Mild Hypercapnia or Normocapnia after Out-of-Hospital Cardiac Arrest.

BACKGROUND: Guidelines recommend normocapnia for adults with coma who are resuscitated after out-of-hospital cardiac arrest. However, mild hypercapnia increases cerebral blood flow and may improve neurologic outcomes. METHODS: We randomly assigned adults with coma who had been resuscitated after out-of-hospital cardiac arrest of presumed cardiac or unknown cause and admitted to the intensive care unit (ICU) in a 1:1 ratio to either 24 hours of mild hypercapnia (target partial pressure of arterial carbon dioxide [Paco2], 50 to 55 mm Hg) or normocapnia (target Paco2, 35 to 45 mm Hg). The primary outcome was a favorable neurologic outcome, defined as a score of 5 (indicating lower moderate disability) or higher, as assessed with the use of the Glasgow Outcome Scale-Extended (range, 1 [death] to 8, with higher scores indicating better neurologic outcome) at 6 months. Secondary outcomes included death within 6 months. RESULTS: A total of 1700 patients from 63 ICUs in 17 countries were recruited, with 847 patients assigned to targeted mild hypercapnia and 853 to targeted normocapnia. A favorable neurologic outcome at 6 months occurred in 332 of 764 patients (43.5%) in the mild hypercapnia group and in 350 of 784 (44.6%) in the normocapnia group (relative risk, 0.98; 95% confidence interval [CI], 0.87 to 1.11; P = 0.76). Death within 6 months after randomization occurred in 393 of 816 patients (48.2%) in the mild hypercapnia group and in 382 of 832 (45.9%) in the normocapnia group (relative risk, 1.05; 95% CI, 0.94 to 1.16). The incidence of adverse events did not differ significantly between groups. CONCLUSIONS: In patients with coma who were resuscitated after out-of-hospital cardiac arrest, targeted mild hypercapnia did not lead to better neurologic outcomes at 6 months than targeted normocapnia. (Funded by the National Health and Medical Research Council of Australia and others; TAME ClinicalTrials.gov number, NCT03114033.).

2021 European Resuscitation Council/European Society of Intensive Care Medicine Algorithm for Prognostication of Poor Neurological Outcome After Cardiac Arrest-Can Entry Criteria Be Broadened?

OBJECTIVES: To explore broadened entry criteria of the 2021 European Resuscitation Council/European Society of Intensive Care Medicine (ERC/ESICM) algorithm for neuroprognostication including patients with ongoing sedation and Glasgow Coma Scale-Motor score (GCS-M) scores 4-5. DESIGN: Retrospective multicenter observational study. SETTING: Four ICUs, Skane, Sweden. PATIENTS: Postcardiac arrest patients managed at targeted temperature 36°C, 2014-2018. Neurologic outcome was assessed after 2-6 months according to the Cerebral Performance Category scale. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: In 794 included patients, median age was 69.5 years (interquartile range, 60.6-77.0 yr), 241 (30.4%) were female, 550 (69.3%) had an out-of-hospital cardiac arrest, and 314 (41.3%) had a shockable rhythm. Four hundred ninety-five patients were dead at follow-up, 330 of 495 died after a decision on withdrawal of life-sustaining therapies. At 72 hours after cardiac arrest 218 patients remained unconscious. The entry criteria of the original algorithm (GCS-M 1-3) was fulfilled by 163 patients and 115 patients with poor outcome were identified, with false positive rate (FPR) of 0% (95% CI, 0-79.4%) and sensitivity of 71.0% (95% CI, 63.6-77.4%). Inclusion of patients with ongoing sedation identified another 13 patients with poor outcome, generating FPR of 0% (95% CI, 0-65.8%) and sensitivity of 69.6% (95% CI, 62.6-75.8%). Inclusion of all unconscious patients (GCS-M 1-5), regardless of sedation, identified one additional patient, generating FPR of 0% (95% CI, 0-22.8) and sensitivity of 62.9% (95% CI, 56.1-69.2). The few patients with true negative prediction (patients with good outcome not fulfilling guideline criteria of a poor outcome) generated wide 95% CI for FPR. CONCLUSION: The 2021 ERC/ESICM algorithm for neuroprognostication predicted poor neurologic outcome with a FPR of 0%. Broadening inclusion criteria to include all unconscious patients regardless of ongoing sedation identified an additional small number of patients with poor outcome but did not affect the FPR. Results are limited by high rate of withdrawal of life-sustaining therapies and few patients with true negative prediction.

Plasma glial fibrillary acidic protein and tau: predictors of neurological outcome after cardiac arrest.

BACKGROUND: The purpose was to evaluate glial fibrillary acidic protein (GFAP) and total-tau in plasma as predictors of poor neurological outcome after out-of-hospital (OHCA) and in-hospital cardiac arrest (IHCA), including comparisons with neurofilament light (NFL) and neuron-specific enolase (NSE). METHODS: Retrospective multicentre observational study of patients admitted to an intensive care unit (ICU) in three hospitals in Sweden 2014-2018. Blood samples were collected at ICU admission, 12 h, and 48 h post-cardiac arrest. Poor neurological outcome was defined as Cerebral Performance Category 3-5 at 2-6 months after cardiac arrest. Plasma samples were retrospectively analysed for GFAP, tau, and NFL. Serum NSE was analysed in clinical care. Prognostic performances were tested with the area under the receiver operating characteristics curve (AUC). RESULTS: Of the 428 included patients, 328 were OHCA, and 100 were IHCA. At ICU admission, 12 h and 48 h post-cardiac arrest, GFAP predicted neurological outcome after OHCA with AUC (95% CI) 0.76 (0.70-0.82), 0.86 (0.81-0.90) and 0.91 (0.87-0.96), and after IHCA with AUC (95% CI) 0.77 (0.66-0.87), 0.83 (0.74-0.92) and 0.83 (0.71-0.95). At the same time points, tau predicted outcome after OHCA with AUC (95% CI) 0.72 (0.66-0.79), 0.75 (0.69-0.81), and 0.93 (0.89-0.96) and after IHCA with AUC (95% CI) 0.61 (0.49-0.74), 0.68 (0.56-0.79), and 0.77 (0.65-0.90). Adding the change in biomarker levels between time points did not improve predictive accuracy compared to the last time point. In a subset of patients, GFAP at 12 h and 48 h, as well as tau at 48 h, offered similar predictive value as NSE at 48 h (the earliest time point NSE is recommended in guidelines) after both OHCA and IHCA. The predictive performance of NFL was similar or superior to GFAP and tau at all time points after OHCA and IHCA. CONCLUSION: GFAP and tau are promising biomarkers for neuroprognostication, with the highest predictive performance at 48 h after OHCA, but not superior to NFL. The predictive ability of GFAP may be sufficiently high for clinical use at 12 h after cardiac arrest.

Changes in Practice of Controlled Hypothermia after Cardiac Arrest in the Past 20 Years: A Critical Care Perspective.

For 20 years, induced hypothermia and targeted temperature management have been recommended to mitigate brain injury and increase survival after cardiac arrest. On the basis of animal research and small clinical trials, the International Liaison Committee on Resuscitation strongly advocated hypothermia at 32-34 °C for 12-24 hours for comatose patients with out-of-hospital cardiac arrest with initial rhythm of ventricular fibrillation or nonperfusing ventricular tachycardia. The intervention was implemented worldwide. In the past decade, hypothermia and targeted temperature management have been investigated in larger clinical randomized trials focusing on target temperature depth, target temperature duration, prehospital versus in-hospital initiation, nonshockable rhythms, and in-hospital cardiac arrest. Systematic reviews suggest little or no effect of delivering the intervention on the basis of the summary of evidence, and the International Liaison Committee on Resuscitation today recommends only to treat fever and keep body temperature below 37.5 °C (weak recommendation, low-certainty evidence). Here we describe the evolution of temperature management for patients with cardiac arrest during the past 20 years and how the accrued evidence has influenced not only the recommendations but also the guideline process. We also discuss possible paths forward in this field, bringing up both whether fever management is at all beneficial for patients with cardiac arrest and which knowledge gaps future clinical trials in temperature management should address.

Plasma neurofilament light is a predictor of neurological outcome 12 h after cardiac arrest.

BACKGROUND: Previous studies have reported high prognostic accuracy of circulating neurofilament light (NfL) at 24-72 h after out-of-hospital cardiac arrest (OHCA), but performance at earlier time points and after in-hospital cardiac arrest (IHCA) is less investigated. We aimed to assess plasma NfL during the first 48 h after OHCA and IHCA to predict long-term outcomes. METHODS: Observational multicentre cohort study in adults admitted to intensive care after cardiac arrest. NfL was retrospectively analysed in plasma collected on admission to intensive care, 12 and 48 h after cardiac arrest. The outcome was assessed at two to six months using the Cerebral Performance Category (CPC) scale, where CPC 1-2 was considered a good outcome and CPC 3-5 a poor outcome. Predictive performance was measured with the area under the receiver operating characteristic curve (AUROC). RESULTS: Of 428 patients, 328 (77%) suffered OHCA and 100 (23%) IHCA. Poor outcome was found in 68% of OHCA and 55% of IHCA patients. The overall prognostic performance of NfL was excellent at 12 and 48 h after OHCA, with AUROCs of 0.93 and 0.97, respectively. The predictive ability was lower after IHCA than OHCA at 12 and 48 h, with AUROCs of 0.81 and 0.86 (p ≤ 0.03). AUROCs on admission were 0.77 and 0.67 after OHCA and IHCA, respectively. At 12 and 48 h after OHCA, high NfL levels predicted poor outcome at 95% specificity with 70 and 89% sensitivity, while low NfL levels predicted good outcome at 95% sensitivity with 71 and 74% specificity and negative predictive values of 86 and 88%. CONCLUSIONS: The prognostic accuracy of NfL for predicting good and poor outcomes is excellent as early as 12 h after OHCA. NfL is less reliable for the prediction of outcome after IHCA.

Neuropsychological outcome after cardiac arrest: results from a sub-study of the targeted hypothermia versus targeted normothermia after out-of-hospital cardiac arrest (TTM2) trial.

BACKGROUND: Cognitive impairment is common following out-of-hospital cardiac arrest (OHCA), but the nature of the impairment is poorly understood. Our objective was to describe cognitive impairment in OHCA survivors, with the hypothesis that OHCA survivors would perform significantly worse on neuropsychological tests of cognition than controls with acute myocardial infarction (MI). Another aim was to investigate the relationship between cognitive performance and the associated factors of emotional problems, fatigue, insomnia, and cardiovascular risk factors following OHCA. METHODS: This was a prospective case-control sub-study of The Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trial. Eight of 61 TTM2-sites in Sweden, Denmark, and the United Kingdom included adults with OHCA of presumed cardiac or unknown cause. A matched non-arrest control group with acute MI was recruited. At approximately 7 months post-event, we administered an extensive neuropsychological test battery and questionnaires on anxiety, depression, fatigue, and insomnia, and collected information on the cardiovascular risk factors hypertension and diabetes. RESULTS: Of 184 eligible OHCA survivors, 108 were included, with 92 MI controls enrolled. Amongst OHCA survivors, 29% performed z-score ≤ - 1 (at least borderline-mild impairment) in ≥ 2 cognitive domains, 14% performed z-score ≤ - 2 (major impairment) in ≥ 1 cognitive domain while 54% performed without impairment in any domain. Impairment was most pronounced in episodic memory, executive functions, and processing speed. OHCA survivors performed significantly worse than MI controls in episodic memory (mean difference, MD = - 0.37, 95% confidence intervals [- 0.61, - 0.12]), verbal (MD = - 0.34 [- 0.62, - 0.07]), and visual/constructive functions (MD = - 0.26 [- 0.47, - 0.04]) on linear regressions adjusted for educational attainment and sex. When additionally adjusting for anxiety, depression, fatigue, insomnia, hypertension, and diabetes, executive functions (MD = - 0.44 [- 0.82, - 0.06]) were also worse following OHCA. Diabetes, symptoms of anxiety, depression, and fatigue were significantly associated with worse cognitive performance. CONCLUSIONS: In our study population, cognitive impairment was generally mild following OHCA. OHCA survivors performed worse than MI controls in 3 of 6 domains. These results support current guidelines that a post-OHCA follow-up service should screen for cognitive impairment, emotional problems, and fatigue. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03543371. Registered 1 June 2018.

High-dose dexamethasone in low pain responders undergoing total knee arthroplasty: a randomised double-blind trial.

BACKGROUND: Postoperative pain after total knee arthroplasty (TKA) is a continuing problem despite optimised multimodal analgesia. Previous studies have shown preoperative glucocorticoids to reduce postoperative pain, but knowledge about specific doses and effects in specific patient groups is lacking. METHODS: A two-centre, double-blind, two-arm study comparing preoperative dexamethasone (1 mg kg-1vs 0.3 mg kg-1 i.v.) on postoperative pain in 160 planned TKA subjects with low preoperative pain catastrophising and no opioid use. Subjects received multimodal analgesia with paracetamol, cyclooxygenase-2 inhibitors, local anaesthetic infiltration analgesia, and rescue opioids. The primary outcome was percentage of subjects experiencing moderate to severe pain (visual analogue scale >30 mm) upon ambulation at 24 h. Secondary outcomes included pain scores, postoperative inflammation (C-reactive protein), opioid and antiemetics use, and 'Quality of Recovery-15' and 'Opioid-Related Symptom Distress Scale', length of stay, readmissions, and complications up to Day 90. RESULTS: A total of 157 subjects (80 vs 77) were included. No difference was found between groups in the incidence of subjects experiencing visual analogue scale >30 on ambulation 24 h after surgery (56% vs 53%, relative risk =1.07, confidence interval: 0.8-1.4, P=0.65). No differences in other pain outcomes or use of rescue opioids and antiemetics, in Quality of Recovery-15 and Opioid-Related Symptom Distress Scale, length of stay, readmissions, or complications. C-reactive protein values were comparable at 24 h (13 [6-25] mg L-1vs 16 [9-38] mg L-1, P = 0.07), but lower at 48 h (26 [9-52] mg L-1vs 50 [30-72] mg L-1, P<0.01) in the high-dose group. CONCLUSION: Use of 1 mg kg-1vs 0.3 mg kg-1 i.v. dexamethasone in low pain responders after TKA did not improve early postoperative pain or other outcomes in contrast to benefits in a high pain responder population. CLINICAL TRIAL REGISTRATION: NCT03758170 (first registration 29-11-2018).

External validation of the CREST model to predict early circulatory-etiology death after out-of-hospital cardiac arrest without initial ST-segment elevation myocardial infarction.

BACKGROUND: The CREST model is a prediction model, quantitating the risk of circulatory-etiology death (CED) after cardiac arrest based on variables available at hospital admission, and intend to guide the triage of comatose patients without ST-segment-elevation myocardial infarction after successful cardiopulmonary resuscitation. This study assessed performance of the CREST model in the Target Temperature Management (TTM) trial cohort. METHODS: We retrospectively analyzed data from resuscitated out-of-hospital cardiac arrest (OHCA) patients in the TTM-trial. Demographics, clinical characteristics, and CREST variables (history of coronary artery disease, initial heart rhythm, initial ejection fraction, shock at admission and ischemic time > 25 min) were assessed in univariate and multivariable analysis. The primary outcome was CED. The discriminatory power of the logistic regression model was assessed using the C-statistic and goodness of fit was tested according to Hosmer-Lemeshow. RESULTS: Among 329 patients eligible for final analysis, 71 (22%) had CED. History of ischemic heart disease, previous arrhythmia, older age, initial non-shockable rhythm, shock at admission, ischemic time > 25 min and severe left ventricular dysfunction were variables associated with CED in univariate analysis. CREST variables were entered into a logistic regression model and the area under the curve for the model was 0.73 with adequate calibration according to Hosmer-Lemeshow test (p = 0.602). CONCLUSIONS: The CREST model had good validity and a discrimination capability for predicting circulatory-etiology death after resuscitation from cardiac arrest without ST-segment elevation myocardial infarction. Application of this model could help to triage high-risk patients for transfer to specialized cardiac centers.

Repeat dose steroid in high pain responders after total knee arthroplasty: A study protocol.

Pain after total knee arthroplasty (TKA) is a well-known clinical problem potentially delaying ambulation and recovery. Perioperative glucocorticoids reduce pain and facilitate early recovery, but the optimal timing and dose are still unknown. High pain catastrophizers have an increased risk of poorly controlled postoperative pain, and moderate to severe pain at 24 h is associated with a risk of pain relapse at 48 h. To evaluate the effect of a repeat moderate dose of glucocorticoids after TKA in high pain catastrophizers presenting with moderate to severe pain 24 h postoperatively, having received preoperative high-dose glucocorticoids. High pain catastrophizers (Pain Catastrophizing Scale > 20) undergoing TKA are screened 24 h postoperatively and are included if they experience moderate to severe pain (VAS > 30) during a 5 m walk test. The included patients will receive either oral 24 mg dexamethasone (n = 55) or placebo (n = 55) on the evening of Day 1 (~30-37 h) after surgery. In addition, patients receive a standard multimodal analgesic regimen, including paracetamol, celecoxib, local infiltration analgesia, and preoperative dexamethasone (1 mg/kg). Patients will fill out a pain diary for 7 days after surgery. The primary outcome is moderate to severe pain (VAS > 30) during a 5 m walk test on the morning of Day 2 after surgery. The secondary outcomes include cumulated pain at rest and during ambulation, cumulated use of rescue analgesics, quality of sleep, lethargy, dizziness, nausea, satisfaction with the analgesic regimen, length of stay, morbidity, mortality, and reasons for readmissions. Follow-up is at 8 and 30 days. The data from this study will provide evidence for the effect of a repeated dose of dexamethasone as an analgesic adjuvant in patients undergoing TKA with a high risk of postoperative pain.

Cardiac Arrest Treatment Center Differences in Sedation and Analgesia Dosing During Targeted Temperature Management.

BACKGROUND: Sedation and analgesia are recommended during targeted temperature management (TTM) after cardiac arrest, but there are few data to provide guidance on dosing to bedside clinicians. We evaluated differences in patient-level sedation and analgesia dosing in an international multicenter TTM trial to better characterize current practice and clinically important outcomes. METHODS: A total 950 patients in the international TTM trial were randomly assigned to a TTM of 33 °C or 36 °C after resuscitation from cardiac arrest in 36 intensive care units. We recorded cumulative doses of sedative and analgesic drugs at 12, 24, and 48 h and normalized to midazolam and fentanyl equivalents. We compared number of medications used, dosing, and titration among centers by using multivariable models, including common severity of illness factors. We also compared dosing with time to awakening, incidence of clinical seizures, and survival. RESULTS: A total of 614 patients at 18 centers were analyzed. Propofol (70%) and fentanyl (51%) were most frequently used. The average dosages of midazolam and fentanyl equivalents were 0.13 (0.07, 0.22) mg/kg/h and 1.16 (0.49, 1.81) µg/kg/h, respectively. There were significant differences in number of medications (p < 0.001), average dosages (p < 0.001), and titration at all time points between centers (p < 0.001), and the outcomes of patients in these centers were associated with all parameters described in the multivariate analysis, except for a difference in the titration of sedatives between 12 and 24 h (p = 0.40). There were associations between higher dosing at 48 h (p = 0.003, odds ratio [OR] 1.75) and increased titration of analgesics between 24 and 48 h (p = 0.005, OR 4.89) with awakening after 5 days, increased titration of sedatives between 24 and 48 h with awakening after 5 days (p < 0.001, OR > 100), and increased titration of sedatives between 24 and 48 h with a higher incidence of clinical seizures in the multivariate analysis (p = 0.04, OR 240). There were also significant associations between decreased titration of analgesics and survival at 6 months in the multivariate analysis (p = 0.048). CONCLUSIONS: There is significant variation in choice of drug, dosing, and titration when providing sedation and analgesics between centers. Sedation and analgesia dosing and titration were associated with delayed awakening, incidence of clinical seizures, and survival, but the causal relation of these findings cannot be proven.

High dose dexamethasone in high pain responders undergoing total hip arthroplasty: A randomized controlled trial.

BACKGROUND: Postoperative pain after total hip arthroplasty (THA) may delay postoperative mobilization and discharge. Postoperative pain has been shown to be higher in pain catastrophisers and patients receiving opioids. A single dose of glucocorticoid reduces pain after THA, and an increased dose of glucocorticoids has been found to be effective in patients at high risk of postoperative pain after total knee arthroplasty (TKA), however, the ideal dose in THA remains unknown. OBJECTIVE: To evaluate the effect of a high dose (1 mg kg -1 ) vs. intermediate dose (0.3 mg kg -1 ) of dexamethasone on pain after THA. DESIGN: A randomized double-blind controlled study. SETTING: A two-centre study including two large arthroplasty sites in Denmark was conducted from February 2019 to August 2020. PATIENTS: A total of 160 patients undergoing THA by neuraxial block with multimodal analgesia, having a Pain Catastrophising Scale score >20 and/or preoperative opioid use were included. INTERVENTION: Patients were randomly assigned to receive dexamethasone 1 mg kg -1 or 0.3 mg kg -1 before THA. MAIN OUTCOME MEASURES: Primary outcome was percentage of patients experiencing moderate to severe pain (visual analogue scale, VAS > 30 mm on a 0 to 100 mm scale) on ambulating 24 h after surgery. Secondary outcomes included cumulated pain scores, C-reactive protein (CRP), opioid use, postoperative recovery scores, length of stay, complications, and re-admission within 30 and 90 days. RESULTS: No difference was found in percentage of VAS >30 mm 24 h after surgery in the 5-m walk test (VAS > 30/VAS ≤ 30%); 33/42 (44%) vs. 32/43 (43%), relative risk = 1.04 (95% confidence interval 0.72-1.51; P  = 0.814) in 1 mg kg -1vs. 0.3 mg kg -1 respectively. No differences were found in CRP and opioid use between groups. Also, no intergroup differences were found in recovery scores, re-admissions, or complications. CONCLUSION: 1 mg kg -1vs. 0.3 mg kg -1 dexamethasone improved neither postoperative pain nor recovery in THA in a cohort of predicted high pain responders. TRIAL REGISTRATION: ClinicalTrials.gov ID-number NCT03763760 and EudraCT-number 2018-2636-25.

Trends in survival after cardiac arrest: a Swedish nationwide study over 30 years.

AIMS: Trends in characteristics, management, and survival in out-of-hospital cardiac arrest (OHCA) and in-hospital cardiac arrest (IHCA) were studied in the Swedish Cardiopulmonary Resuscitation Registry (SCRR). METHODS AND RESULTS: The SCRR was used to study 106 296 cases of OHCA (1990-2020) and 30 032 cases of IHCA (2004-20) in whom resuscitation was attempted. In OHCA, survival increased from 5.7% in 1990 to 10.1% in 2011 and remained unchanged thereafter. Odds ratios [ORs, 95% confidence interval (CI)] for survival in 2017-20 vs. 1990-93 were 2.17 (1.93-2.43) overall, 2.36 (2.07-2.71) for men, and 1.67 (1.34-2.10) for women. Survival increased for all aetiologies, except trauma, suffocation, and drowning. OR for cardiac aetiology in 2017-20 vs. 1990-93 was 0.45 (0.42-0.48). Bystander cardiopulmonary resuscitation increased from 30.9% to 82.2%. Shockable rhythm decreased from 39.5% in 1990 to 17.4% in 2020. Use of targeted temperature management decreased from 42.1% (2010) to 18.2% (2020). In IHCA, OR for survival in 2017-20 vs. 2004-07 was 1.18 (1.06-1.31), showing a non-linear trend with probability of survival increasing by 46.6% during 2011-20. Myocardial ischaemia or infarction as aetiology decreased during 2004-20 from 67.4% to 28.3% [OR 0.30 (0.27-0.34)]. Shockable rhythm decreased from 37.4% to 23.0% [OR 0.57 (0.51-0.64)]. Approximately 90% of survivors (IHCA and OHCA) had no or mild neurological sequelae. CONCLUSION: Survival increased 2.2-fold in OHCA during 1990-2020 but without any improvement in the final decade, and 1.2-fold in IHCA during 2004-20, with rapid improvement the last decade. Cardiac aetiology and shockable rhythms were halved. Neurological outcome has not improved.

Influence of temperature management at 33 °C versus normothermia on survival in patients with vasopressor support after out-of-hospital cardiac arrest: a post hoc analysis of the TTM-2 trial.

BACKGROUND: Targeted temperature management at 33 °C (TTM33) has been employed in effort to mitigate brain injury in unconscious survivors of out-of-hospital cardiac arrest (OHCA). Current guidelines recommend prevention of fever, not excluding TTM33. The main objective of this study was to investigate if TTM33 is associated with mortality in patients with vasopressor support on admission after OHCA. METHODS: We performed a post hoc analysis of patients included in the TTM-2 trial, an international, multicenter trial, investigating outcomes in unconscious adult OHCA patients randomized to TTM33 versus normothermia. Patients were grouped according to level of circulatory support on admission: (1) no-vasopressor support, mean arterial blood pressure (MAP) ≥ 70 mmHg; (2) moderate-vasopressor support MAP < 70 mmHg or any dose of dopamine/dobutamine or noradrenaline/adrenaline dose ≤ 0.25 µg/kg/min; and (3) high-vasopressor support, noradrenaline/adrenaline dose > 0.25 µg/kg/min. Hazard ratios with TTM33 were calculated for all-cause 180-day mortality in these groups. RESULTS: The TTM-2 trial enrolled 1900 patients. Data on primary outcome were available for 1850 patients, with 662, 896, and 292 patients in the, no-, moderate-, or high-vasopressor support groups, respectively. Hazard ratio for 180-day mortality was 1.04 [98.3% CI 0.78-1.39] in the no-, 1.22 [98.3% CI 0.97-1.53] in the moderate-, and 0.97 [98.3% CI 0.68-1.38] in the high-vasopressor support groups with regard to TTM33. Results were consistent in an imputed, adjusted sensitivity analysis. CONCLUSIONS: In this exploratory analysis, temperature control at 33 °C after OHCA, compared to normothermia, was not associated with higher incidence of death in patients stratified according to vasopressor support on admission. Trial registration Clinical trials identifier NCT02908308 , registered September 20, 2016.

Oxygen targets and 6-month outcome after out of hospital cardiac arrest: a pre-planned sub-analysis of the targeted hypothermia versus targeted normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trial.

BACKGROUND: Optimal oxygen targets in patients resuscitated after cardiac arrest are uncertain. The primary aim of this study was to describe the values of partial pressure of oxygen values (PaO2) and the episodes of hypoxemia and hyperoxemia occurring within the first 72 h of mechanical ventilation in out of hospital cardiac arrest (OHCA) patients. The secondary aim was to evaluate the association of PaO2 with patients' outcome. METHODS: Preplanned secondary analysis of the targeted hypothermia versus targeted normothermia after OHCA (TTM2) trial. Arterial blood gases values were collected from randomization every 4 h for the first 32 h, and then, every 8 h until day 3. Hypoxemia was defined as PaO2 < 60 mmHg and severe hyperoxemia as PaO2 > 300 mmHg. Mortality and poor neurological outcome (defined according to modified Rankin scale) were collected at 6 months. RESULTS: 1418 patients were included in the analysis. The mean age was 64 ± 14 years, and 292 patients (20.6%) were female. 24.9% of patients had at least one episode of hypoxemia, and 7.6% of patients had at least one episode of severe hyperoxemia. Both hypoxemia and hyperoxemia were independently associated with 6-month mortality, but not with poor neurological outcome. The best cutoff point associated with 6-month mortality for hypoxemia was 69 mmHg (Risk Ratio, RR = 1.009, 95% CI 0.93-1.09), and for hyperoxemia was 195 mmHg (RR = 1.006, 95% CI 0.95-1.06). The time exposure, i.e., the area under the curve (PaO2-AUC), for hyperoxemia was significantly associated with mortality (p = 0.003). CONCLUSIONS: In OHCA patients, both hypoxemia and hyperoxemia are associated with 6-months mortality, with an effect mediated by the timing exposure to high values of oxygen. Precise titration of oxygen levels should be considered in this group of patients. TRIAL REGISTRATION: clinicaltrials.gov NCT02908308 , Registered September 20, 2016.

Speed of cooling after cardiac arrest in relation to the intervention effect: a sub-study from the TTM2-trial.

BACKGROUND: Targeted temperature management (TTM) is recommended following cardiac arrest; however, time to target temperature varies in clinical practice. We hypothesised the effects of a target temperature of 33 °C when compared to normothermia would differ based on average time to hypothermia and those patients achieving hypothermia fastest would have more favorable outcomes. METHODS: In this post-hoc analysis of the TTM-2 trial, patients after out of hospital cardiac arrest were randomized to targeted hypothermia (33 °C), followed by controlled re-warming, or normothermia with early treatment of fever (body temperature, ≥ 37.8 °C). The average temperature at 4 h (240 min) after return of spontaneous circulation (ROSC) was calculated for participating sites. Primary outcome was death from any cause at 6 months. Secondary outcome was poor functional outcome at 6 months (score of 4-6 on modified Rankin scale). RESULTS: A total of 1592 participants were evaluated for the primary outcome. We found no evidence of heterogeneity of intervention effect based on the average time to target temperature on mortality (p = 0.17). Of patients allocated to hypothermia at the fastest sites, 71 of 145 (49%) had died compared to 68 of 148 (46%) of the normothermia group (relative risk with hypothermia, 1.07; 95% confidence interval 0.84-1.36). Poor functional outcome was reported in 74/144 (51%) patients in the hypothermia group, and 75/147 (51%) patients in the normothermia group (relative risk with hypothermia 1.01 (95% CI 0.80-1.26). CONCLUSIONS: Using a hospital's average time to hypothermia did not significantly alter the effect of TTM of 33 °C compared to normothermia and early treatment of fever.

High-dose steroids in high pain responders undergoing total knee arthroplasty: a randomised double-blind trial.

BACKGROUND: Total knee arthroplasty (TKA) is associated with moderate-to-severe postoperative pain despite multimodal opioid-sparing analgesia. Pain catastrophising or preoperative opioid therapy is associated with increased postoperative pain. Preoperative glucocorticoid improves pain after TKA, but dose-finding studies and benefit in high pain responders are lacking. METHODS: A randomised double-blind controlled trial with preoperative high-dose intravenous dexamethasone 1 mg kg-1 or intermediate-dose dexamethasone 0.3 mg kg-1 in 88 patients undergoing TKA with preoperative pain catastrophising score >20 or regular opioid use was designed. The primary outcome was the proportion of patients experiencing moderate-to-severe pain (VAS >30) during a 5 m walk 24 h postoperatively. Secondary outcomes included pain at rest during nights and at passive leg raise, C-reactive protein, opioid use, quality of sleep, Quality of Recovery-15 and Opioid-Related Symptom Distress Scale, readmission, and complications. RESULTS: Moderate-to-severe pain when walking 24 h postoperatively was reduced (high dose vs intermediate dose, 49% vs 79%; P<0.01), along with pain at leg raise at 24 and 48 h (14% vs 29%, P=0.02 and 12% vs 31%, P=0.03, respectively). C-reactive protein was reduced in the high-dose group at both 24 and 48 h (both P<0.01). Quality of Recovery-15 was also improved (P<0.01). CONCLUSIONS: When compared with preoperative dexamethasone 0.3 mg kg-1 i.v., dexamethasone 1 mg kg-1 reduced moderate-to-severe pain 24 h after TKA and improved recovery in high pain responders without apparent side-effects. CLINICAL TRIAL REGISTRATION: NCT03763734.

Protocol for an individual patient data meta-analysis on blood pressure targets after cardiac arrest.

BACKGROUND: Hypotension is common after cardiac arrest (CA), and current guidelines recommend using vasopressors to target mean arterial blood pressure (MAP) higher than 65 mmHg. Pilot trials have compared higher and lower MAP targets. We will review the evidence on whether higher MAP improves outcome after cardiac arrest. METHODS: This systematic review and meta-analysis will be conducted based on a systematic search of relevant major medical databases from their inception onwards, including MEDLINE, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL), as well as clinical trial registries. We will identify randomised controlled trials published in the English language that compare targeting a MAP higher than 65-70 mmHg in CA patients using vasopressors, inotropes and intravenous fluids. The data extraction will be performed separately by two authors (a third author will be involved in case of disagreement), followed by a bias assessment with the Cochrane Risk of Bias tool using an eight-step procedure for assessing if thresholds for clinical significance are crossed. The outcomes will be all-cause mortality, functional long-term outcomes and serious adverse events. We will contact the authors of the identified trials to request individual anonymised patient data to enable individual patient data meta-analysis, aggregate data meta-analyses, trial sequential analyses and multivariable regression, controlling for baseline characteristics. The certainty of the evidence will be assessed by the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. We will register this systematic review with Prospero and aim to redo it when larger trials are published in the near future. CONCLUSIONS: This protocol defines the performance of a systematic review on whether a higher MAP after cardiac arrest improves patient outcome. Repeating this systematic review including more data likely will allow for more certainty regarding the effect of the intervention and possible sub-groups differences.

Serum neurofilament light levels are correlated to long-term neurocognitive outcome measures after cardiac arrest.

OBJECTIVE: To explore associations between four methods assessing long-term neurocognitive outcome after out-of-hospital cardiac arrest and early hypoxic-ischemic neuronal brain injury assessed by the biomarker serum neurofilament light (NFL), and to compare the agreement for the outcome methods. METHODS: An explorative post-hoc study was conducted on survivor data from the international Target Temperature Management after Out-of-hospital Cardiac Arrest trial, investigating serum NFL sampled 48/72-hours post-arrest and neurocognitive outcome 6 months post-arrest. RESULTS: Among the long-term surviving participants (N = 457), serum NFL (n = 384) was associated to all outcome instruments, also when controlling for demographic and cardiovascular risk factors. Associations between NFL and the patient-reported Two Simple Questions (TSQ) were however attenuated when adjusting for vitality and mental health. NFL predicted results on the outcome instruments to varying degrees, with an excellent area under the curve for the clinician-report Cerebral Performance Category (CPC 1-2: 0.90). Most participants were classified as CPC 1 (79%). Outcome instrument correlations ranged from small (Mini-Mental State Examination [MMSE]-TSQ) to strong (CPC-MMSE). CONCLUSIONS: The clinician-reported CPC was mostly related to hypoxic-ischemic brain injury, but with a ceiling effect. These results may be useful when selecting methods and instruments for clinical follow-up models.

Predicting neurological outcome after out-of-hospital cardiac arrest with cumulative information; development and internal validation of an artificial neural network algorithm.

BACKGROUND: Prognostication of neurological outcome in patients who remain comatose after cardiac arrest resuscitation is complex. Clinical variables, as well as biomarkers of brain injury, cardiac injury, and systemic inflammation, all yield some prognostic value. We hypothesised that cumulative information obtained during the first three days of intensive care could produce a reliable model for predicting neurological outcome following out-of-hospital cardiac arrest (OHCA) using artificial neural network (ANN) with and without biomarkers. METHODS: We performed a post hoc analysis of 932 patients from the Target Temperature Management trial. We focused on comatose patients at 24, 48, and 72 h post-cardiac arrest and excluded patients who were awake or deceased at these time points. 80% of the patients were allocated for model development (training set) and 20% for internal validation (test set). To investigate the prognostic potential of different levels of biomarkers (clinically available and research-grade), patients' background information, and intensive care observation and treatment, we created three models for each time point: (1) clinical variables, (2) adding clinically accessible biomarkers, e.g., neuron-specific enolase (NSE) and (3) adding research-grade biomarkers, e.g., neurofilament light (NFL). Patient outcome was the dichotomised Cerebral Performance Category (CPC) at six months; a good outcome was defined as CPC 1-2 whilst a poor outcome was defined as CPC 3-5. The area under the receiver operating characteristic curve (AUROC) was calculated for all test sets. RESULTS: AUROC remained below 90% when using only clinical variables throughout the first three days in the ICU. Adding clinically accessible biomarkers such as NSE, AUROC increased from 82 to 94% (p < 0.01). The prognostic accuracy remained excellent from day 1 to day 3 with an AUROC at approximately 95% when adding research-grade biomarkers. The models which included NSE after 72 h and NFL on any of the three days had a low risk of false-positive predictions while retaining a low number of false-negative predictions. CONCLUSIONS: In this exploratory study, ANNs provided good to excellent prognostic accuracy in predicting neurological outcome in comatose patients post OHCA. The models which included NSE after 72 h and NFL on all days showed promising prognostic performance.

Interventions for treatment of COVID-19: A living systematic review with meta-analyses and trial sequential analyses (The LIVING Project).

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a rapidly spreading disease that has caused extensive burden to individuals, families, countries, and the world. Effective treatments of COVID-19 are urgently needed. METHODS AND FINDINGS: This is the first edition of a living systematic review of randomized clinical trials comparing the effects of all treatment interventions for participants in all age groups with COVID-19. We planned to conduct aggregate data meta-analyses, trial sequential analyses, network meta-analysis, and individual patient data meta-analyses. Our systematic review is based on Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) and Cochrane guidelines, and our 8-step procedure for better validation of clinical significance of meta-analysis results. We performed both fixed-effect and random-effects meta-analyses. Primary outcomes were all-cause mortality and serious adverse events. Secondary outcomes were admission to intensive care, mechanical ventilation, renal replacement therapy, quality of life, and nonserious adverse events. We used Grading of Recommendations Assessment, Development and Evaluation (GRADE) to assess the certainty of evidence. We searched relevant databases and websites for published and unpublished trials until August 7, 2020. Two reviewers independently extracted data and assessed trial methodology. We included 33 randomized clinical trials enrolling a total of 13,312 participants. All trials were at overall high risk of bias. We identified one trial randomizing 6,425 participants to dexamethasone versus standard care. This trial showed evidence of a beneficial effect of dexamethasone on all-cause mortality (rate ratio 0.83; 95% confidence interval [CI] 0.75-0.93; p < 0.001; low certainty) and on mechanical ventilation (risk ratio [RR] 0.77; 95% CI 0.62-0.95; p = 0.021; low certainty). It was possible to perform meta-analysis of 10 comparisons. Meta-analysis showed no evidence of a difference between remdesivir versus placebo on all-cause mortality (RR 0.74; 95% CI 0.40-1.37; p = 0.34, I2 = 58%; 2 trials; very low certainty) or nonserious adverse events (RR 0.94; 95% CI 0.80-1.11; p = 0.48, I2 = 29%; 2 trials; low certainty). Meta-analysis showed evidence of a beneficial effect of remdesivir versus placebo on serious adverse events (RR 0.77; 95% CI 0.63-0.94; p = 0.009, I2 = 0%; 2 trials; very low certainty) mainly driven by respiratory failure in one trial. Meta-analyses and trial sequential analyses showed that we could exclude the possibility that hydroxychloroquine versus standard care reduced the risk of all-cause mortality (RR 1.07; 95% CI 0.97-1.19; p = 0.17; I2 = 0%; 7 trials; low certainty) and serious adverse events (RR 1.07; 95% CI 0.96-1.18; p = 0.21; I2 = 0%; 7 trials; low certainty) by 20% or more, and meta-analysis showed evidence of a harmful effect on nonserious adverse events (RR 2.40; 95% CI 2.01-2.87; p < 0.00001; I2 = 90%; 6 trials; very low certainty). Meta-analysis showed no evidence of a difference between lopinavir-ritonavir versus standard care on serious adverse events (RR 0.64; 95% CI 0.39-1.04; p = 0.07, I2 = 0%; 2 trials; very low certainty) or nonserious adverse events (RR 1.14; 95% CI 0.85-1.53; p = 0.38, I2 = 75%; 2 trials; very low certainty). Meta-analysis showed no evidence of a difference between convalescent plasma versus standard care on all-cause mortality (RR 0.60; 95% CI 0.33-1.10; p = 0.10, I2 = 0%; 2 trials; very low certainty). Five single trials showed statistically significant results but were underpowered to confirm or reject realistic intervention effects. None of the remaining trials showed evidence of a difference on our predefined outcomes. Because of the lack of relevant data, it was not possible to perform other meta-analyses, network meta-analysis, or individual patient data meta-analyses. The main limitation of this living review is the paucity of data currently available. Furthermore, the included trials were all at risks of systematic errors and random errors. CONCLUSIONS: Our results show that dexamethasone and remdesivir might be beneficial for COVID-19 patients, but the certainty of the evidence was low to very low, so more trials are needed. We can exclude the possibility of hydroxychloroquine versus standard care reducing the risk of death and serious adverse events by 20% or more. Otherwise, no evidence-based treatment for COVID-19 currently exists. This review will continuously inform best practice in treatment and clinical research of COVID-19.