Optimization of quenched fluorescent peptide substrates of SARS-CoV-2 3CLpro main protease (Mpro) from proteomic identification of P6-P6' active site specificity.

SARS-CoV-2 3C-like main protease (3CLpro) is essential for protein excision from the viral polyprotein. 3CLpro inhibitor drug development to block SARS-CoV-2 replication focuses on the catalytic non-prime (P) side for specificity and potency, but the importance of the prime (P') side in substrate specificity and for drug development remains underappreciated. We determined the P6-P6' specificity for 3CLpro from >800 cleavage sites that we identified using Proteomic Identification of Cleavage site Specificity (PICS). Cleavage occurred after the canonical P1-Gln and non-canonical P1-His and P1-Met residues. Moreover, P3 showed a preference for Arg/Lys and P3' for His. Essential H-bonds between the N-terminal Ser1 of protomer-B in 3CLpro dimers form with P1-His, but not with P1-Met. Nonetheless, cleavage occurs at P1-Met456 in native MAP4K5. Elevated reactive oxygen species in SARS-CoV-2 infection oxidize methionines. Molecular simulations revealed P1-MetOX forms an H-bond with Ser1 and notably, strong positive cooperativity between P1-Met with P3'-His was revealed, which enhanced peptide-cleavage rates. The highly plastic S3' subsite accommodates P3'-His that displays stabilizing backbone H-bonds with Thr25 lying central in a "'threonine trio" (Thr24-Thr25-Thr26) in the P'-binding domain I. Molecular docking simulations unveiled structure-activity relationships impacting 3CLpro-substrate interactions, and the role of these structural determinants was confirmed by MALDI-TOF-MS cleavage assays of P1'- and P3'-positional scanning peptide libraries carrying a 2nd optimal cut-site as an internal positive control. These data informed the design of two new and highly soluble 3CLproquenched-fluorescent peptide substrates for improved FRET monitoring of 3CLpro activity with 15× improved sensitivity over current assays.IMPORTANCEFrom global proteomics identification of >800 cleavage sites, we characterized the P6-P6' active site specificity of SARS-CoV-2 3CLpro using proteome-derived peptide library screens, molecular modeling simulations, and focussed positional peptide libraries. In P1', we show that alanine and serine are cleaved 3× faster than glycine and the hydrophobic small amino acids Leu, Ile, or Val prevent cleavage of otherwise optimal non-prime sequences. In characterizing non-canonical non-prime P1 specificity, we explored the unusual P1-Met specificity, discovering enhanced cleavage when in the oxidized state (P1-MetOX). We unveiled unexpected amino acid cooperativity at P1-Met with P3'-His and noncanonical P1-His with P2-Phe, and the importance of the threonine trio (Thr24-Thr25-Thr26) in the prime side binding domain I in defining prime side binding in SARS-CoV-2 3CLpro. From these analyses, we rationally designed quenched-fluorescence natural amino acid peptide substrates with >15× improved sensitivity and high peptide solubility, facilitating handling and application for screening of new antiviral drugs.

How are Long-Covid, Post-Sepsis-Syndrome and Post-Intensive-Care-Syndrome related? A conceptional approach based on the current research literature.

Long-Covid (LC), Post-Sepsis-Syndrome (PSS) and Post-Intensive-Care-Syndrome (PICS) show remarkable overlaps in their clinical presentation. Nevertheless, it is unclear if they are distinct syndromes, which may co-occur in the same patient, or if they are three different labels to describe similar symptoms, assigned on the basis on patient history and professional perspective of the treating physician. Therefore, we reviewed the current literature on the relation between LC, PSS and PICS. To date, the three syndromes cannot reliably be distinguished due similarities in clinical presentation as they share the cognitive, psychological and physical impairments with only different probabilities of occurrence and a heterogeneity in individual expression. The diagnosis is furthermore hindered by a lack of specific diagnostic tools. It can be concluded that survivors after COVID-19 sepsis likely have more frequent and more severe consequences than patients with milder COVID-19 courses, and that are some COVID-19-specific sequelae, e.g. an increased risk for venous thromboembolism in the 30 days after the acute disease, which occur less often after sepsis of other causes. Patients may profit from leveraging synergies from PICS, PSS and LC treatment as well as from experiences gained from infection-associated chronic conditions in general. Disentangling molecular pathomechanisms may enable future targeted therapies that go beyond symptomatic treatment.

Risk factors, biomarkers, and mechanisms for persistent inflammation, immunosuppression, and catabolism syndrome (PICS): a systematic review and meta-analysis.

INTRODUCTION: Persistent inflammation, immunosuppression, and catabolism syndrome (PICS) has been proposed as an endotype of chronic critical illness (CCI). The aim of this systematic review is to synthesise the available evidence of risk factors, biomarkers, and biological mechanisms underlying PICS. METHODS: MEDLINE, CENTRAL, and EMBASE were searched on June 2, 2023. Our population of interest was adult intensive care unit survivors. The exposure group was patients with PICS and the comparator group was patients with no PICS, CCI, or rapid recovery. Mean differences were pooled for each biomarker using a random effects DerSimonian-Laird method. Risk of bias assessment was done using the Newcastle-Ottawa Scale. RESULTS: Six papers were included. Five were single-centre retrospective cohort studies, and one was a prospective cohort study, with sample sizes ranging from 22 to 391 patients. Two studies showed an increased incidence of PICS with age, and two studies showed an association between PICS and Charlson Comorbidity Index scores. PICS was associated with requiring mechanical ventilation in four studies. Meta-analysis showed a 34.4 mg L-1 higher C-reactive protein (95% confidence interval [CI] 12.7-56.2 mg L-1; P<0.01), a 4.4 g L-1 lower albumin (95% CI 0.5-8.3 g L-1; P<0.01), and a 0.36×109 L-1 lower lymphocyte count (95% CI 0.25-0.47×109 L-1; P=0.01) in the PICS compared with the non-PICS group. There are a large variety of other potential biomarkers but limited validation studies. The overall quality of evidence is limited, and these results should be interpreted accordingly. CONCLUSIONS: While older patients and those with co-morbidities could be at greater risk for PICS, acquired risk factors, such as injury severity, are potentially more predictive of PICS than intrinsic patient characteristics. There are many potential biomarkers for PICS, but limited validation studies have been conducted. Persistent myeloid-derived suppressor cell expansion, the continual release of danger-associated molecular patterns and pathogen-associated molecular patterns propagating inflammation, and bioenergetic failure are all mechanisms underlying PICS that could offer potential for novel biomarkers and therapeutic interventions. CLINICAL TRIAL REGISTRATION: International Prospective Register of Systematic Reviews (PROSPERO; CRD42023427749).

Charting the course for improved outcomes in chronic critical illness: therapeutic strategies for persistent inflammation, immunosuppression, and catabolism syndrome (PICS).

Enhanced critical care delivery has led to improved survival rates in critically ill patients, yet sepsis remains a leading cause of multiorgan failure with variable recovery outcomes. Chronic critical illness, characterised by prolonged ICU stays and persistent end-organ dysfunction, presents a significant challenge in patient management, often requiring multifaceted interventions. Recent research, highlighted in a comprehensive review in the British Journal of Anaesthesia, focuses on addressing the pathophysiological drivers of chronic critical illness, such as persistent inflammation, immunosuppression, and catabolism, through targeted therapeutic strategies including immunomodulation, muscle wasting prevention, nutritional support, and microbiome modulation. Although promising avenues exist, challenges remain in patient heterogeneity, treatment timing, and the need for multimodal approaches.

Persistent inflammation, immunosuppression, and catabolism syndrome (PICS): a review of definitions, potential therapies, and research priorities.

Persistent Inflammation, Immunosuppression, and Catabolism Syndrome (PICS) is a clinical endotype of chronic critical illness. PICS consists of a self-perpetuating cycle of ongoing organ dysfunction, inflammation, and catabolism resulting in sarcopenia, immunosuppression leading to recurrent infections, metabolic derangements, and changes in bone marrow function. There is heterogeneity regarding the definition of PICS. Currently, there are no licensed treatments specifically for PICS. However, findings can be extrapolated from studies in other conditions with similar features to repurpose drugs, and in animal models. Drugs that can restore immune homeostasis by stimulating lymphocyte production could have potential efficacy. Another treatment could be modifying myeloid-derived suppressor cell (MDSC) activation after day 14 when they are immunosuppressive. Drugs such as interleukin (IL)-1 and IL-6 receptor antagonists might reduce persistent inflammation, although they need to be given at specific time points to avoid adverse effects. Antioxidants could treat the oxidative stress caused by mitochondrial dysfunction in PICS. Possible anti-catabolic agents include testosterone, oxandrolone, IGF-1 (insulin-like growth factor-1), bortezomib, and MURF1 (muscle RING-finger protein-1) inhibitors. Nutritional support strategies that could slow PICS progression include ketogenic feeding and probiotics. The field would benefit from a consensus definition of PICS using biologically based cut-off values. Future research should focus on expanding knowledge on underlying pathophysiological mechanisms of PICS to identify and validate other potential endotypes of chronic critical illness and subsequent treatable traits. There is unlikely to be a universal treatment for PICS, and a multimodal, timely, and personalised therapeutic strategy will be needed to improve outcomes for this growing cohort of patients.

Prehospitalization Trauma and Physiologic Factors Associated with the Presence of Post-traumatic Stress 3 Months After PICU Discharge.

BACKGROUND: Children admitted to the pediatric intensive care unit (PICU) have post-traumatic stress (PTS) rates up to 64%, and up to 28% of them meet criteria for PTS disorder (PTSD). We aim to examine whether a prior trauma history and increased physiologic parameters due to a heightened sympathetic response are associated with later PTS. Our hypothesis was children with history of prehospitalization trauma, higher heart rates, blood pressures, cortisol, and extrinsic catecholamine administration during PICU admission are more likely to have PTS after discharge. METHODS: This is a prospective, observational study of children admitted to the PICU at an urban, quaternary, academic children's hospital. Children aged 8 to 17 years old without developmental delay, severe psychiatric disorder, or traumatic brain injury were included. Children's prehospitalization trauma history was assessed with a semistructured interview. All in-hospital variables were from the electronic medical record. PTS was present if children had 4 of the Diagnostic and Statistical Manual of Mental Disorders IV criteria for PTSD. Student's t- and chi-squared tests were used to compare the presence or absence of prior trauma and all of the PICU-associated variables. RESULTS: Of the 110 children at baseline, 67 had 3-month follow-up. In the latter group, 46% met the criteria for PTS, mean age of 13 years (SD 3), 57% male, a mean PRISM III score of 4.9 (SD 4.3), and intensive care unit length of stay 6.5 days (SD 7.8). There were no statistically significant differences in the demographics of the children with and without PTS. The only variable to show significance was trauma history; children with prehospitalization trauma were more likely to have PTS at 3-month follow-up (P = .02). CONCLUSIONS: Prehospitalization trauma history was associated with the presence of PTS after admission to the PICU. This study suggests future studies should shift to the potential predictive benefit of screening children for trauma history upon PICU admission.

Functional outcome after interdisciplinary, acute rehabilitation in COVID-19 patients: a retrospective study.

BACKGROUND: Survivors of severe COVID-19 often exhibit a variety of sequelae including loss of mobility and ADL (activities of daily living) capacity. Acute rehabilitation (AR) is an interdisciplinary rehabilitation intervention applied early while still in a hospital setting. The goal of AR is to improve functional limitations and to increase functional independence at discharge. It is established in the treatment of patients with other severe diseases such as sepsis, polytrauma, or stroke. Data concerning AR in COVID-19 are sparse. AIM: To evaluate the changes in physical function during AR in patients after severe COVID-19. METHODS: This monocentric, retrospective observational study examined the functional outcomes of a sample of COVID-19-patients who received interdisciplinary AR at a university hospital. Inclusion criteria were a positive SARS-CoV-2 test in 05/2020-01/2022 and transfer to AR after intensive care treatment. 87 patients were elegible for evaluation, 3 of whom were excluded because of death during AR. Data were extracted from the hospital information system. In a pre-post analysis, mobility (Charité Mobility Index), ADL (Barthel Index), and oxygen demand were assessed. In addition, discharge location after AR, factors associated with AR unit length of stay, and functional improvements were analyzed. RESULTS: Data of 84 patients were analyzed. Mobility increased significantly from a median of 4 [1.25-6] CHARMI points at admission to a median of 9 [8.25-9] at discharge (p < 0.001). ADL increased significantly from a median of 52.5 [35.0-68.75] Barthel Index points at admission to a median of 92.5 [85-95] at discharge (p < 0.001). Oxygen demand decreased from 80.7 to 30.5% of patients. The majority (55.9%) of patients were discharged home, while 36.9% received direct follow-up rehabilitation. Older age correlated significantly with lower scores on the discharge assessment for mobility (Spearman's ϱ = -0.285, p = 0.009) and ADL (Spearman's ϱ = -0.297, p = 0.006). CONCLUSION: Acute rehabilitation is a viable option for COVID-19 patients with severe functional deficits after ICU treatment to achieve functional progress in mobility and ADL, reduce oxygen requirements and enable follow-up rehabilitation. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION FOR PROSPECTIVELY REGISTERED TRIALS: Trial registration number: DRKS00025239. Date of registration: 08 Sep 2021.

Prevalence and Management of Oral Intake Restrictions in Critically Ill Patients: Insights from a Multicenter Point Prevalence Study.

Oral intake restrictions due to dysphagia in the intensive care unit (ICU) can increase morbidity, mortality, and negatively impact quality of life. The current oral intake practice and clinical management strategies for addressing dysphagia in the ICU are not well-defined. This study aimed to elucidate the clinical practices surrounding oral intake restrictions due to dysphagia and its management strategies in the ICU. A multicenter, prospective, cross-sectional, 2-day point prevalence study was conducted in Japan. Relevant data on the clinical circumstances surrounding oral intake practice and the implementation of strategies to prevent dysphagia for patients admitted to the ICU on November 1, 2023, and December 1, 2023, were collected. The primary outcome was the prevalence of oral intake restrictions in patients, defined by a Functional Oral Intake Scale score of less than 7 among eligible patients for oral intake. Out of 326 participants, 187 were eligible for the final analysis after excluding 139 patients who were not eligible for oral intake, primarily due to tracheal intubation. Among those eligible, 69.0% (129/187) encountered oral intake restrictions. About 52.4% (98/187) of patients underwent swallowing screenings; 36.7% (36/98) of these were suspected of having dysphagia. Compensatory and behavioral swallowing rehabilitation were provided to 21.9% (41/187) and 10.6% (20/187) of patients, respectively, from ICU admission to the survey date. Only 27.4% (14/51) of post-extubation and 9.3% (3/32) of post-stroke patients received swallowing rehabilitation. Notably, no ICUs had dedicated speech and language therapists, and most (85.7%, 18/21) lacked established swallowing rehabilitation protocols. This 2-point prevalence survey study revealed that oral intake restrictions due to dysphagia are common in ICUs, but few patients are screened for swallowing issues or receive rehabilitation. More clinical studies are needed to develop effective protocols for identifying and managing dysphagia, including screenings and rehabilitation in the ICU.

Parental emotional, social and transitional health in the first 6 months after childhood critical illness: A longitudinal qualitative study.

AIM: To explore the experiences and support needs of parents in the first 6 months after paediatric critical care. DESIGN: Longitudinal qualitative design. METHODS: Sequential semi-structured qualitative interviews were conducted with a sample of 28 parents in succession at 1 month and at 6 months (n = 22) after their child's discharge from paediatric critical care using purposive sampling. Data were analysed using the adapted five-stage framework analysis. RESULTS: Data were developed into eight synthesized themes, three domains and an overarching theme: Regaining Normalcy. Families of children requiring medical treatment at 6 months showed signs of adaption to daily care routines. The two domains were Parental Emotional Health and Parental Social Health. Parental Transitional Health, a third domain, was added to the Post Intensive Care Syndrome-paediatric framework. Parents were forward-looking and discussed emotional health, relating to current caregiving issues. Emotional attention was related to present challenges and concerns about current health and possible readmission to the hospital. In terms of Parental Social Health, families isolated themselves for infection control while remaining connected with families using chat applications. Parents were selective to whom they allowed access to their lives. The impact of parental transitional health was evident and emphasized the daily challenges associated with integration back to home life. Flexible work arrangements allowed working parents to support caregiving needs in the first 6 months after discharge. CONCLUSION: In the first 6 months after paediatric critical illness, most families reported having moved past the experiences while having provoking memories of the admission period. Parents viewed the point of normalcy as child returned to school or when all medications were discontinued. Extension of transitional support can facilitate discharge experiences between paediatric critical care and normalcy. The findings highlight the importance of understanding the medium- and longer-term impact of paediatric critical care. IMPACT: What problem did the study address? ○ Limited understanding of long-term parental experiences and support needs after PICU discharge. What were the main findings? ○ Most families regained normalcy when child returns to school or when medications were discontinued. Some families continued to show signs of adaptations at 6 months after PICU discharge. Where and on whom did the research have an impact? ○ The research has an impact on improving the understanding of long-term parental experiences and support needs after PICU discharge, informing clinical practice, guiding policy development and shaping parental support programs. REPORTING METHOD: We reported this study using the COREQ guidelines. PATIENT OR PUBLIC CONTRIBUTION: Prior to confirming the interview guide, three parents of critically ill children actively participated by reviewing and providing feedback on its content. They provided suggestions to refine the wording and ensure clarity to enhance the participants' understanding. By including the perspectives of these parents, we aimed to improve the overall quality and relevance of the interview guide.

Intensive care unit follow-up clinic activities: a scoping review.

The importance of ongoing post-discharge follow-up to prevent functional impairment in patients discharged from intensive care units (ICUs) is being increasingly recognized. Therefore, we conducted a scoping review, which included existing ICU follow-up clinic methodologies using the CENTRAL, MEDLINE, and CINAHL databases from their inception to December 2022. Data were examined for country or region, outpatient name, location, opening days, lead profession, eligible patients, timing of the follow-up, and assessment tools. Twelve studies were included in our review. The results obtained revealed that the methods employed by ICU follow-up clinics varied among countries and regions. The names of outpatient follow-up clinics also varied; however, all were located within the facility. These clinics were mainly physician or nurse led; however, pharmacists, physical therapists, neuropsychologists, and social workers were also involved. Some clinics were limited to critically ill patients with sepsis or those requiring ventilation. Ten studies reported the first outpatient visit 1-3 months after discharge. All studies assessed physical function, cognitive function, mental health, and the health-related quality of life. This scoping review revealed that an optimal operating format for ICU follow-up clinics needs to be established according to the categories of critically ill patients.

Making it real: Actioning the mental health strategy with Pacific Island communities.

OBJECTIVE: This paper explores the practical implications of the World Health Organization strategy of focussing on community-based mental health and wellbeing ecosystems in the context of the Pacific Island Countries. It draws on the expertise of the participants of a collaborative workshop held during the Creating Futures conference in 2023 to discuss successes, challenges, barriers, opportunities in the implementation of the framework and to examine potential future actions. CONCLUSIONS: Some of the significant factors that make for effective and sustained community-based mental health systems include appropriate central coordination and oversight of community-based services, adequate frameworks for quality assurance, meaningful data collection and sustained long-term funding, as well as a range of workforce factors. Flexible and place-based approaches also need to be considered in effective implementation, moving away from Western diagnostic 'labels' to communication that is effective at the local level. Positive community resources as well as the relative youth of the mental health sector in the Pacific Island Nations are huge opportunities to develop affective and appropriate community mental health systems.

Relationship between critical care nutrition and post-intensive care syndrome in surviving ventilated patients with COVID-19: a multicenter prospective observational study.

The impact of nutrition therapy in the acute phase on post-intensive care syndrome (PICS) remains unclear. We conducted a multicenter prospective study on adult patients with COVID-19 who required mechanical ventilation for more than three days. The questionnaire was mailed after discharge. Physical PICS, defined as less than 90 points on the Barthel index (BI), was assigned as the primary outcome. We examined the types of nutrition therapy in the first week that affected PICS components. 269 eligible patients were evaluated 10 months after discharge. Supplemental parenteral nutrition (SPN) >400 kcal/day correlated with a lower occurrence of physical PICS (10% vs 21.92%, p = 0.042), whereas the amounts of energy and protein provided, early enteral nutrition, and a gradual increase in nutrition delivery did not, and none correlated with cognitive or mental PICS. A multivariable regression analysis revealed that SPN had an independent impact on physical PICS (odds ratio 0.33, 95% CI 0.12-0.92, p = 0.034), even after adjustments for age, sex, body mass index and severity. Protein provision ≥1.2 g/kg/day was associated with a lower occurrence of physical PICS (odds ratio 0.42, 95% CI 0.16-1.08, p = 0.071). In conclusion, SPN in the acute phase had a positive impact on physical PICS for ventilated patients with COVID-19.

Relatives' experiences of the transition from intensive care to home for acutely admitted intensive care patients-A qualitative study.

BACKGROUND: Acute admission to an intensive care unit (ICU) can negatively affect quality of life for patients and their relatives. Relatives play an important caregiving role after the patient's admission. More knowledge and understanding of their needs are necessary as the patient transitions home. AIM: This study aims to explore relatives' experiences of acutely admitted ICU patients' transition from the ICU to a general ward and then home. STUDY DESIGN: A qualitative study with a phenomenological approach was conducted. Interviews were in-depth and featured open-ended questions. The interviews took place after the patients transitioned from ICU to home and were conducted online by videoconference. Data were analysed using Colaizzi's seven-step method. RESULTS: Twelve relatives of acutely admitted ICU patients were interviewed. Five main themes emerged: (1) mixed feelings, (2) sense of not being involved, (3) limited information provision, (4) lack of acknowledgement as a caregiver, and (5) an uncertain future perspective. Relatives experience major uncertainties during transitions and prefer to be actively involved in care and care decisions. CONCLUSIONS: This study indicates that relatives of ICU patients experience a lack of guidance during the transitions from the ICU to a general ward and to home, or a follow-up facility. More focus is needed on the themes of mixed feelings, the sense of not being involved, limited information provision, lack of acknowledgement as a caregiver, and an uncertain future perspective. This increased focus might improve the guidance during these transitions. RELEVANCE TO CLINICAL PRACTICE: The insights from this study may help to improve the care of patients and their relatives during the transitions.

Long-term outcomes after paediatric sepsis (LOTUS)-A protocol for an Australian cohort study.

BACKGROUND: Globally, sepsis has been identified as one of the leading causes of preventable childhood mortality and morbidity. Previous studies on intensive care patients estimated that approximately 30% of children with sepsis experience some form of disability at discharge. Development of care has seen growing numbers of children treated for sepsis not requiring a PICU admission; however, outcomes in this population are yet to be understood. Further focus is required to understand sepsis survivorship across the wider population to address knowledge gaps and morbidity burden in the broader surviving population. AIMS: To assess the cognitive, physical, emotional and social health of children surviving sepsis 2 years after hospital discharge. STUDY DESIGN: A prospective, observational cohort study. RESULTS: Two hundred and thirty-two children will be screened, 2 years after their hospital admission, and approached for participation in this study. Children who are <18 years of age at follow-up, treated for sepsis-related organ dysfunction or septic shock in Queensland between October 2018 and December 2019, will be included. Children who are deceased at follow-up, under care of the state, or require English interpreters will be excluded from participation. Data will be collected through an online follow-up survey comprising validated caregiver-reported questionnaires covering the four Post Intensive Care Syndrome-paediatrics (PICS-p) domains (cognitive, physical, emotional and social health; Manning et al. Pediatr Crit Care Med, 2018, 19, 298-300). The primary outcome is an adaptive behaviour of the participants assessed using the Vinelands-3 tool. Secondary outcomes will include neurodevelopment, quality of life, child distress, overall function, executive function, caregiver's distress and caregiver's stress. Analysis of variance (ANOVA), Kruskal-Wallis and Fisher's exact test/chi-squared tests will be used for statistical analyses. No adjustments will be made for multiple comparisons but it is acknowledged that comparisons made in this study are exploratory. RELEVANCE TO CLINICAL PRACTICE: With more children surviving sepsis, there is a need for a more comprehensive assessment of patient and family outcomes to allow support structures for families leaving the hospital after sepsis. This study is expected to inform clinicians and stakeholders of patient and family well-being after sepsis survivorship.

Caffeine does not influence persistent inward current contribution to motoneuron firing.

The purpose of this study was to investigate whether caffeine consumption would change persistent inward current (PIC) contribution to motoneuron firing at increased contraction intensities and after repetitive sustained maximal contractions. Before and after the consumption of 6 mg·kg-1 of caffeine or placebo, 16 individuals performed isometric triangular-shaped ramp dorsiflexion contractions (to 20% and 40% of peak torque), followed by four maximal contractions sustained until torque production dropped to 60% of maximum, and consecutive 20% triangular-shaped contractions. Tibialis anterior motor unit firing frequencies were analyzed from high-density surface electromyograms. PIC contribution to motor unit firing was estimated by calculating the delta frequency (ΔF) using the paired motor unit technique. Motoneuron peak firing frequencies at 20% and 40% contractions and total torque-time integral during the repetitive sustained maximal contractions were also assessed. ΔF increased 0.69 peaks per second (pps) (95% CI = -0.98, -0.405; d = -0.87) from 20% to 40% contraction intensities and reduced 0.85 pps (95% CI = 0.66, 1.05; d = 0.99) after the repetitive sustained maximal contractions, regardless of caffeine consumption. Participants produced 337 Nm·s (95% CI = 49.9, 624; d = 0.63) more torque integral during the repetitive sustained maximal contractions after caffeine consumption. A strong repeated-measures correlation (r = 0.61; 95% CI = 0.49, 0.69) was observed between reductions of ΔF and peak firing frequencies after the repetitive sustained maximal contractions. PIC contribution to motoneuron firing increases from 20% to 40% contraction intensities, with no effect of caffeine (on rested tibialis anterior). Repetitive sustained maximal contractions reduced PIC contribution to motoneuron firing, regardless of caffeine or placebo consumption, evidencing that changes in intrinsic motoneuron properties contributed to performance loss. Caffeine-attenuated reduction of torque production capacity was unlikely mediated by PICs.NEW & NOTEWORTHY Persistent inward current (PIC) contribution to motoneuron firing increases with contraction intensities and is reduced after repetitive sustained maximal contractions, regardless of caffeine consumption. Reductions of PIC contribution to motoneuron firing and peak firing frequencies were largely associated, evidencing a novel mechanism underpinning decrements in maximal torque production capacity following repetitive sustained maximal contractions. Caffeine consumption attenuated neuromuscular performance reductions-allowing higher time-torque integral production during repetitive sustained maximal contractions. This was unlikely mediated by PIC.

Intensive Care Unit-Acquired Weakness in Patients With Acute Kidney Injury: A Contemporary Review.

Acute kidney injury (AKI) and intensive care unit-acquired weakness (ICU-AW) are 2 frequent complications of critical illness that, until recently, have been considered unrelated processes. The adverse impact of AKI on ICU mortality is clear, but its relationship with muscle weakness-a major source of ICU morbidity-has not been fully elucidated. Furthermore, improving ICU survival rates have refocused the field of intensive care toward improving long-term functional outcomes of ICU survivors. We begin our review with the epidemiology of AKI in the ICU and of ICU-AW, highlighting emerging data suggesting that AKI and AKI treated with kidney replacement therapy (AKI-KRT) may independently contribute to the development of ICU-AW. We then delve into human and animal data exploring the pathophysiologic mechanisms linking AKI and acute KRT to muscle wasting, including altered amino acid and protein metabolism, inflammatory signaling, and deleterious removal of micronutrients by KRT. We next discuss the currently available interventions that may mitigate the risk of ICU-AW in patients with AKI and AKI-KRT. We conclude that additional studies are needed to better characterize the epidemiologic and pathophysiologic relationship between AKI, AKI-KRT, and ICU-AW and to prospectively test interventions to improve the long-term functional status and quality of life of AKI survivors.

Objective and subjective cognition in survivors of COVID-19 one year after ICU discharge: the role of demographic, clinical, and emotional factors.

BACKGROUND: Intensive Care Unit (ICU) COVID-19 survivors may present long-term cognitive and emotional difficulties after hospital discharge. This study aims to characterize the neuropsychological dysfunction of COVID-19 survivors 12 months after ICU discharge, and to study whether the use of a measure of perceived cognitive deficit allows the detection of objective cognitive impairment. We also explore the relationship between demographic, clinical and emotional factors, and both objective and subjective cognitive deficits. METHODS: Critically ill COVID-19 survivors from two medical ICUs underwent cognitive and emotional assessment one year after discharge. The perception of cognitive deficit and emotional state was screened through self-rated questionnaires (Perceived Deficits Questionnaire, Hospital Anxiety and Depression Scale and Davidson Trauma Scale), and a comprehensive neuropsychological evaluation was carried out. Demographic and clinical data from ICU admission were collected retrospectively. RESULTS: Out of eighty participants included in the final analysis, 31.3% were women, 61.3% received mechanical ventilation and the median age of patients was 60.73 years. Objective cognitive impairment was observed in 30% of COVID-19 survivors. The worst performance was detected in executive functions, processing speed and recognition memory. Almost one in three patients manifested cognitive complaints, and 22.5%, 26.3% and 27.5% reported anxiety, depression and post-traumatic stress disorder (PTSD) symptoms, respectively. No significant differences were found in the perception of cognitive deficit between patients with and without objective cognitive impairment. Gender and PTSD symptomatology were significantly associated with perceived cognitive deficit, and cognitive reserve with objective cognitive impairment. CONCLUSIONS: One-third of COVID-19 survivors suffered objective cognitive impairment with a frontal-subcortical dysfunction 12 months after ICU discharge. Emotional disturbances and perceived cognitive deficits were common. Female gender and PTSD symptoms emerged as predictive factors for perceiving worse cognitive performance. Cognitive reserve emerged as a protective factor for objective cognitive functioning. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04422444; June 9, 2021.

Guideline on multimodal rehabilitation for patients with post-intensive care syndrome.

BACKGROUND: Intensive Care Unit (ICU) survivors often experience several impairments in their physical, cognitive, and psychological health status, which are labeled as post-intensive care syndrome (PICS). The aim of this work is to develop a multidisciplinary and -professional guideline for the rehabilitative therapy of PICS. METHODS: A multidisciplinary/-professional task force of 15 healthcare professionals applied a structured, evidence-based approach to address 10 scientific questions. For each PICO-question (Population, Intervention, Comparison, and Outcome), best available evidence was identified. Recommendations were rated as "strong recommendation", "recommendation" or "therapy option", based on Grading of Recommendations, Assessment, Development and Evaluation principles. In addition, evidence gaps were identified. RESULTS: The evidence resulted in 12 recommendations, 4 therapy options, and one statement for the prevention or treatment of PICS. RECOMMENDATIONS: early mobilization, motor training, and nutrition/dysphagia management should be performed. Delirium prophylaxis focuses on behavioral interventions. ICU diaries can prevent/treat psychological health issues like anxiety and post-traumatic stress disorders. Early rehabilitation approaches as well as long-term access to specialized rehabilitation centers are recommended. Therapy options include additional physical rehabilitation interventions. Statement: A prerequisite for the treatment of PICS are the regular and repeated assessments of the physical, cognitive and psychological health in patients at risk for or having PICS. CONCLUSIONS: PICS is a variable and complex syndrome that requires an individual multidisciplinary, and multiprofessional approach. Rehabilitation of PICS should include an assessment and therapy of motor-, cognitive-, and psychological health impairments.

Scoping Review: Neurocognitive Outcome Assessments After Critical Illness in Children.

OBJECTIVES: To map the literature regarding assessment of neurocognitive outcomes in PICU survivors. Secondary objectives were to identify literature gaps and to provide data for development of a Core Outcome Measures Set in the domain. METHODS: Planned, a priori analysis was performed of data from an over-all scoping review of Post-Intensive Care Syndrome-pediatrics (PICS-p) functional outcomes. English-language databases and registries from 1970 to 2017 were searched by a medical librarian to identify manuscripts reporting on Post Intensive Care Syndrome-pediatrics (PICS-p). Further, detailed data extraction for neurocognitive outcomes was performed focusing on study characteristics, instruments used, and populations. RESULTS: 114 instruments evaluated neurocognitive function in 183 manuscripts. 83% of manuscripts were published after 2000. Median of 3 (IQR 2-5) neurocognitive instruments per manuscript were reported. Wechsler Scales (45%), clinical neurologic evaluations (21%), Pediatric Cerebral Performance Category (20%), Bayley Scales of Infant Development (16%), and Vineland Adaptive Behavior Scales (11%) were the most commonly used instruments. Median sample size was 65 (IQR 32-129) subjects. Most (63%) assessments were conducted in-person and parents/guardians (40%) provided the information. Patients with congenital heart disease and traumatic brain injury were most commonly evaluated (31% and 24% of manuscripts, respectively). Adolescents were the most commonly studied age group (34%). Baseline function was infrequently assessed (11% of manuscripts); most studies assessed patients at only one time point after PICU discharge. Within studies, neurocognitive assessments were often combined with others - especially social (18%) and physical (8%). CONCLUSIONS: 183 manuscripts studied the neurocognitive domain of PICS-p. Studies were quantitative and tended to focus on populations with anticipated cognitive impairment. Considerable variability exists among the chosen 114 instruments used; however, 4 instruments were frequently chosen with focus on intelligence, cerebral functioning, and developmental and adaptive behavior. The literature is marked by lack of agreement on methodologies but reflects the burgeoning interest in studying PICS-p neurocognitive outcomes.

Factors Influencing Engagement with in-Person Intensive Care Unit Recovery Clinic Services.

Background: Intensive Care Unit recovery clinics (ICU-RC), are multidisciplinary outpatient clinics designed to identify and treat post-intensive care syndrome impairments unique to each survivor of critical illness. Engagement is limited, thus we aimed to describe patient- and hospitalization-related sociodemographic factors associated with scheduling and attending in-person ICU-RC visits. Design: Consecutive case series of prospectively collected ICU-RC referral data. Setting: Data was collected over a 9-year period (2012-2020) for patients referred to an ICU-RC from ICUs at an academic medical center in the southeast United States. Participants: 251 adults admitted to a medical, surgical, burn, or trauma ICU referred to the ICU-RC and eligible to be scheduled for a visit. Main Outcome and Measures: The main study outcome was scheduling and completing an ICU-RC visit. Independent variables included patient demographics, ICU visit characteristics (eg, diagnosis, ventilator days), severity of illness, discharge disposition, ICU-RC referral criteria (eg, shock, delirium), and clinic scheduling administrative data (eg, referral date, clinic visit date). Results: Of 251 ICU-RC referrals eligible for a visit, 128 were scheduled, and 91 completed a visit. In univariate models older age, unspecified shock, and distance from the clinic location were associated with decreased in-person ICU-RC engagement. In a multivariable logistic regression using the same predictors and interactions, older age, unspecified shock, and home-to-clinic distance remained as factors decreasing the likelihood of ICU-RC engagement. There was a decreasing likelihood of scheduling and attending an ICU-RC visit for every additional mile of distance the patient lived from the ICU-RC. Male sex was a strong predictor of completing an ICU-RC visit. Conclusions: Older ICU survivors and those who live farther from the clinic site are less likely to engage in an in-person ICU-RC. Innovation and telemedicine strategies are needed to improve access to ICU recovery care for these populations.