Prolonged activation of nasal immune cell populations and development of tissue-resident SARS-CoV-2-specific CD8+ T cell responses following COVID-19.

Systemic immune cell dynamics during coronavirus disease 2019 (COVID-19) are extensively documented, but these are less well studied in the (upper) respiratory tract, where severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replicates1-6. Here, we characterized nasal and systemic immune cells in individuals with COVID-19 who were hospitalized or convalescent and compared the immune cells to those seen in healthy donors. We observed increased nasal granulocytes, monocytes, CD11c+ natural killer (NK) cells and CD4+ T effector cells during acute COVID-19. The mucosal proinflammatory populations positively associated with peripheral blood human leukocyte antigen (HLA)-DRlow monocytes, CD38+PD1+CD4+ T effector (Teff) cells and plasmablasts. However, there was no general lymphopenia in nasal mucosa, unlike in peripheral blood. Moreover, nasal neutrophils negatively associated with oxygen saturation levels in blood. Following convalescence, nasal immune cells mostly normalized, except for CD127+ granulocytes and CD38+CD8+ tissue-resident memory T cells (TRM). SARS-CoV-2-specific CD8+ T cells persisted at least 2 months after viral clearance in the nasal mucosa, indicating that COVID-19 has both transient and long-term effects on upper respiratory tract immune responses.

Platelet Transfusion before CVC Placement in Patients with Thrombocytopenia.

BACKGROUND: Transfusion guidelines regarding platelet-count thresholds before the placement of a central venous catheter (CVC) offer conflicting recommendations because of a lack of good-quality evidence. The routine use of ultrasound guidance has decreased CVC-related bleeding complications. METHODS: In a multicenter, randomized, controlled, noninferiority trial, we randomly assigned patients with severe thrombocytopenia (platelet count, 10,000 to 50,000 per cubic millimeter) who were being treated on the hematology ward or in the intensive care unit to receive either one unit of prophylactic platelet transfusion or no platelet transfusion before ultrasound-guided CVC placement. The primary outcome was catheter-related bleeding of grade 2 to 4; a key secondary outcome was grade 3 or 4 bleeding. The noninferiority margin was an upper boundary of the 90% confidence interval of 3.5 for the relative risk. RESULTS: We included 373 episodes of CVC placement involving 338 patients in the per-protocol primary analysis. Catheter-related bleeding of grade 2 to 4 occurred in 9 of 188 patients (4.8%) in the transfusion group and in 22 of 185 patients (11.9%) in the no-transfusion group (relative risk, 2.45; 90% confidence interval [CI], 1.27 to 4.70). Catheter-related bleeding of grade 3 or 4 occurred in 4 of 188 patients (2.1%) in the transfusion group and in 9 of 185 patients (4.9%) in the no-transfusion group (relative risk, 2.43; 95% CI, 0.75 to 7.93). A total of 15 adverse events were observed; of these events, 13 (all grade 3 catheter-related bleeding [4 in the transfusion group and 9 in the no-transfusion group]) were categorized as serious. The net savings of withholding prophylactic platelet transfusion before CVC placement was $410 per catheter placement. CONCLUSIONS: The withholding of prophylactic platelet transfusion before CVC placement in patients with a platelet count of 10,000 to 50,000 per cubic millimeter did not meet the predefined margin for noninferiority and resulted in more CVC-related bleeding events than prophylactic platelet transfusion. (Funded by ZonMw; PACER Dutch Trial Register number, NL5534.).

Fat-soluble vitamins as biomarkers of nutritional status and their relation with complications in polytrauma patients.

BACKGROUND AND AIMS: This exploratory observational prospective study aimed to evaluate fat-soluble vitamin plasma levels during hospital admission and its relation with the development of malnutrition and complications in polytrauma patients, considering the protocolized multivitamin supplementation during intensive care unit (ICU) admission. METHODS: In 49 well-nourished polytrauma (injury severity score ≥ 16) patients admitted to the ICU of two level-1 trauma centers, vitamin A, D, and E levels were assessed weekly during hospital stay. All patients received multivitamin supplementation during ICU stay. Linear mixed-effect models were used to assess a trend in vitamin levels over time during hospital stay. Mixed-effects logistic regression analysis was performed to relate vitamin concentrations with malnutrition, defined as a subjective global assessment score ≤5, and complications. RESULTS: Vitamin A levels increased 0.17 µmol/L per week (95% confidence interval 0.12-0.22, p < 0.001), vitamin D levels increased 1.49 nmol/L per week (95% confidence interval 0.64-2.33, p < 0.01), vitamin E levels increased 1.17 µmol/L per week (95% confidence interval 0.61-1.73, p < 0.001) during hospital stay (29 ± 17 days). Vitamin levels were not related to malnutrition or complications during hospital stay. CONCLUSION: Vitamin A, D, and E levels increased due to supplementation during hospital admission. Plasma levels of vitamins A, D, and E do not seem to be useful as biomarkers for the nutritional status of polytrauma patients during hospital stay. No correlation with complications could be demonstrated.

Predicting organ functioning with and without blood transfusion in critically ill patients with anemia.

BACKGROUND: To develop a model for the prediction of the (most likely) effect of red blood cell (RBC) transfusion on subsequent organ functioning in nonbleeding critically ill patients with hemoglobin concentrations between 6 and 9 g/dL. STUDY DESIGN AND METHODS: We conducted a retrospective cohort study using electronic health care data of nonbleeding patients admitted between November 2004 and May 2016 at the intensive care unit (ICU) of the Leiden University Medical Center, The Netherlands. We analyzed the associations between transfusion (yes/no) and next-day SOFA scores (Sequential Organ Failure Assessment-as a measure for organ functioning) for all observed combinations of hemoglobin values (between 6 and 9 g/dL) and concurrent clinical variables. RESULTS: Data of 6425 ICU admission of 5756 critically ill patients with 28,702 hemoglobin values between 6 and 9 g/dL (transfusion decision moments) of which 22.1% were followed by a transfusion were analyzed. The adjusted average difference between the next-day SOFA score of transfused versus not-transfused patients was 0.08 (95% confidence interval [CI] -0.03 to 0.18). At singular transfusion decision moments, the score predicted a beneficial effect of transfusion on next-day SOFA score for some subgroups and medical conditions and a harmful effect in other occasions. CONCLUSIONS: Among these critically ill patients with hemoglobin concentrations between 6 and 9 g/dL the population average effect of transfusion on the next SOFA score was negligible. Further, our results support caution in clinical decision-making regarding transfusion of critical ill, nonbleeding ICU patients.

Incidence of transfusion-related acute lung injury temporally associated with solvent/detergent plasma use in the ICU: A retrospective before and after implementation study.

BACKGROUND: Transfusion-related acute lung injury (TRALI) is a severe complication of plasma transfusion, though the use of solvent/detergent pooled plasma (SDP) has nearly eliminated reported TRALI cases. The goal of this study was to investigate the incidence of TRALI in intensive care units (ICU) following the replacement of quarantined fresh frozen plasma (qFFP) by SDP. STUDY DESIGN AND METHODS: A retrospective multicenter observational before-after cohort study was performed during two 6-month periods, before (April-October 2014) and after the introduction of SDP (April-October 2015), accounting for a washout period. A full chart review was performed for patients who received ≥1 plasma units and developed hypoxemia within 24 h. RESULTS: During the study period, 8944 patients were admitted to the ICU. Exactly 1171 quarantine fresh frozen plasma (qFFP) units were transfused in 376 patients, and respectively, 2008 SDP units to 396 patients after implementation. Ten TRALI cases occurred during the qFFP and nine cases occurred during the SDP period, in which plasma was transfused. The incidence was 0.85% (CI95%: 0.33%-1.4%) per unit qFFP and 0.45% (CI95%: 0.21%-0.79%, p = 0.221) per SDP unit. One instance of TRALI occurred after a single SDP unit. Mortality was 70% for patients developing TRALI in the ICU compared with 22% in patients receiving at least one plasma transfusion. CONCLUSION: Implementation of SDP lowered the incidence of TRALI in which plasma products were implicated, though not significantly. Clinically diagnosed TRALI can still occur following SDP transfusion. Developing TRALI in the ICU was associated with high mortality rates, therefore, clinicians should remain vigilant.

Corticosteroid use in COVID-19 patients: a systematic review and meta-analysis on clinical outcomes.

BACKGROUND: In the current SARS-CoV-2 pandemic, there has been worldwide debate on the use of corticosteroids in COVID-19. In the recent RECOVERY trial, evaluating the effect of dexamethasone, a reduced 28-day mortality in patients requiring oxygen therapy or mechanical ventilation was shown. Their results have led to considering amendments in guidelines or actually already recommending corticosteroids in COVID-19. However, the effectiveness and safety of corticosteroids still remain uncertain, and reliable data to further shed light on the benefit and harm are needed. OBJECTIVES: The aim of this systematic review and meta-analysis was to evaluate the effectiveness and safety of corticosteroids in COVID-19. METHODS: A systematic literature search of RCTS and observational studies on adult patients was performed across Medline/PubMed, Embase and Web of Science from December 1, 2019, until October 1, 2020, according to the PRISMA guidelines. Primary outcomes were short-term mortality and viral clearance (based on RT-PCR in respiratory specimens). Secondary outcomes were: need for mechanical ventilation, need for other oxygen therapy, length of hospital stay and secondary infections. RESULTS: Forty-four studies were included, covering 20.197 patients. In twenty-two studies, the effect of corticosteroid use on mortality was quantified. The overall pooled estimate (observational studies and RCTs) showed a significant reduced mortality in the corticosteroid group (OR 0.72 (95%CI 0.57-0.87). Furthermore, viral clearance time ranged from 10 to 29 days in the corticosteroid group and from 8 to 24 days in the standard of care group. Fourteen studies reported a positive effect of corticosteroids on need for and duration of mechanical ventilation. A trend toward more infections and antibiotic use was present. CONCLUSIONS: Our findings from both observational studies and RCTs confirm a beneficial effect of corticosteroids on short-term mortality and a reduction in need for mechanical ventilation. And although data in the studies were too sparse to draw any firm conclusions, there might be a signal of delayed viral clearance and an increase in secondary infections.

Association between first-week propofol administration and long-term outcomes of critically ill mechanically ventilated patients: A retrospective cohort study.

BACKGROUND & AIM: Propofol is commonly used in ICUs, but its long-term effects have not been thoroughly studied. In vitro studies suggest it may harm mitochondrial function, potentially affecting clinical outcomes. This study aimed to investigate the association between substantial propofol sedation and clinical outcomes in critically ill patients. METHODS: We conducted a single-centre cohort study of critically ill, mechanically ventilated (≥7 days) adults to compare patients who received a substantial dose of propofol (cumulative >500 mg) during the first week of ICU admission with those who did not. The primary outcome was the association between substantial propofol administration and 6-month mortality, adjusted for relevant covariates. Subanalyses were performed for administration in the early (day 1-3) and late (day 4-7) acute phases of critical illness due to the metabolic changes in this period. Secondary outcomes included tracheostomy need and duration, length of ICU and hospital stay (LOS), discharge destinations, ICU, hospital, and 3-month mortality. RESULTS: A total of 839 patients were enrolled, with 73.7 % receiving substantial propofol administration (substantial propofol dose group). Six-month all-cause mortality was 32.4 %. After adjusting for relevant variables, we found no statistically significant difference in 6-month mortality between both groups. There were also no significant differences in secondary outcomes. CONCLUSION: Our study suggests that substantial propofol administration during the first week of ICU stay in the least sick critically ill, mechanically ventilated adult patients is safe, with no significant associations found with 6-month mortality, ICU or hospital LOS, differences in discharge destinations or need for tracheostomy.

Total plasma N-glycomic signature of SARS-CoV-2 infection.

Total plasma protein N-glycosylation (TPNG) changes are a hallmark of many diseases. Here, we analyzed the TPNG of 169 COVID-19 patients and 12 healthy controls, using mass spectrometry, resulting in the relative quantification of 85 N-glycans. We found a COVID-19 N-glycomic signature, with 59 glycans differing between patients and controls, many of them additionally differentiating between severe and mild COVID-19. Tri- and tetra-antennary N-glycans were increased in patients, showing additionally elevated levels of antennary α2,6-sialylation. Conversely, bisection of di-antennary, core-fucosylated, nonsialylated glycans was low in COVID-19, particularly in severe cases, potentially driven by the previously observed low levels of bisection on antibodies of severely diseased COVID-19 patients. These glycomic changes point toward systemic changes in the blood glycoproteome, particularly involvement of acute-phase proteins, immunoglobulins and the complement cascade. Further research is needed to dissect glycosylation changes in a protein- and site-specific way to obtain specific functional leads.

Relevance of plasma lipoproteins and small metabolites in assessment of nutritional status among patients with severe injuries.

Background: This study aimed to identify plasma lipoproteins and small metabolites associated with high risk of malnutrition during intensive care unit (ICU) stay in patients with severe injuries. Methods: This observational prospective exploratory study was conducted at two level-1 trauma centers in the Netherlands. Adult patients (aged ≥18 years) who were admitted to the ICU for more than 48 h between July 2018 and April 2022 owing to severe injuries (polytrauma, as defined by Injury Severity Scores of ≥16) caused by blunt trauma were eligible for inclusion. Partial least squares discriminant analysis was used to analyze the relationship of 112 lipoprotein-related components and 23 small metabolites with the risk of malnutrition (modified Nutrition Risk in Critically Ill score). Malnutrition was diagnosed based on Subjective Global Assessment scores. The relationship of lipoprotein properties and small metabolite concentrations with malnutrition (during ICU admission) was evaluated using mixed effects logistic regression. Results: Overall, 51 patients were included. Lower (very) low-density lipoprotein ([V]LDL) (free) cholesterol and phospholipid levels, low particle number, and higher levels of LDL triglycerides were associated with a higher risk of malnutrition (variable importance in projection [VIP] value >1.5). Low levels of most (V)LDL and intermediate-density lipoprotein subfractions and high levels of high-density lipoprotein Apo-A1 were associated with the diagnosis of malnutrition (VIP value >1.5). Increased levels of dimethyl sulfone, trimethylamine N-oxide, creatinine, N, N-dimethylglycine, and pyruvic acid and decreased levels of creatine, methionine, and acetoacetic acid were also indicative of malnutrition (VIP value >1.5). Overall, 14 lipoproteins and 1 small metabolite were significantly associated with a high risk of malnutrition during ICU admission (P <0.05); however, the association did not persist after correcting the false discovery rate (P=0.35 for all). Conclusion: Increased triglyceride in several lipoprotein subfractions and decreased levels of other lipoprotein subfraction lipids and several small metabolites (involved in the homocysteine cycle, ketone body formation, and muscle metabolism) may be indicative of malnutrition risk. Following validation in larger cohorts, these indicators may guide institution of preventive nutritional measures in patients admitted to the ICU with severe injuries.

Description of mitochondrial oxygen tension and its variability in healthy volunteers.

OBJECTIVES: Describing mitochondrial oxygenation (mitoPO2) and its within- and between-subject variability over time after 5-aminolevulinic acid (ALA) plaster application in healthy volunteers. DESIGN: Prospective cohort study. SETTING: Measurements were performed in Leiden University Medical Center, the Netherlands. PARTICIPANTS: Healthy volunteers enrolled from July to September 2020. INTERVENTIONS: Two ALA plasters were placed parasternal left and right, with a 3-hour time interval, to examine the influence of the calendar time on the value of mitoPO2. We measured mitoPO2 at 4, 5, 7, 10, 28, and 31 hours after ALA plaster 1 application, and at 4, 5, 7, 25, and 28 hours after ALA plaster 2 application. PRIMARY AND SECONDARY OUTCOME MEASURES: At each time point, five mitoPO2 measurements were performed. Within-subject variability was defined as the standard deviation (SD) of the mean of five measurements per timepoint of a study participant. The between-subject variability was the SD of the mean mitoPO2 value of the study population per timepoint. RESULTS: In 16 completed inclusions, median mitoPO2 values and within-subject variability were relatively similar over time at all time points for both plasters. An increase in overall between-subject variability was seen after 25 hours ALA plaster time (19.6 mm Hg vs 23.9 mm Hg after respectively 10 and 25 hours ALA plaster time). CONCLUSIONS: The mitoPO2 values and within-subject variability remained relatively stable over time in healthy volunteers. An increase in between-subject variability was seen after 25 hours ALA plaster time warranting replacement of the ALA plaster one day after its application. TRIAL REGISTRATION: ClinicalTrials.gov with trial number NCT04626661.

Longitudinal soluble marker profiles reveal strong association between cytokine storms resulting from macrophage activation and disease severity in COVID-19 disease.

SARS-CoV2 infection results in a range of disease severities, but the underlying differential pathogenesis is still not completely understood. At presentation it remains difficult to estimate and predict severity, in particular, identify individuals at greatest risk of progression towards the most severe disease-states. Here we used advanced models with circulating serum analytes as variables in combination with daily assessment of disease severity using the SCODA-score, not only at single time points but also during the course of disease, to correlate analyte levels and disease severity. We identified a remarkably strong pro-inflammatory cytokine/chemokine profile with high levels for sCD163, CCL20, HGF, CHintinase3like1 and Pentraxin3 in serum which correlated with COVID-19 disease severity and overall outcome. Although precise analyte levels differed, resulting biomarker profiles were highly similar at early and late disease stages, and even during convalescence similar biomarkers were elevated and further included CXCL3, CXCL6 and Osteopontin. Taken together, strong pro-inflammatory marker profiles were identified in patients with COVID-19 disease which correlated with overall outcome and disease severity.

A simulation of skin mitochondrial Po2 in circulatory shock.

Circulatory shock is the inadequacy to supply mitochondria with enough oxygen to sustain aerobic energy metabolism. A novel noninvasive bedside measurement was recently introduced to monitor the mitochondrial oxygen tension in the skin (mitoPo2). As the most downstream marker of oxygen balance in the skin, mitoPo2 may provide additional information to improve shock management. However, a physiological basis for the interpretation of mitoPo2 values has not been established yet. In this paper, we developed a mathematical model of skin mitoPo2 using a network of parallel microvessels, based on Krogh's cylinder model. The model contains skin blood flow velocity, heterogeneity of blood flow, hematocrit, arteriolar oxygen saturation, and mitochondrial oxygen consumption as major variables. The major results of the model show that normal physiological mitoPo2 is in the range of 40-60 mmHg. The relationship of mitoPo2 with skin blood flow velocity follows a logarithmic growth curve, reaching a plateau at high skin blood flow velocity, suggesting that oxygen balance remains stable while peripheral perfusion declines. The model shows that a critical range exists where mitoPo2 rapidly deteriorates if skin perfusion further decreases. The model intuitively shows how tissue hypoxia could occur in the setting of septic shock, due to the profound impact of microcirculatory disturbance on mitoPo2, even at sustained cardiac output. MitoPo2 is the result of a complex interaction between all factors of oxygen delivery and microcirculation. This mathematical framework can be used to interpret mitoPo2 values in shock, with the potential to enhance personalized clinical trial design.NEW & NOTEWORTHY This is the first paper to simulate mitochondrial oxygen tension in skin in circulatory shock. The relationships of mitoPo2 with parameters of (microcirculatory) oxygen delivery aid in the understanding of noninvasive bedside measurement of mitoPo2 values and show that mitochondrial oxygen tension is two orders of magnitude higher than classically assumed. The model can be used to enhance clinical trial design investigating mitoPo2 as a resuscitation target in circulatory shock.

Rapid Response to Remdesivir in Hospitalised COVID-19 Patients: A Propensity Score Weighted Multicentre Cohort Study.

INTRODUCTION: Remdesivir is a registered treatment for hospitalised patients with COVID-19 that has moderate clinical effectiveness. Anecdotally, some patients' respiratory insufficiency seemed to recover particularly rapidly after initiation of remdesivir. In this study, we investigated if this rapid improvement was caused by remdesivir, and which patient characteristics might predict a rapid clinical improvement in response to remdesivir. METHODS: This was a multicentre observational cohort study of hospitalised patients with COVID-19 who required supplemental oxygen and were treated with dexamethasone. Rapid clinical improvement in response to treatment was defined by a reduction of at least 1 L of supplemental oxygen per minute or discharge from the hospital within 72 h after admission. Inverse probability of treatment-weighted logistic regression modelling was used to assess the association between remdesivir and rapid clinical improvement. Secondary endpoints included in-hospital mortality, ICU admission rate and hospitalisation duration. RESULTS: Of 871 patients included, 445 were treated with remdesivir. There was no influence of remdesivir on the occurrence of rapid clinical improvement (62% vs 61% OR 1.05, 95% CI 0.79-1.40; p = 0.76). The in-hospital mortality was lower (14.7% vs 19.8% OR 0.70, 95% CI 0.48-1.02; p = 0.06) for the remdesivir-treated patients. Rapid clinical improvement occurred more often in patients with low C-reactive protein (≤ 75 mg/L) and short duration of symptoms prior to hospitalisation (< 7 days) (OR 2.84, 95% CI 1.07-7.56). CONCLUSION: Remdesivir generally does not increase the incidence of rapid clinical improvement in hospitalised patients with COVID-19, but it might have an effect in patients with short duration of symptoms and limited signs of systemic inflammation.

Immunoglobulin G1 Fc glycosylation as an early hallmark of severe COVID-19.

BACKGROUND: Immunoglobulin G1 (IgG1) effector functions are impacted by the structure of fragment crystallizable (Fc) tail-linked N-glycans. Low fucosylation levels on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein-specific IgG1 has been described as a hallmark of severe coronavirus disease 2019 (COVID-19) and may lead to activation of macrophages via immune complexes thereby promoting inflammatory responses, altogether suggesting involvement of IgG1 Fc glycosylation modulated immune mechanisms in COVID-19. METHODS: In this prospective, observational single center cohort study, IgG1 Fc glycosylation was analyzed by liquid chromatography-mass spectrometry following affinity capturing from serial plasma samples of 159 SARS-CoV-2 infected hospitalized patients. FINDINGS: At baseline close to disease onset, anti-S IgG1 glycosylation was highly skewed when compared to total plasma IgG1. A rapid, general reduction in glycosylation skewing was observed during the disease course. Low anti-S IgG1 galactosylation and sialylation as well as high bisection were early hallmarks of disease severity, whilst high galactosylation and sialylation and low bisection were found in patients with low disease severity. In line with these observations, anti-S IgG1 glycosylation correlated with various inflammatory markers. INTERPRETATION: Association of low galactosylation, sialylation as well as high bisection with disease severity and inflammatory markers suggests that further studies are needed to understand how anti-S IgG1 glycosylation may contribute to disease mechanism and to evaluate its biomarker potential. FUNDING: This project received funding from the European Commission's Horizon2020 research and innovation program for H2020-MSCA-ITN IMforFUTURE, under grant agreement number 721815, and supported by Crowdfunding Wake Up To Corona, organized by the Leiden University Fund.

Development and validation of an early warning model for hospitalized COVID-19 patients: a multi-center retrospective cohort study.

BACKGROUND: Timely identification of deteriorating COVID-19 patients is needed to guide changes in clinical management and admission to intensive care units (ICUs). There is significant concern that widely used Early warning scores (EWSs) underestimate illness severity in COVID-19 patients and therefore, we developed an early warning model specifically for COVID-19 patients. METHODS: We retrospectively collected electronic medical record data to extract predictors and used these to fit a random forest model. To simulate the situation in which the model would have been developed after the first and implemented during the second COVID-19 'wave' in the Netherlands, we performed a temporal validation by splitting all included patients into groups admitted before and after August 1, 2020. Furthermore, we propose a method for dynamic model updating to retain model performance over time. We evaluated model discrimination and calibration, performed a decision curve analysis, and quantified the importance of predictors using SHapley Additive exPlanations values. RESULTS: We included 3514 COVID-19 patient admissions from six Dutch hospitals between February 2020 and May 2021, and included a total of 18 predictors for model fitting. The model showed a higher discriminative performance in terms of partial area under the receiver operating characteristic curve (0.82 [0.80-0.84]) compared to the National early warning score (0.72 [0.69-0.74]) and the Modified early warning score (0.67 [0.65-0.69]), a greater net benefit over a range of clinically relevant model thresholds, and relatively good calibration (intercept = 0.03 [- 0.09 to 0.14], slope = 0.79 [0.73-0.86]). CONCLUSIONS: This study shows the potential benefit of moving from early warning models for the general inpatient population to models for specific patient groups. Further (independent) validation of the model is needed.

Immune Determinants of Viral Clearance in Hospitalised COVID-19 Patients: Reduced Circulating Naïve CD4+ T Cell Counts Correspond with Delayed Viral Clearance.

Virus-specific cellular and humoral responses are major determinants for protection from critical illness after SARS-CoV-2 infection. However, the magnitude of the contribution of each of the components to viral clearance remains unclear. Here, we studied the timing of viral clearance in relation to 122 immune parameters in 102 hospitalised patients with moderate and severe COVID-19 in a longitudinal design. Delayed viral clearance was associated with more severe disease and was associated with higher levels of SARS-CoV-2-specific (neutralising) antibodies over time, increased numbers of neutrophils, monocytes, basophils, and a range of pro-inflammatory cyto-/chemokines illustrating ongoing, partially Th2 dominating, immune activation. In contrast, early viral clearance and less critical illness correlated with the peak of neutralising antibodies, higher levels of CD4 T cells, and in particular naïve CD4+ T cells, suggesting their role in early control of SARS-CoV-2 possibly by proving appropriate B cell help. Higher counts of naïve CD4+ T cells also correlated with lower levels of MIF, IL-9, and TNF-beta, suggesting an indirect role in averting prolonged virus-induced tissue damage. Collectively, our data show that naïve CD4+ T cell play a critical role in rapid viral T cell control, obviating aberrant antibody and cytokine profiles and disease deterioration. These data may help in guiding risk stratification for severe COVID-19.

Progress testing in intensive care medicine training: useful and feasible?!

So far the in-training assessment of knowledge is perhaps underrepresented in postgraduate assessment frameworks in intensive care medicine (ICM). In most contemporary training programs a predominant emphasis is placed on workplace based learning and workplace based assessment. This article provides a concise general background on the nature and use of progress testing, and touches upon potential strengths, and constraints regarding its potential implementation and use in the postgraduate ICM training programs.

Ketamine produces effective and long-term pain relief in patients with Complex Regional Pain Syndrome Type 1.

Complex Regional Pain Syndrome Type 1 (CRPS-1) responds poorly to standard pain treatment. We evaluated if the N-methyl-D-aspartate receptor antagonist S(+)-ketamine improves pain in CRPS-1 patients. Sixty CRPS-1 patients (48 females) with severe pain participated in a double-blind randomized placebo-controlled parallel-group trial. Patients were given a 4.2-day intravenous infusion of low-dose ketamine (n=30) or placebo (n=30) using an individualized stepwise tailoring of dosage based on effect (pain relief) and side effects (nausea/vomiting/psychomimetic effects). The primary outcome of the study was the pain score (numerical rating score: 0-10) during the 12-week study period. The median (range) disease duration of the patients was 7.4 (0.1-31.9) years. At the end of infusion, the ketamine dose was 22.2+/-2.0 mg/h/70 kg. Pain scores over the 12-week study period in patients receiving ketamine were significantly lower than those in patients receiving placebo (P<0.001). The lowest pain score was at the end of week 1: ketamine 2.68+/-0.51, placebo 5.45+/-0.48. In week 12, significance in pain relief between groups was lost (P=0.07). Treatment did not cause functional improvement. Patients receiving ketamine more often experienced mild to moderate psychomimetic side effects during drug infusion (76% versus 18%, P<0.001). In conclusion, in a population of mostly chronic CRPS-1 patients with severe pain at baseline, a multiple day ketamine infusion resulted in significant pain relief without functional improvement. Treatment with ketamine was safe with psychomimetic side effects that were acceptable to most patients.