Clinical review: beyond immediate survival from resuscitation-long-term outcome considerations after cardiac arrest

Adrenaline to improve survival in out-of-hospital cardiac arrest: the PARAMEDIC2 RCT

BACKGROUND

Adrenaline has been used as a treatment for cardiac arrest for many years, despite uncertainty about its effects on long-term outcomes and concerns that it may cause worse neurological outcomes.

OBJECTIVES

The objectives were to evaluate the effects of adrenaline on survival and neurological outcomes, and to assess the cost-effectiveness of adrenaline use.

DESIGN

This was a pragmatic, randomised, allocation-concealed, placebo-controlled, parallel-group superiority trial and economic evaluation. Costs are expressed in Great British pounds and reported in 2016/17 prices.

SETTING

This trial was set in five NHS ambulance services in England and Wales.

PARTICIPANTS

Adults treated for an out-of-hospital cardiac arrest were included. Patients were ineligible if they were pregnant, if they were aged < 16 years, if the cardiac arrest had been caused by anaphylaxis or life-threatening asthma, or if adrenaline had already been given.

INTERVENTIONS

Participants were randomised to either adrenaline (1 mg) or placebo in a 1 : 1 allocation ratio by the opening of allocation-concealed treatment packs.

MAIN OUTCOME MEASURES

The primary outcome was survival to 30 days. The secondary outcomes were survival to hospital admission, survival to hospital discharge, survival at 3, 6 and 12 months, neurological outcomes and health-related quality of life through to 6 months. The economic evaluation assessed the incremental cost per quality-adjusted life-year gained from the perspective of the NHS and Personal Social Services. Participants, clinical teams and those assessing patient outcomes were masked to the treatment allocation.

RESULTS

From December 2014 to October 2017, 8014 participants were assigned to the adrenaline (n = 4015) or to the placebo (n = 3999) arm. At 30 days, 130 out of 4012 participants (3.2%) in the adrenaline arm and 94 out of 3995 (2.4%) in the placebo arm were alive (adjusted odds ratio for survival 1.47, 95% confidence interval 1.09 to 1.97). For secondary outcomes, survival to hospital admission was higher for those receiving adrenaline than for those receiving placebo (23.6% vs. 8.0%; adjusted odds ratio 3.83, 95% confidence interval 3.30 to 4.43). The rate of favourable neurological outcome at hospital discharge was not significantly different between the arms (2.2% vs. 1.9%; adjusted odds ratio 1.19, 95% confidence interval 0.85 to 1.68). The pattern of improved survival but no significant improvement in neurological outcomes continued through to 6 months. By 12 months, survival in the adrenaline arm was 2.7%, compared with 2.0% in the placebo arm (adjusted odds ratio 1.38, 95% confidence interval 1.00 to 1.92). An adjusted subgroup analysis did not identify significant interactions. The incremental cost-effectiveness ratio for adrenaline was estimated at £1,693,003 per quality-adjusted life-year gained over the first 6 months after the cardiac arrest event and £81,070 per quality-adjusted life-year gained over the lifetime of survivors. Additional economic analyses estimated incremental cost-effectiveness ratios for adrenaline at £982,880 per percentage point increase in overall survival and £377,232 per percentage point increase in neurological outcomes over the first 6 months after the cardiac arrest.

LIMITATIONS

The estimate for survival with a favourable neurological outcome is imprecise because of the small numbers of patients surviving with a good outcome.

CONCLUSIONS

Adrenaline improved long-term survival, but there was no evidence that it significantly improved neurological outcomes. The incremental cost-effectiveness ratio per quality-adjusted life-year exceeds the threshold of £20,000-30,000 per quality-adjusted life-year usually supported by the NHS.

FUTURE WORK

Further research is required to better understand patients' preferences in relation to survival and neurological outcomes after out-of-hospital cardiac arrest and to aid interpretation of the trial findings from a patient and public perspective.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN73485024 and EudraCT 2014-000792-11.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 25. See the NIHR Journals Library website for further project information.

Long term outcomes of participants in the PARAMEDIC2 randomised trial of adrenaline in out-of-hospital cardiac arrest

AIMS

We recently reported early outcomes in patients enrolled in a randomised trial of adrenaline in out-of-hospital cardiac arrest: the PARAMEDIC2 (Prehospital Assessment of the Role of Adrenaline: Measuring the Effectiveness of Drug Administration in Cardiac Arrest) trial. The purpose of the present paper is to report long-term survival, quality of life, functional and cognitive outcomes at 3, 6 and 12-months.

METHODS

PARAMEDIC2 was a pragmatic, individually randomised, double blind, controlled trial with an economic evaluation. Patients were randomised to either adrenaline or placebo. This paper reports results on the modified Rankin Scale scores at 6-months, survival at 6 and 12-months, as well as other cognitive, functional and quality of life outcomes collected at 3 and 6 months (Two Simple Questions, the Mini Mental State Examination, the Informant Questionnaire on Cognitive Decline Evaluation for Cardiac Arrest, Hospital Anxiety and Depression Scale, the Post Traumatic Stress Disorder Checklist - Civilian Version, Short-Form 12-item Health Survey and the EuroQoL EQ-5D-5L).

RESULTS

8014 patients were randomised with confirmed trial drug administration. At 6-months, 78 (2.0%) of the patients in the adrenaline group and 58 (1.5%) of patients in the placebo group had a favourable neurological outcome (adjusted odds ratio 1.35 [95% confidence interval: 0.93, 1.97]). 117 (2.9%) patients were alive at 6-months in the adrenaline group compared with 86 (2.2%) in the placebo group (1.43 [1.05, 1.96], reducing to 107 (2.7%) and 80 (2.0%) respectively at 12-months (1.38 [1.00, 1.92]). Measures of 3 and 6-month cognitive, functional and quality of life outcomes were reduced, but there was no strong evidence of differences between groups.

CONCLUSION

Adrenaline improved survival through to 12-months follow-up. The study did not find evidence of improvements in favourable neurological outcomes. (ISCRTN 73485024).

Teriflunomide provides protective properties after oxygen-glucose-deprivation in hippocampal and cerebellar slice cultures

One of the major challenges in emergency medicine is out-of-hospital cardiac arrest (OHCA). Every year, about 53-62/100 000 people worldwide suffer an out-of-hospital cardiac arrest with serious consequences, whereas persistent brain injury is a major cause of morbidity and mortality of those surviving a cardiac arrest. Today, only few and insufficient strategies are known to limit neurological damage of ischemia and reperfusion injury. The aim of the present study was to investigate whether teriflunomide, an approved drug for treatment of relapsing-remitting-multiple-sclerosis, exerts a protective effect on brain cells in an in vitro model of ischemia. Therefore, organotypic slice cultures from rat hippocampus and cerebellum were exposed to oxygen-glucose-deprivation and subsequently treated with teriflunomide. The administration of teriflunomide in the reperfusion time on both hippocampal and cerebellar slice cultures significantly decreased the amount of detectable propidium iodide signal compared with an untreated culture, indicating that more cells survive after oxygen-glucose-deprivation. However, hippocampal slice cultures showed a higher vulnerability to ischemic conditions and a more sensitive response to teriflunomide compared with cerebellar slice cultures. Our study suggests that teriflunomide, applied as a post-treatment after an oxygen-glucose-deprivation, has a protective effect on hippocampal and cerebellar cells in organotypic slice cultures of rats. All procedures were conducted under established standards of the German federal state of North Rhine Westphalia, in accordance with the European Communities Council Directive 2010/63/EU on the protection of animals used for scientific purposes.

Design paper of the "Blood pressure targets in post-resuscitation care and bedside monitoring of cerebral energy state: a randomized clinical trial"

BACKGROUND

Neurological injuries remain the leading cause of death in comatose patients resuscitated from out-of-hospital cardiac arrest (OHCA). Adequate blood pressure is of paramount importance to optimize cerebral perfusion and to minimize secondary brain injury. Markers measuring global cerebral ischemia caused by cardiac arrest and consecutive resuscitation and reflecting the metabolic variations after successful resuscitation are needed to assist a more individualized post-resuscitation care. Currently, no technique is available for bedside evaluation of global cerebral energy state, and until now blood pressure targets have been based on limited clinical evidence. Recent experimental and clinical studies indicate that it might be possible to evaluate cerebral oxidative metabolism from measuring the lactate-to-pyruvate (LP) ratio of the draining venous blood. In this study, jugular bulb microdialysis and immediate bedside biochemical analysis are introduced as new diagnostic tools to evaluate the effect of higher mean arterial blood pressure on global cerebral metabolism and the degree of cellular damage after OHCA.

METHODS/DESIGN

This is a single-center, randomized, double-blinded, superiority trial. Sixty unconscious patients with sustained return of spontaneous circulation after OHCA will be randomly assigned in a one-to-one fashion to low (63 mm Hg) or high (77 mm Hg) mean arterial blood pressure target. The primary end-point will be a difference in mean LP ratio within 48 h between blood pressure groups. Secondary end-points are (1) association between LP ratio and all-cause intensive care unit (ICU) mortality and (2) association between LP ratio and survival to hospital discharge with poor neurological function.

DISCUSSION

Markers measuring cerebral ischemia caused by cardiac arrest and consecutive resuscitation and reflecting the metabolic changes after successful resuscitation are urgently needed to enable a more personalized post-resuscitation care and prognostication. Jugular bulb microdialysis may provide a reliable global estimate of cerebral metabolic state and can be implemented as an entirely new and less invasive diagnostic tool for ICU patients after OHCA and has implications for early prognosis and treatment.

TRIAL REGISTRATION

ClinicalTrials.gov (ClinicalTrials.gov Identifier: NCT03095742 ). Registered March 30, 2017.

Physiology-directed cardiopulmonary resuscitation: advances in precision monitoring during cardiac arrest

PURPOSE OF REVIEW

We review the recent advances in physiologic monitoring during cardiac arrest and offer an evidence-based framework for prioritizing physiologic targets during cardiopulmonary resuscitation (CPR).

RECENT FINDINGS

Current CPR guidelines recommend a uniform approach for all patients in cardiac arrest, but newer data support a precision strategy that uses the individual patient's physiology to guide resuscitation. Coronary perfusion pressure and arterial DBP are associated with survival outcomes in recent animal and human studies. End-tidal carbon dioxide is a reasonable noninvasive alternative, but may be inferior to invasive hemodynamic endpoints. Cerebral oximetry and cardiac ultrasound are emerging physiologic indicators of CPR effectiveness.

SUMMARY

Physiologic monitoring can and should be used to deliver precision CPR whenever possible and may improve outcomes after cardiac arrest.

Prehospital randomised assessment of a mechanical compression device in out-of-hospital cardiac arrest (PARAMEDIC): a pragmatic, cluster randomised trial and economic evaluation

BACKGROUND

Mechanical chest compression devices may help to maintain high-quality cardiopulmonary resuscitation (CPR), but little evidence exists for their effectiveness. We evaluated whether or not the introduction of Lund University Cardiopulmonary Assistance System-2 (LUCAS-2; Jolife AB, Lund, Sweden) mechanical CPR into front-line emergency response vehicles would improve survival from out-of-hospital cardiac arrest (OHCA).

OBJECTIVE

Evaluation of the LUCAS-2 device as a routine ambulance service treatment for OHCA.

DESIGN

Pragmatic, cluster randomised trial including adults with non-traumatic OHCA. Ambulance dispatch staff and those collecting the primary outcome were blind to treatment allocation. Blinding of the ambulance staff who delivered the interventions and reported initial response to treatment was not possible. We also conducted a health economic evaluation and a systematic review of all trials of out-of-hospital mechanical chest compression.

SETTING

Four UK ambulance services (West Midlands, North East England, Wales and South Central), comprising 91 urban and semiurban ambulance stations. Clusters were ambulance service vehicles, which were randomly assigned (approximately 1 : 2) to the LUCAS-2 device or manual CPR.

PARTICIPANTS

Patients were included if they were in cardiac arrest in the out-of-hospital environment. Exclusions were patients with cardiac arrest as a result of trauma, with known or clinically apparent pregnancy, or aged < 18 years.

INTERVENTIONS

Patients received LUCAS-2 mechanical chest compression or manual chest compressions according to the first trial vehicle to arrive on scene.

MAIN OUTCOME MEASURES

Survival at 30 days following cardiac arrest; survival without significant neurological impairment [Cerebral Performance Category (CPC) score of 1 or 2].

RESULTS

We enrolled 4471 eligible patients (1652 assigned to the LUCAS-2 device and 2819 assigned to control) between 15 April 2010 and 10 June 2013. A total of 985 (60%) patients in the LUCAS-2 group received mechanical chest compression and 11 (< 1%) patients in the control group received LUCAS-2. In the intention-to-treat analysis, 30-day survival was similar in the LUCAS-2 (104/1652, 6.3%) and manual CPR groups [193/2819, 6.8%; adjusted odds ratio (OR) 0.86, 95% confidence interval (CI) 0.64 to 1.15]. Survival with a CPC score of 1 or 2 may have been worse in the LUCAS-2 group (adjusted OR 0.72, 95% CI 0.52 to 0.99). No serious adverse events were noted. The systematic review found no evidence of a survival advantage if mechanical chest compression was used. The health economic analysis showed that LUCAS-2 was dominated by manual chest compression.

LIMITATIONS

There was substantial non-compliance in the LUCAS-2 arm. For 272 out of 1652 patients (16.5%), mechanical chest compression was not used for reasons that would not occur in clinical practice. We addressed this issue by using complier average causal effect analyses. We attempted to measure CPR quality during the resuscitation attempts of trial participants, but were unable to do so.

CONCLUSIONS

There was no evidence of improvement in 30-day survival with LUCAS-2 compared with manual compressions. Our systematic review of recent randomised trials did not suggest that survival or survival without significant disability may be improved by the use of mechanical chest compression.

FUTURE WORK

The use of mechanical chest compression for in-hospital cardiac arrest, and in specific circumstances (e.g. transport), has not yet been evaluated.

TRIAI REGISTRATION

Current Controlled Trials ISRCTN08233942.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 11. See the NIHR Journals Library website for further project information.

Post-admission outcomes of participants in the PARAMEDIC trial: A cluster randomised trial of mechanical or manual chest compressions

BACKGROUND

The PARAMEDIC cluster randomised trial evaluated the LUCAS mechanical chest compression device, and did not find evidence that use of mechanical chest compression led to an improvement in survival at 30 days. This paper reports patient outcomes from admission to hospital to 12 months after randomisation.

METHODS

Information about hospital length of stay and intensive care management was obtained through linkage with Hospital Episode Statistics and the Intensive Care National Audit and Research Centre. Patients surviving to hospital discharge were approached to complete questionnaires (SF-12v2, EQ-5D, MMSE, HADS and PTSD-CL) at 90days and 12 months. The study is registered with Current Controlled Trials, number ISRCTN08233942.

RESULTS

377 patients in the LUCAS arm and 658 patients in the manual chest compression were admitted to hospital. Hospital and intensive care length of stay were similar. Long term follow-up assessments were limited by poor response rates (53.7% at 3 months and 55.6% at 12 months). Follow-up rates were lower in those with worse neurological function. Among respondents, long term health related quality of life outcomes and emotional well-being was similar between groups. Cognitive function, measured by MMSE, was marginally lower in the LUCAS arm mean 26.9 (SD 3.7) compared to control mean 28.0 (SD 2.3), adjusted mean difference -1.5 (95% CI -2.6 to -0.4).

CONCLUSION

There were no clinically important differences identified in outcomes at long term follow-up between those allocated to the mechanical chest compression compared to those receiving manual chest compression.

High survival rate of 43% in out-of-hospital cardiac arrest patients in an optimised chain of survival

AIMS

Survival to hospital discharge after out-of-hospital cardiac arrest (OHCA) varies widely. This study describes short-term survival after OHCA in a region with an extensive care path and a follow-up of 1 year.

METHODS

Consecutive patients ≥16 years admitted to the emergency department between April 2011 and December 2012 were included. In July 2014 a follow-up took place. Socio-demographic data, characteristics of the OHCA and interventions were described and associations with survival were determined.

RESULTS

Two hundred forty-two patients were included (73 % male, median age 65 years). In 76 % the cardiac arrest was of cardiac origin and 52 % had a shockable rhythm. In 74 % the cardiac arrest was witnessed, 76 % received bystander cardiopulmonary resuscitation and in 39 % an automatic external defibrillator (AED) was used. Of the 168 hospitalised patients, 144 underwent therapeutic procedures. A total of 105 patients survived until hospital discharge. Younger age, cardiac arrest in public area, witnessed cardiac arrest, cardiac origin with a shockable rhythm, the use of an AED, shorter time until return of spontaneous circulation, Glasgow Coma Scale (GCS) ≥13 during transport and longer length of hospital stay were associated with survival. Of the 105 survivors 72 survived for at least 1 year after cardiac arrest and 6 patients died.

CONCLUSION

A survival rate of 43 % after OHCA is achievable. Witnessed cardiac arrest, cardiac cause of arrest, initial cardiac rhythm and GCS ≥13 were associated with higher survival.

Brain resuscitation and prognosis after cardiac arrest

Brain injury represents the major cause of long-term disability and mortality among patients resuscitated from cardiac arrest. Brain-directed therapies include maintenance of normal oxygenation, hemodynamic support to optimize cerebral perfusion, glycemic control, and targeted temperature management. Pertinent guidelines and recommendations are reviewed for brain-directed treatment. The latest clinical trial data regarding targeted temperature management are also reviewed. Contemporary prognostication among initially comatose cardiac arrest survivors uses a combination of clinical and electrophysiologic tests. The most recent guidelines for prognostication after cardiac arrest are reviewed. Ongoing research regarding the effects of induced hypothermia on prognostic algorithms is also reviewed.