Prehospital Tranexamic Acid for Severe Trauma.

BACKGROUND: Whether prehospital administration of tranexamic acid increases the likelihood of survival with a favorable functional outcome among patients with major trauma and suspected trauma-induced coagulopathy who are being treated in advanced trauma systems is uncertain. METHODS: We randomly assigned adults with major trauma who were at risk for trauma-induced coagulopathy to receive tranexamic acid (administered intravenously as a bolus dose of 1 g before hospital admission, followed by a 1-g infusion over a period of 8 hours after arrival at the hospital) or matched placebo. The primary outcome was survival with a favorable functional outcome at 6 months after injury, as assessed with the use of the Glasgow Outcome Scale-Extended (GOS-E). Levels on the GOS-E range from 1 (death) to 8 ("upper good recovery" [no injury-related problems]). We defined survival with a favorable functional outcome as a GOS-E level of 5 ("lower moderate disability") or higher. Secondary outcomes included death from any cause within 28 days and within 6 months after injury. RESULTS: A total of 1310 patients were recruited by 15 emergency medical services in Australia, New Zealand, and Germany. Of these patients, 661 were assigned to receive tranexamic acid, and 646 were assigned to receive placebo; the trial-group assignment was unknown for 3 patients. Survival with a favorable functional outcome at 6 months occurred in 307 of 572 patients (53.7%) in the tranexamic acid group and in 299 of 559 (53.5%) in the placebo group (risk ratio, 1.00; 95% confidence interval [CI], 0.90 to 1.12; P = 0.95). At 28 days after injury, 113 of 653 patients (17.3%) in the tranexamic acid group and 139 of 637 (21.8%) in the placebo group had died (risk ratio, 0.79; 95% CI, 0.63 to 0.99). By 6 months, 123 of 648 patients (19.0%) in the tranexamic acid group and 144 of 629 (22.9%) in the placebo group had died (risk ratio, 0.83; 95% CI, 0.67 to 1.03). The number of serious adverse events, including vascular occlusive events, did not differ meaningfully between the groups. CONCLUSIONS: Among adults with major trauma and suspected trauma-induced coagulopathy who were being treated in advanced trauma systems, prehospital administration of tranexamic acid followed by an infusion over 8 hours did not result in a greater number of patients surviving with a favorable functional outcome at 6 months than placebo. (Funded by the Australian National Health and Medical Research Council and others; PATCH-Trauma ClinicalTrials.gov number, NCT02187120.).

Mild Hypercapnia or Normocapnia after Out-of-Hospital Cardiac Arrest.

BACKGROUND: Guidelines recommend normocapnia for adults with coma who are resuscitated after out-of-hospital cardiac arrest. However, mild hypercapnia increases cerebral blood flow and may improve neurologic outcomes. METHODS: We randomly assigned adults with coma who had been resuscitated after out-of-hospital cardiac arrest of presumed cardiac or unknown cause and admitted to the intensive care unit (ICU) in a 1:1 ratio to either 24 hours of mild hypercapnia (target partial pressure of arterial carbon dioxide [Paco2], 50 to 55 mm Hg) or normocapnia (target Paco2, 35 to 45 mm Hg). The primary outcome was a favorable neurologic outcome, defined as a score of 5 (indicating lower moderate disability) or higher, as assessed with the use of the Glasgow Outcome Scale-Extended (range, 1 [death] to 8, with higher scores indicating better neurologic outcome) at 6 months. Secondary outcomes included death within 6 months. RESULTS: A total of 1700 patients from 63 ICUs in 17 countries were recruited, with 847 patients assigned to targeted mild hypercapnia and 853 to targeted normocapnia. A favorable neurologic outcome at 6 months occurred in 332 of 764 patients (43.5%) in the mild hypercapnia group and in 350 of 784 (44.6%) in the normocapnia group (relative risk, 0.98; 95% confidence interval [CI], 0.87 to 1.11; P = 0.76). Death within 6 months after randomization occurred in 393 of 816 patients (48.2%) in the mild hypercapnia group and in 382 of 832 (45.9%) in the normocapnia group (relative risk, 1.05; 95% CI, 0.94 to 1.16). The incidence of adverse events did not differ significantly between groups. CONCLUSIONS: In patients with coma who were resuscitated after out-of-hospital cardiac arrest, targeted mild hypercapnia did not lead to better neurologic outcomes at 6 months than targeted normocapnia. (Funded by the National Health and Medical Research Council of Australia and others; TAME ClinicalTrials.gov number, NCT03114033.).

Intubation Rates following Prehospital Administration of Ketamine for Acute Agitation: A Systematic Review and Meta-Analysis.

BACKGROUND: Ketamine is a fast-acting, dissociative anesthetic with a favorable adverse effect profile that is effective for managing acute agitation as a chemical restraint in the prehospital and emergency department (ED) settings. However, some previously published individual studies have reported high intubation rates when ketamine was administered prehospitally. OBJECTIVE: This systematic review aims to determine the rate and settings in which intubation following prehospital administration of ketamine for agitation is occurring, as well as associated indications and adverse events. METHODS: We searched PubMed, Scopus, Ovid MEDLINE, Embase, CINAHL Plus, PsycINFO, the Cochrane Library, ClinicalTrials.gov, OpenGrey, Open Access Theses and Dissertation, and Google Scholar from the earliest possible date until 13/February/2022. Inclusion criteria required studies to describe agitated patients who received ketamine in the prehospital setting as a first-line drug to control acute agitation. Reference lists of appraised studies were screened for additional relevant articles. Study quality was assessed using the Newcastle-Ottawa quality assessment scale. Synthesis of results was completed via meta-analysis, and the GRADE tool was used for certainty assessment. RESULTS: The search yielded 1466 unique records and abstracts, of which 50 full texts were reviewed, resulting in 18 being included in the analysis. All studies were observational in nature and 15 were from USA. There were 3476 patients in total, and the overall rate of intubation was 16% (95% confidence interval [CI] = 8%-26%). Most intubations occurred in the ED. Within the studies, the prehospital intubation rate ranged from 0% to 7.9% and the ED intubation rate ranged from 0 to 60%. The overall pooled prehospital intubation rate was 1% (95% CI = 0%-2%). The overall pooled ED intubation rate was 19% (95% CI = 11%-30%). The most common indications for intubation were for airway protection and respiratory depression/failure. CONCLUSIONS: There is wide variation in intubation rates between and within studies. The majority of intubations performed following prehospital administration of ketamine for agitation took place in the ED.

Impact of prehospital opioid dose on angiographic and clinical outcomes in acute coronary syndromes.

BACKGROUND: An adverse interaction whereby opioids impair and delay the gastrointestinal absorption of oral P2Y12 inhibitors has been established, however the clinical significance of this in acute coronary syndrome (ACS) is uncertain. We sought to characterise the relationship between prehospital opioid dose and clinical outcomes in patients with ACS. METHODS: Patients given opioid treatment by emergency medical services (EMS) with ACS who underwent percutaneous coronary intervention (PCI) between 1 January 2014 and 31 December 2018 were included in this retrospective cohort analysis using data linkage between the Ambulance Victoria, Victorian Cardiac Outcomes Registry and Melbourne Interventional Group databases. Patients with cardiogenic shock, out-of-hospital cardiac arrest and fibrinolysis were excluded. The primary end point was the risk-adjusted odds of 30-day major adverse cardiac events (MACE) between patients who received opioids and those that did not. RESULTS: 10 531 patients were included in the primary analysis. There was no significant difference in 30-day MACE between patients receiving opioids and those who did not after adjusting for key patient and clinical factors. Among patients with ST-elevation myocardial infarction (STEMI), there were significantly more patients with thrombolysis in myocardial infarction (TIMI) 0 or 1 flow pre-PCI in a subset of patients with high opioid dose versus no opioids (56% vs 25%, p<0.001). This remained significant after adjusting for known confounders with a higher predicted probability of TIMI 0/1 flow in the high versus no opioid groups (33% vs 11%, p<0.001). CONCLUSIONS: Opioid use was not associated with 30-day MACE. There were higher rates of TIMI 0/1 flow pre-PCI in patients with STEMI prescribed opioids. Future prospective research is required to verify these findings and investigate alternative analgesia for ischaemic chest pain.

Prehospital benzodiazepine use and need for respiratory support in paediatric seizures.

BACKGROUND: Paramedics are frequently called to attend seizures in children. High-quality evidence on second-line treatment of benzodiazepine (BZD)-refractory convulsions with parenteral long-acting antiepileptic drugs in children has become available from the ED. In order to address the potential need for an alternative agent, we set out to determine the association of BZD use prehospital and the need for respiratory support. METHODS: We conducted a retrospective observational study of state-wide ambulance service data (Ambulance Victoria in Victoria, Australia, population: 6.5 million). Children aged 0-17 years assessed for seizures by paramedics were analysed for demographics, process factors, treatment and airway management. We calculated adjusted ORs (AOR) of the requirement for respiratory support in relation to the number of BZD doses administered. RESULTS: Paramedics attended 5112 children with suspected seizures over 1 year (1 July 2018 to 30 June 2019). Overall, need for respiratory support was low (n=166; 3.2%). Before ambulance arrival, 509 (10.0%) had already received a BZD and 420 (8.2%) were treated with midazolam by paramedics. Of the 846 (16.5%) patients treated with BZD, 597 (70.6%) received 1 BZD dose, 156 (18.4%) 2 doses and 93 (11.0%) >2 doses of BZD. Patients who were administered 1, 2 and >2 doses of BZD received respiratory support in 8.9%, 32.1% (AOR 4.6 vs 1 dose, 95% CI 2.9 to 7.4) and 49.5% (AOR 10.3 vs 1 dose, 95% CI 6.0 to 17.9), respectively. CONCLUSIONS: Increasing administration of BZD doses was associated with higher use of respiratory support. Alternative prehospital antiepileptic drugs to minimise respiratory depression should be investigated in future research.

Predictors of hospital prenotification for STEMI and association of prenotification with outcomes.

BACKGROUND: Delay to reperfusion in ST-elevation myocardial infarction (STEMI) is detrimental, but can be minimised with prehospital notification by ambulance to the treating hospital. We aimed to assess whether prenotification was associated with improved first medical contact to balloon times (FMC-BT) and whether this resulted in better clinical outcomes. We also aimed to identify factors associated with use of prenotification. METHODS: This was a retrospective study of prospective Victorian Cardiac Outcomes Registry data for patients undergoing primary percutaneous coronary intervention for STEMI from 2013-2018. Postcardiac arrest were excluded. Patients were grouped by whether they arrived by ambulance with prenotification (group 1), arrived by ambulance without prenotification (group 2) or self-presented (group 3). We compared groups by FMC-BT, incidence of major adverse cardiac and cerebrovascular events (MACCE), mortality and factors associated with the use of prenotification. RESULTS: 2891 patients were in group 1 (79.3% male), 1620 in group 2 (75.7% male) and 1220 in group 3 (82.9% male). Patients who had prenotification were more likely to present in-hours (p=0.004) and self-presenters had lowest rates of cardiogenic shock (p<0.001). Prenotification had shorter FMC-BT than without prenotification (104 min vs 132 min, p<0.001) Self-presenters had superior clinical outcomes, with no difference between ambulance groups. Groups 1 and 2 had similar 30-day MACCE outcomes (7.4% group 1 vs 9.1% group 2, p=0.05) and similar mortality (4.6% group 1 vs 5.9% group 2, p=0.07). In multivariable analysis, male gender, right coronary artery culprit and in-hours presentation independently predicted use of prenotification (all p<0.05). CONCLUSION: Differences in clinical characteristics, particularly gender, time of presentation and culprit vessel may influence ambulance prenotification. Ambulance cohorts have high-risk features and worse outcomes compared with self-presenters. Improving system inequality in prehospital STEMI diagnosis is recommended for fastest STEMI treatment.

Temporal changes in blood pressure following prehospital rapid sequence intubation.

BACKGROUND: Rapid Sequence intubation (RSI) is an airway procedure that uses sedative and paralytic drugs to facilitate endotracheal intubation. It is known that RSI could impact blood pressure in the peri-intubation period. However, little is known about blood pressure changes in longer time frames. Therefore, this analysis aims to describe the changes in systolic blood pressure in a large cohort of paramedic-led RSI cases over the whole prehospital timespan. METHODS: Intensive Care Paramedics in Victoria, Australia, are authorised to use RSI in medical or trauma patients with a Glasgow Coma Scale <10. This retrospective cohort study analysed data from patientcare records for patients aged 12 years and above that had received RSI, from 1 January 2008 to 31 December 2019. This study quantifies the systolic blood pressure changes using regression with fractional polynomial terms. The analysis is further stratified by high versus Low Shock Index (LSI). The shock index is calculated by dividing pulse rate by systolic blood pressure. RESULTS: During the study period RSI was used in 8613 patients. The median number of blood pressure measurements was 5 (IQR 3-8). Systolic blood pressure rose significantly by 3.4 mm Hg (p<0.001) and then returned to baseline in the first 5 min after intubation for LSI cases. No initial rise in blood pressure is apparent in High Shock Index (HSI) cases. Across the whole cohort, systolic blood pressure decreased by 7.1 mm Hg (95% CI 7.9 to 6.3 mm Hg; p<0.001) from the first to the last blood pressure measured. CONCLUSIONS: Our study shows that in RSI patients a small transient elevation in systolic blood pressure in the immediate postintubation period is found in LSI, but this elevation is not apparent in HSI. Blood pressure decreased over the prehospital phase in RSI patients with LSI, but increased for HSI cases.

Effect of Lower vs Higher Oxygen Saturation Targets on Survival to Hospital Discharge Among Patients Resuscitated After Out-of-Hospital Cardiac Arrest: The EXACT Randomized Clinical Trial.

Importance: The administration of a high fraction of oxygen following return of spontaneous circulation in out-of-hospital cardiac arrest may increase reperfusion brain injury. Objective: To determine whether targeting a lower oxygen saturation in the early phase of postresuscitation care for out-of-hospital cardiac arrest improves survival at hospital discharge. Design, Setting, and Participants: This multicenter, parallel-group, randomized clinical trial included unconscious adults with return of spontaneous circulation and a peripheral oxygen saturation (Spo2) of at least 95% while receiving 100% oxygen. The trial was conducted in 2 emergency medical services and 15 hospitals in Victoria and South Australia, Australia, between December 11, 2017, and August 11, 2020, with data collection from ambulance and hospital medical records (final follow-up date, August 25, 2021). The trial enrolled 428 of a planned 1416 patients. Interventions: Patients were randomized by paramedics to receive oxygen titration to achieve an oxygen saturation of either 90% to 94% (intervention; n = 216) or 98% to 100% (standard care; n = 212) until arrival in the intensive care unit. Main Outcomes and Measures: The primary outcome was survival to hospital discharge. There were 9 secondary outcomes collected, including hypoxic episodes (Spo2 <90%) and prespecified serious adverse events, which included hypoxia with rearrest. Results: The trial was stopped early due to the COVID-19 pandemic. Of the 428 patients who were randomized, 425 were included in the primary analysis (median age, 65.5 years; 100 [23.5%] women) and all completed the trial. Overall, 82 of 214 patients (38.3%) in the intervention group survived to hospital discharge compared with 101 of 211 (47.9%) in the standard care group (difference, -9.6% [95% CI, -18.9% to -0.2%]; unadjusted odds ratio, 0.68 [95% CI, 0.46-1.00]; P = .05). Of the 9 prespecified secondary outcomes collected during hospital stay, 8 showed no significant difference. A hypoxic episode prior to intensive care was observed in 31.3% (n = 67) of participants in the intervention group and 16.1% (n = 34) in the standard care group (difference, 15.2% [95% CI, 7.2%-23.1%]; OR, 2.37 [95% CI, 1.49-3.79]; P < .001). Conclusions and Relevance: Among patients achieving return of spontaneous circulation after out-of-hospital cardiac arrest, targeting an oxygen saturation of 90% to 94%, compared with 98% to 100%, until admission to the intensive care unit did not significantly improve survival to hospital discharge. Although the trial is limited by early termination due to the COVID-19 pandemic, the findings do not support use of an oxygen saturation target of 90% to 94% in the out-of-hospital setting after resuscitation from cardiac arrest. Trial Registration: ClinicalTrials.gov Identifier: NCT03138005.

Utility of Severity-Based Prehospital Triage for Endovascular Thrombectomy: ACT-FAST Validation Study.

BACKGROUND AND PURPOSE: Severity-based assessment tools may assist in prehospital triage of patients to comprehensive stroke centers (CSCs) for endovascular thrombectomy (EVT), but criticisms regarding diagnostic inaccuracy have not been adequately addressed. This study aimed to quantify the benefits and disadvantages of severity-based triage in a large real-world paramedic validation of the Ambulance Clinical Triage for Acute Stroke Treatment (ACT-FAST) algorithm. METHODS: Ambulance Victoria paramedics assessed the prehospital ACT-FAST algorithm in patients with suspected stroke from November 2017 to July 2019 following an 8-minute training video. All patients were transported to the nearest stroke center as per current guidelines. ACT-FAST diagnostic accuracy was compared with hospital imaging for the presence of large vessel occlusion (LVO) and need for CSC-level care (LVO, intracranial hemorrhage, and tumor). Patient-level time saving to EVT was modeled using a validated Google Maps algorithm. Disadvantages of CSC bypass examined potential thrombolysis delays in non-LVO infarcts, proportion of patients with false-negative EVT, and CSC overburdening. RESULTS: Of 517 prehospital assessments, 168/517 (32.5%) were ACT-FAST positive and 132/517 (25.5%) had LVO. ACT-FAST sensitivity and specificity for LVO was 75.8% and 81.8%, respectively. Positive predictive value was 58.8% for LVO and 80.0% when intracranial hemorrhage and tumor (CSC-level care) were included. Within the metropolitan region, 29/55 (52.7%) of ACT-FAST-positive patients requiring EVT underwent a secondary interhospital transfer. Prehospital bypass with avoidance of secondary transfers was modeled to save 52 minutes (95% CI, 40.0-61.5) to EVT commencement. ACT-FAST was false-positive in 8 patients receiving thrombolysis (8.1% of 99 non-LVO infarcts) and false-negative in 4 patients with EVT requiring secondary transfer (5.4% of 74 EVT cases). CSC bypass was estimated to over-triage 1.1 patients-per-CSC-per-week in our region. CONCLUSIONS: The overall benefits of an ACT-FAST algorithm bypass strategy in expediting EVT and avoiding secondary transfers are estimated to substantially outweigh the disadvantages of potentially delayed thrombolysis and over-triage, with only a small proportion of EVT patients missed.

Endotracheal Tube Intracuff Pressure Changes in Patients Transported by a Helicopter Emergency Medical Service: A Prospective Observational Study.

OBJECTIVE: The pressure within an endotracheal tube cuff is of particular importance in helicopter emergency medical services (HEMS) transport because the unpressurized cabin is subjected to decreases in atmospheric pressure. This can cause the cuff to overinflate and may be associated with clinical complications. We sought to evaluate endotracheal tube cuff pressure changes among intubated patients during HEMS transport. METHODS: A prospective observational study was performed including adult patients who were intubated and transported by helicopter between April 2017 and October 2018. Cuff pressures were measured before, during, and after HEMS transport with a commercial manometer. RESULTS: A total of 208 patients were included. The median maximum flight altitude was 3,000 (interquartile range [IQR], 2,000-5,000) ft. The median initial cuff pressure before takeoff was 35 (IQR, 24-50) cm H2O, which increased to 50 (IQR, 35-70) cm H2O at maximum altitude. A total of 169 (81.3%) patients had a cuff pressure > 30 cm H2O at maximum altitude. There was a moderate correlation between altitude and cuff pressure (r = 0.532, P < .001). CONCLUSIONS: Cuff pressure increased during HEMS transport, demonstrating the need for routine cuff pressure monitoring during flight. Further research is required to determine if exposure to transient increases in cuff pressure for short durations is clinically significant.

Melbourne Mobile Stroke Unit and Reperfusion Therapy: Greater Clinical Impact of Thrombectomy Than Thrombolysis.

Background and Purpose- Mobile stroke units (MSUs) are increasingly used worldwide to provide prehospital triage and treatment. The benefits of MSUs in giving earlier thrombolysis have been well established, but the impacts of MSUs on endovascular thrombectomy (EVT) and effect on disability avoidance are largely unknown. We aimed to determine the clinical impact and disability reduction for reperfusion therapies in the first operational year of the Melbourne MSU. Methods- Treatment time metrics for MSU patients receiving reperfusion therapy were compared with control patients presenting to metropolitan Melbourne stroke units via standard ambulance within MSU operating hours. The primary outcome was median time difference in first ambulance dispatch to treatment modeled using quantile regression analysis. Time savings were subsequently converted to disability-adjusted life years avoided using published estimates. Results- In the first 365-day operation of the Melbourne MSU, prehospital thrombolysis was administered to 100 patients (mean age, 73.8 years; 62% men). The median time savings per MSU patient, compared with the control cohort, was 26 minutes (P<0.001) for dispatch to hospital arrival and 15 minutes (P<0.001) for hospital arrival to thrombolysis. The calculated overall time saving from dispatch to thrombolysis was 42.5 minutes (95% CI, 36.0-49.0). In the same period, 41 MSU patients received EVT (mean age, 76 years; 61% men) with median dispatch-to-treatment time saving of 51 minutes ([95% CI, 30.1-71.9], P<0.001). This included a median time saving of 17 minutes ([95% CI, 7.6-26.4], P=0.001) for EVT hospital arrival to arterial puncture for MSU patients. Estimated median disability-adjusted life years saved through earlier provision of reperfusion therapies were 20.9 for thrombolysis and 24.6 for EVT. Conclusions- The Melbourne MSU substantially reduced time to reperfusion therapies, with the greatest estimated disability avoidance driven by the more powerful impact of earlier EVT. These findings highlight the benefits of prehospital notification and direct triage to EVT centers with facilitated workflow on arrival by the MSU.

Management of adult cardiac arrest in the COVID-19 era: consensus statement from the Australasian College for Emergency Medicine.

INTRODUCTION: The global pandemic of coronavirus disease 2019 (COVID-19) has caused significant worldwide disruption. Although Australia and New Zealand have not been affected as much as some other countries, resuscitation may still pose a risk to health care workers and necessitates a change to our traditional approach. This consensus statement for adult cardiac arrest in the setting of COVID-19 has been produced by the Australasian College for Emergency Medicine (ACEM) and aligns with national and international recommendations. MAIN RECOMMENDATIONS: In a setting of low community transmission, most cardiac arrests are not due to COVID-19. Early defibrillation saves lives and is not considered an aerosol generating procedure. Compression-only cardiopulmonary resuscitation is thought to be a low risk procedure and can be safely initiated with the patient's mouth and nose covered. All other resuscitative procedures are considered aerosol generating and require the use of airborne personal protective equipment (PPE). It is important to balance the appropriateness of resuscitation against the risk of infection. Methods to reduce nosocomial transmission of COVID-19 include a physical barrier such as a towel or mask over the patient's mouth and nose, appropriate use of PPE, minimising the staff involved in resuscitation, and use of mechanical chest compression devices when available. If COVID-19 significantly affects hospital resource availability, the ethics of resource allocation must be considered. CHANGES IN MANAGEMENT: The changes outlined in this document require a significant adaptation for many doctors, nurses and paramedics. It is critically important that all health care workers have regular PPE and advanced life support training, are able to access in situ simulation sessions, and receive extensive debriefing after actual resuscitations. This will ensure safe, timely and effective management of the patients with cardiac arrest in the COVID-19 era.

Temporal Trends in the Incidence, Characteristics, and Outcomes of Hanging-Related Out-of-Hospital Cardiac Arrest.

Aim: The aim of this study was to describe temporal trends in the incidence, characteristics, and outcomes of hanging-related out-of-hospital cardiac arrest (OHCA). Method: A retrospective study of all hanging-related OHCA in Victoria, Australia, between 2000 and 2017 was conducted. Trends in incidence, characteristics, and outcomes were assessed using linear regression and a non-parametric test for trend, as appropriate. Predictors of survival to hospital discharge were identified using multivariable logistic regression. Results: Between 2000 and 2017, emergency medical services (EMS)-attended 3,891 cases of hanging-related OHCA, of which 876 cases (23%) received an attempted resuscitation. The overall incidence rate of EMS-attended cases was 3.8 cases per 100,000 person-years increasing from 2.3 cases per 100,000 person-years in 2000 to 4.7 cases in 2017 (p for trend <0.001). Incidence rates increased approximately two-fold in young adults (18-44 years) and three-fold in middle aged adults (45-64 years). Despite improvement in the rate of bystander cardiopulmonary resuscitation (from 49% in 2000-2005 to 75% in 2012-2017), the survival to hospital discharge rate remained unchanged (3% overall). Among adult survivors with 12-month follow-up (n = 10), five patients responded to telephone interviews. Of those, three (60%) reported severe functional disability. Five patients responded to telephone interviews, of which 3 patients reported severe functional disability. An initial shockable rhythm (OR 23.17, 95% CI: 5.75, 93.36) or pulseless electrical activity (OR 13.14, 95% CI: 4.79, 36.03) were associated with survival. Conclusion: The incidence of hanging-related OHCA doubled over the 18 year period with no change to survival rates. New preventative strategies are needed to reduce the community burden of these events.

Seasonal Variation in Out-of-Hospital Cardiac Arrest in Victoria 2008-2017: Winter Peak.

Background: Out-of-Hospital Cardiac Arrest (OHCA) incidence and survival rates are known to vary between seasons in some locations. The winter of 2017 saw the highest ever incidence and lowest survival rate of OHCA recorded in Victoria at the time. Seasonal variation of OHCA has not previously been examined in Australia and there may be a significant effect. We aimed to describe the seasonal incidence of OHCA and examine seasonal differences in survival to discharge and 12-month quality of life outcomes. In addition, we investigated whether recent respiratory infection or pre existing respiratory disease influenced OHCA outcomes. Methods: The Victorian Ambulance Cardiac Arrest Registry (VACAR) was used to identify OHCA occurring in Victoria between 2008 and 2017. We examined OHCA characteristics and outcomes between seasons. We then used multivariate logistic regression, adjusting for the Utstein factors, to examine if season, recent respiratory infection or preexisting respiratory disease is associated with survival to discharge and 12-month quality of life. Results: There were 44 973 OHCA cases of which 22 209 received an attempted resuscitation (49.4%). The incidence of OHCA was highest during winter (22 per 100 000 vs. 18 per 100 000 in summer). In winter, survival to discharge was lower for OHCA patients (12.2% vs. 15.9% in summer). Both recent respiratory infection (AOR: 0.67, 95% CI: 0.52 - 0.87) and OHCA occurring during winter (AOR: 0.79 95% CI: 0.70 - 0.91) were associated with lower odds of survival to discharge. Preexisting respiratory disease was associated with lower odds of moderate to good recovery at 12 months (AOR:0.60 95% CI: 0.41 - 0.89). Conclusion: In winter the incidence of OHCA was at its highest and survival to discharge was at its lowest compared to other seasons. Recent respiratory infection was associated with lower odds of survival to discharge. Measures targeted to vulnerable groups, such as preventative public health measures for respiratory infections and the influenza vaccine may reduce the incidence of OHCA and improve survival rates.

The utility of the brain trauma evidence to inform paramedic rapid sequence intubation in out-of-hospital stroke.

BACKGROUND: Rapid sequence intubation (RSI) is used to secure the airway of stroke patients. Randomized controlled trial evidence exists to support the use of paramedic RSI for traumatic brain injury (TBI), but cannot necessarily be applied to stroke RSI because of differences between the stroke and TBI patient. To understand if the TBI evidence can be used for stroke RSI, we analysed a retrospective cohort of TBI and strokes to compare how survival is impacted differently by RSI when comparing strokes and TBI. METHODS: This study was a retrospective analysis of 10 years of in-hospital and out-of-hospital data for all stroke and TBI patients attended by Ambulance Victoria, Australia. Logistic regression predicted the survival for ischemic and haemorrhagic strokes as well as TBI. The constituents of RSI, such a medications, intubation success and time intervals were analysed against survival using interactions to asses if RSI impacts survival differently for strokes compared to TBI. RESULTS: This analysis found significant interactions in the RSI-only group for age, number of intubation attempts, atropine, fentanyl, pulse rate and perhaps scene time and time- to-RSI. Such interactions imply that RSI impact survival differently for TBI versus strokes. Additionally, no significant difference in survival for TBI was found, with a - 0.7% lesser survival for RSI compared to no-RSI; OR 0.86 (95% CI 0.67 to 1.11; p = 0.25). Survival for haemorrhagic stroke was - 14.1% less for RSI versus no-RSI; OR 0.44 (95% CI 0.33 to 0.58; p = 0.01) and was - 4.3%; OR 0.67 (95% CI 0.49 to 0.91; p = 0.01) lesser for ischemic strokes. CONCLUSIONS: Rapid sequence intubation and related factors interact with stroke and TBI, which suggests that RSI effects stroke survival in a different way from TBI. If RSI impact survival differently for strokes compared to TBI, then perhaps the TBI evidence cannot be used for stroke RSI.

Palliative care in paramedic practice: A retrospective cohort study.

BACKGROUND: Paramedics may be involved in the care of patients experiencing a health crisis associated with palliative care. However, little is known about the paramedic's role in the care of these patients. AIM: To describe the incidence and nature of cases attended by paramedics and the care provided where the reason for attendance was associated with a history of palliative care. DESIGN: This is a retrospective cohort study. SETTING/PARTICIPANTS: Adult patients (aged >17 years) attended by paramedics in the Australian state of Victoria between 1 July 2015 and 30 June 2016 where terms associated with palliative care or end of life were recorded in the patient care record. Secondary transfers including inter-hospital transport cases were excluded. RESULTS: A total of 4348 cases met inclusion criteria. Median age was 74 years (interquartile range 64-83). The most common paramedic assessments were 'respiratory' (20.1%), 'pain' (15.8%) and 'deceased' (7.9%); 74.4% ( n = 3237) were transported, with the most common destination being a hospital (99.5%, n = 3221). Of those with pain as the primary impression, 359 (53.9%) received an analgesic, morphine, fentanyl or methoxyflurane, and 356 (99.2%) were transported following analgesic administration. Resuscitation was attempted in 98 (29.1%) of the 337 cases coded as cardiac arrest. Among non-transported cases, there were 105 (9.6%) cases where paramedics re-attended the patient within 24 h of the previous attendance. CONCLUSION: Paramedics have a significant role in caring for patients receiving palliative care. These results should inform the design of integrated systems of care that involve ambulance services in the planning and delivery of community-based palliative care.

The association of paramedic rapid sequence intubation and survival in out-of-hospital stroke.

INTRODUCTION: Ambulance transport of patients with stroke is common, with rapid sequence intubation (RSI) to secure the airway used regularly. Randomised controlled trial evidence exists to support the use of RSI in traumatic brain injuries (TBIs), but it is not clear whether the RSI evidence from TBI can be applied to the patient with stroke. To this end, we analysed a retrospective stroke dataset to compare survival of patients with RSI compared with patients that did not receive RSI. METHODS: This study was a retrospective analysis of 10 years of in-hospital and out-of-hospital data for all patients with stroke attended by Ambulance Victoria, in Victoria Australia. Generalised boosted logistic regression was used to predict propensity scores, with initial vital signs, age and demographic variables as well as measures of illness severity and comorbidity included in the prediction model. This analysis employed a 1:1 nearest-neighbour matching which was applied to generate a dataset from which we calculated the OR of survival to hospital discharge of patients receiving RSI versus no-RSI. The sensitivity of these results to unmeasured confounding was assessed with deterministic sensitivity analysis. RESULTS: The propensity score-matched cohort showed a decreased survival for RSI in strokes with an OR 0.61 (95% CI 0.45 to 0.82; p=0.001) when compared with no-RSI. A subgroup analysis showed no significant survival difference for ischaemic strokes: OR 0.66 (95% CI 40 to 1.07; p=0.09). The survival for haemorrhagic stroke was OR 0.60 (95% CI 0.41 to 0.90; p=0.01) lesser for RSI. Results were likely robust to unmeasured confounding and missing data. CONCLUSIONS: Our retrospective analysis shows a decrease in survival when RSI is utilised by paramedics for stroke. Since RSI is commonly used for strokes, controlled trial evidence to support this practice is urgently needed.

Comparison of Magnetic Resonance Analysis of Myocardial Scarring With Biomarker Release Following S-T Elevation Myocardial Infarction.

BACKGROUND: Late gadolinium enhancement (LGE) with cardiac magnetic resonance (CMR) is commonly assumed to represent myocardial fibrosis; however, comparative human histological data are limited, and there is no consensus on the most accurate method for LGE quantitation. We evaluated the relationship between CMR assessment of regional fibrosis and infarct size assessment using serial biomarkers after ST elevation acute myocardial infarction (STEMI). METHODS: Ninety-three patients treated for STEMI (59±10 years, 86% male) underwent CMR 6 months after infarction. Infarct size was quantified by CMR-LGE using manual and range of semi-automated thresholds (range: 2-10 standard deviations [SD]) above reference myocardium and the full width-half maximum (FWHM) technique, and compared with the rise in serum biomarkers. The agreement between CMR and biomarker in the identification of large infarcts based on peak troponin (TnI) levels was also analysed. RESULTS: Quantification methods had a strong influence on the infarct size assessment with CMR-LGE. Significant correlations were observed between LGE and biomarkers across all of the signal intensity thresholds. Whilst there was a wide variation with respect to the estimation of total LGE size (from 6.8±7.7 to 32.1±11.3 grams), the variation in the correlation with peak troponin level was much smaller (r-values ranging from 0.670 to 0.876). There was good agreement between CMR-LGE and biomarker assessment of infarct size; the best agreement between CMR-LGE and large infarction using a threshold of 8SD for peak TnI>50ng/mL (Cohen's kappa (κ)=0.722), and a threshold of 4SD for peak TnI >95ng/mL (κ=0.761). CONCLUSIONS: The correlation between CMR-LGE quantification of infarct size and biomarker release following STEMI at a range of semi-automated thresholds was consistently strong, with good agreement between measures across a range of thresholds.

Ambulance Clinical Triage for Acute Stroke Treatment: Paramedic Triage Algorithm for Large Vessel Occlusion.

BACKGROUND AND PURPOSE: Clinical triage scales for prehospital recognition of large vessel occlusion (LVO) are limited by low specificity when applied by paramedics. We created the 3-step ambulance clinical triage for acute stroke treatment (ACT-FAST) as the first algorithmic LVO identification tool, designed to improve specificity by recognizing only severe clinical syndromes and optimizing paramedic usability and reliability. METHODS: The ACT-FAST algorithm consists of (1) unilateral arm drift to stretcher <10 seconds, (2) severe language deficit (if right arm is weak) or gaze deviation/hemineglect assessed by simple shoulder tap test (if left arm is weak), and (3) eligibility and stroke mimic screen. ACT-FAST examination steps were retrospectively validated, and then prospectively validated by paramedics transporting culturally and linguistically diverse patients with suspected stroke in the emergency department, for the identification of internal carotid or proximal middle cerebral artery occlusion. The diagnostic performance of the full ACT-FAST algorithm was then validated for patients accepted for thrombectomy. RESULTS: In retrospective (n=565) and prospective paramedic (n=104) validation, ACT-FAST displayed higher overall accuracy and specificity, when compared with existing LVO triage scales. Agreement of ACT-FAST between paramedics and doctors was excellent (κ=0.91; 95% confidence interval, 0.79-1.0). The full ACT-FAST algorithm (n=60) assessed by paramedics showed high overall accuracy (91.7%), sensitivity (85.7%), specificity (93.5%), and positive predictive value (80%) for recognition of endovascular-eligible LVO. CONCLUSIONS: The 3-step ACT-FAST algorithm shows higher specificity and reliability than existing scales for clinical LVO recognition, despite requiring just 2 examination steps. The inclusion of an eligibility step allowed recognition of endovascular-eligible patients with high accuracy. Using a sequential algorithmic approach eliminates scoring confusion and reduces assessment time. Future studies will test whether field application of ACT-FAST by paramedics to bypass suspected patients with LVO directly to endovascular-capable centers can reduce delays to endovascular thrombectomy.