Prehospital emergency medicine research by additional teams on scene - Concepts and lessons learned.

While the initial minutes of acute emergencies significantly influence clinical outcomes, prehospital research often receives inadequate attention due to several challenges. Retrospective chart reviews carry the risk of incomplete and inaccurate data. Furthermore, prehospital intervention trials frequently encounter difficulties related to extensive training requirements, even during the planning phase. Consequently, we have implemented prospective research concepts involving additional paramedics and physicians directly at the scene during major emergency calls. Three concepts were used: (I) Paramedic field supervisor units, (II) a paramedic + physician field supervisor unit, (III) a special physician-based research car. This paper provides insights into our historical perspective, the current situation, and the lessons learned while overcoming certain barriers and using existing and novel facilitators. Our objective is to support other research groups with our experiences in their planning of upcoming prehospital trials.

Laryngeal Tube Practice in a Metropolitan Ambulance Service: A Five-year Retrospective Observational Study (2009-2013).

Background: The endotracheal tube (ETT) is considered the gold standard in emergency airway management, although supraglottic airway devices, especially the laryngeal tube (LT), have recently gained in importance. Although regarded as an emergency device in case of failure of endotracheal intubation in most systems, we investigated the dynamics of the use of the LT in a metropolitan ambulance service without any regulations on the choice of airway device. Methods: A retrospective, observational study on all patients from the Municipal Ambulance Service, Vienna in need of advanced airway management over a 5-year period. Differences between years were compared; influencing factors for the use of the LT were analyzed using multivariable logistic regression. Results: In total 5,175 patients (mean age 62 ± 20 years, 36.6% female) underwent advanced airway management. Of these, 15.6% received the LT. LT use increased from 20 out of 1,001 (2.0%) in 2009 to 292 of 1,085 (26.9%) in 2013 (p < 0.001). The increase between each consecutive year was also significant. Paramedics more frequently inserted the LT than physicians (RR 1.80 (95%CI 1.48-2.16); p < 0.001). Female patients received a LT less frequently (RR 0.84 (95%CI 0.72-0.97), p = 0.013). There was no difference regarding airway device due to underlying causes requiring airway management and no relationship to the NACA-score. Conclusion: In a European EMS system of physician and paramedic response, the proportion of airway managed by LT over ETT rose considerably over five years. Although the ET is still the gold standard, the LT is gaining in importance for EMS physicians and paramedics.

Initial end-tidal carbon dioxide as a predictive factor for return of spontaneous circulation in nonshockable out-of-hospital cardiac arrest patients: A retrospective observational study.

BACKGROUND: Early outcome prediction in out-of-hospital cardiac arrest is still a challenge. End-tidal carbon dioxide (ETCO2) has been shown to be a reliable parameter to reflect the quality of cardiopulmonary resuscitation and the chance of return of spontaneous circulation (ROSC). OBJECTIVES: This study assessed the validity of early capnography as a predictive factor for ROSC and survival in out-of-hospital cardiac arrest victims with an underlying nonshockable rhythm. DESIGN: Retrospective observational study. SETTING/PATIENTS: During a 2-year observational period, data from 2223 out-of-hospital cardiac arrest victims within the city of Vienna were analysed. The focus was on the following patients: age more than 18 years, an underlying nonshockable rhythm, and advanced airway management within the first 15 min of advanced life support with subsequent capnography. INTERVENTION: No specific intervention was set in this observational study. MAIN OUTCOME MEASURES: The first measured ETCO2, assessed immediately after placement of an advanced airway, was used for further analysis. The primary outcome was defined as sustained ROSC, and the secondary outcome was 30-day survival. RESULTS: A total of 526 patients met the inclusion criteria. These were stratified into three groups according to initial ETCO2 values (<20, 20 to 45, >45 mmHg). Baseline data and resuscitation factors were similar among all groups. The odds of sustained ROSC and survival were significantly higher for patients presenting with higher values of initial ETCO2 (>45 mmHg): 3.59 [95% CI, 2.19 to 5.85] P = 0.001 and 5.02 [95% CI, 2.25 to 11.23] P = 0.001, respectively. On the contrary ETCO2 levels less than 20 mmHg were associated with significantly poorer outcomes. CONCLUSION: Patients with a nonshockable out-of-hospital cardiac arrest who presented with higher values of initial ETCO2 had an increased chance of sustained ROSC and survival. This finding could help decision making as regards continuation of resuscitation efforts.

The impact of airway strategy on the patient outcome after out-of-hospital cardiac arrest: A propensity score matched analysis.

BACKGROUND: While guidelines mentioned supraglottic airway management in the case of out-of- hospital cardiac arrest, robust data of their impact on the patient outcome remain scare and results are inconclusive. METHODS: To assess the impact of the airway strategy on the patient outcome we prospectively enrolled 2224 individuals suffering cardiac arrest who were treated by the Viennese municipal emergency medical service. To control for potential confounders, propensity score matching was performed. Patients were matched in four groups with a 1:1:1:1 ratio ( n=210/group) according to bag-mask-valve, laryngeal tube, endotracheal intubation and secondary endotracheal intubation after primary laryngeal tube ventilation. RESULTS: The laryngeal tube subgroup showed the lowest 30-day survival rate among all tested devices ( p<0.001). However, in the case of endotracheal intubation after primary laryngeal tube ventilation, survival rates were comparable to the primary endotracheal tube subgroup. The use of a laryngeal tube was independently and directly associated with mortality with an adjusted odds ratio of 1.97 (confidence interval: 1.14-3.39; p=0.015). Additionally, patients receiving laryngeal tube ventilation showed the lowest rate of good neurological performance (6.7%; p<0.001) among subgroups. However, if patients received endotracheal intubation after initial laryngeal tube ventilation, the outcome proved to be significantly better (9.5%; p<0.001). CONCLUSION: We found that the use of a laryngeal tube for airway management in cardiac arrest was significantly associated with poor 30-day survival rates and unfavourable neurological outcome. A primary endotracheal airway management needs to be considered at the scene, or an earliest possible secondary endotracheal intubation during both pre-hospital and in-hospital post-return of spontaneous circulation critical care seems crucial and most beneficial for the patient outcome.

Improvements in the quality of advanced life support and patient outcome after implementation of a standardized real-life post-resuscitation feedback system.

BACKGROUND: Educational aspects in the training of advanced life support (ALS) represent a key role in critical care management of patients with out-of-hospital cardiac arrest (OHCA) and received special attention in guidelines of various international societies. While a positive association of feedback on ALS performance in training conditions is well established, data on the impact of a real-life post-resuscitation feedback on both ALS quality and outcome remain scarce and inconclusive. We aimed to elucidate the impact of a standardized post-resuscitation feedback on quality of ALS and improvements in patient outcome, in a real-life out-of-hospital setting. METHODS: We prospectively enrolled and analyzed 2209 patients presenting with OHCA receiving resuscitation attempts by the municipal emergency medical service (EMS) of Vienna over a two-year period. A standardized post-resuscitation feedback protocol was delivered to the respective EMS-team to elucidate its impact on the quality of ALS. RESULTS: We observed that both chest compression rates and ratios were in accordance to recommendations of recent guidelines. While interruptions of chest compressions longer than 30s declined during the observation period (-6.5%) rates of the recommended chest compressions during defibrillator-charging periods increased (+8.9%). Since the percentage of ROSC and 30-day survival remained balanced, the frequencies of both survival until hospital discharge (+6.3%) and favorable neurological outcome (+16%) in survivors significantly increased during the observation period. CONCLUSION: Improvements in the quality of advanced life support as well the patient outcome were observed after the implementation of a standardized post-resuscitation feedback protocol.

Age-specific prognostication after out-of-hospital cardiac arrest - The ethical dilemma between 'life-sustaining treatment' and 'the right to die' in the elderly.

BACKGROUND: While prognostic values on survival after out-of-hospital cardiac arrest have been well investigated, less attention has been paid to their age-specific relevance. Therefore, we aimed to identify suitable age-specific early prognostication in elderly patients suffering out-of-hospital cardiac arrest in order to reduce the burden of unnecessary treatment and harm. METHODS: In a prospective population-based observational trial on individuals suffering out-of-hospital cardiac arrest, a total of 2223 patients receiving resuscitation attempts by the local emergency medical service in Vienna, Austria, were enrolled. Patients were stratified according to age as follows: young and middle-aged individuals (<65 years), young old individuals (65-74 years), old individuals (75-84 years) and very old individuals (>85 years). RESULTS: There was an increasing rate of 30-day mortality (+21.8%, p < 0.001) and unfavourable neurological outcome (+18.8%, p < 0.001) with increasing age among age groups. Established predictive variables lost their prognostic potential with increasing age, even after adjusting for potential confounders. Independently, an initially shockable electrocardiogram proved to be directly associated with survival, with an adjusted hazard ratio (HR) of 2.04 (95% confidence interval (CI) 1.89-2.38, p = 0.003) for >85-year-olds. Frailty was directly associated with mortality (HR 1.22, 95% CI 1.01-1.51, p = 0.049), showing a 30-day survival of 5.6% and a favourable neurological outcome of 1.1% among elderly individuals. CONCLUSION: An initially shockable electrocardiogram proved to be a suitable tool for risk assessment and decision making in order to predict a successful outcome in elderly victims of out-of-hospital cardiac arrest. However, the outcomes of elderly patients seemed to be exceptionally poor in frail individuals and need to be considered in order to reduce unnecessary treatment decisions.

Safety and feasibility of the RhinoChill immediate transnasal evaporative cooling device during out-of-hospital cardiopulmonary resuscitation: A single-center, observational study.

We investigated feasibility and safety of the RhinoChill (RC) transnasal cooling system initiated before achieving a protected airway during cardiopulmonary resuscitation (CPR) in a prehospital setting.In out-of-hospital cardiac arrest (OHCA), transnasal evaporative cooling was initiated during CPR, before a protected airway was established and continued until either the patient was declared dead, standard institutional systemic cooling methods were implemented or cooling supply was empty. Patients were monitored throughout the hypothermia period until either death or hospital discharge. Clinical assessments and relevant adverse events (AEs) were documented over this period of time.In total 21 patients were included. Four were excluded due to user errors or meeting exclusion criteria. Finally, 17 patients (f = 6; mean age 65.5 years, CI95%: 57.7-73.4) were analyzed. Device-related AEs, like epistaxis or nose whitening, occurred in 2 patients. They were mild and had no consequence on the patient's outcome. According to the field reports of the emergency medical services (EMS) personnel, no severe technical problems occurred by using the RC device that led to a delay or the impairment of quality of the CPR.Early application of the RC device, during OHCA is feasible, safe, easy to handle, and does not delay or hinder CPR, or establishment of a secure intubation. For efficacy and further safety data additional studies will be needed.

Editor's Choice-Progress in the chain of survival and its impact on outcomes of patients admitted to a specialized high-volume cardiac arrest center during the past two decades.

AIM: Cardiac arrest (CA) is still associated with high mortality and morbidity. Data on the changes in management and outcomes over a long period of time are limited. Using data from a single emergency department (ED), we assessed changes over two decades. METHODS: In this single-center observational study, we prospectively included 4133 patients receiving cardiopulmonary resuscitation and being admitted to the ED of a tertiary care hospital between January 1992 and December 2012. RESULTS: There was a significant improvement in both 6-month survival rates (+10.8%; p < 0.001) and favorable neurological outcome (+4.7%; p < 0.001). While the number of witnessed CA cases decreased (-4.7%; p < 0.001) the proportion of patients receiving bystander basic life support increased (+8.3%; p < 0.001). The proportion of patients with initially shockable ECG rhythms remained unchanged, but cardiovascular causes of CA decreased (-9.6%; p < 0.001). Interestingly, the time from CA until ED admission increased (+0.1 hours; p = 0.024). The use of percutaneous coronary intervention and therapeutic hypothermia were significantly associated with survival. CONCLUSIONS: Outcomes of patients with CA treated at a specialized ED have improved significantly within the last 20 years. Improvements in every link in the chain of survival were noted.

Mechanical chest compression does not seem to improve outcome after out-of hospital cardiac arrest. A single center observational trial.

AIM: Recently three large post product placement studies, comparing mechanical chest compression (cc) devices to those who received manual cc, found equivalent outcome results for both groups. Thus the question arises whether those results could be replicated using the devices on a daily routine. METHODS: We prospectively enrolled 948 patients over a 12 months period. Chi-Square test and Mann-Whitney-U test were used to assess differences between "manual" and "mechanical" cc subgroups. Uni- and multivariate Cox regression hazard analysis were used to assess the influence of cc type on survival. RESULTS: A mechanical cc device was used in 30.1% (n=283) cases. Patients who received mechanical cc had a significantly worse neurological outcome - measured in cerebral performance category (CPC) - than the manual cc group (56.8% vs. 78.6%, p=0.009). Patients receiving mechanical cc were significantly younger, more were male and were more likely to have bystander CPR and an initially shock-able ECG rhythm. There was no difference in the quality of CPR that might explain the worse outcome in mechanical cc patients. CONCLUSION: Even with high quality CPR in both, manual and mechanical cc groups, outcome in patients who received mechanical cc was significantly worse. The anticipated benefits of a higher compression ratio and a steadier compression depth of a mechanical cc device remain uncertain. In this study selection for mechanical cc was not standardized, and was non-random. This merits further investigation. Further research on how mechanical cc is chosen and used should be considered. CLINICAL TRIAL REGISTRATION: https://ekmeduniwien.at/core/catalog/2013/ (EK-Nr:1221/2013).

The incidence of "load&go" out-of-hospital cardiac arrest candidates for emergency department utilization of emergency extracorporeal life support: A one-year review.

BACKGROUND: The outcome of patients after out-of-hospital cardiac arrest (OHCA) is poor and gets worse after prolonged resuscitation. Recently introduced attempts like an early installed emergency extracorporeal life support (E-ECLS) in patients with persisting cardiac arrest at the emergency department (ED) are tried. The "Vienna Cardiac Arrest Registry" (VICAR) was introduced August 2013 to collect Utstein-style data. The aim of this observational study was to identify the incidence of patients which fulfil "load&go"-criteria for E-ECLS at the ED. METHODS: VICAR was retrospectively analyzed for following criteria: age <75 years; witnessed OHCA; basic life support; ventricular fibrillation/ventricular tachycardia; no return-of-spontaneous-circulation (ROSC) within 15 min of advanced-life-support, which were supposed as potential optimal criteria for "load&go" plus successful E-ECLS treatment at the ED. The observation period was from August 1, 2013 to July 31, 2014. RESULTS: Over 948 OHCA patients registered during the study period; data were exploitable for 864 patients. Of all patients, "load&go"-criteria were fulfilled by 55 (6%). However, 96 (11%) were transported with on-going CPR to the ED. Of these 96 patients, only 16 (17%) met the "load&go"-criteria. Similarly, among the 96 patients, 12 adults were treated with E-ECLS at the ED, with only 5 meeting the criteria. Among these 12 patients, favourable neurological outcome (CPC 1/2) was obtained in 1 patient without criteria. CONCLUSION: Further promotion of these criteria within the ambulance crews is needed. May be these criteria could serve as a decision support for emergency physicians/paramedics, which patients to transport with on-going CPR to the ED for E-ECLS.

The capability of professional- and lay-rescuers to estimate the chest compression-depth target: a short, randomized experiment.

BACKGROUND: In CPR, sufficient compression depth is essential. The American Heart Association ("at least 5cm", AHA-R) and the European Resuscitation Council ("at least 5cm, but not to exceed 6cm", ERC-R) recommendations differ, and both are hardly achieved. This study aims to investigate the effects of differing target depth instructions on compression depth performances of professional and lay-rescuers. METHODS: 110 professional-rescuers and 110 lay-rescuers were randomized (1:1, 4 groups) to estimate the AHA-R or ERC-R on a paper sheet (given horizontal axis) using a pencil and to perform chest compressions according to AHA-R or ERC-R on a manikin. Distance estimation and compression depth were the outcome variables. RESULTS: Professional-rescuers estimated the distance according to AHA-R in 19/55 (34.5%) and to ERC-R in 20/55 (36.4%) cases (p=0.84). Professional-rescuers achieved correct compression depth according to AHA-R in 39/55 (70.9%) and to ERC-R in 36/55 (65.4%) cases (p=0.97). Lay-rescuers estimated the distance correctly according to AHA-R in 18/55 (32.7%) and to ERC-R in 20/55 (36.4%) cases (p=0.59). Lay-rescuers yielded correct compression depth according to AHA-R in 39/55 (70.9%) and to ERC-R in 26/55 (47.3%) cases (p=0.02). CONCLUSION: Professional and lay-rescuers have severe difficulties in correctly estimating distance on a sheet of paper. Professional-rescuers are able to yield AHA-R and ERC-R targets likewise. In lay-rescuers AHA-R was associated with significantly higher success rates. The inability to estimate distance could explain the failure to appropriately perform chest compressions. For teaching lay-rescuers, the AHA-R with no upper limit of compression depth might be preferable.

Strategic target temperature management in myocardial infarction--a feasibility trial.

OBJECTIVE: The purpose of this study was to demonstrate the feasibility of a combined cooling strategy started out of hospital as an adjunctive to percutaneous coronary intervention (PCI) in the treatment of ST-elevation acute coronary syndrome (STE-ACS). DESIGN: Non-randomised, single-centre feasibility trial. SETTING: Department of emergency medicine of a tertiary-care facility, Medical University of Vienna, Vienna, Austria. In cooperation with the Municipal ambulance service of the city of Vienna. PATIENTS: Consecutive patients with STE-ACS presenting to the emergency medical service within 6 h after symptom onset. INTERVENTIONS: Cooling was initiated with surface cooling pads in the out-of-hospital setting, followed by the administration of 1000-2000 mL of cold saline at hospital arrival and completed by endovascular cooling in the catheterisation laboratory. MAIN OUTCOME MEASURES: Feasibility of lowering core temperature below 35.0°C prior to immediately performed revascularisation. Safety and tolerability of the cooling procedure. RESULTS: In enrolled 19 patients (one woman, median age 51 years (IQR 45-59)), symptom onset to first medical contact (FMC) was 45 min (IQR 31-85). A core temperature below 35.0°C at reperfusion of the culprit lesion was achieved in 11 patients (78%) within 100 min (IQR 90-111) after FMC without any cooling-related serious adverse event. Temperature could be lowered from baseline 36.4°C (IQR 36.2-36.5°C) to 34.4°C (IQR 34.1-35.0°C) at the time of reperfusion. CONCLUSIONS: With limitations an immediate out-of-hospital therapeutic hypothermia strategy was feasible and safe in patients with STE-ACS undergoing primary PCI. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov/ct2/show/NCT01864343; clinical trials unique identifier: NCT01864343.

Out of hospital cardiac arrest in Vienna: incidence and outcome.

AIM OF THE STUDY: To determine the incidence of out-of-hospital cardiac arrest and the survival rate of those patients who received CPR in the city of Vienna. METHODS: A cohort of patients with out-of-hospital cardiac arrests and who were treated by the Vienna Ambulance Service between January 1, 2009, and December 31, 2010, were followed up until either death or hospital discharge. The associations of survival and neurological outcome with their potential predictors were analysed using simple logistic regression models. Odds ratios were estimated for each factor. RESULTS: During the observation period, a total of 7030 (206.8/100,000 inhabitants/year) patients without signs of circulation were assessed by teams of the Vienna Ambulance Service, and 1448 adult patients were resuscitated by emergency medical service personnel. A sustained return of spontaneous circulation was reported in 361 (24.9%) of the treated patients, and in all 479 (33.0%) of the patients were taken to the emergency department. A total of 164 (11.3%) of the patients were discharged from the hospital alive, and 126 (8.7%) of the patients showed cerebral performance categories of 1 or 2 at the time of discharge. Younger age, an arrest in a public area, a witnessed arrest and a shockable rhythm were associated with a higher probability of survival to hospital discharge. CONCLUSION: Survival rates for out-of-hospital cardiac arrests remain low. Efforts should be focused on rapidly initiating basic life support, early defibrillation, and high-quality CPR by emergency medical services and state-of-the art post-resuscitation care.