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.).

Treating Rhythmic and Periodic EEG Patterns in Comatose Survivors of Cardiac Arrest.

BACKGROUND: Whether the treatment of rhythmic and periodic electroencephalographic (EEG) patterns in comatose survivors of cardiac arrest improves outcomes is uncertain. METHODS: We conducted an open-label trial of suppressing rhythmic and periodic EEG patterns detected on continuous EEG monitoring in comatose survivors of cardiac arrest. Patients were randomly assigned in a 1:1 ratio to a stepwise strategy of antiseizure medications to suppress this activity for at least 48 consecutive hours plus standard care (antiseizure-treatment group) or to standard care alone (control group); standard care included targeted temperature management in both groups. The primary outcome was neurologic outcome according to the score on the Cerebral Performance Category (CPC) scale at 3 months, dichotomized as a good outcome (CPC score indicating no, mild, or moderate disability) or a poor outcome (CPC score indicating severe disability, coma, or death). Secondary outcomes were mortality, length of stay in the intensive care unit (ICU), and duration of mechanical ventilation. RESULTS: We enrolled 172 patients, with 88 assigned to the antiseizure-treatment group and 84 to the control group. Rhythmic or periodic EEG activity was detected a median of 35 hours after cardiac arrest; 98 of 157 patients (62%) with available data had myoclonus. Complete suppression of rhythmic and periodic EEG activity for 48 consecutive hours occurred in 49 of 88 patients (56%) in the antiseizure-treatment group and in 2 of 83 patients (2%) in the control group. At 3 months, 79 of 88 patients (90%) in the antiseizure-treatment group and 77 of 84 patients (92%) in the control group had a poor outcome (difference, 2 percentage points; 95% confidence interval, -7 to 11; P = 0.68). Mortality at 3 months was 80% in the antiseizure-treatment group and 82% in the control group. The mean length of stay in the ICU and mean duration of mechanical ventilation were slightly longer in the antiseizure-treatment group than in the control group. CONCLUSIONS: In comatose survivors of cardiac arrest, the incidence of a poor neurologic outcome at 3 months did not differ significantly between a strategy of suppressing rhythmic and periodic EEG activity with the use of antiseizure medication for at least 48 hours plus standard care and standard care alone. (Funded by the Dutch Epilepsy Foundation; TELSTAR ClinicalTrials.gov number, NCT02056236.).

Hypothermia versus Normothermia after Out-of-Hospital Cardiac Arrest.

BACKGROUND: Targeted temperature management is recommended for patients after cardiac arrest, but the supporting evidence is of low certainty. METHODS: In an open-label trial with blinded assessment of outcomes, we randomly assigned 1900 adults with coma who had had an out-of-hospital cardiac arrest of presumed cardiac or unknown cause to undergo targeted hypothermia at 33°C, followed by controlled rewarming, or targeted normothermia with early treatment of fever (body temperature, ≥37.8°C). The primary outcome was death from any cause at 6 months. Secondary outcomes included functional outcome at 6 months as assessed with the modified Rankin scale. Prespecified subgroups were defined according to sex, age, initial cardiac rhythm, time to return of spontaneous circulation, and presence or absence of shock on admission. Prespecified adverse events were pneumonia, sepsis, bleeding, arrhythmia resulting in hemodynamic compromise, and skin complications related to the temperature management device. RESULTS: A total of 1850 patients were evaluated for the primary outcome. At 6 months, 465 of 925 patients (50%) in the hypothermia group had died, as compared with 446 of 925 (48%) in the normothermia group (relative risk with hypothermia, 1.04; 95% confidence interval [CI], 0.94 to 1.14; P = 0.37). Of the 1747 patients in whom the functional outcome was assessed, 488 of 881 (55%) in the hypothermia group had moderately severe disability or worse (modified Rankin scale score ≥4), as compared with 479 of 866 (55%) in the normothermia group (relative risk with hypothermia, 1.00; 95% CI, 0.92 to 1.09). Outcomes were consistent in the prespecified subgroups. Arrhythmia resulting in hemodynamic compromise was more common in the hypothermia group than in the normothermia group (24% vs. 17%, P<0.001). The incidence of other adverse events did not differ significantly between the two groups. CONCLUSIONS: In patients with coma after out-of-hospital cardiac arrest, targeted hypothermia did not lead to a lower incidence of death by 6 months than targeted normothermia. (Funded by the Swedish Research Council and others; TTM2 ClinicalTrials.gov number, NCT02908308.).

The design of the PRINCESS 2 trial: A randomized trial to study the impact of ultrafast hypothermia on complete neurologic recovery after out-of-hospital cardiac arrest with initial shockable rhythm.

BACKGROUND: Delayed hypothermia, initiated after hospital arrival, several hours after cardiac arrest with 8-10 hours to reach the target temperature, is likely to have limited impact on overall survival. However, the effect of ultrafast hypothermia, i.e., delivered intra-arrest or immediately after return of spontaneous circulation (ROSC), on functional neurologic outcome after out-of-hospital cardiac arrest (OHCA) is unclear. In two prior trials, prehospital trans-nasal evaporative intra-arrest cooling was safe, feasible and reduced time to target temperature compared to delayed cooling. Both studies showed trends towards improved neurologic recovery in patients with shockable rhythms. The aim of the PRINCESS2-study is to assess whether cooling, initiated either intra-arrest or immediately after ROSC, followed by in-hospital hypothermia, significantly increases survival with complete neurologic recovery as compared to standard normothermia care, in OHCA patients with shockable rhythms. METHODS/DESIGN: In this investigator-initiated, randomized, controlled trial, the emergency medical services (EMS) will randomize patients at the scene of cardiac arrest to either trans-nasal cooling within 20 minutes from EMS arrival with subsequent hypothermia at 33°C for 24 hours after hospital admission (intervention), or to standard of care with no prehospital or in-hospital cooling (control). Fever (>37,7°C) will be avoided for the first 72 hours in both groups. All patients will receive post resuscitation care and withdrawal of life support procedures according to current guidelines. Primary outcome is survival with complete neurologic recovery at 90 days, defined as modified Rankin scale (mRS) 0-1. Key secondary outcomes include survival to hospital discharge, survival at 90 days and mRS 0-3 at 90 days. In total, 1022 patients are required to detect an absolute difference of 9% (from 45 to 54%) in survival with neurologic recovery (80% power and one-sided α=0,025, ß=0,2) and assuming 2,5% lost to follow-up. Recruitment starts in Q1 2024 and we expect maximum enrolment to be achieved during Q4 2024 at 20-25 European and US sites. DISCUSSION: This trial will assess the impact of ultrafast hypothermia applied on the scene of cardiac arrest, as compared to normothermia, on 90-day survival with complete neurologic recovery in OHCA patients with initial shockable rhythm. TRIAL REGISTRATION: NCT06025123.

Prognostic Factors Associated With Extubation Failure in Acutely Brain-Injured Patients: A Systematic Review and Meta-Analysis.

OBJECTIVE: Extubation failure in brain-injured patients is associated with increased morbidity. Our objective was to systematically review prognostic factors associated with extubation failure in acutely brain-injured adult patients receiving invasive ventilation in an ICU. DATA SOURCES: MEDLINE, Embase, and Cochrane Central were searched from inception to January 31, 2022. STUDY SELECTION: Two reviewers independently screened citations and selected English-language cohort studies and randomized trials examining the association of prognostic factors with extubation failure. Studies were considered if they included greater than or equal to 80% adult patients with acute brain injury admitted to the ICU and mechanically ventilated for greater than or equal to 24 hours. DATA EXTRACTION: Two reviewers extracted data on population, prognostic factors, extubation outcomes, and risk of bias (using the quality in prognostic factors tool). DATA SYNTHESIS: In the primary analysis, adjusted odds ratios (aOR) for each prognostic factor were pooled using random-effects models. Certainty of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation. The search identified 7,626 citations, of which 21 studies met selection criteria. Moderate-certainty evidence suggested increased risk of extubation failure with older age (aOR, 3.0 for upper vs lower tertile; 95% CI, 1.78-5.07) and longer duration of mechanical ventilation (aOR, 3.47 for upper vs lower tertile; 95% CI, 1.68-7.19). Presence of cough (aOR, 0.40; 95% CI, 0.28-0.57) and intact swallow (aOR, 0.34; 95% CI, 0.21-0.54) probably decreased risk of extubation failure (moderate certainty). Associations of other factors with extubation failure were informed by low or very low certainty evidence. CONCLUSIONS: Patient age, duration of mechanical ventilation, and airway reflexes were associated with extubation failure in brain-injured patients with moderate certainty. Future studies are needed to determine the optimal application of these variables in clinical practice.

Neutralization of extracellular histones by sodium-Β-O-methyl cellobioside sulfate in septic shock.

BACKGROUND: Extracellular histones have been associated with severity and outcome in sepsis. The aim of the present study was to assess the effects of sodium-ß-O-Methyl cellobioside sulfate (mCBS), a histone-neutralizing polyanion, on the severity and outcome of sepsis in an experimental model. METHODS: This randomized placebo-controlled experimental study was performed in 24 mechanically ventilated female sheep. Sepsis was induced by fecal peritonitis. Animals were randomized to three groups: control, early treatment, and late treatment (n = 8 each). mCBS was given as a bolus (1 mg/kg) followed by a continuous infusion (1 mg/kg/h) just after sepsis induction in the early treatment group, and 4 h later in the late treatment group. Fluid administration and antimicrobial therapy were initiated 4 h T4 after feces injection, peritoneal lavage performed, and a norepinephrine infusion titrated to maintain mean arterial pressure (MAP) between 65-75 mmHg. The experiment was blinded and lasted maximum 24 h. RESULTS: During the first 4 h, MAP remained > 65 mmHg in the early treatment group but decreased significantly in the others (p < 0.01 for interaction, median value at T4: (79 [70-90] mmHg for early treatment, 57 [70-90] mmHg for late treatment, and 55 [49-60] mmHg for the control group). mCBS-treated animals required significantly less norepinephrine to maintain MAP than controls (p < 0.01 for interaction) and had lower creatinine (p < 0.01), lactate (p < 0.01), and interleukin-6 (p < 0.01) levels, associated with reduced changes in H3.1 nucleosome levels (p = 0.02). Early treatment was associated with lower norepinephrine requirements than later treatment. Two control animals died; all the mCBS-treated animals survived. CONCLUSIONS: Neutralization of extracellular histones with mCBS was associated with reduced norepinephrine requirements, improved tissue perfusion, less renal dysfunction, and lower circulating IL-6 in experimental septic shock and may represent a new therapeutic approach to be tested in clinical trials.

Extracorporeal CPR after the INCEPTION trial: No one steps twice into the same river.

The use of veno-arterial extracorporeal membrane oxygenation as extracorporeal cardiopulmonary resuscitation in patients suffering out-of-hospital cardiac arrest, largely increased in the last decade despite evidence supporting this practice being limited to non-randomized studies. However, between 2020 and 2023, four randomized studies were published comparing extracorporeal cardiopulmonary resuscitation to conventional cardiopulmonary resuscitation with controversial findings that triggered great debates. In this controversy, we discuss merits and pitfalls, and provide a critical interpretation of the available evidence from randomized trials on the use of extracorporeal cardiopulmonary resuscitation, with a particular focus on the recent multi-center INCEPTION trial.

Processed Electroencephalogram-Based Monitoring to Guide Sedation in Critically Ill Adult Patients: Recommendations from an International Expert Panel-Based Consensus.

BACKGROUND: The use of processed electroencephalography (pEEG) for depth of sedation (DOS) monitoring is increasing in anesthesia; however, how to use of this type of monitoring for critical care adult patients within the intensive care unit (ICU) remains unclear. METHODS: A multidisciplinary panel of international experts consisting of 21 clinicians involved in monitoring DOS in ICU patients was carefully selected on the basis of their expertise in neurocritical care and neuroanesthesiology. Panelists were assigned four domains (techniques for electroencephalography [EEG] monitoring, patient selection, use of the EEG monitors, competency, and training the principles of pEEG monitoring) from which a list of questions and statements was created to be addressed. A Delphi method based on iterative approach was used to produce the final statements. Statements were classified as highly appropriate or highly inappropriate (median rating ≥ 8), appropriate (median rating ≥ 7 but < 8), or uncertain (median rating < 7) and with a strong disagreement index (DI) (DI < 0.5) or weak DI (DI ≥ 0.5 but < 1) consensus. RESULTS: According to the statements evaluated by the panel, frontal pEEG (which includes a continuous colored density spectrogram) has been considered adequate to monitor the level of sedation (strong consensus), and it is recommended by the panel that all sedated patients (paralyzed or nonparalyzed) unfit for clinical evaluation would benefit from DOS monitoring (strong consensus) after a specific training program has been performed by the ICU staff. To cover the gap between knowledge/rational and routine application, some barriers must be broken, including lack of knowledge, validation for prolonged sedation, standardization between monitors based on different EEG analysis algorithms, and economic issues. CONCLUSIONS: Evidence on using DOS monitors in ICU is still scarce, and further research is required to better define the benefits of using pEEG. This consensus highlights that some critically ill patients may benefit from this type of neuromonitoring.

Myocardial effects of angiotensin II compared to norepinephrine in an animal model of septic shock.

BACKGROUND: Angiotensin II is one of the vasopressors available for use in septic shock. However, its effects on the septic myocardium remain unclear. The aim of the study was to compare the effects of angiotensin II and norepinephrine on cardiac function and myocardial oxygen consumption, inflammation and injury in experimental septic shock. METHODS: This randomized, open-label, controlled study was performed in 20 anesthetized and mechanically ventilated pigs. Septic shock was induced by fecal peritonitis in 16 animals, and four pigs served as shams. Resuscitation with fluids, antimicrobial therapy and abdominal drainage was initiated one hour after the onset of septic shock. Septic pigs were randomly allocated to receive one of the two drugs to maintain mean arterial pressure between 65 and 75 mmHg for 8 h. RESULTS: There were no differences in MAP, cardiac output, heart rate, fluid balance or tissue perfusion indices in the two treatment groups but myocardial oxygen consumption was greater in the norepinephrine-treated animals. Myocardial mRNA expression of interleukin-6, interleukin-6 receptor, interleukin-1 alpha, and interleukin-1 beta was higher in the norepinephrine than in the angiotensin II group. CONCLUSIONS: In septic shock, angiotensin II administration is associated with a similar level of cardiovascular resuscitation and less myocardial oxygen consumption, and inflammation compared to norepinephrine.

Respiratory support in patients with severe COVID-19 in the International Severe Acute Respiratory and Emerging Infection (ISARIC) COVID-19 study: a prospective, multinational, observational study.

BACKGROUND: Up to 30% of hospitalised patients with COVID-19 require advanced respiratory support, including high-flow nasal cannulas (HFNC), non-invasive mechanical ventilation (NIV), or invasive mechanical ventilation (IMV). We aimed to describe the clinical characteristics, outcomes and risk factors for failing non-invasive respiratory support in patients treated with severe COVID-19 during the first two years of the pandemic in high-income countries (HICs) and low middle-income countries (LMICs). METHODS: This is a multinational, multicentre, prospective cohort study embedded in the ISARIC-WHO COVID-19 Clinical Characterisation Protocol. Patients with laboratory-confirmed SARS-CoV-2 infection who required hospital admission were recruited prospectively. Patients treated with HFNC, NIV, or IMV within the first 24 h of hospital admission were included in this study. Descriptive statistics, random forest, and logistic regression analyses were used to describe clinical characteristics and compare clinical outcomes among patients treated with the different types of advanced respiratory support. RESULTS: A total of 66,565 patients were included in this study. Overall, 82.6% of patients were treated in HIC, and 40.6% were admitted to the hospital during the first pandemic wave. During the first 24 h after hospital admission, patients in HICs were more frequently treated with HFNC (48.0%), followed by NIV (38.6%) and IMV (13.4%). In contrast, patients admitted in lower- and middle-income countries (LMICs) were less frequently treated with HFNC (16.1%) and the majority received IMV (59.1%). The failure rate of non-invasive respiratory support (i.e. HFNC or NIV) was 15.5%, of which 71.2% were from HIC and 28.8% from LMIC. The variables most strongly associated with non-invasive ventilation failure, defined as progression to IMV, were high leukocyte counts at hospital admission (OR [95%CI]; 5.86 [4.83-7.10]), treatment in an LMIC (OR [95%CI]; 2.04 [1.97-2.11]), and tachypnoea at hospital admission (OR [95%CI]; 1.16 [1.14-1.18]). Patients who failed HFNC/NIV had a higher 28-day fatality ratio (OR [95%CI]; 1.27 [1.25-1.30]). CONCLUSIONS: In the present international cohort, the most frequently used advanced respiratory support was the HFNC. However, IMV was used more often in LMIC. Higher leucocyte count, tachypnoea, and treatment in LMIC were risk factors for HFNC/NIV failure. HFNC/NIV failure was related to worse clinical outcomes, such as 28-day mortality. Trial registration This is a prospective observational study; therefore, no health care interventions were applied to participants, and trial registration is not applicable.

Creatinine correction to account for fluid overload in children with acute respiratory distress syndrome treated with extracorporeal membrane oxygenation: an initial exploratory report.

BACKGROUND: Creatinine is distributed between the intracellular and extracellular compartments, and as a result, the measurement of its concentration is strongly related to the fluid status of the patient. An interest has been shown in correcting measured serum creatinine levels according to the fluid balance in order to better specify the degree of acute kidney injury (AKI). METHODS: We conducted a retrospective observational study of 33 children, aged 0 to 5 years, admitted to the pediatric intensive care unit for acute respiratory distress syndrome treated by extracorporeal membrane oxygenation. We compared measured and corrected creatinine and assessed the degree of agreement between these values using both Cohen's kappa and Krippendorff's alpha coefficient. RESULTS: In our cohort, 37% of the classifications made according to measured creatinine levels were erroneous and, in the majority of cases, the degree of AKI was underestimated. CONCLUSION: Correction of the measured creatinine value according to the degree of fluid overload may result in more accurate diagnosis of AKI. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information.

The Cerebrospinal Fluid Proteomic Response to Traumatic and Nontraumatic Acute Brain Injury: A Prospective Study.

BACKGROUND: Quantitative analysis of ventricular cerebrospinal fluid (vCSF) proteins following acute brain injury (ABI) may help identify pathophysiological pathways and potential biomarkers that can predict unfavorable outcome. METHODS: In this prospective proteomic analysis study, consecutive patients with severe ABI expected to require intraventricular catheterization for intracranial pressure (ICP) monitoring for at least 5 days and patients without ABI admitted for elective clipping of an unruptured cerebral aneurysm were included. vCSF samples were collected within the first 24 h after ABI and ventriculostomy insertion and then every 24 h for 5 days. In patients without ABI, a single vCSF sample was collected at the time of elective clipping. Data-independent acquisition and sequential window acquisition of all theoretical spectra (SWATH) mass spectrometry were used to compare differences in protein expression in patients with ABI and patients without ABI and in patients with traumatic and nontraumatic ABI. Differences in protein expression according to different ICP values, intensive care unit outcome, subarachnoid hemorrhage (SAH) versus traumatic brain injury (TBI), and good versus poor 3-month functional status (assessed by using the Glasgow Outcome Scale) were also evaluated. vCSF proteins with significant differences between groups were compared by using linear models and selected for gene ontology analysis using R Language and the Panther database. RESULTS: We included 50 patients with ABI (SAH n = 23, TBI n = 15, intracranial hemorrhage n = 6, ischemic stroke n = 3, others n = 3) and 12 patients without ABI. There were significant differences in the expression of 255 proteins between patients with and without ABI (p < 0.01). There were intraday and interday differences in expression of seven proteins related to increased inflammation, apoptosis, oxidative stress, and cellular response to hypoxia and injury. Among these, glial fibrillary acidic protein expression was higher in patients with ABI with severe intracranial hypertension (ICH) (ICP ≥ 30 mm Hg) or death compared to those without (log 2 fold change: + 2.4; p < 0.001), suggesting extensive primary astroglial injury or death. There were differences in the expression of 96 proteins between patients with traumatic and nontraumatic ABI (p < 0.05); intraday and interday differences were observed for six proteins related to structural damage, complement activation, and cholesterol metabolism. Thirty-nine vCSF proteins were associated with an increased risk of severe ICH (ICP ≥ 30 mm Hg) in patients with traumatic compared with nontraumatic ABI (p < 0.05). No significant differences were found in protein expression between patients with SAH versus TBI or between those with good versus poor 3-month Glasgow Outcome Scale score. CONCLUSIONS: Dysregulated vCSF protein expression after ABI may be associated with an increased risk of severe ICH and death.

Early ß-lactam concentrations and infectious complications after lung transplantation.

Antibiotic underdosing in prophylactic antibiotic regimes after lung transplantation (LTx) can increase the risk of infection. We aimed to study whether ß-lactam concentrations achieved desirable pharmacodynamic targets in the early phase after LTx and the association between drug concentrations and the development of early infections or the acquisition of multidrug-resistant (MDR) strains. We reviewed patients in whom broad-spectrum ß-lactam levels were measured after LTx during antibiotic prophylaxis. ß-Lactam concentrations were considered "insufficient" if drug levels remained below four times the clinical breakpoint of the minimal inhibitory concentration for Pseudomonas aeruginosa. The primary outcome was the occurrence of an infection and/or acquisition of MDR pathogens in the first 14 days after transplantation. A total of 70 patients were included. "Insufficient" drug concentrations were found in 40% of patients. In 27% of patients, an early MDR pathogen was identified and 49% patients were diagnosed with an early posttransplant infection. Patients with "insufficient" drug concentrations acquired more frequently MDR bacteria and/or developed an infection than others (22/28, 79% vs. 20/42, 48% - p = .01). ß-Lactam levels were often found to be below the desired drug targets in the early phase after transplantation and may be associated with the occurrence of early infectious complications.

Association of cerebrospinal fluid protein biomarkers with outcomes in patients with traumatic and non-traumatic acute brain injury: systematic review of the literature.

BACKGROUND: Acute brain injuries are associated with high mortality rates and poor long-term functional outcomes. Measurement of cerebrospinal fluid (CSF) biomarkers in patients with acute brain injuries may help elucidate some of the pathophysiological pathways involved in the prognosis of these patients. METHODS: We performed a systematic search and descriptive review using the MEDLINE database and the PubMed interface from inception up to June 29, 2021, to retrieve observational studies in which the relationship between CSF concentrations of protein biomarkers and neurological outcomes was reported in patients with acute brain injury [traumatic brain injury, subarachnoid hemorrhage, acute ischemic stroke, status epilepticus or post-cardiac arrest]. We classified the studies according to whether or not biomarker concentrations were associated with neurological outcomes. The methodological quality of the studies was evaluated using the Newcastle-Ottawa quality assessment scale. RESULTS: Of the 39 studies that met our criteria, 30 reported that the biomarker concentration was associated with neurological outcome and 9 reported no association. In TBI, increased extracellular concentrations of biomarkers related to neuronal cytoskeletal disruption, apoptosis and inflammation were associated with the severity of acute brain injury, early mortality and worse long-term functional outcome. Reduced concentrations of protein biomarkers related to impaired redox function were associated with increased risk of neurological deficit. In non-traumatic acute brain injury, concentrations of CSF protein biomarkers related to dysregulated inflammation and apoptosis were associated with a greater risk of vasospasm and a larger volume of brain ischemia. There was a high risk of bias across the studies. CONCLUSION: In patients with acute brain injury, altered CSF concentrations of protein biomarkers related to cytoskeletal damage, inflammation, apoptosis and oxidative stress may be predictive of worse neurological outcomes.

Extracorporeal Membrane Oxygenation in Patients With COVID-19: An International Multicenter Cohort Study.

BACKGROUND: To report and compare the characteristics and outcomes of COVID-19 patients on extracorporeal membrane oxygenation (ECMO) to non-COVID-19 acute respiratory distress syndrome (ARDS) patients on ECMO. METHODS: We performed an international retrospective study of COVID-19 patients on ECMO from 13 intensive care units from March 1 to April 30, 2020. Demographic data, ECMO characteristics and clinical outcomes were collected. The primary outcome was to assess the complication rate and 28-day mortality; the secondary outcome was to compare patient and ECMO characteristics between COVID-19 patients on ECMO and non-COVID-19 related ARDS patients on ECMO (non-COVID-19; January 1, 2018 until July 31, 2019). RESULTS: During the study period 71 COVID-19 patients received ECMO, mostly veno-venous, for a median duration of 13 days (IQR 7-20). ECMO was initiated at 5 days (IQR 3-10) following invasive mechanical ventilation. Median PaO2/FiO2 ratio prior to initiation of ECMO was similar in COVID-19 patients (58 mmHg [IQR 46-76]) and non-COVID-19 patients (53 mmHg [IQR 44-66]), the latter consisting of 48 patients. 28-day mortality was 37% in COVID-19 patients and 27% in non-COVID-19 patients. However, Kaplan-Meier curves showed that after a 100-day follow-up this non-significant difference resolves. Non-surviving COVID-19 patients were more acidotic prior to initiation ECMO, had a shorter ECMO run and fewer received muscle paralysis compared to survivors. CONCLUSIONS: No significant differences in outcomes were found between COVID-19 patients on ECMO and non-COVID-19 ARDS patients on ECMO. This suggests that ECMO could be considered as a supportive therapy in case of refractory respiratory failure in COVID-19.

Variability in Serum Sodium Concentration and Prognostic Significance in Severe Traumatic Brain Injury: A Multicenter Observational Study.

BACKGROUND/OBJECTIVE: Dysnatremia is common in severe traumatic brain injury (TBI) patients and may contribute to mortality. However, serum sodium variability has not been studied in TBI patients. We hypothesized that such variability would be independently associated with mortality. METHODS: We collected 6-hourly serum sodium levels for the first 7 days of ICU admission from 240 severe TBI patients in 14 neurotrauma ICUs in Europe and Australia. We evaluated the association between daily serum sodium standard deviation (dNaSD), an index of variability, and 28-day mortality. RESULTS: Patients were 46 ± 19 years of age with a median initial GCS of 6 [4-8]. Overall hospital mortality was 28%. Hypernatremia and hyponatremia occurred in 64% and 24% of patients, respectively. Over the first 7 days in ICU, serum sodium standard deviation was 2.8 [2.0-3.9] mmol/L. Maximum daily serum sodium standard deviation (dNaSD) occurred at a median of 2 [1-4] days after admission. There was a significant progressive decrease in dNaSD over the first 7 days (coefficient - 0.15 95% CI [- 0.18 to - 0.12], p < 0.001). After adjusting for baseline TBI severity, diabetes insipidus, the use of osmotherapy, the occurrence of hypernatremia, and hyponatremia and center, dNaSD was significantly independently associated with 28-day mortality (HR 1.27 95% CI (1.01-1.61), p = 0.048). CONCLUSIONS: Our study demonstrates that daily serum sodium variability is an independent predictor of 28-day mortality in severe TBI patients. Further prospective investigations are necessary to confirm the significance of sodium variability in larger cohorts of TBI patients and test whether attenuating such variability confers outcome benefits to such patients.

The impact of intra-arrest hypothermia.

PURPOSE OF REVIEW: To address the impact of therapeutic hypothermia induced already during cardiopulmonary resuscitation (i.e. intra-arrest cooling) and its association with neurologic functional outcome. RECENT FINDINGS: Intra-arrest cooling is superior than post-ROSC cooling to mitigate brain injuries in experimental models of cardiac arrest. The delayed initiation of hypothermia in human studies may not have adequately addressed the underlying pathophysiology of ischemia and reperfusion. The assessment of early initiation of cooling has been complicated by increased rate of hemodynamic adverse events caused by infusion of cold intravenous fluids. These adverse events have been more deleterious in patients with initial shockable rhythms. A recent randomized study shows that an alternative intra-arrest cooling method using trans-nasal evaporative cooling was well tolerated and effective to shorten time to target temperature. However, the neurologic outcomes (CPC 1-2 at 90 days) in favor of intra-arrest cooling compared to hospital cooling (34.8% vs 25.9%, P = 0.11) in patients with initial shockable rhythms did not reach statistical significance. SUMMARY: Therapeutic intra-arrest hypothermia can be initiated safely at the scene of the arrest using transnasal evaporative cooling. The potential beneficial effect of intra-arrest cooling on neurologic recovery in patients with initial shockable rhythms should be explored further.

Hypothermic to ischemic ratio and mortality in post-cardiac arrest patients.

BACKGROUND: We studied the associations between ischemia and hypothermia duration, that is, the hypothermic to ischemic ratio (H/I ratio), with mortality in patients included in a trial on two durations of targeted temperature management (TTM) at 33°C. METHODS: The TTH48 (NCT01689077) trial compared 24 and 48 hours of TTM in patients after cardiac arrest. We calculated the hypothermia time from return of spontaneous circulation (ROSC) until the patient reached 37°C after TTM and the ischemic time from CA to ROSC. We compared continuous variables with the Mann-Whitney U test. Using COX regression, we studied the independent association of the logarithmically transformed H/I ratio and time to death as well as interaction between time to ROSC, hypothermia duration, and intervention group. We visualized the predictive ability of variables with receiver operating characteristic curve analysis. RESULTS: Of the 338 patients, 237 (70%) survived for 6 months. The H/I ratio was 155 (IQR 111-238) in survivors and 114 (IQR 80-169) in non-survivors (P < .001). In a Cox regression model including factors associated with outcome in univariate analysis, the logarithmically transformed H/I ratio was a significant predictor of outcome (hazard ratio 0.52 (0.37-0.72, P = .001)). After removing an outlier, we found no interaction between time to ROSC and intervention group (P = .55) or hypothermia duration in quartiles (P = .07) with mortality. There was no significant difference in the area under the curve (AUC) between time to ROSC and H/I ratio (ΔAUC 0.03 95% CI -0.006-0.07, P = .10). CONCLUSIONS: We did not find any consistent evidence of a modification of the effect of TTM based on ischemia duration.

Brain Ultrasonography Consensus on Skill Recommendations and Competence Levels Within the Critical Care Setting.

BACKGROUND: To report a consensus on the different competency levels for the elaboration of skill recommendations in performing brain ultrasonography within the neurocritical care setting. METHODS: Four brain ultrasound experts, supported by a methodologist, performed a preselection of indicators and skills based on the current literature and clinical expertise. An international panel of experts was recruited and subjected to web-based questionnaires according to a Delphi method presented in three separate rounds. A pre-defined threshold of agreement was established on expert subjective opinions, > 84% of votes was set to support a strong recommendation and > 68% for a weak recommendation. Below these thresholds, no recommendation reached. RESULTS: We defined four different skill levels (basic, basic-plus, pre-advanced, advanced). Twenty-five experts participated to the full process. After four rounds of questions, two items received a strong recommendation in the basic skill category, three in the advanced, twelve in the basic-plus, and seven in the pre-advanced. Two items in the pre-advanced category received a weak recommendation and three could not be collocated and were excluded from the list. CONCLUSIONS: Results from this consensus permitted stratification of the different ultrasound examination skills in four levels with progressively increasing competences. This consensus can be useful as a guide for beginners in brain ultrasonography and for the development of specific training programs within this field.

Early initiation of extracorporeal life support in refractory out-of-hospital cardiac arrest: Design and rationale of the INCEPTION trial.

Return of spontaneous circulation occurs in less than 10% of patients with cardiac arrest undergoing cardiopulmonary resuscitation (CPR) for more than 15 minutes. Studies suggest that extracorporeal life support during cardiopulmonary resuscitation (ECPR) improves survival rate in these patients. These studies, however, are hampered by their non-randomized, observational design and are mostly single-center. A multicenter, randomized controlled trial is urgently warranted to evaluate the effectiveness of ECPR. HYPOTHESIS: We hypothesize that early initiation of ECPR in refractory out-of-hospital cardiac arrest (OHCA) improves the survival rate with favorable neurological status. STUDY DESIGN: The INCEPTION trial is an investigator-initiated, prospective, multicenter trial that will randomly allocate 110 patients to either continued CPR or ECPR in a 1:1 ratio. Patients eligible for inclusion are adults (≤ 70 years) with witnessed OHCA presenting with an initial rhythm of ventricular fibrillation (VF) or ventricular tachycardia (VT), who received bystander basic life support and who fail to achieve sustained return of spontaneous circulation within 15 minutes of cardiopulmonary resuscitation by emergency medical services. The primary endpoint of the study is 30-day survival rate with favorable neurological status, defined as 1 or 2 on the Cerebral Performance Category score. The secondary endpoints include 3, 6 and 12-month survival rate with favorable neurological status and the cost-effectiveness of ECPR compared to CCPR. SUMMARY: The INCEPTION trial aims to determine the clinical benefit for the use of ECPR in patients with refractory OHCA presenting with VF/VT. Additionally, the feasibility and cost-effectiveness of ECPR will be evaluated.