Prehospital Management of Penetrating Neck Injuries: An Evaluation of Practice.

OBJECTIVE: Penetrating neck injuries (PNIs) can occur at multiple anatomic sites and involve airway, nerve, vascular, and gastrointestinal structures. They pose a unique challenge to clinicians, especially in the prehospital setting. Published guidance on the prehospital management of PNIs is limited, and there is no review of the current prehospital practice. METHODS: A retrospective electronic case note review of PNIs managed within 1 UK helicopter emergency medical service (HEMS) over a 7-year period was undertaken. Data were collected on the zone of injury, mechanism of injury, prehospital times, patient demographics, prehospital interventions, and on-scene mortality. RESULTS: Ninety-eight patients met the study inclusion criteria, 40% of whom had zone 2 neck injuries. Eighty-three percent were male with a mean age of 42 years. The predominant injury mechanism was interpersonal violence (51%) followed by self-harm (47%). Fifteen percent underwent prehospital emergency anesthesia, 17% underwent prehospital blood transfusion, and 30% had a hemostatic dressing applied. No patients underwent cervical spine immobilization. One percent underwent resuscitative thoracotomy. Five percent were pronounced life extinct after HEMS arrival following interventions by the HEMS team. CONCLUSION: Time-critical and emergent interventions in this select patient population must be minimal and focus on optimizing care during rapid transfer to the hospital. Airway and hemorrhagic pathologies must be managed, often concomitantly. Targeted injury prevention to reduce interpersonal violence must ensue. The author group intends to devise a national Delphi and derive consensus guidelines for the management of prehospital PNIs.

Association of red blood cells and plasma transfusion versus red blood cell transfusion only with survival for treatment of major traumatic hemorrhage in prehospital setting in England: a multicenter study.

BACKGROUND: In-hospital acute resuscitation in trauma has evolved toward early and balanced transfusion resuscitation with red blood cells (RBC) and plasma being transfused in equal ratios. Being able to deliver this ratio in prehospital environments is a challenge. A combined component, like leukocyte-depleted red cell and plasma (RCP), could facilitate early prehospital resuscitation with RBC and plasma, while at the same time improving logistics for the team. However, there is limited evidence on the clinical benefits of RCP. OBJECTIVE: To compare prehospital transfusion of combined RCP versus RBC alone or RBC and plasma separately (RBC + P) on mortality in trauma bleeding patients. METHODS: Data were collected prospectively on patients who received prehospital transfusion (RBC + thawed plasma/Lyoplas or RCP) for traumatic hemorrhage from six prehospital services in England (2018-2020). Retrospective data on patients who transfused RBC from 2015 to 2018 were included for comparison. The association between transfusion arms and 24-h and 30-day mortality, adjusting for age, injury mechanism, age, prehospital heart rate and blood pressure, was evaluated using generalized estimating equations. RESULTS: Out of 970 recruited patients, 909 fulfilled the study criteria (RBC + P = 391, RCP = 295, RBC = 223). RBC + P patients were older (mean age 42 vs 35 years for RCP and RBC), and 80% had a blunt injury (RCP = 52%, RBC = 56%). RCP and RBC + P were associated with lower odds of death at 24-h, compared to RBC alone (adjusted odds ratio [aOR] 0.69 [95%CI: 0.52; 0.92] and 0.60 [95%CI: 0.32; 1.13], respectively). The lower odds of death for RBC + P and RCP vs RBC were driven by penetrating injury (aOR 0.22 [95%CI: 0.10; 0.53] and 0.39 [95%CI: 0.20; 0.76], respectively). There was no association between RCP or RBC + P with 30-day survival vs RBC. CONCLUSION: Prehospital plasma transfusion for penetrating injury was associated with lower odds of death at 24-h compared to RBC alone. Large trials are needed to confirm these findings.

A Physical Basis for Kinetic Compensation.

Kinetic compensation is a strong, positive correlation between the Arrhenius activation energy E and the frequency factor A for a reaction between the same reactants under similar experimental conditions or similar reactants under the same conditions, even though these parameters are supposed to be independent. The kinetic compensation effect (KCE) is demonstrated by a linear relationship between ln[A] and E/R in the eponymous Constable plot and has been the subject of more than 50 000 publications over the past 100 years, with no consensus opinion about the cause of this effect. In this paper, it is suggested that the linear relationship between ln[A] and E is the result of a real or spurious path dependence of the reaction history between the initial state of the pure reactant(s) and the final state of the pure product(s) having standard enthalpy and entropy differences, ΔH° and ΔS°, respectively. The single-step rate law approximation of a reversible reaction leads to T0 = H°/ΔS° as the dynamic thermal (thermodynamic) equilibrium temperature and 1/T0 = (ln[A̅/k0])/(E̅/R) as the slope of a Constable/KCE plot or the crossover temperature of Arrhenius lines in an isokinetic relationship (IKR), where A̅ and E̅ are mean values for the ensemble of compensating {Ei, Ai} pairs and k0 is a constant that accounts for the path dependence of the reaction history and reconciles the KCE with the IKR. This proposed physical basis for the KCE and IKR is supported by qualitative agreement between ΔH° and ΔS° calculated from the statistics of compensating {Ei, Ai} pairs in the literature, and the difference in the standard enthalpies and entropies of formation of the products and reactants for thermal decomposition of organic peroxides, calcium carbonate, and poly(methyl methacrylate).

A comparison between sudden cardiac arrest on military bases and non-military settings.

INTRODUCTION: Out-of-hospital cardiac arrests contribute to significant morbidity and mortality in both non-military/civilian and military populations. Early CPR and AED use have been linked with improved outcomes. There is public health interest in identifying communities with high rates of both with the hopes of creating generalizable tactics for improving cardiac arrest survival. METHODS: We examined a national registry of EMS activations in the United States (NEMSIS). Inclusion criteria were witnessed cardiac arrests from January 2020 to September 2022 where EMS providers documented the location of the arrest, whether CPR was provided prior to their arrival (yes/no), and whether an AED was applied prior to their arrival (yes/no). Cardiac arrests were then classified as occurring on a military base or in a non-military setting. RESULTS: A total of 60 witnessed cardiac arrests on military bases and 202,605 witnessed cardiac arrests in non-military settings met inclusion criteria. Importantly, the prevalence of CPR and AED use prior to EMS arrival was significantly higher on military bases compared to non-military settings. CONCLUSIONS: Reasons for the trends we observed may be a greater availability of CPR-trained individuals and AEDs on military bases, as well as a widespread willingness to provide aid to victims of cardiac arrest. Further research should examine cardiac arrests on military bases.

Understanding pre-hospital blood transfusion decision-making for injured patients: an interview study.

BACKGROUND: Blood transfusion for bleeding trauma patients is a promising pre-hospital intervention with potential to improve outcomes. However, it is not yet clear which patients may benefit from pre-hospital transfusions. The aim of this study was to enhance our understanding of how experienced pre-hospital clinicians make decisions regarding patient blood loss and the need for transfusion, and explore the factors that influence clinical decision-making. METHODS: Pre-hospital physicians, from two air ambulance sites in the south of England, were interviewed between December 2018 and January 2019. Participants were involved in teaching or publishing on the management of bleeding trauma patients and had at least 5 years of continuous and contemporary practice at consultant level. Interviews were semi-structured and explored how decisions were made and what made decisions difficult. A qualitative description approach was used with inductive thematic analysis to identify themes and subthemes related to blood transfusion decision-making in trauma. RESULTS: Ten pre-hospital physicians were interviewed and three themes were identified: recognition-primed analysis, uncertainty and imperfect decision analysis. The first theme describes how participants make decisions using selected cues, incorporating their experience and are influenced by external rules and group expectations. What made decisions difficult for the participants was encapsulated in the uncertainty theme. Uncertainty emerged regarding the patient's true underlying physiological state and the treatment effect of blood transfusion. The last theme focuses on the issues with decision-making itself. Participants demonstrated lapses in decision awareness, often incomplete decision evaluation and described challenges to effective learning due to incomplete patient outcome information. CONCLUSION: Pre-hospital clinicians make decisions about bleeding and transfusion which are recognition-primed and incorporate significant uncertainty. Decisions are influenced by experience and are subject to bias. Improved understanding of the decision-making processes provides a theoretical perspective of how decisions might be supported in the future.

What are the demographic and clinical differences between those older adults with traumatic brain injury who receive a neurosurgical intervention to those that do not? A systematic literature review with narrative synthesis.

OBJECTIVES: This review aimed to identify the demographic and clinical differences between those older adults admitted directly under neurosurgical care and those that were not, and whether EMS clinicians could use these differences to improve patient triage. METHODS: The authors searched for papers that included older adults who had suffered a TBI and were either admitted directly under neurosurgical care or were not. Titles and abstracts were screened, shortlisting potentially eligible papers before performing a full-text review. The Newcastle-Ottawa Scale was used to assess the risk of bias. RESULTS: A total of nine studies were eligible for inclusion. A high abbreviated injury score head, Marshall score or subdural hematoma greater than 10 mm were associated with neurosurgical care. There were few differences between those patients who did and did not receive neurosurgical intervention. CONCLUSIONS: Absence of guidelines and clinician bias means that differences between those treated aggressively and conservatively observed in the literature are fraught with bias. Further work is required to understand which patients would benefit from an escalation of care and whether EMS can identify these patients so they are transported directly to a hospital with the appropriate services on-site.

Mechanical Cardiopulmonary Resuscitation's Role in Helicopter Air Ambulances: A Narrative Review.

Helicopter emergency medical services (HEMS) frequently respond to out-of-hospital cardiac arrest (OHCA) situations. Some have speculated mechanical cardiopulmonary resuscitation (mCPR) may be able to rectify the inadequacy of human performance of cardiopulmonary resuscitation (CPR) during transport. A number of studies have examined the performance of mCPR devices in the air medical setting specifically. Many aspects of the HEMS environment seem uniquely conducive to mCPR, and a growing body of research seems to suggest mCPR holds promise for the treatment of cardiac arrest by HEMS clinicians. Simulation studies show that mCPR leads to improved CPR performance compared with manual CPR in HEMS. Case reports and the experience of several HEMS programs suggest that mCPR can be effectively integrated into HEMS care. However, further research regarding the effectiveness of mCPR in the HEMS environment and in general cardiac arrest care is needed.

Prehospital clinical signs are a poor predictor of raised intracranial pressure following traumatic brain injury.

BACKGROUND: For the prehospital diagnosis of raised intracranial pressure (ICP), clinicians are reliant on clinical signs such as the Glasgow Coma Score (GCS), pupillary response and/or Cushing's triad (hypertension, bradycardia and an irregular breathing pattern). This study aimed to explore the diagnostic accuracy of these signs as indicators of a raised ICP. METHODS: We performed a retrospective cohort study of adult patients attended by a Helicopter Emergency Medical Service (Air Ambulance Kent, Surrey Sussex), who had sustained a traumatic brain injury (TBI), requiring prehospital anaesthesia between 1 January 2016 and 1 January 2018. We established optimal cut-off values for clinical signs to identify patients with a raised ICP and investigated diagnostic accuracy for combinations of these values. RESULTS: Outcome data for 249 patients with TBI were available, of which 87 (35%) had a raised ICP. Optimal cut-off points for systolic blood pressure (SBP), heart rate (HR) and pupil diameter to discriminate patients with a raised ICP were, respectively, >160 mm Hg,<60 bpm and >5 mm. Cushing criteria (SBP >160 mm Hg and HR <60 bpm) and pupillary response and size were complimentary in their ability to detect patients with a raised ICP. The presence of a fixed blown pupil or a Cushing's response had a specificity of 93.2 (88.2-96.6)%, and a positive likelihood ratio (LR+) of 5.4 (2.9-10.2), whereas sensitivity and LR- were only 36.8 (26.7-47.8)% and 0.7 (0.6-0.8), respectively, (Area Under the Curve (AUC) 0.65 (0.57-0.73)). Sensitivity analysis revealed that optimal cut-off values and resultant accuracy were dependent on injury pattern. CONCLUSION: Traditional clinical signs of raised ICP may under triage patients to prehospital treatment with hyperosmolar drugs. Further research should identify more accurate clinical signs or alternative non-invasive diagnostic aids in the prehospital environment.

Feasibility of Prehospital Emergency Anesthesia in the Cabin of an AW169 Helicopter Wearing Personal Protective Equipment During Coronavirus Disease 2019.

OBJECTIVE: Prehospital emergency anesthesia in the form of rapid sequence intubation (RSI) is a critical intervention delivered by advanced prehospital critical care teams. Our previous simulation study determined the feasibility of in-aircraft RSI. We now examine whether this feasibility is preserved in a simulated setting when clinicians wear personal protective equipment (PPE) for aerosol-generating procedures (AGPs) for in-aircraft, on-the-ground RSI. METHODS: Air Ambulance Kent Surrey Sussex is a helicopter emergency medical service that uses an AW169 cabin simulator. Wearing full AGP PPE (eye protection, FFP3 mask, gown, and gloves), 10 doctor-paramedic teams performed RSI in a standard "can intubate, can ventilate" scenario and a "can't intubate, can't oxygenate" (CICO) scenario. Prespecified timings were reported, and participant feedback was sought by questionnaire. RESULTS: RSI was most commonly performed by direct laryngoscopy and was successfully achieved in all scenarios. The time to completed endotracheal intubation (ETI) was fastest (287 seconds) in the standard scenario and slower (370 seconds, P = .01) in the CICO scenario. The time to ETI was not significantly delayed by wearing PPE in the standard (P = .19) or CICO variant (P = .97). Communication challenges, equipment complications, and PPE difficulties were reported, but ways to mitigate these were also reported. CONCLUSION: In-aircraft RSI (aircraft on the ground) while wearing PPE for AGPs had no significant impact on the time to successful completion of ETI in a simulated setting. Patient safety is paramount in civilian helicopter emergency medical services, but the adoption of in-aircraft RSI could confer significant patient benefit in terms of prehospital time savings, and further research is warranted.

Auditory Measures for the Next Billion Users.

A range of new technologies have the potential to help people, whether traditionally considered hearing impaired or not. These technologies include more sophisticated personal sound amplification products, as well as real-time speech enhancement and speech recognition. They can improve user's communication abilities, but these new approaches require new ways to describe their success and allow engineers to optimize their properties. Speech recognition systems are often optimized using the word-error rate, but when the results are presented in real time, user interface issues become a lot more important than conventional measures of auditory performance. For example, there is a tradeoff between minimizing recognition time (latency) by quickly displaying results versus disturbing the user's cognitive flow by rewriting the results on the screen when the recognizer later needs to change its decisions. This article describes current, new, and future directions for helping billions of people with their hearing. These new technologies bring auditory assistance to new users, especially to those in areas of the world without access to professional medical expertise. In the short term, audio enhancement technologies in inexpensive mobile forms, devices that are quickly becoming necessary to navigate all aspects of our lives, can bring better audio signals to many people. Alternatively, current speech recognition technology may obviate the need for audio amplification or enhancement at all and could be useful for listeners with normal hearing or with hearing loss. With new and dramatically better technology based on deep neural networks, speech enhancement improves the signal to noise ratio, and audio classifiers can recognize sounds in the user's environment. Both use deep neural networks to improve a user's experiences. Longer term, auditory attention decoding is expected to allow our devices to understand where a user is directing their attention and thus allow our devices to respond better to their needs. In all these cases, the technologies turn the hearing assistance problem on its head, and thus require new ways to measure their performance.

Prehospital critical care is associated with increased survival in adult trauma patients in Scotland.

BACKGROUND: Scotland has three prehospital critical care teams (PHCCTs) providing enhanced care support to a usually paramedic-delivered ambulance service. The effect of the PHCCTs on patient survival following trauma in Scotland is not currently known nationally. METHODS: National registry-based retrospective cohort study using 2011-2016 data from the Scottish Trauma Audit Group. 30-day mortality was compared between groups after multivariate analysis to account for confounding variables. RESULTS: Our data set comprised 17 157 patients, with a mean age of 54.7 years and 8206 (57.5%) of male gender. 2877 patients in the registry were excluded due to incomplete data on their level of prehospital care, leaving an eligible group of 14 280. 13 504 injured adults who received care from ambulance clinicians (paramedics or technicians) were compared with 776 whose care included input from a PHCCT. The median Injury Severity Score (ISS) across all eligible patients was 9; 3076 patients (21.5%) met the ISS>15 criterion for major trauma. Patients in the PHCCT cohort were statistically significantly (all p<0.01) more likely to be male; be transported to a prospective Major Trauma Centre; have suffered major trauma; have suffered a severe head injury; be transported by air and be intubated prior to arrival in hospital. Following multivariate analysis, the OR for 30-day mortality for patients seen by a PHCCT was 0.56 (95% CI 0.36 to 0.86, p=0.01). CONCLUSION: Prehospital care provided by a physician-led critical care team was associated with an increased chance of survival at 30 days when compared with care provided by ambulance clinicians.

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.

Isokinetics.

The study of the rates of chemical reactions and their relationship to temperature began in the 19th century with empirical measurements of the time required to reach a particular reaction end point at a constant temperature. By the mid-20th century, the theory of reaction rates had advanced and instruments had been developed in which the temperature of the sample could be increased at a constant rate. These nonisothermal methods are now widely used to determine the kinetic parameters of reactions because of their convenience. In this paper, the mathematical relationship between measurements at constant temperature (isothermal) and constant heating rate (nonisothermal) is developed and it is shown that there is a point in the temperature history of a single-step reaction at which the isothermal and nonisothermal reaction rates are equal. This equal (iso) kinetic point occurs at a temperature early in the heating history of nonisothermal analyses at which the reaction rate begins to accelerate. The isokinetic temperature is the basis for a new method of nonisothermal kinetic analysis that provides a direct measurement of the Arrhenius frequency factor A and activation energy Ea for the elementary step of a solid-state reaction without any assumptions about the relationship between these parameters (i.e., kinetic compensation) or the reaction mechanism.

Prehospital Death After Traumatic Cardiac Arrest: Time for Better Feedback?

OBJECTIVE: The aim of this study was to establish if in patients who die at scene as a result of traumatic cardiac arrest (TCA), their cause of death could be determined through coroners reports, and to ascertain the quality of the feedback provided. METHODS: This is a retrospective study of all patients presenting in TCA who were attended by the Air Ambulance Kent, Surrey and Sussex between January 1, 2015, and June 30, 2016. RESULTS: In total, 159 patients were attended to during the study period. Postmortem reports could not be obtained for 37 patients, mainly because of unestablished identities at the scene. Forty of the 122 reports obtained were full postmortem reports, 3 were inquest reports, and for 79 patients only their (presumed) cause of death was provided. A specific cause of death was provided for 68 patients, whereas in the remaining 54 patients the cause of death was given as "multiple injuries." In 32% of the patients with a full postmortem report, injuries were identified during the postmortem examination that had not been noted on scene. CONCLUSION: Feedback from coroners to prehospital teams after patients die as a result of TCA is important but currently suboptimal.

Quadratic distortion in a nonlinear cascade model of the human cochlea.

The cascade of asymmetric resonators with fast-acting compression (CARFAC) is a cascade filterbank model that performed well in a comparative study of cochlear models, but exhibited two anomalies in its frequency response and excitation pattern. It is shown here that the underlying reason is CARFAC's inclusion of quadratic distortion, which generates DC and low-frequency components that in a real cochlea would be canceled by reflections at the helicotrema, but since cascade filterbanks lack the reflection mechanism, these low-frequency components cause the observed anomalies. The simulations demonstrate that the anomalies disappear when the model's quadratic distortion parameter is zeroed, while other successful features of the model remain intact.

Hypoxia and hypotension in patients intubated by physician staffed helicopter emergency medical services - a prospective observational multi-centre study.

BACKGROUND: The effective treatment of airway compromise in trauma and non-trauma patients is important. Hypoxia and hypotension are predictors of negative patient outcomes and increased mortality, and may be important quality indicators of care provided by emergency medical services. Excluding cardiac arrests, critical trauma and non-trauma patients remain the two major groups to which helicopter emergency medical services (HEMS) are dispatched. Several studies describe the impact of pre-hospital hypoxia or hypotension on trauma patients, but few studies compare this in trauma and non-trauma patients. The primary aim was to describe the incidence of pre-hospital hypoxia and hypotension in the two groups receiving pre-hospital tracheal intubation (TI) by physician-staffed HEMS. METHODS: Data were collected prospectively over a 12-month period, using a uniform Utstein-style airway template. Twenty-one physician-staffed HEMS in Europe and Australia participated. We compared peripheral oxygen saturation and systolic blood pressure before and after definitive airway management. Data were analysed using Cochran-Mantel-Haenszel methods and mixed-effects models. RESULTS: Eight hundred forty three trauma patients and 422 non-trauma patients receiving pre-hospital TI were included. Non-trauma patients had significantly lower predicted mean pre-intervention SpO2 compared to trauma patients. Post-intervention and admission SpO2 for the two groups were comparable. However, 3% in both groups were still hypoxic at admission. For hypotension, the differences between the groups were less prominent. However, 9% of trauma and 10% of non-trauma patients were still hypotensive at admission. There was no difference in short-term survival between trauma (97%) and non-trauma patients (95%). Decreased level of consciousness was the most frequent indication for TI, and was associated with increased survival to hospital (cOR 2.8; 95% CI: 1.4-5.4). CONCLUSIONS: Our results showed that non-trauma patients had a higher incidence of hypoxia before TI than trauma patients, but few were hypoxic at admission. The difference for hypotension was less prominent, but one in ten patients were still hypotensive at admission. Further investigations are needed to identify reversible causes that may be corrected to improve haemodynamics in the pre-hospital setting. We found high survival rates to hospital in both groups, suggesting that physician-staffed HEMS provide high-quality emergency airway management in trauma and non-trauma patients. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT01502111 . Registered 22 Desember 2011.

The Impact of Helicopter Emergency Medical Service Night Operations in South East England.

OBJECTIVE: This study sought to assess the impact of a helicopter emergency medical service (HEMS) capable of night operations. METHODS: This is a retrospective case review of all night HEMS missions attended by a charity air ambulance service in South East England over a 2-year period (October 1, 2013, to October 1, 2015). RESULTS: During the 2-year trial period, the HEMS service undertook a total of 5,004 missions and attended to 3,728 patients. Of these, 1,373 missions, or 27.4% of the total HEMS activity, were night missions. Night missions increased from year 1 (n = 617) to year 2 (n = 756). A mean of 1.9 missions per night were conducted, resulting in the treatment of 1.3 patients per night. A higher proportion of patients were transported to a major trauma center at night (64% vs. 51%, χ2 = 41.8, P < .0001). Weather conditions prevented HEMS from responding at night via air for 15% of the night operational hours. CONCLUSION: A 2-year trial period of a night HEMS service in South East England showed the predicted activation rate, with a mean of 1.3 patients attended to per night. Patients transported to a major trauma center had a mean Injury Severity Score of 23. Further research is warranted to determine if the night HEMS service conveys a patient outcome benefit.

Todd's Paresis in Acute Mild Head Trauma.

We present the case of an adult male who sustained Todd's paresis after a traumatically induced seizure in a patient with an isolated facial injury. The precipitating event was head trauma from a golf club. The patient had no previous history of seizures and went on to make a complete neurologic recovery with no cerebral pathology noted. A literature review suggests that Todd's paresis after trauma is very rare as opposed to occurring in the medical or long-term brain injury settings. Although the authors acknowledge that it may occur in trauma, the awareness within the prehospital setting is sufficiently rare for this case report to be of interest to prehospital clinicians; it is important prehospital clinicians are aware of this condition.

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.

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.