The Impact of Nursing Delirium Preventive Interventions in the ICU: A Multicenter Cluster-randomized Controlled Clinical Trial.

Rationale: Delirium is common in critically ill patients and is associated with deleterious outcomes. Nonpharmacological interventions are recommended in current delirium guidelines, but their effects have not been unequivocally established. Objectives: To determine the effects of a multicomponent nursing intervention program on delirium in the ICU. Methods: A stepped-wedge cluster-randomized controlled trial was conducted in ICUs of 10 centers. Adult critically ill surgical, medical, or trauma patients at high risk of developing delirium were included. A multicomponent nursing intervention program focusing on modifiable risk factors was implemented as standard of care. The primary outcome was the number of delirium-free and coma-free days alive in 28 days after ICU admission. Measurements and Main Results: A total of 1,749 patients were included. Time spent on interventions per 8-hour shift was median (interquartile range) 38 (14-116) minutes in the intervention period and median 32 (13-73) minutes in the control period (P = 0.44). Patients in the intervention period had a median of 23 (4-27) delirium-free and coma-free days alive compared with a median of 23 (5-27) days for patients in the control group (mean difference, -1.21 days; 95% confidence interval, -2.84 to 0.42 d; P = 0.15). In addition, the number of delirium days was similar: median 2 (1-4) days (ratio of medians, 0.90; 95% confidence interval, 0.75 to 1.09; P = 0.27). Conclusions: In this large randomized controlled trial in adult ICU patients, a limited increase in the use of nursing interventions was achieved, and no change in the number of delirium-free and coma-free days alive in 28 days could be determined. Clinical trial registered with www.clinicaltrials.gov (NCT03002701).

Brain death/death by neurologic criteria determination: an update.

PURPOSE OF REVIEW: Brain death, also known as death by neurologic criteria (DNC), is a well-established concept. In this article, we present a short history of the concept and give an overview of recent changes and a practical update on diagnosis and definitions of brain death/DNC. Unresolved issues will be discussed. RECENT FINDINGS: There is variability in brain death/DNC determination worldwide. In recent years, successful attempts have been made to harmonize these criteria and, consequently, to improve public trust in the process and diagnosis. An international multidisciplinary collaboration has been created and it has published minimum criteria, provided guidance for professionals and encouragement to revise or develop guidelines on brain death/DNC worldwide. SUMMARY: There are two sets of criteria for declaration of death. First, if there is neither cardiac output nor respiratory effort, then cardiopulmonary criteria are used. Second, if both the cerebrum and brainstem have completely and permanently lost all functions, and there is a persistent coma, absent brainstem reflexes and no spontaneous respiratory effort, death can be declared on the basis of brain death/DNC. Although attempts to formulate uniform criteria are ongoing, consensus has been reached on the minimum criteria. Some inconsistencies and questions remain.

Copeptin as a marker of outcome after cardiac arrest: a sub-study of the TTM trial.

BACKGROUND: Arginine vasopressin has complex actions in critically ill patients, involving vasoregulatory status, plasma volume, and cortisol levels. Copeptin, a surrogate marker for arginine vasopressin, has shown promising prognostic features in small observational studies and is used clinically for early rule out of acute coronary syndrome. The objective of this study was to explore the association between early measurements of copeptin, circulatory status, and short-term survival after out-of-hospital cardiac arrest. METHODS: Serial blood samples were collected at 24, 48, and 72 h as part of the target temperature management at 33 °C versus 36 °C after cardiac arrest trial, an international multicenter randomized trial where unconscious survivors after out-of-hospital cardiac arrest were allocated to an intervention of 33 or 36 °C for 24 h. Primary outcome was 30-day survival with secondary endpoints circulatory cause of death and cardiovascular deterioration composite; in addition, we examined the correlation with extended the cardiovascular sequential organ failure assessment (eCvSOFA) score. RESULTS: Six hundred ninety patients were included in the analyses, of whom 203 (30.3%) developed cardiovascular deterioration within 24 h, and 273 (39.6%) died within 30 days. Copeptin measured at 24 h was found to be independently associated with 30-day survival, hazard ratio 1.17 [1.06-1.28], p = 0.001; circulatory cause of death, odds ratio 1.03 [1.01-1.04], p = 0.001; and cardiovascular deterioration composite, odds ratio of 1.05 [1.02-1.08], p < 0.001. Copeptin at 24 h was correlated with eCvSOFA score with rho 0.19 [0.12-0.27], p < 0.001. CONCLUSION: Copeptin is an independent marker of severity of the post cardiac arrest syndrome, partially related to circulatory failure. TRIAL REGISTRATION: Clinical Trials, NCT01020916. Registered November 26, 2009.

Circulating Levels of Brain-Enriched MicroRNAs Correlate with Neuron Specific Enolase after Cardiac Arrest-A Substudy of the Target Temperature Management Trial.

Outcome prognostication after cardiac arrest (CA) is challenging. Current multimodal prediction approaches would benefit from new biomarkers. MicroRNAs constitute a novel class of disease markers and circulating levels of brain-enriched ones have been associated with outcome after CA. To determine whether these levels reflect the extent of brain damage in CA patients, we assessed their correlation with neuron-specific enolase (NSE), a marker of brain damage. Blood samples taken 48 h after return of spontaneous circulation from two groups of patients from the Targeted Temperature Management trial were used. Patients were grouped depending on their neurological outcome at six months. Circulating levels of microRNAs were assessed by sequencing. NSE was measured at the same time-point. Among the 673 microRNAs detected, brain-enriched miR9-3p, miR124-3p and miR129-5p positively correlated with NSE levels (all p < 0.001). Interestingly, these correlations were absent when only the good outcome group was analyzed (p > 0.5). Moreover, these correlations were unaffected by demographic and clinical characteristics. All three microRNAs predicted neurological outcome at 6 months. Circulating levels of brain-enriched microRNAs are correlated with NSE levels and hence can reflect the extent of brain injury in patients after CA. This observation strengthens the potential of brain-enriched microRNAs to aid in outcome prognostication after CA.

Targeted hypothermia versus targeted Normothermia after out-of-hospital cardiac arrest (TTM2): A randomized clinical trial-Rationale and design.

BACKGROUND: Less than 500 participants have been included in randomized trials comparing hypothermia with regular care for out-of-hospital cardiac arrest patients, and many of these trials were small and at a high risk of bias. Consequently, the accrued data on this potentially beneficial intervention resembles that of a drug following small phase II trials. A large confirmatory trial is therefore warranted. METHODS: The TTM2-trial is an international, multicenter, parallel group, investigator-initiated, randomized, superiority trial in which a target temperature of 33°C after cardiac arrest will be compared with a strategy to maintain normothermia and early treatment of fever (≥37.8°C). Participants will be randomized within 3 hours of return of spontaneous circulation with the intervention period lasting 40 hours in both groups. Sedation will be mandatory for all patients throughout the intervention period. The clinical team involved with direct patient care will not be blinded to allocation group due to the inherent difficulty in blinding the intervention. Prognosticators, outcome-assessors, the steering group, the trial coordinating team, and trial statistician will be blinded. The primary outcome will be all-cause mortality at 180 days after randomization. We estimate a 55% mortality in the control group. To detect an absolute risk reduction of 7.5% with an alpha of 0.05 and 90% power, 1900 participants will be enrolled. The main secondary neurological outcome will be poor functional outcome (modified Rankin Scale 4-6) at 180 days after arrest. DISCUSSION: The TTM2-trial will compare hypothermia to 33°C with normothermia and early treatment of fever (≥37.8°C) after out-of-hospital cardiac arrest.

Associations between partial pressure of oxygen and neurological outcome in out-of-hospital cardiac arrest patients: an explorative analysis of a randomized trial.

OBJECTIVE: Exposure to hyperoxemia and hypoxemia is common in out-of-hospital cardiac arrest (OHCA) patients following return of spontaneous circulation (ROSC), but its effects on neurological outcome are uncertain, and study results are inconsistent. METHODS: Exploratory post hoc substudy of the Target Temperature Management (TTM) trial, including 939 patients after OHCA with return of spontaneous circulation (ROSC). The association between serial arterial partial pressures of oxygen (PaO2) during 37 h following ROSC and neurological outcome at 6 months, evaluated by Cerebral Performance Category (CPC), dichotomized to good (CPC 1-2) and poor (CPC 3-5), was investigated. In our analyses, we tested the association of hyperoxemia and hypoxemia, time-weighted mean PaO2, maximum PaO2 difference, and gradually increasing PaO2 levels (13.3-53.3 kPa) with poor neurological outcome. A subsequent analysis investigated the association between PaO2 and a biomarker of brain injury, peak serum Tau levels. RESULTS: Eight hundred sixty-nine patients were eligible for analysis. Three hundred patients (35%) were exposed to hyperoxemia or hypoxemia at some time point after ROSC. Our analyses did not reveal a significant association between hyperoxemia, hypoxemia, time-weighted mean PaO2 exposure or maximum PaO2 difference and poor neurological outcome at 6-month follow-up after correction for co-variates (all analyses p = 0.146-0.847). We were not able to define a PaO2 level significantly associated with the onset of poor neurological outcome. Peak serum Tau levels at either 48 or 72 h after ROSC were not associated with PaO2. CONCLUSION: Hyperoxemia or hypoxemia exposure occurred in one third of the patients during the first 37 h of hospitalization and was not significantly associated with poor neurological outcome after 6 months or with the peak s-Tau levels at either 48 or 72 h after ROSC.

Serum tau and neurological outcome in cardiac arrest.

OBJECTIVE: To test serum tau as a predictor of neurological outcome after cardiac arrest. METHODS: We measured the neuronal protein tau in serum at 24, 48, and 72 hours after cardiac arrest in 689 patients in the prospective international Target Temperature Management trial. The main outcome was poor neurological outcome, defined as Cerebral Performance Categories 3-5 at 6 months. RESULTS: Increased tau was associated with poor outcome at 6 months after cardiac arrest (median = 38.5, interquartile range [IQR] = 5.7-245ng/l in poor vs median = 1.5, IQR = 0.7-2.4ng/l in good outcome, for tau at 72 hours, p < 0.0001). Tau improved prediction of poor outcome compared to using clinical information (p < 0.0001). Tau cutoffs had low false-positive rates (FPRs) for good outcome while retaining high sensitivity for poor outcome. For example, tau at 72 hours had FPR = 2% (95% CI = 1-4%) with sensitivity = 66% (95% CI = 61-70%). Tau had higher accuracy than serum neuron-specific enolase (NSE; the area under the receiver operating characteristic curve was 0.91 for tau vs 0.86 for NSE at 72 hours, p = 0.00024). During follow-up (up to 956 days), tau was significantly associated with overall survival. The accuracy in predicting outcome by serum tau was equally high for patients randomized to 33 °C and 36 °C targeted temperature after cardiac arrest. INTERPRETATION: Serum tau is a promising novel biomarker for prediction of neurological outcome in patients with cardiac arrest. It may be significantly better than serum NSE, which is recommended in guidelines and currently used in clinical practice in several countries to predict outcome after cardiac arrest. Ann Neurol 2017;82:665-675.

Carbon dioxide dynamics in relation to neurological outcome in resuscitated out-of-hospital cardiac arrest patients: an exploratory Target Temperature Management Trial substudy.

BACKGROUND: Dyscarbia is common in out-of-hospital cardiac arrest (OHCA) patients and its association to neurological outcome is undetermined. METHODS: This is an exploratory post-hoc substudy of the Target Temperature Management (TTM) trial, including resuscitated OHCA patients, investigating the association between serial measurements of arterial partial carbon dioxide pressure (PaCO2) and neurological outcome at 6 months, defined by the Cerebral Performance Category (CPC) scale, dichotomized to good outcome (CPC 1 and 2) and poor outcome (CPC 3-5). The effects of hypercapnia and hypocapnia, and the time-weighted mean PaCO2 and absolute PaCO2 difference were analyzed. Additionally, the association between mild hypercapnia (6.0-7.30 kPa) and neurological outcome, its interaction with target temperature (33 °C and 36 °C), and the association between PaCO2 and peak serum-Tau were evaluated. RESULTS: Of the 939 patients in the TTM trial, 869 were eligible for analysis. Ninety-six percent of patients were exposed to hypocapnia or hypercapnia. None of the analyses indicated a statistical significant association between PaCO2 and neurological outcome (P = 0.13-0.96). Mild hypercapnia was not associated with neurological outcome (P = 0.78) and there was no statistically significant interaction with target temperature (Pinteraction = 0.95). There was no association between PaCO2 and peak serum-Tau levels 48 or 72 h after return of spontaneous circulation (ROSC). CONCLUSIONS: Dyscarbia is common after ROSC. No statistically significant association between PaCO2 in the post-cardiac arrest phase and neurological outcome at 6 months after cardiac arrest was detected. There was no significant interaction between mild hypercapnia and temperature in relation to neurological outcome.

Prediction and Outcome of Intensive Care Unit-Acquired Paresis.

BACKGROUND: Intensive care unit-acquired paresis (ICUAP) is associated with poor outcomes. Our objective was to evaluate predictors for ICUAP and the short-term outcomes associated with this condition. METHODS: A secondary analysis of a prospective study including 4157 mechanically ventilated adults in 494 intensive care units from 39 countries. After sedative interruption, patients were screened for ICUAP daily, which was defined as the presence of symmetric and flaccid quadriparesis associated with decreased or absent deep tendon reflexes. A multinomial logistic regression was used to create a predictive model for ICUAP. Propensity score matching was used to estimate the relationship between ICUAP and short-term outcomes (ie, weaning failure and intensive care unit [ICU] mortality). RESULTS: Overall, 114 (3%) patients had ICUAP. Variables associated with ICUAP were duration of mechanical ventilation (relative risk ratio [RRR] per day, 1.10; 95% confidence interval [CI] 1.08-1.12), steroid therapy (RRR 1.8; 95% CI, 1.2-2.8), insulin therapy (RRR 1.8; 95% CI 1.2-2.7), sepsis (RRR 1.9; 95% CI: 1.2 to 2.9), acute renal failure (RRR 2.2; 95% CI 1.5-3.3), and hematological failure (RRR 1.9; 95% CI: 1.2-2.9). Coefficients were used to generate a weighted scoring system to predict ICUAP. ICUAP was significantly associated with both weaning failure (paired rate difference of 22.1%; 95% CI 9.8-31.6%) and ICU mortality (paired rate difference 10.5%; 95% CI 0.1-24.0%). CONCLUSIONS: Intensive care unit-acquired paresis is relatively uncommon but is significantly associated with weaning failure and ICU mortality. We constructed a weighted scoring system, with good discrimination, to predict ICUAP in mechanically ventilated patients at the time of awakening.

An intermolecular electrostatic interaction controls the prepore-to-pore transition in a cholesterol-dependent cytolysin.

ß-Barrel pore-forming toxins (ßPFTs) form an obligatory oligomeric prepore intermediate before the formation of the ß-barrel pore. The molecular components that control the critical prepore-to-pore transition remain unknown for ßPFTs. Using the archetype ßPFT perfringolysin O, we show that E183 of each monomer within the prepore complex forms an intermolecular electrostatic interaction with K336 of the adjacent monomer on completion of the prepore complex. The signal generated throughout the prepore complex by this interaction irrevocably commits it to the formation of the membrane-inserted giant ß-barrel pore. This interaction supplies the free energy to overcome the energy barrier (determined here to be ∼ 19 kcal/mol) to the prepore-to-pore transition by the coordinated disruption of a critical interface within each monomer. These studies provide the first insight to our knowledge into the molecular mechanism that controls the prepore-to-pore transition for a ßPFT.

Dysglycemia, Glycemic Variability, and Outcome After Cardiac Arrest and Temperature Management at 33°C and 36°C.

OBJECTIVES: Dysglycemia and glycemic variability are associated with poor outcomes in critically ill patients. Targeted temperature management alters blood glucose homeostasis. We investigated the association between blood glucose concentrations and glycemic variability and the neurologic outcomes of patients randomized to targeted temperature management at 33°C or 36°C after cardiac arrest. DESIGN: Post hoc analysis of the multicenter TTM-trial. Primary outcome of this analysis was neurologic outcome after 6 months, referred to as "Cerebral Performance Category." SETTING: Thirty-six sites in Europe and Australia. PATIENTS: All 939 patients with out-of-hospital cardiac arrest of presumed cardiac cause that had been included in the TTM-trial. INTERVENTIONS: Targeted temperature management at 33°C or 36°C. MEASUREMENTS AND MAIN RESULTS: Nonparametric tests as well as multiple logistic regression and mixed effects logistic regression models were used. Median glucose concentrations on hospital admission differed significantly between Cerebral Performance Category outcomes (p < 0.0001). Hyper- and hypoglycemia were associated with poor neurologic outcome (p = 0.001 and p = 0.054). In the multiple logistic regression models, the median glycemic level was an independent predictor of poor Cerebral Performance Category (Cerebral Performance Category, 3-5) with an odds ratio (OR) of 1.13 in the adjusted model (p = 0.008; 95% CI, 1.03-1.24). It was also a predictor in the mixed model, which served as a sensitivity analysis to adjust for the multiple time points. The proportion of hyperglycemia was higher in the 33°C group compared with the 36°C group. CONCLUSION: Higher blood glucose levels at admission and during the first 36 hours, and higher glycemic variability, were associated with poor neurologic outcome and death. More patients in the 33°C treatment arm had hyperglycemia.

Withdrawal of Life-Sustaining Therapy after Cardiac Arrest.

An increasing number of patients are successfully resuscitated from cardiac arrest (CA) and subsequently treated in an intensive care unit due to unconsciousness. Approximately half of these patients will die during the first weeks postarrest, typically after a determination of a poor neurologic prognosis and a decision to withdraw life-sustaining therapy (WLST). These decisions are guided by universal ethical principles. Neurologic prognostication, WLST, and functional outcome after CA are closely correlated, but routines vary between and within countries. Recent studies indicate that premature decisions to withdraw care may be common. This topical review will focus on the decision of WLST for patients remaining unconscious after CA, the guiding ethical principles, and the interaction with neurologic prognostication and outcome.

Protein S100 as outcome predictor after out-of-hospital cardiac arrest and targeted temperature management at 33 °C and 36 °C.

BACKGROUND: We aimed to investigate the diagnostic performance of S100 as an outcome predictor after out-of-hospital cardiac arrest (OHCA) and the potential influence of two target temperatures (33 °C and 36 °C) on serum levels of S100. METHODS: This is a substudy of the Target Temperature Management after Out-of-Hospital Cardiac Arrest (TTM) trial. Serum levels of S100 were measured a posteriori in a core laboratory in samples collected at 24, 48, and 72 h after OHCA. Outcome at 6 months was assessed using the Cerebral Performance Categories Scale (CPC 1-2 = good outcome, CPC 3-5 = poor outcome). RESULTS: We included 687 patients from 29 sites in Europe. Median S100 values were higher in patients with a poor outcome at 24, 48, and 72 h: 0.19 (IQR 0.10-0.49) versus 0.08 (IQR 0.06-0.11) µg/ml, 0.16 (IQR 0.10-0.44) versus 0.07 (IQR 0.06-0.11) µg/L, and 0.13 (IQR 0.08-0.26) versus 0.06 (IQR 0.05-0.09) µg/L (p < 0.001), respectively. The ability to predict outcome was best at 24 h with an AUC of 0.80 (95% CI 0.77-0.83). S100 values were higher at 24 and 72 h in the 33 °C group than in the 36 °C group (0.12 [0.07-0.22] versus 0.10 [0.07-0.21] µg/L and 0.09 [0.06-0.17] versus 0.08 [0.05-0.10], respectively) (p < 0.02). In multivariable analyses including baseline variables and the allocated target temperature, the addition of S100 improved the AUC from 0.80 to 0.84 (95% CI 0.81-0.87) (p < 0.001), but S100 was not an independent outcome predictor. Adding S100 to the same model including neuron-specific enolase (NSE) did not further improve the AUC. CONCLUSIONS: The allocated target temperature did not affect S100 to a clinically relevant degree. High S100 values are predictive of poor outcome but do not add value to present prognostication models with or without NSE. S100 measured at 24 h and afterward is of limited value in clinical outcome prediction after OHCA. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01020916 . Registered on 25 November 2009.

Cognitive function in survivors of out-of-hospital cardiac arrest after target temperature management at 33°C versus 36°C.

BACKGROUND: Target temperature management is recommended as a neuroprotective strategy after out-of-hospital cardiac arrest. Potential effects of different target temperatures on cognitive impairment commonly described in survivors have not been investigated sufficiently. The primary aim of this study was to evaluate whether a target temperature of 33°C compared with 36°C was favorable for cognitive function; the secondary aim was to describe cognitive impairment in cardiac arrest survivors in general. METHODS AND RESULTS: Study sites included 652 cardiac arrest survivors originally randomized and stratified for site to temperature control at 33°C or 36°C within the Target Temperature Management trial. Survival until 180 days after the arrest was 52% (33°C, n=178/328; 36°C, n=164/324). Survivors were invited to a face-to-face follow-up, and 287 cardiac arrest survivors (33°C, n=148/36°C, n=139) were assessed with tests for memory (Rivermead Behavioural Memory Test), executive functions (Frontal Assessment Battery), and attention/mental speed (Symbol Digit Modalities Test). A control group of 119 matched patients hospitalized for acute ST-segment-elevation myocardial infarction without cardiac arrest performed the same assessments. Half of the cardiac arrest survivors had cognitive impairment, which was mostly mild. Cognitive outcome did not differ (P>0.30) between the 2 temperature groups (33°C/36°C). Compared with control subjects with ST-segment-elevation myocardial infarction, attention/mental speed was more affected among cardiac arrest patients, but results for memory and executive functioning were similar. CONCLUSIONS: Cognitive function was comparable in survivors of out-of-hospital cardiac arrest when a temperature of 33°C and 36°C was targeted. Cognitive impairment detected in cardiac arrest survivors was also common in matched control subjects with ST-segment-elevation myocardial infarction not having had a cardiac arrest. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01946932.

Targeted temperature management at 33°C versus 36°C after cardiac arrest.

BACKGROUND: Unconscious survivors of out-of-hospital cardiac arrest have a high risk of death or poor neurologic function. Therapeutic hypothermia is recommended by international guidelines, but the supporting evidence is limited, and the target temperature associated with the best outcome is unknown. Our objective was to compare two target temperatures, both intended to prevent fever. METHODS: In an international trial, we randomly assigned 950 unconscious adults after out-of-hospital cardiac arrest of presumed cardiac cause to targeted temperature management at either 33°C or 36°C. The primary outcome was all-cause mortality through the end of the trial. Secondary outcomes included a composite of poor neurologic function or death at 180 days, as evaluated with the Cerebral Performance Category (CPC) scale and the modified Rankin scale. RESULTS: In total, 939 patients were included in the primary analysis. At the end of the trial, 50% of the patients in the 33°C group (235 of 473 patients) had died, as compared with 48% of the patients in the 36°C group (225 of 466 patients) (hazard ratio with a temperature of 33°C, 1.06; 95% confidence interval [CI], 0.89 to 1.28; P=0.51). At the 180-day follow-up, 54% of the patients in the 33°C group had died or had poor neurologic function according to the CPC, as compared with 52% of patients in the 36°C group (risk ratio, 1.02; 95% CI, 0.88 to 1.16; P=0.78). In the analysis using the modified Rankin scale, the comparable rate was 52% in both groups (risk ratio, 1.01; 95% CI, 0.89 to 1.14; P=0.87). The results of analyses adjusted for known prognostic factors were similar. CONCLUSIONS: In unconscious survivors of out-of-hospital cardiac arrest of presumed cardiac cause, hypothermia at a targeted temperature of 33°C did not confer a benefit as compared with a targeted temperature of 36°C. (Funded by the Swedish Heart-Lung Foundation and others; TTM ClinicalTrials.gov number, NCT01020916.).

Bradycardia During Targeted Temperature Management: An Early Marker of Lower Mortality and Favorable Neurologic Outcome in Comatose Out-of-Hospital Cardiac Arrest Patients.

OBJECTIVES: Bradycardia is common during targeted temperature management, likely being a physiologic response to lower body temperature, and has recently been associated with favorable outcome following out-of-hospital cardiac arrest in smaller observational studies. The present study sought to confirm this finding in a large multicenter cohort of patients treated with targeted temperature management at 33°C and explore the response to targeted temperature management targeting 36°C. DESIGN: Post hoc analysis of a prospective randomized study. SETTING: Thirty-six ICUs in 10 countries. PATIENTS: We studied 447 (targeted temperature management = 33°C) and 430 (targeted temperature management = 36°C) comatose out-of-hospital cardiac arrest patients with available heart rate data, randomly assigned in the targeted temperature management trial from 2010 to 2013. INTERVENTIONS: Targeted temperature management at 33°C and 36°C. MEASUREMENTS AND MAIN RESULTS: Endpoints were 180-day mortality and unfavorable neurologic function (cerebral performance category 3-5). Patients were stratified by target temperature and minimum heart rate during targeted temperature management (< 50, 50-59, and ≥ 60 beats/min [reference]) at 12, 20, and 28 hours after randomization. Heart rates less than 50 beats/min and 50-59 beats/min were recorded in 132 (30%) and 131 (29%) of the 33°C group, respectively. Crude 180-day mortality increased with increasing minimum heart rate (< 50 beats/min = 32%, 50-59 beats/min = 43%, and ≥ 60 beats/min = 60%; p(log-rank) < 0.0001). Bradycardia less than 50 beats/min was independently associated with lower 180-day mortality (hazard ratio(adjusted) = 0.50 [0.34-0.74; p < 0.001]) and lower odds of unfavorable neurologic outcome (odds ratio(adjusted) = 0.38 [ 0.21-0.68; p < 0.01]) in models adjusting for potential confounders including age, initial rhythm, time to return of spontaneous circulation, and lactate at admission. Similar, albeit less strong, independent associations of lower heart rates and favorable outcome were found in patients treated with targeted temperature management at 36°C. CONCLUSIONS: This study confirms an independent association of bradycardia and lower mortality and favorable neurologic outcome in a large cohort of comatose out-of-hospital cardiac arrest patients treated by targeted temperature management at 33°C. Bradycardia during targeted temperature management at 33°C may thus be a novel, early marker of favorable outcome.

New classification of donation after circulatory death donors definitions and terminology.

In the face of a crisis in organ donation, the transplant community are increasingly utilizing donation after circulatory death (DCD) donors. Over the last 10 years, with the increasing usage of DCD donors, we have seen the introduction in a number of new terms and definitions. We report the results of the 6th International Conference in Organ Donation held in Paris in 2013 and report a consensus agreement of an established expert European Working Group on the definitions and terminology regarding DCD donation, including refinement of the Maastricht definitions. This document forms part of a special series where recommendations are presented for uncontrolled and controlled DCD donation and organ specific guidelines for kidney, pancreas, liver and lung transplantation. An expert panel formed a consensus on definitions and terms aiming to establish consistent usage of terms in DCD donation.

Intravascular versus surface cooling for targeted temperature management after out-of-hospital cardiac arrest - an analysis of the TTM trial data.

BACKGROUND: Targeted temperature management is recommended after out-of-hospital cardiac arrest and may be achieved using a variety of cooling devices. This study was conducted to explore the performance and outcomes for intravascular versus surface devices for targeted temperature management after out-of-hospital cardiac arrest. METHOD: A retrospective analysis of data from the Targeted Temperature Management trial. N = 934. A total of 240 patients (26%) managed with intravascular versus 694 (74%) with surface devices. Devices were assessed for speed and precision during the induction, maintenance and rewarming phases in addition to adverse events. All-cause mortality, as well as a composite of poor neurological function or death, as evaluated by the Cerebral Performance Category and modified Rankin scale were analysed. RESULTS: For patients managed at 33 °C there was no difference between intravascular and surface groups in the median time taken to achieve target temperature (210 [interquartile range (IQR) 180] minutes vs. 240 [IQR 180] minutes, p = 0.58), maximum rate of cooling (1.0 [0.7] vs. 1.0 [0.9] °C/hr, p = 0.44), the number of patients who reached target temperature (within 4 hours (65% vs. 60%, p = 0.30); or ever (100% vs. 97%, p = 0.47), or episodes of overcooling (8% vs. 34%, p = 0.15). In the maintenance phase, cumulative temperature deviation (median 3.2 [IQR 5.0] °C hr vs. 9.3 [IQR 8.0] °C hr, p = <0.001), number of patients ever out of range (57.0% vs. 91.5%, p = 0.006) and median time out of range (1 [IQR 4.0] hours vs. 8.0 [IQR 9.0] hours, p = <0.001) were all significantly greater in the surface group although there was no difference in the occurrence of pyrexia. Adverse events were not different between intravascular and surface groups. There was no statistically significant difference in mortality (intravascular 46.3% vs. surface 50.0%; p = 0.32), Cerebral Performance Category scale 3-5 (49.0% vs. 54.3%; p = 0.18) or modified Rankin scale 4-6 (49.0% vs. 53.0%; p = 0.48). CONCLUSIONS: Intravascular and surface cooling was equally effective during induction of mild hypothermia. However, surface cooling was associated with less precision during the maintenance phase. There was no difference in adverse events, mortality or poor neurological outcomes between patients treated with intravascular and surface cooling devices. TRIAL REGISTRATION: TTM trial ClinicalTrials.gov number https://clinicaltrials.gov/ct2/show/NCT01020916 NCT01020916; 25 November 2009.

The structural basis for membrane binding and pore formation by lymphocyte perforin.

Natural killer cells and cytotoxic T lymphocytes accomplish the critically important function of killing virus-infected and neoplastic cells. They do this by releasing the pore-forming protein perforin and granzyme proteases from cytoplasmic granules into the cleft formed between the abutting killer and target cell membranes. Perforin, a 67-kilodalton multidomain protein, oligomerizes to form pores that deliver the pro-apoptopic granzymes into the cytosol of the target cell. The importance of perforin is highlighted by the fatal consequences of congenital perforin deficiency, with more than 50 different perforin mutations linked to familial haemophagocytic lymphohistiocytosis (type 2 FHL). Here we elucidate the mechanism of perforin pore formation by determining the X-ray crystal structure of monomeric murine perforin, together with a cryo-electron microscopy reconstruction of the entire perforin pore. Perforin is a thin 'key-shaped' molecule, comprising an amino-terminal membrane attack complex perforin-like (MACPF)/cholesterol dependent cytolysin (CDC) domain followed by an epidermal growth factor (EGF) domain that, together with the extreme carboxy-terminal sequence, forms a central shelf-like structure. A C-terminal C2 domain mediates initial, Ca(2+)-dependent membrane binding. Most unexpectedly, however, electron microscopy reveals that the orientation of the perforin MACPF domain in the pore is inside-out relative to the subunit arrangement in CDCs. These data reveal remarkable flexibility in the mechanism of action of the conserved MACPF/CDC fold and provide new insights into how related immune defence molecules such as complement proteins assemble into pores.

Comorbidity burden is not associated with higher mortality after out-of-hospital cardiac arrest.

OBJECTIVES: We investigated whether comorbidity burden of comatose survivors of out-of-hospital cardiac arrest (OHCA) affects outcome and if comorbidity modifies the effect of target temperature management (TTM) on final outcome. DESIGN: The TTM trial randomized 939 patients to 24 h of TTM at either 33 or 36 °C with no difference regarding mortality and neurological outcome. This post-hoc study of the TTM-trial formed a modified comorbidity index (mCI), based on available comorbidities from the Charlson comorbidity index (CCI). RESULTS: Bystander cardiopulmonary resuscitation (CPR) decreased with higher comorbidity group, p = 0.01. Comorbidity groups were univariately associated with higher mortality compared to mCI0 (HRmCI1: 1.55, CI: 1.25-1.93, p < 0.001, HRmCI2: 2.01, CI: 1.55-2.62, p < 0.001, HRmCI ≥ 3: 2.16, CI: 1.57-2.97, p < 0.001). When adjusting for confounders there was a consistent, nonsignificant association between level of comorbidity and mortality (HRmC11: 1.17, CI: 0.92-1.48, p = 0.21, HRmCI2: 1.28, CI: 0.96-1.71, p = 0.10, HRmCI ≥ 3: 1.37, CI: 0.97-1.95, p = 0.08). There was no interaction between comorbidity burden and level of TTM on outcome, p = 0.61. CONCLUSION: Comorbidity burden was associated with higher mortality following OHCA, but when adjusting for confounders, the influence was no longer significant. The association between mCI and mortality was not modified by TTM. Comorbidity burden is associated with lower rates of bystander cardiopulmonary resuscitation after OHCA.