatric patients, 56 of those preterm neonates. A total of 41 patients were ventilated, 45 requiring oxygen prior to the transport, 57 transferred from an intensive care unit (ICU), and 48 to an ICU. Patients were transported by using Learjet 31A, Learjet 45, Learjet 55, and Bombardier Challenger 604, with a median transport distance of 1,008 nautical miles (NM), median transport time of 04:45 hours (median flight time = 03:00 hours), flight time ≥8 hours in 15 flights, and transport time ≥8 hours in 29 missions. All transports were accompanied by a pediatric physician/nurse team. An increase in FiO 2 during the transport was documented in 47/167 patients (28%). Therapy escalation (other than increased oxygen) was reported in 18 patients, and technical adverse events in 3 patients. No patient required CPR or died during the transport. Clinical transport outcome was rated by the accompanying physician as unchanged in 163 transports, improved in 4, and deteriorated in none. In summary, international, long-distance transport of neonatal and pediatric patients performed by experienced and well-equipped transport teams is feasible. Neither major adverse events nor physician-rated clinical deteriorations were observed in this group of patients.