A data-driven algorithm to support the clinical decision-making of patient extrication following a road traffic collision.

BACKGROUND: Some patients involved in a road traffic collision (RTC) are physically entrapped and extrication is required to provide critical interventions. This can be performed either in an expedited way, or in a more controlled manner. In this study we aimed to derive a data-driven extrication algorithm intended to be used as a decision-support tool by on scene emergency service providers to decide on the optimal method of patient extrication from the vehicle. METHODS: A retrospective observational study was performed of all trauma patients trapped after an RTC who were attended by a Helicopter Emergency Medical Service (HEMS) in the United Kingdom between March 2013 and December 2021. Variables were identified that were associated with the need for HEMS interventions (as a surrogate for the need for expedited extrication), based on which a practical extrication algorithm was devised. RESULTS: During the study period 12,931 patients were attended, of which 920 were physically trapped. Patients who scored an "A" on the AVPU score (n = 531) rarely required HEMS interventions (3%). Those who did were characterised by a shorter than average (29 vs. 37 min) 999/112 emergency call to HEMS on-scene arrival interval. A third of all patients responding to voice required HEMS interventions. Absence of a patent airway (OR 6.98 [1.74-28.03] p < .001) and the absence of palpable radial pulses (OR 9.99 [2.48-40.18] p < .001) were independently associated with the need for (one or more) HEMS interventions in this group. Patients only responding to pain and unresponsive patients almost invariably needed HEMS interventions post extrication (90% and 86% respectively). Based on these findings, a practical and easy to remember algorithm "APEX" was derived. CONCLUSION: A simple, data-driven algorithm, remembered by the acronym "APEX", may help emergency service providers on scene to determine the preferred method of extrication for patients who are trapped after a road traffic collision. This has the potential to facilitate earlier recognition of a 'sick' critical patient trapped in an RTC, decrease entrapment and extrication time, and may contribute to an improved outcome for these patients.

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

OBJECTIVE: Prehospital 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. METHODS: Using 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. RESULTS: Endotracheal 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). CONCLUSION: In-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.

Pre-hospital transfusion of packed red blood cells in 147 patients from a UK helicopter emergency medical service.

BACKGROUND: Early transfusion of packed red blood cells (PRBC) has been associated with improved survival in patients with haemorrhagic shock. This study aims to describe the characteristics of patients receiving pre-hospital blood transfusion and evaluate their subsequent need for in-hospital transfusion and surgery. METHODS: The decision to administer a pre-hospital PRBC transfusion was based on clinical judgment. All patients transfused pre-hospital PRBC between February 2013 and December 2014 were included. Pre-hospital and in-hospital records were retrospectively reviewed. RESULTS: One hundred forty-seven patients were included. 142 patients had traumatic injuries and 5 patients had haemorrhagic shock from a medical origin. Median Injury Severity Score was 30. 90% of patients receiving PRBC had an ISS of >15. Patients received a mean of 2.4(±1.1) units of PRBC in the pre-hospital phase. Median time from initial emergency call to hospital arrival was 114 min (IQR 103-140). There was significant improvement in systolic (p < 0.001), diastolic (p < 0.001) and mean arterial pressures (p < 0.001) with PRBC transfusion but there was no difference in HR (p = 0.961). Patients received PRBC significantly faster in the field than waiting until hospital arrival. At the receiving hospital 57% required an urgent surgical or interventional radiology procedure. At hospital arrival, patients had a mean lactate of 5.4(±4.4) mmol/L, pH of 6.9(±1.3) and base deficit of -8.1(±6.7). Mean initial serum adjusted calcium was 2.26(±0.29) mmol/L. 89% received further blood products in hospital. No transfusion complications or significant incidents occurred and 100% traceability was achieved. DISCUSSION: Pre-hospital transfusion of packed red cells has the potential to improvde outcome for trauma patients with major haemorrhage. The pre-hospital time for trauma patients can be several hours, suggesting transfusion needs to start in the pre-hospital phase. Hospital transfusion research suggests a 1:1 ratio of packed red blood cells to plasma improves outcome and further research into pre-hospital adoption of this strategy is needed. CONCLUSION: Pre-hospital PRBC transfusion significantly reduces the time to transfusion for major trauma patients with suspected major haemorrhage. The majority of patients receiving pre-hospital PRBC were severely injured and required further transfusion in hospital. Further research is warranted to determine which patients are most likely to have outcome benefit from pre-hospital blood products and what triggers should be used for pre-hospital transfusion.

The Need for a UK Helicopter Emergency Medical Service by Night: A Prospective, Simulation Study.

BACKGROUND: Major trauma commonly occurs at night. Helicopter emergency medical services (HEMS) can provide advanced prehospital care to victims of major trauma but do not routinely operate at night in the United Kingdom. We sought to prospectively examine the need for a night HEMS service in Kent, Surrey, and Sussex in the United Kingdom. METHODS: A 4-month, prospective study was conducted (July 1, 2012-October 31, 2012). HEMS dispatch paramedics were present in the ambulance dispatch center and undertook simulated HEMS activations when a suitable case was identified. All trauma cases from the 4-month study period were collated. Five independent HEMS clinicians reviewed the simulated tasking and trauma cases and gave an opinion on whether the patient met HEMS activation criteria. RESULTS: A mission rate of 1 case per night was predefined as cost-effective. During the prospective study, 145 calls were identified by the HEMS dispatch paramedic as appropriate for an HEMS response. If HEMS had deployed to all 145 incidents, this would have resulted in an average mission rate of 1.2 activations per night. Two hundred eight incidents were identified as potentially appropriate for HEMS activation. Responding to all 208 incidents would have resulted in a mean activation rate of 1.7 per night. CONCLUSION: This study justifies the need for Kent, Surrey and Sussex Air Ambulance Trust to operate a service at night for a trial period, with an estimated average mission load of 1 per night spread over the entire night period. Further research is warranted to determine the potential impact of a night HEMS service on outcome from major trauma.

Significant modification of traditional rapid sequence induction improves safety and effectiveness of pre-hospital trauma anaesthesia.

INTRODUCTION: Rapid Sequence Induction of anaesthesia (RSI) is the recommended method to facilitate emergency tracheal intubation in trauma patients. In emergency situations, a simple and standardised RSI protocol may improve the safety and effectiveness of the procedure. A crucial component of developing a standardised protocol is the selection of induction agents. The aim of this study is to compare the safety and effectiveness of a traditional RSI protocol using etomidate and suxamethonium with a modified RSI protocol using fentanyl, ketamine and rocuronium. METHODS: We performed a comparative cohort study of major trauma patients undergoing pre-hospital RSI by a physician-led Helicopter Emergency Medical Service. Group 1 underwent RSI using etomidate and suxamethonium and Group 2 underwent RSI using fentanyl, ketamine and rocuronium. Apart from the induction agents, the RSI protocol was identical in both groups. Outcomes measured included laryngoscopy view, intubation success, haemodynamic response to laryngoscopy and tracheal intubation, and mortality. RESULTS: Compared to Group 1 (n = 116), Group 2 RSI (n = 145) produced significantly better laryngoscopy views (p = 0.013) and resulted in significantly higher first-pass intubation success (95% versus 100%; p = 0.007). A hypertensive response to laryngoscopy and tracheal intubation was less frequent following Group 2 RSI (79% versus 37%; p < 0.0001). A hypotensive response was uncommon in both groups (1% versus 6%; p = 0.05). Only one patient in each group developed true hypotension (SBP < 90 mmHg) on induction. CONCLUSIONS: In a comparative, cohort study, pre-hospital RSI using fentanyl, ketamine and rocuronium produced superior intubating conditions and a more favourable haemodynamic response to laryngoscopy and tracheal intubation. An RSI protocol using fixed ratios of these agents delivers effective pre-hospital trauma anaesthesia.

Helicopter emergency medical services response to equestrian accidents.

BACKGROUND: Horse riding is a common leisure activity associated with a significant rate of injury. Helicopter emergency medical services (HEMS) may be called to equestrian accidents. Accurate HEMS tasking is important to ensure appropriate use of this valuable medical resource. We sought to review HEMS response to equestrian accidents and identify factors associated with the need for HEMS intervention or transport of the patient to a major trauma centre. METHODS: Retrospective case review of all missions flown by Kent, Surrey & Sussex Air Ambulance Trust over a 1-year period (1 July 2011 to 1 July 2012). All missions were screened for accidents involving a horse. Call details, patient demographics, suspected injuries, clinical interventions and patient disposition were all analysed. RESULTS: In the 12-month data collection period there were 47 equestrian accidents, representing ∼3% of the total annual missions. Of the 42 cases HEMS attended, one patient was pronounced life extinct at the scene. In 15 (36%) cases the patient was airlifted to hospital. In four (10%) cases, the patient underwent prehospital anaesthesia. There were no specific predictors of HEMS intervention. Admission to a major trauma centre was associated with the rider not wearing a helmet, a fall onto their head or the horse falling onto the rider. CONCLUSION: Equestrian accidents represent a significant proportion of HEMS missions. The majority of patients injured in equestrian accidents do not require HEMS intervention, however, a small proportion have life-threatening injuries, requiring immediate critical intervention. Further research is warranted, particularly regarding HEMS dispatch, to further improve accuracy of tasking to equestrian accidents.