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.

Induction of Therapeutic Hypothermia During Out-of-Hospital Cardiac Arrest Using a Rapid Infusion of Cold Saline: The RINSE Trial (Rapid Infusion of Cold Normal Saline).

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.

Sex Differences in Incidence and Outcome of Out-of-Hospital Cardiac Arrest Within a Local Health Network.

Introduction: Sex and gender differences in presentation and characteristics of out-of-hospital cardiac arrest (OHCA) are established in cohorts with presumed cardiac aetiology but not non-cardiac etiology. This study investigated the effect of sex on incidence and outcome of OHCA according to presumed and adjudicated aetiology within a local health network. Methods: Population-based observational cohort study of emergency medical services (EMS) attended OHCAs within an Australian local health network. Cases identified from an EMS registry between 2012-2016 were linked to a hospital registry. Age-standardised incidence and baseline characteristics were stratified by sex for EMS-treated OHCA, non-EMS witnessed presumed cardiac and obvious non-cardiac sub-cohorts, and hospitalised cases. Logistic regression was used to explore the primary outcome of survival to hospital discharge. Results: We identified 2,024 EMS-attended and 780 EMS-treated OHCAs. The non-EMS witnessed sub-cohorts comprised 504 presumed cardiac and 168 obvious non-cardiac OHCAs. Adjudicated aetiology was recorded in 123 hospitalised cases. Age-standardised incidence for women was almost half that of men across all groups. Across cohorts, women were generally older and arrested with a non-shockable initial rhythm in an area of low socioeconomic status. There was no sex difference in the primary outcome for the main EMS-treated cohort or in the non-cardiac sub-cohorts. The sex difference in outcome in the presumed cardiac sub-cohort was not present after multivariable adjustment. Conclusions: There are sex differences in incidence and outcome of EMS-treated OHCA that appear to be driven by differences in susceptibility to cardiac arrhythmias and underlying etiology, rather than treatment delays or disparities.

Design of the RINSE trial: the rapid infusion of cold normal saline by paramedics during CPR.

BACKGROUND: The International Liaison Committee on Resuscitation (ILCOR) now recommends therapeutic hypothermia (TH) (33 °C for 12-24 hours) as soon as possible for patients who remain comatose after resuscitation from shockable rhythm in out-of-hospital cardiac arrest and that it be considered for non shockable rhythms. The optimal timing of TH is still uncertain. Laboratory data have suggested that there is significantly decreased neurological injury if cooling is initiated during CPR. In addition, peri-arrest cooling may increase the rate of successful defibrillation. This study aims to determine whether paramedic cooling during CPR improves outcome compared standard treatment in patients who are being resuscitated from out-of-hospital cardiac arrest. METHODS/DESIGN: This paper describes the methodology for a definitive multi-centre, randomised, controlled trial of paramedic cooling during CPR compared with standard treatment. Paramedic cooling during CPR will be achieved using a rapid infusion of large volume (20-40 mL/kg to a maximum of 2 litres) ice-cold (4 °C) normal saline.The primary outcome measure is survival at hospital discharge. Secondary outcome measures are rates of return of spontaneous circulation, rate of survival to hospital admission, temperature on arrival at hospital, and 12 month quality of life of survivors. DISCUSSION: This trial will test the effect of the administration of ice cold saline during CPR on survival outcomes. If this simple treatment is found to improve outcomes, it will have generalisability to prehospital services globally. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01172678.

A new part task trainer for teaching and learning confirmation of endotracheal intubation.

Endotracheal intubation is a skill employed by a diverse range of healthcare professionals in a wide variety of circumstances. Failure to put this tube in the right place (in the trachea) can result in serious injury and death. There are a wide variety of methods for verification of proper placement. Some are more widely accepted than others. A universal guideline should be adopted to allow consistent and safe practice in all situations by all who do this procedure. Training for endotracheal intubation must also include training in the verification methods. We have developed a new airway part-task trainer that allows the use of all of the methods of tube placement verification.

Care of the patient with invasive meningococcal disease by prehospital emergency medical service clinicians: a scoping review.

OBJECTIVE: The objective of this scoping review is to systematically map the literature to identify the scope, depth, key concepts and gaps in the evidence regarding care of the patient with invasive meningococcal disease by emergency medical service (EMS) clinicians. DESIGN: Scoping review. This review is reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews reporting guideline. ELIGIBILITY CRITERIA: Sources which focused on patients with invasive meningococcal disease (population), where the care of EMS clinicians was the focus (concept), in EMS systems worldwide (context) were eligible for inclusion. SEARCH STRATEGY: This review utilised a comprehensive search strategy including MEDLINE, Embase, Emcare, CINAHL, Scopus, Web of Science, Google Scholar and 'grey' literature databases from 1992 to January 2019. The search also included a Google search, a hand-search of relevant journals, screening of reference lists, contact with authors of included sources and use of social media in an attempt to locate all sources of evidence which fit the inclusion criteria of the review. Two reviewers independently screened sources for inclusion. RESULTS: The search yielded 1803 unique records, of which 10 were included in the synthesis. No original research papers were identified, with all sources classed as either clinical audit or text and opinion literature. The dominant concept throughout the literature is that early antibiotic therapy is critical in the treatment of invasive meningococcal disease. CONCLUSIONS: Overall, there is a very narrow scope and shallow depth of literature on the topic of interest. There are gaps in the evidence regarding the care of the patient with invasive meningococcal disease by EMS clinicians. Despite these shortfalls, current consensus-based guidelines should direct clinical practice. Further research is planned to bridge the gaps in knowledge to support best practice.

The EXACT protocol: A multi-centre, single-blind, randomised, parallel-group, controlled trial to determine whether early oxygen titration improves survival to hospital discharge in adult OHCA patients.

BACKGROUND: Experimental and observational research suggests hyperoxia following resuscitation from cardiac arrest is associated with neurological injury and worse clinical outcomes. This paper describes the rationale and design of the EXACT trial. EXACT aims to determine whether reducing oxygen in the acute phase of post-resuscitation care for out-of-hospital cardiac arrest (OHCA) improves survival. METHODS: EXACT is a multi-centre, randomised (1:1), single-blind, parallel trial. Presumed cardiac OHCA cases who achieve a return of spontaneous circulation will be eligible if they are comatose, with an advanced airway and have an oxygen saturation (SpO2) ≥95% on >10 L/min (or 100% oxygen). Paramedics will randomise 1416 eligible cases to receive oxygen therapy targeting an SpO2 of 90-94% (intervention) or 98-100% (control). Study treatment will continue until admission to an intensive care unit or hospital ward. The primary outcome is survival to hospital discharge. Secondary outcomes include 12-month survival and quality of life. RESULTS: The study has commenced in the Australian states of Victoria and South Australia, and has enrolled 167 eligible cases to date (80 intervention and 87 control). Further sites are due to commence in 2019, recruitment is expected to take three years. CONCLUSION: This study will determine if early reduction of oxygen leads to improved outcomes in OHCA. Such a finding may potentially change clinical practice with implications on future OHCA survival outcomes. TRIAL REGISTRATION NUMBER: NCT03138005.

A 12-month audit of laryngeal mask airway (LMA) use in a South Australian ambulance service.

BACKGROUND: The aim of the study was to provide an accurate account of current practice of laryngeal mask airway (LMA) use within SA Ambulance Service (SAAS) and identify issues that could lead to constructive training for paramedics and improve clinical care and patient safety. MATERIALS AND METHODS: A clinical audit of LMA use within SAAS was registered with the Director of Clinical Governance at Flinders Medical Centre in South Australia. Data were collected prospectively in a state wide all inclusive study over 12 months (February 2006 to January 2007). The primary outcome variable we determined was successful insertion after one or two attempts. Secondary outcome measures were overall success rate and reasons for failure. RESULTS: Insertion of an LMA was attempted by 179 paramedical staff in 164 patients. Success after one or two attempts was obtained in 65% of patients (107/164). Overall success rate (any number of attempts) was 74% (121/164), of those 45% were on the first attempt, 20% on the second attempt and the remainder (9%) required three or more attempts to achieve successful insertion. Reported failures were ascribed to patient anatomy (13), technique (9), airway soiling (7), device (6), trismus (1), high Glasgow Coma Score (1), trauma (1) or unknown (5). CONCLUSION: This clinical audit provides a comprehensive account of LMA use within SA Ambulance Service. Although the current practice was found to be acceptable, these results are below those of comparable groups and should be improved upon.

Oxygen titration after resuscitation from out-of-hospital cardiac arrest: A multi-centre, randomised controlled pilot study (the EXACT pilot trial).

INTRODUCTION: Recent studies suggest the administration of 100% oxygen to hyperoxic levels following return-of-spontaneous-circulation (ROSC) post-cardiac arrest may be harmful. However, the feasibility and safety of oxygen titration in the prehospital setting is unknown. We conducted a multi-centre, phase-2 study testing whether prehospital titration of oxygen results in an equivalent number of patients arriving at hospital with oxygen saturations SpO2 ≥ 94%. METHODS: We enrolled unconscious adults with: sustained ROSC; initial shockable rhythm; an advanced airway; and an SpO2 ≥ 95%. Initially (Sept 2015-March 2016) patients were randomised 1:1 to either 2 L/minute (L/min) oxygen (titrated) or >10 L/min oxygen (control) via a bag-valve reservoir. However, one site experienced a high number of desaturations (SpO2 < 94%) in the titrated arm and this arm was changed (April 2016) to an initial reduction of oxygen to 4 L/min then, if tolerated, to 2 L/min, and the desaturation limit was decreased to <90%. RESULTS: We randomised 61 patients to titrated (n = 37: 2L/min = 20 and 2-4 L/min = 17) oxygen or control (n = 24). Patients allocated to titrated oxygen were more likely to desaturate compared to controls ((SpO2 < 94%: 43% vs. 4%, p = 0.001; SpO2 < 90%: 19% vs. 4%, p = 0.09). The majority of desaturations (81%) occurred at 2L/min. On arrival at hospital the majority of patients had a SpO2 ≥ 94% (titrated: 90% vs. control: 100%) and all patients had a SpO2 ≥ 90%. One patient (control) re-arrested. Survival to hospital discharge was similar. CONCLUSION: Oxygen titration post-ROSC is feasible in the prehospital environment, but incremental titration commencing at 4L/min oxygen flow may be needed to maintain an oxygen saturation >90% (NCT02499042).

Regional variation in the characteristics, incidence and outcomes of out-of-hospital cardiac arrest in Australia and New Zealand: Results from the Aus-ROC Epistry.

INTRODUCTION: The aim of this study was to investigate regional variation in the characteristics, incidence and outcomes of out-of-hospital cardiac arrest (OHCA) in Australia and New Zealand. METHODS: This was a population-based cohort study of OHCA using data from the Aus-ROC Australian and New Zealand OHCA Epistry over the period of 01 January 2015-31 December 2015. Seven ambulance services contributed data to the Epistry with a capture population of 19.8 million people. All OHCA attended by ambulance, regardless of aetiology or patient age, were included. RESULTS: In 2015, there were 19,722 OHCA cases recorded in the Aus-ROC Epistry with an overall crude incidence of 102.5 cases per 100,000 population (range: 51.0-107.7 per 100,000 population). Of all OHCA cases attended by EMS (excluding EMS-witnessed cases), bystander CPR was performed in 41% of cases (range: 36%-50%). Resuscitation was attempted (by EMS) in 48% of cases (range: 40%-68%). The crude incidence for attempted resuscitation cases was 47.6 per 100,000 population (range: 34.7-54.1 per 100,000 population). Of cases with attempted resuscitation, 28% survived the event (range: 21%-36%) and 12% survived to hospital discharge or 30 days (range: 9%-17%; data provided by five ambulance services). CONCLUSION: In the first results of the Aus-ROC Australian and New Zealand OHCA Epistry, significant regional variation in the incidence, characteristics and outcomes was observed. Understanding the system-level and public health drivers of this variation will assist in optimisation of the chain of survival provided to OHCA patients with the aim of improving outcomes.

Randomized comparison of the SLIPA (Streamlined Liner of the Pharynx Airway) and the SS-LM (Soft Seal Laryngeal Mask) by medical students.

OBJECTIVE: The aim of the study was to compare the Streamlined Liner of the Pharynx Airway (SLIPA; Hudson RCI), a new supraglottic airway device, with the Soft Seal Laryngeal Mask (SS-LM; Portex) when used by novices. METHODS: Thirty-six medical students with no previous airway experience, received manikin training in the use of the SLIPA and the SS-LM. Once proficient, the students inserted each device in randomized sequence, in two separate patients in the operating theatre. Only two insertion attempts per patient were allowed. Students were assessed in terms of: device preference; success or failure; success at first attempt and time to ventilation. RESULTS: Sixty-seven per cent of the students preferred to use the SLIPA (95% confidence interval 49-81%). The SLIPA was successfully inserted (one or two attempts) in 94% of patients (34/36) and the SS-LM in 89% (32/36) (P = 0.39). First attempt success rates were 83% (30/36) and 67% (24/36) in the SLIPA and SS-LM, respectively (P = 0.10). Median time to ventilation was shorter with the SLIPA (40.6 s) than with the SS-LM (66.9 s) when it was the first device used (P = 0.004), but times were similar when inserting the second device (43.8 s vs 42.9 s) (P = 0.75). CONCLUSIONS: In the present study novice users demonstrated high success rates with both devices. The SLIPA group achieved shorter times to ventilation when it was the first device they inserted, which might prove to be of clinical significance, particularly in resuscitation attempts. Although the Laryngeal Mask has gained wide recognition for use by both novice users and as a rescue airway in failed intubation, the data presented here suggest that the SLIPA might also prove useful in these areas.

Establishing the Aus-ROC Australian and New Zealand out-of-hospital cardiac arrest Epistry.

INTRODUCTION: Out-of-hospital cardiac arrest (OHCA) is a global health problem with low survival. Regional variation in survival has heightened interest in combining cardiac arrest registries to understand and improve OHCA outcomes. While individual OHCA registries exist in Australian and New Zealand ambulance services, until recently these registries have not been combined. The aim of this protocol paper is to describe the rationale and methods of the Australian Resuscitation Outcomes Consortium (Aus-ROC) OHCA epidemiological registry (Epistry). METHODS AND ANALYSIS: The Aus-ROC Epistry is designed as a population-based cohort study. Data collection started in 2014. Six ambulance services in Australia (Ambulance Victoria, SA Ambulance Service, St John Ambulance Western Australia and Queensland Ambulance Service) and New Zealand (St John New Zealand and Wellington Free Ambulance) currently contribute data. All OHCA attended by ambulance, regardless of aetiology or patient age, are included in the Epistry. The catchment population is approximately 19.3 million persons, representing 63% of the Australian population and 100% of the New Zealand population. Data are collected using Utstein-style definitions. Information incorporated into the Epistry includes demographics, arrest features, ambulance response times, treatment and patient outcomes. The primary outcome is 'survival to hospital discharge', with 'return of spontaneous circulation' as a key secondary outcome. ETHICS AND DISSEMINATION: Ethics approval was independently sought by each of the contributing registries. Overarching ethics for the Epistry was provided by Monash University HREC (Approval No. CF12/3938-2012001888). A population-based OHCA registry capturing the majority of Australia and New Zealand will allow risk-adjusted outcomes to be determined, to enable benchmarking across ambulance providers, facilitate the identification of system-wide strategies associated with survival from OHCA, and allow monitoring of temporal trends in process and outcomes to improve patient care. Findings will be shared with participating ambulance services and the academic community.

Description of the ambulance services participating in the Aus-ROC Australian and New Zealand out-of-hospital cardiac arrest Epistry.

OBJECTIVE: The present study aimed to describe and examine similarities and differences in the current service provision and resuscitation protocols of the ambulance services participating in the Aus-ROC Australian and New Zealand out-of-hospital cardiac arrest (OHCA) Epistry. Understanding these similarities and differences is important in identifying ambulance service factors that might explain regional variation in survival of OHCA in the Aus-ROC Epistry. METHODS: A structured questionnaire was completed by each of the ambulance services participating in the Aus-ROC Epistry. These ambulance services were SA Ambulance Service, Ambulance Victoria, St John Ambulance Western Australia, Queensland Ambulance Service, St John Ambulance NT, St John New Zealand and Wellington Free Ambulance. The survey aimed to describe ambulance service and dispatch characteristics, resuscitation protocols and details of cardiac arrest registries. RESULTS: We observed similarities between services with respect to the treatment of OHCA and dispatch systems. Differences between services were observed in the serviced population; the proportion of paramedics with basic life support, advanced life support or intensive care training skills; the number of OHCA cases attended; guidelines related to withholding or terminating resuscitation attempts; and the variables that might be used to define 'attempted resuscitation'. All seven participating ambulance services were noted to have existing OHCA registries. CONCLUSION: There is marked variation between ambulance services currently participating in the Aus-ROC Australian and New Zealand OHCA Epistry with respect to workforce characteristics and key variable definitions. This variation between ambulance services might account for a proportion of the regional variation in survival of OHCA.

A training program for novice paramedics provides initial laryngeal mask airway insertion skill and improves skill retention at 6 months.

INTRODUCTION: Major resuscitation councils endorse the use of the laryngeal mask airway (LMA) by paramedics for lifesaving airway interventions. Learning and maintaining adequate skill level is important for patient safety. The aim of this project was to develop a training program that provides student paramedics with initial knowledge and experience in LMA insertion skills but equally important to provide ongoing skill retention. METHODS: After ethics approval and informed consent, 55 first year Paramedic degree students watched a manufacturer's LMA instruction video and practiced insertion in three different part task trainers. Six months later, subjects were randomized to an intervention (reviewing the video and 10 minutes unsupervised practice) or control group before participating in a high-fidelity simulated clinical scenario. For equity of training, the control group received the intervention after the scenario. Main outcomes measured were time to insertion; success rate; and LMA skill retention (sum of LMA orientation; cuff inflation; bite block; securing; patient positioning; and overall subject performance). RESULTS: Fifty subjects completed the study. Those in the intervention group displayed significantly shorter insertion times (P = 0.029), fewer attempts to achieve success (P = 0.033), and had significantly higher LMA skill performance levels (P = 0.019) at 6 months. CONCLUSIONS: We devised a short intervention based on our training program using a video and practice in part task trainers. In an assessment using high-fidelity simulation, we demonstrated significant improvements in maintenance of LMA insertion skills in student paramedics at 6 months. Our model of just-in-time assessment and reinforcement of training prevents skill decay and has implications for healthcare skills training in general.