Improving Appropriate Neurologic Prognostication after Cardiac Arrest. A Stepped Wedge Cluster Randomized Controlled Trial

Randomized controlled trials in resuscitation

Randomized controlled trials (RCTs) are a gold standard in research and crucial to our understanding of resuscitation science. Many trials in resuscitation have had neutral findings, questioning which treatments are effective in cardiac resuscitation. While it is possible than many interventions do not improve patient outcomes, it is also possible that the large proportion of neutral findings are partially due to design limitations. RCTs can be challenging to implement, and require extensive resources, time, and funding. In addition, conducting RCTs in the out-of-hospital setting provides unique challenges that must be considered for a successful trial. This article will outline many important aspects of conducting trials in resuscitation in the out-of-hospital setting including patient and outcome selection, trial design, and statistical analysis.

Identifying behaviour change techniques in 287 randomized controlled trials of audit and feedback interventions targeting practice change among healthcare professionals

BACKGROUND

Audit and feedback (A&F) is among the most widely used implementation strategies, providing healthcare professionals with summaries of their practice performance to prompt behaviour change and optimize care. Wide variability in effectiveness of A&F has spurred efforts to explore why some A&F interventions are more effective than others. Unpacking the variability of the content of A&F interventions in terms of their component behaviours change techniques (BCTs) may help advance our understanding of how A&F works best. This study aimed to systematically specify BCTs in A&F interventions targeting healthcare professional practice change.

METHODS

We conducted a directed content analysis of intervention descriptions in 287 randomized trials included in an ongoing Cochrane systematic review update of A&F interventions (searched up to June 2020). Three trained researchers identified and categorized BCTs in all trial arms (treatment & control/comparator) using the 93-item BCT Taxonomy version 1. The original BCT definitions and examples in the taxonomy were adapted to include A&F-specific decision rules and examples. Two additional BCTs ('Education (unspecified)' and 'Feedback (unspecified)') were added, such that 95 BCTs were considered for coding.

RESULTS

In total, 47/95 BCTs (49%) were identified across 360 treatment arms at least once (median = 5.0, IQR = 2.3, range = 129 per arm). The most common BCTs were 'Feedback on behaviour' (present 89% of the time; e.g. feedback on drug prescribing), 'Instruction on how to perform the behaviour' (71%; e.g. issuing a clinical guideline), 'Social comparison' (52%; e.g. feedback on performance of peers), 'Credible source' (41%; e.g. endorsements from respected professional body), and 'Education (unspecified)' (31%; e.g. giving a lecture to staff). A total of 130/287 (45%) control/comparator arms contained at least one BCT (median = 2.0, IQR = 3.0, range = 0-15 per arm), of which the most common were identical to those identified in treatment arms.

CONCLUSIONS

A&F interventions to improve healthcare professional practice include a moderate range of BCTs, focusing predominantly on providing behavioural feedback, sharing guidelines, peer comparison data, education, and leveraging credible sources. We encourage the use of our A&F-specific list of BCTs to improve knowledge of what is being delivered in A&F interventions. Our study provides a basis for exploring which BCTs are associated with intervention effectiveness.

TRIAL REGISTRATIONS

N/A.

Associations between clinical characteristics of cardiac arrest and early CT head findings of hypoxic ischaemic brain injury following out-of-hospital cardiac arrest

BACKGROUND/OBJECTIVE

Post-cardiac arrest patients are vulnerable to hypoxic-ischaemic brain injury (HIBI), but HIBI may not be identified until computed tomography (CT) scan of the brain is obtained post-resuscitation and stabilization. We aimed to evaluate the association of clinical arrest characteristics with early CT findings of HIBI to identify those at the highest risk for HIBI.

METHODS

This is a retrospective analysis of out-of-hospital cardiac arrest (OHCA) patients who underwent whole-body imaging. Head CT reports were analyzed with an emphasis on findings suggestive of HIBI; HIBI was present if any of the following were noted on the neuroradiologist read: global cerebral oedema, sulcal effacement, blurred grey-white junction, and ventricular compression. The primary exposure was duration of cardiac arrest. Secondary exposures included age, cardiac vs noncardiac etiology, and witnessed vs unwitnessed arrest. The primary outcome was CT findings of HIBI.

RESULTS

A total of 180 patients (average age 54 years, 32% female, 71% White, 53% witnessed arrest, 32% cardiac etiology of arrest, mean CPR duration of 15 ± 10 minutes) were included in this analysis. CT findings of HIBI were seen in 47 (48.3%) patients. Multivariate logistic regression demonstrated a significant association between CPR duration and HIBI (adjusted OR = 1.1, 95% CI 1.01-1.11, p < 0.01).

CONCLUSION

Signs of HIBI are commonly seen on CT head within 6 hours of OHCA, occurring in approximately half of patients, and are associated with CPR duration. Determining risk factors for abnormal CT findings can help clinically identify patients at higher risk for HIBI and target interventions appropriately.

Neuroprognostication in the Post Cardiac Arrest Patient: A Canadian Cardiovascular Society Position Statement

Cardiac arrest (CA) is associated with a low rate of survival with favourable neurologic recovery. The most common mechanism of death after successful resuscitation from CA is withdrawal of life-sustaining measures on the basis of perceived poor neurologic prognosis due to underlying hypoxic-ischemic brain injury. Neuroprognostication is an important component of the care pathway for CA patients admitted to hospital but is complex, challenging, and often guided by limited evidence. Using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to evaluate the evidence underlying factors or diagnostic modalities available to determine prognosis, recommendations were generated in the following domains: (1) circumstances immediately after CA; (2) focused neurologic exam; (3) myoclonus and seizures; (4) serum biomarkers; (5) neuroimaging; (6) neurophysiologic testing; and (7) multimodal neuroprognostication. This position statement aims to serve as a practical guide to enhance in-hospital care of CA patients and emphasizes the adoption of a systematic, multimodal approach to neuroprognostication. It also highlights evidence gaps.

Review Paper on Penetrating Brain Injury: Ethical Quandaries in the Trauma Bay and Beyond

OBJECTIVE

The aim of this review was to review the ethical and multidisciplinary clinical challenges facing trauma surgeons when resuscitating patients presenting with penetrating brain injury (PBI) and multicavitary trauma.

BACKGROUND

While there is a significant gap in the literature on managing PBI in patients presenting with multisystem trauma, recent data demonstrate that resuscitation and prognostic features for such patients remains poorly described, with trauma guidelines out of date in this field.

METHODS

We reviewed a combination of recent multidisciplinary evidence-informed guidelines for PBI and coupled this with expert opinion from trauma, neurosurgery, neurocritical care, pediatric and transplant surgery, surgical ethics and importantly our community partners.

RESULTS

Traditional prognostic signs utilized in traumatic brain injury may not be applicable to PBI with a multidisciplinary team approach suggested on a case-by-case basis. Even with no role for neurosurgical intervention, neurocritical care, and neurointerventional support may be warranted, in parallel to multicavitary operative intervention. Special considerations should be afforded for pediatric PBI. Ethical considerations center on providing the patient with the best chance of survival. Consideration of organ donation should be considered as part of the continuum of patient, proxy and family-centric support and care. Community input is crucial in guiding decision making or protocol establishment on an institutional level.

CONCLUSIONS

Support of the patient after multicavitary PBI can be complex and is best addressed in a multidisciplinary fashion with extensive community involvement.

Methods of Capturing Process Outcomes in Quality Improvement Trials: A Systematic Review

ABSTRACT

Healthcare quality can be measured by studying structure, processes, and outcomes. This study examines how trialists capture process outcomes in implementation trials to provide guidance for researchers and health professionals. Electronic databases were searched, and two researchers performed the title, abstract, and full-text selection. Only implementation studies involving nonpharmacological approaches were included. Data were extracted by one reviewer and checked for accuracy and completeness by a second reviewer. Study quality was independently assessed by two reviewers. Of the 3,186 articles screened, 24 studies matched our inclusion criteria. Most studies were cluster randomized control trials, followed by interrupted time series studies and stepped wedge studies. The population in the studies was diverse and settings included hospitals, community centers, residential aged care facilities, and primary care. The reporting of process measures across the included studies varied, and there was limited information about the mechanisms of data collection procedures. Nineteen studies extracted information about processes from electronic medical records, patient records, or chart reviews. The remaining five studies used staff surveys. Challenges remain in the practical aspect of data collection for measuring process outcomes, particularly outside of hospital settings or where processes are hard to capture in patient records.

Inappropriate use of clinical practices in Canada: a systematic review

Background:

Inappropriate health care leads to negative patient experiences, poor health outcomes and inefficient use of resources. We aimed to conduct a systematic review of inappropriately used clinical practices in Canada.

Methods:

We searched multiple bibliometric databases and grey literature to identify inappropriately used clinical practices in Canada between 2007 and 2021. Two team members independently screened citations, extracted data and assessed methodological quality. Findings were synthesized in 2 categories: diagnostics and therapeutics. We reported ranges of proportions of inappropriate use for all practices. Medians and interquartile ranges (IQRs), based on the percentage of patients not receiving recommended practices (underuse) or receiving practices not recommended (overuse), were calculated. All statistics are at the study summary level.

Results:

We included 174 studies, representing 228 clinical practices and 28 900 762 patients. The median proportion of inappropriate care, as assessed in the studies, was 30.0% (IQR 12.0%–56.6%). Underuse (median 43.9%, IQR 23.8%–66.3%) was more frequent than overuse (median 13.6%, IQR 3.2%–30.7%). The most frequently investigated diagnostics were glycated hemoglobin (underused, range 18.0%–85.7%, n = 9) and thyroid-stimulating hormone (overused, range 3.0%–35.1%, n = 5). The most frequently investigated therapeutics were statin medications (underused, range 18.5%–71.0%, n = 6) and potentially inappropriate medications (overused, range 13.5%–97.3%, n = 9).

Interpretation:

We have provided a summary of inappropriately used clinical practices in Canadian health care systems. Our findings can be used to support health care professionals and quality agencies to improve patient care and safety in Canada.

Consent models in Canadian critical care randomized controlled trials: a scoping review

PURPOSE

Our primary objective was to describe consent models used in Canadian-led adult and pediatric intensive care unit (ICU/PICU) randomized controlled trials (RCTs). Our secondary objectives were to determine the consent rate of ICU/PICU RCTs that did and did not use an alternate consent model to describe consent procedures.

SOURCE

Using scoping review methodology, we searched MEDLINE, Embase, and CENTRAL databases (from 1998 to June 2019) for trials published in English or French. We included Canadian-led RCTs that reported on the effects of an intervention on ICU/PICU patients or their families. Two independent reviewers assessed eligibility, abstracted data, and achieved consensus.

PRINCIPAL FINDINGS

We identified 48 RCTs of 17,558 patients. Included RCTs had ethics approval to use prior informed consent (43/48; 90%), deferred consent (13/48; 27%), waived consent (5/48; 10%), and verbal consent (1/48; 2%) models. Fifteen RCTs (15/48; 31%) had ethics approval to use more than one consent model. Twice as many trials used alternate consent between 2010 and 2019 (13/19) than between 2000 and 2009 (6/19). The consent rate for RCTs using only prior informed consent ranged from 54 to 91% (ICU) and 43 to 94% (PICU) and from 78 to 100% (ICU) and 74 to 87% (PICU) in trials using an alternate/hybrid consent model.

CONCLUSION

Alternate consent models were used in the minority of Canadian-led ICU/PICU RCTs but have been used more frequently over the last decade. This suggests that Canadian ethics boards and research communities are becoming more accepting of alternate consent models in ICU/PICU trials.

Rationale, Methodological Quality, and Reporting of Cluster-Randomized Controlled Trials in Critical Care Medicine: A Systematic Review

OBJECTIVE

Compared with individual-patient randomized controlled trials, cluster randomized controlled trials have unique methodological and ethical considerations. We evaluated the rationale, methodological quality, and reporting of cluster randomized controlled trials in critical care studies.

DATA SOURCES

Systematic searches of Medline, Embase, and Cochrane Central Register were performed.

STUDY SELECTION

We included all cluster randomized controlled trials conducted in adult, pediatric, or neonatal critical care units from January 2005 to September 2019.

DATA EXTRACTION

Two reviewers independently screened citations, reviewed full texts, protocols, and supplements of potentially eligible studies, abstracted data, and assessed methodology of included studies.

DATA SYNTHESIS

From 1,902 citations, 59 cluster randomized controlled trials met criteria. Most focused on quality improvement (24, 41%), antimicrobial therapy (9, 15%), or infection control (9, 15%) interventions. Designs included parallel-group (25, 42%), crossover (21, 36%), and stepped-wedge (13, 22%). Concealment of allocation was reported in 21 studies (36%). Thirteen studies (22%) reported at least one method of blinding. The median total sample size was 1,660 patients (interquartile range, 813-4,295); the median number of clusters was 12 (interquartile range, 5-24); and the median patients per cluster was 141 (interquartile range, 54-452). Sample size calculations were reported in 90% of trials, but only 54% met Consolidated Standards of Reporting Trials guidance for sample size reporting. Twenty-seven of the studies (46%) identified a fixed number of available clusters prior to trial commencement, and only nine (15%) prespecified both the number of clusters and patients required to detect the expected effect size. Overall, 36 trials (68%) achieved the total prespecified sample size. When analyzing data, 44 studies (75%) appropriately adjusted for clustering when analyzing the primary outcome. Only 12 (20%) reported an intracluster coefficient (median 0.047 [interquartile range, 0.01-0.13]).

CONCLUSIONS

Cluster randomized controlled trials in critical care typically involve a small and fixed number of relatively large clusters. The reporting of key methodological aspects of these trials is often inadequate.

Audit and Feedback in emergency: a systematic review and an Italian project to investigate and improve quality of care

The Audit and Feedback process (AandF) is commonly accepted as a good way to improve quality in health care, also in Emergency Departments (ED), where health aspects and pathologies are very different, usually acute and highly complex. Within an Italian Ministry of Health research project called EASY-NET, we conducted a systematic review of literature on AandF in EDs from 2014 to December 2019 to evaluate the impact of this approach in a particular setting where time-dependent indicators are fundamental. We selected 24 articles: 9 about infective pathologies (i.e. antibiotic stewardship), 6 about cardiovascular acute emergencies (i.e. cardiac arrest), 2 about stroke, 3 about laboratory tests, and 4 about other fields (i.e. diabetic ketoacidosis or use of prothrombin complex). Most of articles proposed a multimodal approach: only 7 concerned AandF alone. Despite the wide range on interventions modality and the poor comparability of the considered studies, the results are encouraging and confirm the importance to implement AandF both in emergency and in other clinical settings.

Cerebral Edema After Cardiopulmonary Resuscitation: A Therapeutic Target Following Cardiac Arrest?

We sought to review the role that cerebral edema plays in neurologic outcome following cardiac arrest, to understand whether cerebral edema might be an appropriate therapeutic target for neuroprotection in patients who survive cardiopulmonary resuscitation. Articles indexed in PubMed and written in English. Following cardiac arrest, cerebral edema is a cardinal feature of brain injury and is a powerful prognosticator of neurologic outcome. Like other conditions characterized by cerebral ischemia/reperfusion, neuroprotection after cardiac arrest has proven to be difficult to achieve. Neuroprotection after cardiac arrest generally has focused on protecting neurons, not the microvascular endothelium or blood-brain barrier. Limited preclinical data suggest that strategies to reduce cerebral edema may improve neurologic outcome. Ongoing research will be necessary to determine whether targeting cerebral edema will improve patient outcomes after cardiac arrest.

Prognostication via early computed tomography head in patients treated with targeted temperature management after cardiac arrest

BACKGROUND

We evaluated computed tomography head (CTH) imaging obtained prior to targeted temperature management (TTM) in patients after cardiac arrest, and its role in prognostication.

METHODS

In this retrospective cohort study in a tertiary-care hospital, 341 adults presenting with out-of-hospital cardiac arrest received a CTH prior to TTM. Associations between outcomes and neuroimaging variables were evaluated with Chi-square analysis for significant associations that yielded a composite neuroimaging score-Tennessee Early Neuroimaging Score (TENS). Univariable and multivariable logistic regression analysis including TENS as an independent variable and the four outcome dependent variables were analyzed.

RESULTS

Four of the neuroimaging variables-sulcal effacement, partial gray-white matter effacement, total gray-white matter effacement, deep nuclei effacement-had significant associations with each of the four outcome variables and yielded TENS. In multivariable logistic regression models adjusted for potential confounders, TENS was associated with poor discharge CPC (OR 2.15, 95%CI 1.16-3.98, p = .015), poor disposition (OR 2.62, 95%CI 1.37-5.02, p = .004), in-hospital mortality (OR 1.99, 95%CI 1.09-3.62, p = .024), and ICU mortality (OR 1.89, 95%CI 1.12-3.20, p = .018).

CONCLUSION

Imaging prior to TTM may help identify post-cardiac arrest patients with severe anoxic brain injury and poor outcomes.

Does Calculated Prognostic Estimation Lead to Different Outcomes Compared With Experience-Based Prognostication in the ICU? A Systematic Review

Little is known about the impact of providing calculator/guideline based versus clinical experiential-based prognostic estimates to patients/caregivers in the ICU. We sought to determine whether studies have compared types of prognostic estimation in the ICU and associations with outcomes.

Data Sources

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, databases searched were PubMed, Embase, Web of Science, and Cochrane Library. The search was run on January 4, 2016, and April 12, 2017. References for included articles were searched.

Study Selection

Studies meeting the following criteria were included in the analysis: communication of prognostic estimates, a comparator group, and in the adult ICU setting.

Data Extraction

Titles/abstracts were reviewed by two researchers. We identified 10,704 articles of which 10 met inclusion criteria. Seven of the studies included estimates obtained from calculators/guidelines and three were based on subjective estimation wherein clinicians were asked to estimate prognosis based on experience. Only the seven using calculated/guideline based estimation were used for pooled analysis. Of these, one was a randomized trial, and six were nonrandomized before/after studies. All of the studies communicated the calculated/guideline-based estimates to the clinician. Two studies involved the communication of calculated prognostic estimates to the ICU physicians for all ICU patients. Four included identification of high-risk patients based on guidelines or review of historical local data which triggered a palliative care/ethics consultation, and one study included communication to physicians about guideline based likely outcomes for neurologic recovery for patients with out-of-hospital cardiac arrest survivors. The comparator arm in all studies was usual care without protocolized prognostication.

Data Synthesis

Included studies were assessed for risk of bias. The most common outcomes measured were hospital mortality; do-not-resuscitate status; and medical ICU length of stay. In pooled analyses, there was an association between calculated/guideline based prognostic estimation and decreased medical ICU length of stay as well as increased do-not-resuscitate status, but no difference in hospital mortality.

Conclusions

Protocolized assessment of calculator/guideline based prognosis in ICU patients is associated with decreased medical ICU length of stay and increased do-not-resuscitate status but does not have a significant effect on mortality. Future studies should explore how communicating these estimates to physicians changes behaviors including communication to patients/families and whether calculator/guideline based prognostication is associated with improved patient and family rated outcomes.

Adrenaline and vasopressin for cardiac arrest

BACKGROUND

Adrenaline and vasopressin are widely used to treat people with cardiac arrest, but there is uncertainty about the safety, effectiveness and the optimal dose.

OBJECTIVES

To determine whether adrenaline or vasopressin, or both, administered during cardiac arrest, afford any survival benefit.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase and DARE from their inception to 8 May 2018, and the International Liaison Committee on Resuscitation 2015 Advanced Life Support Consensus on Science and Treatment Recommendations. We also searched four trial registers on 5 September 2018 and checked the reference lists of the included studies and review papers to identify potential papers for review.

SELECTION CRITERIA

Any randomised controlled trial comparing: standard-dose adrenaline versus placebo; standard-dose adrenaline versus high-dose adrenaline; and adrenaline versus vasopressin, in any setting, due to any cause of cardiac arrest, in adults and children. There were no language restrictions.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified trials for review, assessed risks of bias and extracted data, resolving disagreements through re-examination of the trial reports and by discussion. We used risk ratios (RRs) with 95% confidence intervals (CIs) to compare dichotomous outcomes for clinical events. There were no continuous outcomes reported. We examined groups of trials for heterogeneity. We report the quality of evidence for each outcome, using the GRADE approach.

MAIN RESULTS

We included 26 studies (21,704 participants).Moderate-quality evidence found that adrenaline increased survival to hospital discharge compared to placebo (RR 1.44, 95% CI 1.11 to 1.86; 2 studies, 8538 participants; an increase from 23 to 32 per 1000, 95% CI 25 to 42). We are uncertain about survival to hospital discharge for high-dose compared to standard-dose adrenaline (RR 1.10, 95% CI 0.75 to 1.62; participants = 6274; studies = 10); an increase from 33 to 36 per 1000, 95% CI 24 to 53); standard-dose adrenaline versus vasopressin (RR 1.25, 95% CI 0.84 to 1.85; 6 studies; 2511 participants; an increase from 72 to 90 per 1000, 95% CI 60 to 133); and standard-dose adrenaline versus vasopressin plus adrenaline (RR 0.76, 95% CI 0.47 to 1.22; 3 studies; 3242 participants; a possible decrease from 24 to 18 per 1000, 95% CI 11 to 29), due to very low-quality evidence.Moderate-quality evidence found that adrenaline compared with placebo increased survival to hospital admission (RR 2.51, 95% CI 1.67 to 3.76; 2 studies, 8489 participants; an increase from 83 to 209 per 1000, 95% CI 139 to 313). We are uncertain about survival to hospital admission when comparing standard-dose with high-dose adrenaline, due to very low-quality evidence. Vasopressin may improve survival to hospital admission when compared with standard-dose adrenaline (RR 1.27, 95% CI 1.04 to 1.54; 3 studies, 1953 participants; low-quality evidence; an increase from 260 to 330 per 1000, 95% CI 270 to 400), and may make little or no difference when compared to standard-dose adrenaline plus vasopressin (RR 0.95, 95% CI 0.83 to 1.08; 3 studies; 3249 participants; low-quality evidence; a decrease from 218 to 207 per 1000 (95% CI 181 to 236).There was no evidence that adrenaline (any dose) or vasopressin improved neurological outcomes.The rate of return of spontaneous circulation (ROSC) was higher for standard-dose adrenaline versus placebo (RR 2.86, 95% CI 2.21 to 3.71; participants = 8663; studies = 3); moderate-quality evidence; an increase from 115 to 329 per 1000, 95% CI 254 to 427). We are uncertain about the effect on ROSC for the comparison of standard-dose versus high-dose adrenaline and standard-does adrenaline compared to vasopressin, due to very low-quality evidence. Standard-dose adrenaline may make little or no difference to ROSC when compared to standard-dose adrenaline plus vasopressin (RR 0.97, 95% CI 0.87 to 1.08; 3 studies, 3249 participants; low-quality evidence; a possible decrease from 299 to 290 per 1000, 95% CI 260 to 323).The source of funding was not stated in 11 of the 26 studies. The study drugs were provided by the manufacturer in four of the 26 studies, but neither drug represents a profitable commercial option. The other 11 studies were funded by organisations such as research foundations and government funding bodies.

AUTHORS' CONCLUSIONS

This review provides moderate-quality evidence that standard-dose adrenaline compared to placebo improves return of spontaneous circulation, survival to hospital admission and survival to hospital discharge, but low-quality evidence that it did not affect survival with a favourable neurological outcome. Very low -quality evidence found that high-dose adrenaline compared to standard-dose adrenaline improved return of spontaneous circulation and survival to admission. Vasopressin compared to standard dose adrenaline improved survival to admission but not return of spontaneous circulation, whilst the combination of adrenaline and vasopressin compared with adrenaline alone had no effect on these outcomes. Neither standard dose adrenaline, high-dose adrenaline,vasopressin nor a combination of adrenaline and vasopressin improved survival with a favourable neurological outcome. Many of these studies were conducted more than 20 years ago. Treatment has changed in recent years, so the findings from older studies may not reflect current practice.

Systematic review showed that stepped-wedge cluster randomized trials often did not reach their planned sample size

OBJECTIVE

To determine how often stepped-wedge cluster randomized controlled trials reach their planned sample size, and what reasons are reported for choosing a stepped-wedge trial design.

STUDY DESIGN AND SETTING

We conducted a PubMed literature search (period 2012 to 2017) and included articles describing the results of a stepped-wedge cluster randomized trial. We calculated the percentage of studies reaching their prespecified number of participants and clusters, and we summarized the reasons for choosing the stepped-wedge trial design as well as difficulties during enrollment.

RESULTS

Forty-six individual stepped-wedge studies from a total of 53 articles were included in our review. Of the 35 studies, for which recruitment rate could be calculated, 69% recruited their planned number of participants, with 80% having recruited the planned number of clusters. Ethical reasons were the most common motivation for choosing the stepped-wedge trial design. Most important difficulties during study conduct were dropout of clusters and delayed implementation of the intervention.

CONCLUSION

About half of recently published stepped-wedge trials reached their planned sample size indicating that recruitment is also a major problem in these trials. Still, the stepped-wedge trial design can yield practical, ethical, and methodological advantages.

The efficacy and safety of pre-hospital cooling after out-of-hospital cardiac arrest: a systematic review and meta-analysis

Background

Mild therapeutic hypothermia (TH), or targeted temperature management, improves survival and neurological outcomes in patients after out-of-hospital cardiac arrest (OHCA). International guidelines strongly support initiating TH for all eligible individuals presenting with OHCA; however, the timing of cooling initiation remains uncertain. This systematic review and meta-analysis was conducted with all available randomised controlled trials (RCTs) included to explore the efficacy and safety of initiating pre-hospital TH in patients with OHCA.

Methods

The MEDLINE and Cochrane databases were searched from inception to October 2017. Inclusion criteria for full-text review included RCTs comparing pre-hospital TH with no pre-hospital TH after cardiac arrest, patients > 14 years of age with documented cardiac arrest from any rhythm, and outcome data that included survival to hospital discharge and temperature at hospital arrival. Results of retrieved studies were compared through meta-analysis using random effects modelling.

Results

A total of 10 trials comprising 4220 patients were included. There were no significant differences between the two arms for the primary outcome of neurological recovery (risk ratio [RR] 1.04, 95% CI 0.93–1.15) or the secondary outcome of survival to hospital discharge (RR 1.01, 95% CI 0.92–1.11). However, there was a significantly lower temperature at hospital arrival in patients receiving pre-hospital TH (mean difference − 0.83, 95% CI − 1.03 to − 0.63). Pre-hospital TH significantly increased the risk of re-arrest (RR 1.19, 95% CI 1.00 to 1.41). No survival differences were observed among subgroups of patients who received intra-arrest TH vs post-arrest TH or who had shockable vs non-shockable rhythms.

Conclusions

Pre-hospital TH after OHCA effectively decreases body temperature at the time of hospital arrival. However, it does not improve rates of survival with good neurological outcome or overall survival and is associated with increased rates of re-arrest.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-1984-2) contains supplementary material, which is available to authorized users.

Improving Temporal Trends in Survival and Neurological Outcomes After Out-of-Hospital Cardiac Arrest

BACKGROUND

Considerable effort has gone into improving outcomes from out-of-hospital cardiac arrest (OHCA). Studies suggest that survival is improving; however, prior studies had insufficient data to pursue the relationship between markers of guideline compliance and temporal trends. The objective of the study was to evaluate trends in OHCA survival over an 8-year period that included the implementation of the 2005 and 2010 international cardiopulmonary resuscitation (CPR) guidelines.

METHODS AND RESULTS

This was a population-based cohort study of all consecutive treated OHCA patients of presumed cardiac cause between 2006 and 2013 in the City of Toronto, Canada, and surrounding regions. Temporal changes were measured by χ2 trend test. The association between year of the OHCA and survival was evaluated using logistic regression and joinpoint analysis. A total of 23 619 patients with OHCA met study inclusion criteria. During the study period, survival to hospital discharge doubled (4.8% in 2006 to 9.4% in 2013; P<0.0001), and survival with good neurological outcome increased (6.2% in 2010 to 8.5% in 2013; P=0.005). Improvements occurred in the rates of bystander CPR and automated external defibrillator application, high-quality CPR metrics, and in-hospital targeted temperature management. After adjusting for the Utstein variables, survival to hospital discharge (odds ratio, 1.12; 95% confidence interval, 1.09-1.15) and survival with good neurological outcome (odds ratio, 1.13; 95% confidence interval, 1.05-1.22) increased with each year of study.

CONCLUSIONS

Survival after OHCA has improved over time. This trend was associated with improved rates of bystander CPR, automated external defibrillator use, high-quality CPR metrics, and in-hospital targeted temperature management. The results suggest that multiple factors, each improving over time, may have contributed to the observed increase in survival.

Factors associated with post-arrest withdrawal of life-sustaining therapy

INTRODUCTION

Most successfully resuscitated cardiac arrest patients do not survive to hospital discharge. Many have withdrawal of life sustaining therapy (WLST) as a result of the perception of poor neurologic prognosis. The characteristics of these patients and differences in their post-arrest care are largely unknown.

METHODS

Utilizing the Penn Alliance for Therapeutic Hypothermia Registry, we identified a cohort of 1311 post-arrest patients from 26 hospitals from 2010 to 2014 who remained comatose after return of spontaneous circulation. We stratified patients by whether they had WLST post-arrest and analyzed demographic, arrest, and post-arrest variables.

RESULTS

In our cohort, 565 (43%) patients had WLST. In multivariate regression, patients who had WLST were less likely to go to the cardiac catheterization lab (OR 0.40; 95% CI: 0.26-0.62) and had shorter hospital stays (OR 0.93; 95% CI: 0.91-0.95). When multivariate regression was limited to patient demographics and arrest characteristics, patients with WLST were older (OR 1.18; 95% CI: 1.07-1.31 by decade), had a longer arrest duration (OR 1.14; 95% CI: 1.05-1.25 per 10min), more likely to be female (OR: 1.41; 95% CI: 1.01-1.96), and less likely to have a witnessed arrest (OR 0.65; 95% CI: 0.42-0.98).

CONCLUSION

Patients with WLST differ in terms of demographic, arrest, and post-arrest characteristics and treatments from those who did not have WLST. Failure to account for this variability could affect both clinical practice and the interpretation of research.