Ambulance Victoria

BACKGROUND: Cardiac arrest outside the hospital is common and has a poor outcome. Studies in laboratory animals suggest that hypothermia induced shortly after the restoration of spontaneous circulation may improve neurologic outcome, but there have been no conclusive studies in humans. In a randomized, controlled trial, we compared the effects of moderate hypothermia and normothermia in patients who remained unconscious after resuscitation from out-of-hospital cardiac arrest. METHODS: The study subjects were 77 patients who were randomly assigned to treatment with hypothermia (with the core body temperature reduced to 33 degrees C within 2 hours after the return of spontaneous circulation and maintained at that temperature for 12 hours) or normothermia. The primary outcome measure was survival to hospital discharge with sufficiently good neurologic function to be discharged to home or to a rehabilitation facility. RESULTS: The demographic characteristics of the patients were similar in the hypothermia and normothermia groups. Twenty-one of the 43 patients treated with hypothermia (49 percent) survived and had a good outcome--that is, they were discharged home or to a rehabilitation facility--as compared with 9 of the 34 treated with normothermia (26 percent, P=0.046). After adjustment for base-line differences in age and time from collapse to the return of spontaneous circulation, the odds ratio for a good outcome with hypothermia as compared with normothermia was 5.25 (95 percent confidence interval, 1.47 to 18.76; P=0.011). Hypothermia was associated with a lower cardiac index, higher systemic vascular resistance, and hyperglycemia. There was no difference in the frequency of adverse events. CONCLUSIONS: Our preliminary observations suggest that treatment with moderate hypothermia appears to improve outcomes in patients with coma after resuscitation from out-of-hospital cardiac arrest.

BACKGROUND: Oxygen is commonly administered to patients with ST-elevation-myocardial infarction despite previous studies suggesting a possible increase in myocardial injury as a result of coronary vasoconstriction and heightened oxidative stress. METHODS AND RESULTS: We conducted a multicenter, prospective, randomized, controlled trial comparing oxygen (8 L/min) with no supplemental oxygen in patients with ST-elevation-myocardial infarction diagnosed on paramedic 12-lead ECG. Of 638 patients randomized, 441 patients had confirmed ST-elevation-myocardial infarction and underwent primary end-point analysis. The primary end point was myocardial infarct size as assessed by cardiac enzymes, troponin I, and creatine kinase. Secondary end points included recurrent myocardial infarction, cardiac arrhythmia, and myocardial infarct size assessed by cardiac magnetic resonance imaging at 6 months. Mean peak troponin was similar in the oxygen and no oxygen groups (57.4 versus 48.0 μg/L; ratio, 1.20; 95% confidence interval, 0.92-1.56; P=0.18). There was a significant increase in mean peak creatine kinase in the oxygen group compared with the no oxygen group (1948 versus 1543 U/L; means ratio, 1.27; 95% confidence interval, 1.04-1.52; P=0.01). There was an increase in the rate of recurrent myocardial infarction in the oxygen group compared with the no oxygen group (5.5% versus 0.9%; P=0.006) and an increase in frequency of cardiac arrhythmia (40.4% versus 31.4%; P=0.05). At 6 months, the oxygen group had an increase in myocardial infarct size on cardiac magnetic resonance (n=139; 20.3 versus 13.1 g; P=0.04). CONCLUSION: Supplemental oxygen therapy in patients with ST-elevation-myocardial infarction but without hypoxia may increase early myocardial injury and was associated with larger myocardial infarct size assessed at 6 months. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01272713.

DISCLAIMER: Veno-arterial extracorporeal membrane oxygenation (ECMO) is increasingly being deployed for selected patients in cardiac arrest who do not attain a native circulation with conventional CPR (ECPR). This ELSO guideline is intended to be a practical guide to implementing ECPR and the early management following establishment of ECMO support. Where a paucity of high-quality evidence exists, a consensus has been reached amongst the authors to provide guidance to the clinician. This guideline will be updated as further evidence in this field becomes available.

CONTEXT: Prehospital hypertonic saline (HTS) resuscitation of patients with traumatic brain injury (TBI) may increase survival but whether HTS improves neurological outcomes is unknown. OBJECTIVE: To determine whether prehospital resuscitation with intravenous HTS improves long-term neurological outcome in patients with severe TBI compared with resuscitation with conventional fluids. DESIGN, SETTING, AND PATIENTS: Double-blind, randomized controlled trial of 229 patients with TBI who were comatose (Glasgow Coma Scale score, <9) and hypotensive (systolic blood pressure, <100 mm Hg). The patients were enrolled between December 14, 1998, and April 9, 2002, in Melbourne, Australia. INTERVENTIONS: Patients were randomly assigned to receive a rapid intravenous infusion of either 250 mL of 7.5% saline (n = 114) or 250 mL of Ringer's lactate solution (n = 115; controls) in addition to conventional intravenous fluid and resuscitation protocols administered by paramedics. Treatment allocation was concealed. MAIN OUTCOME MEASURE: Neurological function at 6 months, measured by the extended Glasgow Outcome Score (GOSE). RESULTS: Primary outcomes were obtained in 226 (99%) of 229 patients enrolled. Baseline characteristics of the groups were equivalent. At hospital admission, the mean serum sodium level was 149 mEq/L for HTS patients vs 141 mEq/L for controls (P<.001). The proportion of patients surviving to hospital discharge was similar in both groups (n = 63 [55%] for HTS group and n = 57 [50%] for controls; P =.32); at 6 months, survival rates were n = 62 (55%) in the HTS group and n = 53 (47%) in the control group (P =.23). At 6 months, the median (interquartile range) GOSE was 5 (3-6) in the HTS group vs 5 (5-6) in the control group (P =.45). There was no significant difference between the groups in favorable outcomes (moderate disability and good outcome survivors [GOSE of 5-8]) (risk ratio, 0.99; 95% confidence interval, 0.76-1.30; P =.96) or in any other measure of postinjury neurological function. CONCLUSION: In this study, patients with hypotension and severe TBI who received prehospital resuscitation with HTS had almost identical neurological function 6 months after injury as patients who received conventional fluid.

OBJECTIVE: To determine whether paramedic rapid sequence intubation in patients with severe traumatic brain injury (TBI) improves neurologic outcomes at 6 months compared with intubation in the hospital. BACKGROUND: Severe TBI is associated with a high rate of mortality and long-term morbidity. Comatose patients with TBI routinely undergo endo-tracheal intubation to protect the airway, prevent hypoxia, and control ventilation. In many places, paramedics perform intubation prior to hospital arrival. However, it is unknown whether this approach improves outcomes. METHODS: In a prospective, randomized, controlled trial, we assigned adults with severe TBI in an urban setting to either prehospital rapid sequence intubation by paramedics or transport to a hospital emergency department for intubation by physicians. The primary outcome measure was the median extended Glasgow Outcome Scale (GOSe) score at 6 months. Secondary end-points were favorable versus unfavorable outcome at 6 months, length of intensive care and hospital stay, and survival to hospital discharge. RESULTS: A total of 312 patients with severe TBI were randomly assigned to paramedic rapid sequence intubation or hospital intubation. The success rate for paramedic intubation was 97%. At 6 months, the median GOSe score was 5 (interquartile range, 1-6) in patients intubated by paramedics compared with 3 (interquartile range, 1-6) in the patients intubated at hospital (P = 0.28).The proportion of patients with favorable outcome (GOSe, 5-8) was 80 of 157 patients (51%) in the paramedic intubation group compared with 56 of 142 patients (39%) in the hospital intubation group (risk ratio, 1.28; 95% confidence interval, 1.00-1.64; P = 0.046). There were no differences in intensive care or hospital length of stay, or in survival to hospital discharge. CONCLUSIONS: In adults with severe TBI, prehospital rapid sequence intubation by paramedics increases the rate of favorable neurologic outcome at 6 months compared with intubation in the hospital.

Importance: After severe traumatic brain injury, induction of prophylactic hypothermia has been suggested to be neuroprotective and improve long-term neurologic outcomes. Objective: To determine the effectiveness of early prophylactic hypothermia compared with normothermic management of patients after severe traumatic brain injury. Design, Setting, and Participants: The Prophylactic Hypothermia Trial to Lessen Traumatic Brain Injury-Randomized Clinical Trial (POLAR-RCT) was a multicenter randomized trial in 6 countries that recruited 511 patients both out-of-hospital and in emergency departments after severe traumatic brain injury. The first patient was enrolled on December 5, 2010, and the last on November 10, 2017. The final date of follow-up was May 15, 2018. Interventions: There were 266 patients randomized to the prophylactic hypothermia group and 245 to normothermic management. Prophylactic hypothermia targeted the early induction of hypothermia (33°C-35°C) for at least 72 hours and up to 7 days if intracranial pressures were elevated, followed by gradual rewarming. Normothermia targeted 37°C, using surface-cooling wraps when required. Temperature was managed in both groups for 7 days. All other care was at the discretion of the treating physician. Main Outcomes and Measures: The primary outcome was favorable neurologic outcomes or independent living (Glasgow Outcome Scale-Extended score, 5-8 [scale range, 1-8]) obtained by blinded assessors 6 months after injury. Results: Among 511 patients who were randomized, 500 provided ongoing consent (mean age, 34.5 years [SD, 13.4]; 402 men [80.2%]) and 466 completed the primary outcome evaluation. Hypothermia was initiated rapidly after injury (median, 1.8 hours [IQR, 1.0-2.7 hours]) and rewarming occurred slowly (median, 22.5 hours [IQR, 16-27 hours]). Favorable outcomes (Glasgow Outcome Scale-Extended score, 5-8) at 6 months occurred in 117 patients (48.8%) in the hypothermia group and 111 (49.1%) in the normothermia group (risk difference, 0.4% [95% CI, -9.4% to 8.7%]; relative risk with hypothermia, 0.99 [95% CI, 0.82-1.19]; P = .94). In the hypothermia and normothermia groups, the rates of pneumonia were 55.0% vs 51.3%, respectively, and rates of increased intracranial bleeding were 18.1% vs 15.4%, respectively. Conclusions and Relevance: Among patients with severe traumatic brain injury, early prophylactic hypothermia compared with normothermia did not improve neurologic outcomes at 6 months. These findings do not support the use of early prophylactic hypothermia for patients with severe traumatic brain injury. Trial Registration: clinicaltrials.gov Identifier: NCT00987688; Anzctr.org.au Identifier: ACTRN12609000764235.

OBJECTIVE: To describe outcomes of major trauma survivors managed in an organized trauma system, including the association between levels of care and outcomes over time. BACKGROUND: Trauma care systems aim to reduce deaths and disability. Studies have found that regionalization of trauma care reduces mortality but the impact on quality of survival is unknown. Evaluation of a trauma system should include mortality and morbidity. METHODS: Predictors of 12-month functional (Glasgow Outcome Scale-Extended) outcomes after blunt major trauma (Injury Severity Score >15) in an organized trauma system were explored using ordered logistic regression for the period October 2006 to June 2009. Data from the population-based Victorian State Trauma Registry were used. RESULTS: There were 4986 patients older than 18 years. In-hospital mortality decreased from 11.9% in 2006-2007 to 9.9% in 2008-2009. The follow-up rate at 12 months was 86% (n = 3824). Eighty percent reported functional limitations. Odds of better functional outcome increased in the 2007-2008 [adjusted odds ratio (AOR): 1.22; 95% CI: 1.05, 1.41] and 2008-2009 (AOR: 1.16; 95% CI: 1.01, 1.34) years compared with 2006-2007. Cases managed at major trauma services (MTS) achieved better functional outcome (AOR: 1.22; 95% CI: 1.03, 1.45). Female gender, older age, and lower levels of education demonstrated lower adjusted odds of better outcome. CONCLUSIONS: Despite an annual decline in mortality, risk-adjusted functional outcomes improved over time, and cases managed at MTS (level-1 trauma centers) demonstrated better functional outcomes. The findings provide early evidence that this inclusive, regionalized trauma system is achieving its aims.

Importance: Intravenous thrombolysis with tenecteplase improves reperfusion prior to endovascular thrombectomy for ischemic stroke compared with alteplase. Objective: To determine whether 0.40 mg/kg of tenecteplase safely improves reperfusion before endovascular thrombectomy vs 0.25 mg/kg of tenecteplase in patients with large vessel occlusion ischemic stroke. Design, Setting, and Participants: Randomized clinical trial at 27 hospitals in Australia and 1 in New Zealand using open-label treatment and blinded assessment of radiological and clinical outcomes. Patients were enrolled from December 2017 to July 2019 with follow-up until October 2019. Adult patients (N = 300) with ischemic stroke due to occlusion of the intracranial internal carotid, \basilar, or middle cerebral artery were included less than 4.5 hours after symptom onset using standard intravenous thrombolysis eligibility criteria. Interventions: Open-label tenecteplase at 0.40 mg/kg (maximum, 40 mg; n = 150) or 0.25 mg/kg (maximum, 25 mg; n = 150) given as a bolus before endovascular thrombectomy. Main Outcomes and Measures: The primary outcome was reperfusion of greater than 50% of the involved ischemic territory prior to thrombectomy, assessed by consensus of 2 blinded neuroradiologists. Prespecified secondary outcomes were level of disability at day 90 (modified Rankin Scale [mRS] score; range, 0-6); mRS score of 0 to 1 (freedom from disability) or no change from baseline at 90 days; mRS score of 0 to 2 (functional independence) or no change from baseline at 90 days; substantial neurological improvement at 3 days; symptomatic intracranial hemorrhage within 36 hours; and all-cause death. Results: All 300 patients who were randomized (mean age, 72.7 years; 141 [47%] women) completed the trial. The number of participants with greater than 50% reperfusion of the previously occluded vascular territory was 29 of 150 (19.3%) in the 0.40 mg/kg group vs 29 of 150 (19.3%) in the 0.25 mg/kg group (unadjusted risk difference, 0.0% [95% CI, -8.9% to -8.9%]; adjusted risk ratio, 1.03 [95% CI, 0.66-1.61]; P = .89). Among the 6 secondary outcomes, there were no significant differences in any of the 4 functional outcomes between the 0.40 mg/kg and 0.25 mg/kg groups nor in all-cause deaths (26 [17%] vs 22 [15%]; unadjusted risk difference, 2.7% [95% CI, -5.6% to 11.0%]) or symptomatic intracranial hemorrhage (7 [4.7%] vs 2 [1.3%]; unadjusted risk difference, 3.3% [95% CI, -0.5% to 7.2%]). Conclusions and Relevance: Among patients with large vessel occlusion ischemic stroke, a dose of 0.40 mg/kg, compared with 0.25 mg/kg, of tenecteplase did not significantly improve cerebral reperfusion prior to endovascular thrombectomy. The findings suggest that the 0.40-mg/kg dose of tenecteplase does not confer an advantage over the 0.25-mg/kg dose in patients with large vessel occlusion ischemic stroke in whom endovascular thrombectomy is planned. Trial Registration: ClinicalTrials.gov Identifier: NCT03340493.

Background. Increased ambulance utilisation is closely linked with Emergency Department (ED) attendances. Pressures on hospital systems are widely acknowledged with ED overcrowding reported regularly in the media and peer-reviewed literature. Strains on ambulance services are less well-documented or studied. Aims. To review the literature to determine the trends in utilisation of emergency ambulances throughout the developed world and to discuss the major underlying drivers perceived as contributing to this increase. Method. A search of online databases, search engines, peer-reviewed journals and audit reports was undertaken. Findings. Ambulance utilisation has increased in many developed countries over the past 20 years. Annual growth rates throughout Australia and the United Kingdom are similar. Population ageing, changes in social support, accessibility and pricing, and increasing community health awareness have been proposed as associated factors. As the extent of their contribution has not yet been established these factors were reviewed. Conclusion. The continued rise in utilisation of emergency ambulances is placing increasing demands on ambulance services and the wider health system, potentially compromising access, quality, safety and outcomes. A variety of factors may contribute to this increase and targeted strategies to reduce utilisation will require an accurate identification of the major drivers of demand. What is known about the topic? Ambulance utilisation is increasing annually throughout the developed world, with previous research suggesting numerous underlying factors. What does this paper add? These factors have not been previously synthesised in the international literature. This narrative review clearly articulates the underlying problems. What are the implications for practitioners? This paper outlines the need for further research of the causes of increased emergency ambulance utilisation, to enable the development of appropriate strategies to manage demand in the future.

BACKGROUND: Epidemiological studies investigating the role of fine particulate matter (PM2.5; aerodynamic diameter <2.5 μm) in triggering acute coronary events, including out-of-hospital cardiac arrests and ischemic heart disease (IHD), during wildfires have been inconclusive. METHODS AND RESULTS: We examined the associations of out-of-hospital cardiac arrests, IHD, acute myocardial infarction, and angina (hospital admissions and emergency department attendance) with PM2.5 concentrations during the 2006-2007 wildfires in Victoria, Australia, using a time-stratified case-crossover study design. Health data were obtained from comprehensive health-based administrative registries for the study period (December 2006 to January 2007). Modeled and validated air exposure data from wildfire smoke emissions (daily average PM2.5, temperature, relative humidity) were also estimated for this period. There were 457 out-of-hospital cardiac arrests, 2106 emergency department visits, and 3274 hospital admissions for IHD. After adjusting for temperature and relative humidity, an increase in interquartile range of 9.04 μg/m(3) in PM2.5 over 2 days moving average (lag 0-1) was associated with a 6.98% (95% CI 1.03% to 13.29%) increase in risk of out-of-hospital cardiac arrests, with strong association shown by men (9.05%,95%CI 1.63% to 17.02%) and by older adults (aged ≥65 years) (7.25%, 95% CI 0.24% to 14.75%). Increase in risk was (2.07%, 95% CI 0.09% to 4.09%) for IHD-related emergency department attendance and (1.86%, 95% CI: 0.35% to 3.4%) for IHD-related hospital admissions at lag 2 days, with strong associations shown by women (3.21%, 95% CI 0.81% to 5.67%) and by older adults (2.41%, 95% CI 0.82% to 5.67%). CONCLUSION: PM2.5 exposure was associated with increased risk of out-of-hospital cardiac arrests and IHD during the 2006-2007 wildfires in Victoria. This evidence indicates that PM2.5 may act as a triggering factor for acute coronary events during wildfire episodes.

OBJECTIVE: To measure the growth in emergency ambulance use across metropolitan Melbourne since 1995, to measure the impact of population growth and ageing on these services, and to forecast demand for these services in 2015. DESIGN AND SETTING: A population-based retrospective analysis of Ambulance Victoria's metropolitan emergency ambulance transportation data for the period from financial year 1994-95 to 2007-08, and modelling of demand in the financial year 2014-15. MAIN OUTCOME MEASURES: Numbers and rates of emergency ambulance transportations. RESULTS: The crude annual rate of emergency transportations across all age groups increased from 32 per 1000 people in 1994-95 to 58 per 1000 people in 2007-08. The rate of transportation for all ages increased by 75% (95% CI, 62%-89%) over the 14-year study period, representing an average annual growth rate of 4.8% (95% CI, 4.3%-5.3%) beyond that explained by demographic changes. Patients aged ≥ 85 years were eight times (incident rate ratio, 7.9 [95% CI, 7.6-8.3]) as likely to be transported than those aged 45-69 years over this period. Forecast models suggest that the number of transportations will increase by 46%-69% between 2007-08 and 2014-15, disproportionately driven by increasing usage by patients aged ≥ 85 years. CONCLUSIONS: These findings confirm a dramatic rise in emergency transportations over the study period, beyond that expected from demographic changes. Rates increased across all age groups, but more so in older patients. In the future, such acceleration is likely to have major effects on ambulance services and acute hospital capacity. This calls for further investigation of underlying causes and alternative models of care.

BACKGROUND: Coronary thrombosis and pulmonary thromboembolism are common causes of cardiac arrest. We assessed whether the administration of tissue plasminogen activator (t-PA) during cardiopulmonary resuscitation would benefit patients with cardiac arrest and pulseless electrical activity of unknown or presumed cardiovascular cause. METHODS: Patients who were older than 16 years of age and who had more than one minute of pulseless electrical activity that was unresponsive to initial therapy outside the hospital or in the emergency department were eligible. Patients were randomly assigned to receive 100 mg of t-PA or placebo intravenously over a 15-minute period in a double-blind fashion. Standard resuscitation was then continued for at least 15 minutes. The primary outcome was survival to hospital discharge. RESULTS: During the study period, 1583 patients with cardiac arrest were treated and 233 patients were enrolled (117 in the t-PA group and 116 in the placebo group). The characteristics of the patients in the two groups were similar. One patient in the t-PA group survived to hospital discharge, as compared with none in the placebo group (absolute difference between groups, 0.9; 95 percent confidence interval, -2.6 to 4.8; P=0.99). The proportion of patients with return of spontaneous circulation was 21.4 percent in the t-PA group and 23.3 percent in the placebo group (absolute difference between groups, -1.9; 95 percent confidence interval, -12.6 to 8.8; P=0.85). CONCLUSIONS: We found no evidence of a beneficial effect of fibrinolysis in patients with cardiac arrest and pulseless electrical activity of unknown or presumed cardiovascular cause. Our study had limited statistical power, and it remains unknown whether there is a small treatment effect or whether selected subgroups may benefit.

OBJECTIVE: To determine if filgrastim (recombinant human methionyl granulocyte colony-stimulating factor) used in addition to standard inpatient antibiotic therapy accelerated recovery from infection associated with chemotherapy-induced neutropenia. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: Hematology and oncology wards of four teaching hospitals. PATIENTS: 218 patients with cancer who had fever (temperature > 38.2 degrees C) and neutropenia (neutrophil count < 1.0 x 10(9)/L) after chemotherapy. INTERVENTION: Patients were randomly assigned to receive filgrastim (12 micrograms/kg of body weight per day) (n = 109) or placebo (n = 107) beginning within 12 hours of empiric therapy with tobramycin and piperacillin. Patients received treatment and remained in the study until the neutrophil count was greater than 0.5 x 10(9)/L and until 4 days without fever (temperature < 37.5 degrees C) had elapsed. MEASUREMENTS: Days of neutropenia and fever and days in the study (hospitalization); time to resolution of fever and febrile neutropenia; and frequency of the use of alternative antibiotics. RESULTS: Compared with placebo, filgrastim reduced the median number of days of neutropenia (3.0 compared with 4.0 days of a neutrophil count of < 0.5 x 10(9)/L; P = 0.005) and the time to resolution of febrile neutropenia (5.0 compared with 6.0 days; P = 0.01) but not days of fever (3.0 days for both groups). The frequency of the use of alternative antibiotics was similar in the two groups (46% compared with 41%; P = 0.48). The median number of days patients were hospitalized while on study was the same (8.0 days; P = 0.09); however, filgrastim decreased the risk for prolonged hospitalization (> 11 days, 4th quartile) by half (relative risk, 2.1 [95% CI, 1.1 to 4.1]; P = 0.02). In exploratory subset analyses, filgrastim appeared to provide the greatest benefit in patients with documented infection and in patients presenting with neutrophil counts of less than 0.1 x 10(9)/L. CONCLUSIONS: Filgrastim treatment used with antibiotics at the onset of febrile neutropenia in patients with cancer who have received chemotherapy accelerated neutrophil recovery and shortened the duration of febrile neutropenia.

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) is a significant global health problem. There has been considerable investment in improving the emergency medical response to OHCA, with associated improvements in survival. However, concern remains that survivors have a poor quality of life. This study describes the quality of life of OHCA survivors at 1-year postarrest in Victoria, Australia. METHODS AND RESULTS: Adult OHCA patients who arrested between 2010 and 2012 were identified from the Victorian Ambulance Cardiac Arrest Registry. Paramedics attended 15 113 OHCA patients of which 46.3% received an attempted resuscitation. Nine hundred and twenty-seven (13.2%) survived to hospital discharge of which 76 (8.2%) died within 12 months. Interviews were conducted with 697 (80.7%) patients or proxies, who were followed-up via telephone interview, including the Glasgow Outcome Scale-Extended, the 12-item short form health survey, and the EuroQol. The majority (55.6%) of respondents had a good recovery via the Glasgow Outcome Scale-Extended≥7 (41.1% if patients who died postdischarge were included and nonrespondents were assumed to have poor recovery). The mean EuroQol index score for respondents was 0.82 (standard deviation, 0.19), which compared favorably with an adjusted population norm of 0.81 (standard deviation, 0.34). The mean 12-item short form Mental Component Summary score for patients was 53.0 (standard deviation, 10.2), whereas the mean Physical Component Summary score was 46.1 (standard deviation, 11.2). CONCLUSIONS: This is the largest published study assessing the quality of life of OHCA survivors. It provides good evidence that many survivors have an acceptable quality of life 12 months postarrest, particularly in comparison with population norms.

INTRODUCTION: This paper reports on research into the influence of environmental factors (including crowd size, temperature, humidity, and venue type) on the number of patients and the patient problems presenting to first-aid services at large, public events in Australia. Regression models were developed to predict rates of patient presentation and of transportation-to-a-hospital for future mass gatherings. OBJECTIVE: To develop a data set and predictive model that can be applied across venues and types of mass gathering events that is not venue or event specific. Data collected will allow informed event planning for future mass gatherings for which health care services are required. METHODS: Mass gatherings were defined as public events attended by in excess of 25,000 people. Over a period of 12 months, 201 mass gatherings attended by a combined audience in excess of 12 million people were surveyed throughout Australia. The survey was undertaken by St. John Ambulance Australia personnel. The researchers collected data on the incidence and type of patients presenting for treatment and on the environmental factors that may influence these presentations. A standard reporting format and definition of event geography was employed to overcome the event-specific nature of many previous surveys. RESULTS: There are 11,956 patients in the sample. The patient presentation rate across all event types was 0.992/1,000 attendees, and the transportation-to-hospital rate was 0.027/1,000 persons in attendance. The rates of patient presentations declined slightly as crowd sizes increased. The weather (particularly the relative humidity) was related positively to an increase in the rates of presentations. Other factors that influenced the number and type of patients presenting were the mobility of the crowd, the availability of alcohol, the event being enclosed by a boundary, and the number of patient-care personnel on duty. Three regression models were developed to predict presentation rates at future events. CONCLUSIONS: Several features of the event environment influence patient presentation rates, and that the prediction of patient load at these events is complex and multifactorial. The use of regression modeling and close attention to existing historical data for an event can improve planning and the provision of health care services at mass gatherings.

OBJECTIVE: Post-resuscitation care may influence outcome following transport to hospital after resuscitation from out-of-hospital cardiac arrest (OHCA). This study aimed to determine whether receiving hospital characteristics such as 24-h cardiac catheterisation services, total bed number or OHCA patient volume influence the rate of survival. SETTING: Data were analysed from the Victorian Ambulance Cardiac Arrest Registry of patients from January 2003 to March 2010 who were transported to hospital with return of spontaneous circulation (ROSC) after OHCA. RESULTS: Ambulance paramedics attended 9971 patients with OHCA of suspected cardiac cause during the study period. Of these, 2902 (29%) achieved ROSC and were transported to one of 70 hospitals. 1816 (63%) were treated at hospitals with 24-h cardiac interventional services. After adjusting for differences in baseline characteristics, hospital factors significantly associated with survival were treatment at hospitals with 24-h cardiac interventional services (OR 1.40; 95% CI 1.12 to 1.74, p=0.003) and patient reception between 08:00 and 17:00 hours (OR 1.34; 95% CI 1.10 to 1.64, p=0.004). OHCA patient volume and total hospital bed number were not independently associated with outcome. CONCLUSION: Hospital characteristics are associated with improved survival in patients with OHCA. This finding has implications for the establishment of regionalised systems of care for patients who have been resuscitated from OHCA.

AIMS: Traditionally, the opiate antagonist naloxone has been administered parenterally; however, intranasal (i.n.) administration has the potential to reduce the risk of needlestick injury. This is important when working with populations known to have a high prevalence of blood-borne viruses. Preliminary research suggests that i.n. administration might be effective, but suboptimal naloxone solutions were used. This study compared the effectiveness of concentrated (2 mg/ml) i.n. naloxone to intramuscular (i.m.) naloxone for suspected opiate overdose. METHODS: This randomized controlled trial included patients treated for suspected opiate overdose in the pre-hospital setting. Patients received 2 mg of either i.n. or i.m. naloxone. The primary outcome was the proportion of patients who responded within 10 minutes of naloxone treatment. Secondary outcomes included time to adequate response and requirement for supplementary naloxone. Data were analysed using multivariate statistical techniques. RESULTS: A total of 172 patients were enrolled into the study. Median age was 29 years and 74% were male. Rates of response within 10 minutes were similar: i.n. naloxone (60/83, 72.3%) compared with i.m. naloxone (69/89, 77.5%) [difference: -5.2%, 95% confidence interval (CI) -18.2 to 7.7]. No difference was observed in mean response time (i.n.: 8.0, i.m.: 7.9 minutes; difference 0.1, 95% CI -1.3 to 1.5). Supplementary naloxone was administered to fewer patients who received i.m. naloxone (i.n.: 18.1%; i.m.: 4.5%) (difference: 13.6%, 95% CI 4.2-22.9). CONCLUSIONS: Concentrated intranasal naloxone reversed heroin overdose successfully in 82% of patients. Time to adequate response was the same for both routes, suggesting that the i.n. route of administration is of similar effectiveness to the i.m. route as a first-line treatment for heroin overdose.

Abstract Objectives: Although the factors driving emergency department demand have been extensively investigated, a comparatively minimal amount is known about the factors that are driving an increase in emergency ambulance demand. Methods: We conducted a retrospective observational study of consecutive cases attended by Ambulance Victoria in Melbourne, Australia from 2008 to 2015. Incidence rates were calculated, and adjusted time series regression analyses were performed to assess the driving factors of ambulance demand. Results: A total of 2,443,952 consecutive cases were included. Demand grew by 29.2% over the 8-year period. The age-specific incidence increased significantly over time for patients aged < 60 years, but not for patients aged ≥ 60 years. After adjustment for seasonality and population growth, demand increased by 1.4% per annum (incident rate ratio [IRR] = 1.014 [1.011–1.017]). The largest annual growth in demand was observed in patients with a history of mental health issues (IRR = 1.058 [1.054–1.062]), alcohol/drug abuse (IRR = 1.061 [1.056–1.066]), or a Charlson Comorbidity Index [CCI] score ≥ 4 (IRR = 1.045 [1.039–1.051]). Cases involving patients of relative socio-economic/educational disadvantage, younger age, or with no preexisting health conditions according to the CCI also grew faster than the overall patient population. Cases requiring transport to hospital increased by 1.2% annually (IRR = 1.012 [1.009–1.016]), although patients not requiring medical intervention from paramedics increased by 6.7% annually (IRR = 1.067 [1.063–1.072]). Conclusions: Increases in ambulance demand exceeded population growth. Emergency ambulances were increasingly utilized for transport of patients who did not require medical intervention from paramedics. Identifying the characteristics of patients driving ambulance demand will enable targeted demand management strategies.

BACKGROUND AND PURPOSE: Few acute stroke patients are treated with alteplase, partly because of significant prehospital delays after symptom onset. The aim of this study was to determine among ambulance-transported stroke patients factors associated with stroke recognition and factors associated with a call for ambulance assistance within 1 hour from symptom onset. METHODS: For 6 months in 2004, all ambulance-transported stroke or transient ischemic attack patients arriving from a geographically defined region in Melbourne (Australia) to 1 of 3 hospital emergency departments were assessed. Tapes of the call for ambulance assistance were analyzed and the patient and the caller were interviewed. RESULTS: One hundred ninety-eight patients were included in the study. Stroke was reported as the problem in 44% of ambulance calls. Unprompted stroke recognition was independently associated with facial droop (P=0.015) and a history of stroke or transient ischemic attack (P<0.001). More than half of the calls for ambulance assistance were made within 1 hour from symptom onset and only 43% of these callers spontaneously identified the problem as "stroke." Factors independently associated with a call within 1 hour were: speech problems (P=0.009), caller family history of stroke (P=0.017), and the patient was not alone at symptom onset (P=0.018). CONCLUSIONS: Stroke was reported as the problem (unprompted) by <50% of callers. Fewer than half the calls were made within 1 hour from symptom onset. Interventions are needed to more strongly link stroke recognition to immediate action and increase the number of stroke patients eligible for acute treatment.

BACKGROUND: Patients successfully resuscitated by paramedics from out-of-hospital cardiac arrest often have severe neurologic injury. Laboratory and observational clinical reports have suggested that induction of therapeutic hypothermia during cardiopulmonary resuscitation (CPR) may improve neurologic outcomes. One technique for induction of mild therapeutic hypothermia during CPR is a rapid infusion of large-volume cold crystalloid fluid. METHODS: In this multicenter, randomized, controlled trial we assigned adults with out-of-hospital cardiac arrest undergoing CPR to either a rapid intravenous infusion of up to 2 L of cold saline or standard care. The primary outcome measure was survival at hospital discharge; secondary end points included return of a spontaneous circulation. The trial was closed early (at 48% recruitment target) due to changes in temperature management at major receiving hospitals. RESULTS: A total of 1198 patients were assigned to either therapeutic hypothermia during CPR (618 patients) or standard prehospital care (580 patients). Patients allocated to therapeutic hypothermia received a mean (SD) of 1193 (647) mL cold saline. For patients with an initial shockable cardiac rhythm, there was a decrease in the rate of return of a spontaneous circulation in patients who received cold saline compared with standard care (41.2% compared with 50.6%, P=0.03). Overall 10.2% of patients allocated to therapeutic hypothermia during CPR were alive at hospital discharge compared with 11.4% who received standard care (P=0.71). CONCLUSIONS: In adults with out-of-hospital cardiac arrest, induction of mild therapeutic hypothermia using a rapid infusion of large-volume, intravenous cold saline during CPR may decrease the rate of return of a spontaneous circulation in patients with an initial shockable rhythm and produced no trend toward improved outcomes at hospital discharge. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01173393.