Lung–Kidney Cross-Talk in the Critically Ill Patient

Effect of a standardized fluid management algorithm on acute kidney injury and mortality in pediatric patients on extracorporeal support

Acute kidney injury (AKI), fluid overload (FO), and mortality are common in pediatric patients supported by extracorporeal membrane oxygenation (ECMO). The aim of this study is to evaluate if using a fluid management algorithm reduced AKI and mortality in children supported by ECMO. We performed a retrospective study of pediatric patients aged birth to 25 years requiring ECMO at a quaternary level children's hospital from 2007 to 2019 In October 2017, a fluid management algorithm was implemented for protocolized fluid removal after deriving a daily fluid goal using a combination of diuretics and ultrafiltration. Daily algorithm compliance was defined as ≥ 12 h on the algorithm each day. The primary and secondary outcomes were AKI and mortality, respectively, and were assessed in the entire cohort and the sub-analysis of children from the era in which the algorithm was implemented. Two hundred and ninety-nine (median age 5.3 months; IQR: 0.2, 62.3; 45% male) children required ECMO (venoarterial in 85%). The fluid algorithm was applied in 74 patients. The overall AKI rate during ECMO was 38% (26% severe-stage 2/3). Both AKI incidence and mortality were significantly lower in patients managed on the algorithm (p = 0.02 and p = 0.05). After adjusting for confounders, utilization of the algorithm was associated with lower odds of AKI (aOR: 0.40, 95%CI: 0.21, 0.76; p = 0.005) but was not associated with a reduction in mortality. In the sub-analysis, algorithm compliance of 80-100% was associated with a 54% reduction in mortality (ref: < 60% compliant; aOR:0.46, 95%CI:0.22-1.00; p = 0.05).  Conclusion: Among the entire cohort, the use of a fluid management algorithm reduced the odds of AKI. Better compliance on the algorithm was associated with lower mortality. Multicenter studies that implement systematic fluid removal may represent an opportunity for improving ECMO-related outcomes. What is Known: • Acute kidney injury and fluid overload are associated with morbidity and mortality in children supported by extracorporeal membrane oxygenation. What is New: • A systematic and protocolized approach to fluid removal in children supported by extracorporeal membrane oxygenation reduces acute kidney injury incidence. • Greater adherence to a protocolized fluid removal algorithm is associated with a reduction in mortality.

A novel pump-free ultrafiltration rate modulation system for continuous renal replacement therapy applications

Purpose

Extracorporeal ultrafiltration is an attractive alternative to diuretics for removing excess plasma water in critically ill patients suffering from fluid overload. In continuous renal replacement therapy (CRRT), ultrafiltration occurs in isolated form (SCUF) or supplemented by replacement fluid infusion (CVVH) and the net fluid removal rate is controlled by peristaltic pumps. In this work, a pump-free solution for regulating the ultrafiltration rate in CRRT applications is presented.

Methods

The system consists of a motorized clamp on the ultrafiltration line, whose intermittent opening is modulated with a closed-loop control system based on monitoring of ultrafiltrate collected and any replacement fluid infused. The system was tested on two platforms for SCUF and CVVH, with “low-flux” and “high-flux” hemofilter, with various ultrafiltration setpoints and patient net weight loss targets.

Results

In all configurations the set ultrafiltration rate was achieved with a maximum error of 5% and the values recorded were kept within ± 100 ml/h with respect to the setpoint, as recommended by international standard IEC 60601-2-16. The net fluid removal trend was highly correlated with that expected (95%<R2<99%) and the weight loss target was reached in the expected time. For low ultrafiltration rates (60-150 ml/h) the system accuracy was better with the “low-flux” hemofilter.

Conclusion

The developed clamp system represents a valid alternative to state-of-the-art solutions with peristaltic pumps in terms of performance, with potential usability advantages. The compliance with safety requirements given by international standard IEC 60601-2-16 is a prerequisite for clinical use.

Kidney and lung crosstalk during critical illness: large-scale cohort study

BACKGROUND

The relationship between the lung and kidney investigated in animal and clinical models has demonstrated substantial crosstalk. We aimed to evaluate the association between single vs. concurrent AKI and ARDS and its impact on patient outcomes. Secondly, we aimed to assess whether the order of appearance of these pathologies affected patient outcomes in patients with both diseases.

METHODS

This single-center retrospective cohort study included adult patients admitted to the ICU from January 1, 2007 through May 1, 2018 (n = 76,988). Baseline characteristics and outcomes were compared among patients without ARDS or AKI and those with one or both ARDS and AKI. We also assessed outcomes across the order of appearance of these diseases among patients with both AKI and ARDS.

RESULTS

We enrolled 76,988 unique patients in the final analysis: 47,043 patients with neither AKI nor ARDS, 491 patients with ARDS alone, 27,928 patients with AKI alone, and 1,526 patients with both ARDS and AKI. Patients with both ARDS and AKI had higher ICU (21.2%) and hospital (28.4%) mortality compared to patients with ARDS alone (9.0% ICU mortality, 14.0% hospital mortality) or AKI alone (4.4% ICU mortality, 8.4% hospital mortality) (p < 0.001). These findings remained unchanged after adjusting for illness severity and comorbidities. Of the 1136 patients with both AKI and ARDS, 136 (12%) developed AKI first, 303 (27%) ARDS first, and 697 (61%) had simultaneous diseases. Patients who developed ARDS after AKI had significantly increased ICU (29.4%) and hospital (36.8%) mortality compared to patients who developed AKI after ARDS (13.9% ICU mortality, 21.5% hospital mortality) (p < 0.001).

CONCLUSIONS

The combination of AKI and ARDS leads to worse outcomes, including longer hospital and ICU lengths of stay, higher mortality, longer kidney replacement therapy, and longer ventilation requirements than in patients with AKI or ARDS alone. Among patients with both diagnoses, those who developed ARDS after AKI had the highest mortality.

Outcomes comparison between the first and the subsequent SARS-CoV-2 waves - a systematic review and meta-analysis

Background

In the beginning of the SARS-CoV-2 pandemic, health care professionals dealing with COVID-19 had to rely exclusively on general supportive measures since specific treatments were unknown. The subsequent waves could be faced with new diagnostic and therapeutic tools (e.g., anti-viral medications and vaccines). We performed a meta-analysis and systematic review to compare clinical endpoints between the first and subsequent waves.

Methods

Three databases were assessed. The primary outcome was in-hospital mortality. The secondary outcomes were intensive care unit (ICU) mortality, ICU length of stay (LOS), acute renal failure, extracorporeal membrane oxygenation (ECMO) implantation, mechanical ventilation time, hospital LOS, systemic thromboembolism, myocarditis and ventilator associated pneumonia.

Results

A total of 25 studies with 126,153 patients were included. There was no significant difference for the primary endpoint (OR=0.94, 95% CI 0.83-1.07, p=0.35). The first wave group presented higher rates of ICU LOS (SMD= 0.23, 95% CI 0.11-0.35, p<0.01), acute renal failure (OR=1.71, 95% CI 1.36-2.15, p<0.01) and ECMO implantation (OR=1.64, 95% CI 1.06-2.52, p=0.03). The other endpoints did not show significant differences.

Conclusions

The analysis suggests that the first wave group, when compared with the subsequent waves group, presented higher rates of ICU LOS, acute renal failure and ECMO implantation, without significant difference in in-hospital or ICU mortality, mechanical ventilation time, hospital LOS, systemic thromboembolism, myocarditis or ventilator- associated pneumonia.

Extracorporeal Carbon Dioxide Removal: From Pathophysiology to Clinical Applications; Focus on Combined Continuous Renal Replacement Therapy

Lung-protective ventilation (LPV) with low tidal volumes can significantly increase the survival of patients with acute respiratory distress syndrome (ARDS) by limiting ventilator-induced lung injuries. However, one of the main concerns regarding the use of LPV is the risk of developing hypercapnia and respiratory acidosis, which may limit the clinical application of this strategy. This is the reason why different extracorporeal CO2 removal (ECCO2R) techniques and devices have been developed. They include low-flow or high-flow systems that may be performed with dedicated platforms or, alternatively, combined with continuous renal replacement therapy (CRRT). ECCO2R has demonstrated effectiveness in controlling PaCO2 levels, thus allowing LPV in patients with ARDS from different causes, including those affected by Coronavirus disease 2019 (COVID-19). Similarly, the suitability and safety of combined ECCO2R and CRRT (ECCO2R-CRRT), which provides CO2 removal and kidney support simultaneously, have been reported in both retrospective and prospective studies. However, due to the complexity of ARDS patients and the limitations of current evidence, the actual impact of ECCO2R on patient outcome still remains to be defined. In this review, we discuss the main principles of ECCO2R and its clinical application in ARDS patients, in particular looking at clinical experiences of combined ECCO2R-CRRT treatments.

Role of SARS-CoV-2-induced Cytokine Storm in Multi-Organ Failure: Molecular Pathways and Potential Therapeutic Options

Coronavirus disease 2019 (COVID-19) outbreak has become a global public health emergency and has led to devastating results. Mounting evidence proposes that the disease causes severe pulmonary involvement and influences different organs, leading to a critical situation named multi-organ failure. It is yet to be fully clarified how the disease becomes so deadly in some patients. However, it is proven that a condition called “cytokine storm” is involved in the deterioration of COVID-19. Although beneficial, sustained production of cytokines and overabundance of inflammatory mediators causing cytokine storm can lead to collateral vital organ damages. Furthermore, cytokine storm can cause post-COVID-19 syndrome (PCS), an important cause of morbidity after the acute phase of COVID-19. Herein, we aim to explain the possible pathophysiology mechanisms involved in COVID-19-related cytokine storm and its association with multi-organ failure and PCS. We also discuss the latest advances in finding the potential therapeutic targets to control cytokine storm wishing to answer unmet clinical demands for treatment of COVID-19.

MILD TRAUMATIC BRAIN INJURY ATTENUATES PNEUMONIA-INDUCED LUNG INJURY BY MODULATIONS OF ALVEOLAR MACROPHAGE BACTERICIDAL ACTIVITY AND M1 POLARIZATION

ABSTRACT

Traumatic brain injury is one of the main causes of death and disability worldwide, and results in multisystem complications. However, the mechanism of mild traumatic brain injury (MTBI) on lung injury remains unclear. In this study, we used a murine model of MTBI and pneumonia ( Pseudomonas aeruginosa ;) to explore the relationship between these conditions and the underlying mechanism. Methods: Mice (n = 104) were divided into control, MTBI, pneumonia, and MTBI + pneumonia groups. MTBI was induced by the weight-drop method. Pneumonia was induced by intratracheal injection with P. aeruginosa Xen5 strain. Animals were killed 24 h after bacterial challenging. Histological, cellular, and molecular indices of brain and lung injury were assessed using various methods. Results: Mice in both the MTBI and pneumonia groups had more Fluoro-Jade C-positive neurons than did the controls ( P < 0.01), but mice in the MTBI + pneumonia group had fewer Fluoro-Jade C-positive cells than did the pneumonia group ( P < 0.01). The MTBI + pneumonia mice showed decreased bacterial load ( P < 0.05), reduced lung injury score and pulmonary permeability ( P < 0.01), less inflammatory cells, and lower levels of proinflammatory cytokines (TNF-α and IL-1β; P < 0.01) when compared with the pneumonia group. Molecular analysis indicated lower levels of phosphorylated nuclear factor-κB in the lung of MTBI + pneumonia mice compared with the pneumonia group ( P < 0.01). Furthermore, alveolar macrophages from MTBI mice exhibited enhanced bactericidal capacity compared with those from controls ( P < 0.01). Moreover, MTBI + pneumonia mice exhibited less CD86-positive M1 macrophages compared with the pneumonia group ( P < 0.01). Conclusions: MTBI attenuates pneumonia-induced acute lung injury through the modulation of alveolar macrophage bactericidal capacity and M1 polarization in bacterial pneumonia model.

Comorbidities, Associated Diseases, and Risk Assessment in COVID-19-A Systematic Review

It is considered that COVID-19's pandemic expansion is responsible for the particular increase in deaths, especially among the population with comorbidities. The health system is often overwhelmed by the large number of cases of patients addressing it, by the regional limitation of funds, and by the gravity of cases at subjects suffering from this pathology. Several associated conditions including diabetes, cardiovascular illnesses, obesity, persistent lung condition, neurodegenerative diseases, etc., increase the mortality risk and hospitalization of subjects suffering from COVID-19. The rapid identification of patients with increased risk of death from the SARS-CoV-2 virus, the stratification in accordance with the risk and the allocation of human, financial, and logistical resources in proportion must be a priority for health systems worldwide.

Impact of Dexamethasone and Inhaled Nitric Oxide on Severe Acute Kidney Injury in Critically Ill Patients with COVID-19

Background: Acute kidney injury (AKI) is the second most frequent condition after acute respiratory distress syndrome (ARDS) in critically ill patients with severe COVID-19 and is strongly associated with mortality. The aim of this multicentric study was to assess the impact of the specific treatments of COVID-19 and ARDS on the risk of severe AKI in critically ill COVID-19 patients. Methods: In this cohort study, data from consecutive patients older than 18 years admitted to 6 ICUs for COVID-19-related ARDS requiring invasive mechanical ventilation were included. The incidence and severity of AKI, defined according to the 2012 KDIGO definition, were monitored during the entire ICU stay until day 90. Patients older than 18 years admitted to the ICU for COVID-19-related ARDS requiring invasive mechanical ventilation were included. Results: 164 patients were included in the final analysis; 97 (59.1%) displayed AKI, of which 39 (23.8%) had severe stage 3 AKI, and 21 (12.8%) required renal replacement therapy (RRT). In univariate analysis, severe AKI was associated with angiotensin-converting enzyme inhibitors (ACEI) exposure (p = 0.016), arterial hypertension (p = 0.029), APACHE-II score (p = 0.004) and mortality at D28 (p = 0.008), D60 (p < 0.001) and D90 (p < 0.001). In multivariate analysis, the factors associated with the onset of stage 3 AKI were: exposure to ACEI (OR: 4.238 (1.307−13.736), p = 0.016), APACHE II score (without age) (OR: 1.138 (1.044−1.241), p = 0.003) and iNO (OR: 5.694 (1.953−16.606), p = 0.001). Prone positioning (OR: 0.234 (0.057−0.967), p = 0.045) and dexamethasone (OR: 0.194 (0.053−0.713), p = 0.014) were associated with a decreased risk of severe AKI. Conclusions: Dexamethasone was associated with the prevention of the risk of severe AKI and RRT, and iNO was associated with severe AKI and RRT in critically ill patients with COVID-19. iNO should be used with caution in COVID-19-related ARDS.

Acute respiratory distress syndrome: causes, pathophysiology, and phenotypes

Acute respiratory distress syndrome (ARDS) is a common clinical syndrome of acute respiratory failure as a result of diffuse lung inflammation and oedema. ARDS can be precipitated by a variety of causes. The pathophysiology of ARDS is complex and involves the activation and dysregulation of multiple overlapping and interacting pathways of injury, inflammation, and coagulation, both in the lung and systemically. Mechanical ventilation can contribute to a cycle of lung injury and inflammation. Resolution of inflammation is a coordinated process that requires downregulation of proinflammatory pathways and upregulation of anti-inflammatory pathways. The heterogeneity of the clinical syndrome, along with its biology, physiology, and radiology, has increasingly been recognised and incorporated into identification of phenotypes. A precision-medicine approach that improves the identification of more homogeneous ARDS phenotypes should lead to an improved understanding of its pathophysiological mechanisms and how they differ from patient to patient.

Dual Role of Extracellular Vesicles in Sepsis-Associated Kidney and Lung Injury

Extracellular vesicles form a complex intercellular communication network, shuttling a variety of proteins, lipids, and nucleic acids, including regulatory RNAs, such as microRNAs. Transfer of these molecules to target cells allows for the modulation of sets of genes and mediates multiple paracrine and endocrine actions. EVs exert broad pro-inflammatory, pro-oxidant, and pro-apoptotic effects in sepsis, mediating microvascular dysfunction and multiple organ damage. This deleterious role is well documented in sepsis-associated acute kidney injury and acute respiratory distress syndrome. On the other hand, protective effects of stem cell-derived extracellular vesicles have been reported in experimental models of sepsis. Stem cell-derived extracellular vesicles recapitulate beneficial cytoprotective, regenerative, and immunomodulatory properties of parental cells and have shown therapeutic effects in experimental models of sepsis with kidney and lung involvement. Extracellular vesicles are also likely to play a role in deranged kidney-lung crosstalk, a hallmark of sepsis, and may be key to a better understanding of shared mechanisms underlying multiple organ dysfunction. In this review, we analyze the state-of-the-art knowledge on the dual role of EVs in sepsis-associated kidney/lung injury and repair. PubMed library was searched from inception to July 2022, using a combination of medical subject headings (MeSH) and keywords related to EVs, sepsis, acute kidney injury (AKI), acute lung injury (ALI), and acute respiratory distress syndrome (ARDS). Key findings are summarized into two sections on detrimental and beneficial mechanisms of actions of EVs in kidney and lung injury, respectively. The role of EVs in kidney-lung crosstalk is then outlined. Efforts to expand knowledge on EVs may pave the way to employ them as prognostic biomarkers or therapeutic targets to prevent or reduce organ damage in sepsis.

Acute kidney injury and electrolyte disorders in COVID-19

Acute kidney injury (AKI) and electrolyte disorders are important complications of hospitalized coronavirus disease 2019 (COVID-19) patients. AKI is thought to occur due to multiple pathophysiological mechanisms, such as multiple organ dysfunction (mainly cardiac and respiratory), direct viral entry in the renal tubules, and cytokine release syndrome. AKI is present in approximately one in every ten hospitalized COVID-19 patients. The incidence rates of AKI increase in patients who are admitted to the intensive care unit (ICU), with levels higher than 50%. Additionally, renal replacement therapy (RRT) is used in 7% of all AKI cases, but in nearly 20% of patients admitted to an ICU. COVID-19 patients with AKI are considered moderate-to-severe cases and are managed with multiple interdisciplinary conducts. AKI acts as a risk factor for mortality in severe acute respiratory syndrome coronavirus 2 infection, especially when RRT is needed. Electrolyte disorders are also common manifestations in hospitalized COVID-19 patients, mainly hyponatremia, hypokalemia, and hypocalcemia. Hyponatremia occurs due to a combination of syndrome of inappropriate secretion of antidiuretic hormone and gastrointestinal fluid loss from vomiting and diarrhea. When it comes to hypokalemia, its mechanism is not fully understood but may derive from hyperaldosteronism due to renin angiotensin aldosterone system overstimulation and gastrointestinal fluid loss as well. The clinical features of hypokalemia in COVID-19 are similar to those in other conditions. Hypocalcemia is the most common electrolyte disorder in COVID-19 and seems to occur because of vitamin D deficiency and parathyroid imbalance. It is also highly associated with longer hospital and ICU stay.

Clinical characteristics of new-onset acute kidney injury in patients with established acute respiratory distress syndrome: A prospective single-center post hoc observational study

Background

We assessed the incidence and clinical characteristics of acute kidney injury (AKI) in acute respiratory distress syndrome (ARDS) patients and its effect on clinical outcomes.

Methods

We conducted a single-center prospective longitudinal study. Patients who met the Berlin definition of ARDS in the medical ICU in China-Japan Friendship Hospital from March 1, 2016, to September 30, 2020, were included. AKI was defined according to the KDIGO clinical practice guidelines. Early and late AKI were defined as AKI occurring within 48 h after ARDS was diagnosed or after 48 h, respectively.

Results

Of the 311 ARDS patients, 161 (51.8%) developed AKI after ICU admission. Independent risk factors for AKI in ARDS patients were age (OR 1.027, 95% CI 1.009–1.045), a history of diabetes mellitus (OR 2.110, 95%CI 1.100–4.046) and chronic kidney disease (CKD) (OR 9.328, 95%CI 2.393–36.363), APACHE II score (OR 1.049, 95%CI 1.008–1.092), average lactate level in the first 3 days (OR 1.965, 95%CI 1.287–3.020) and using ECMO support (OR 2.359, 95%CI 1.154–4.824). Early AKI was found in 91 (56.5%) patients and late AKI was found in 70 (43.5%). Early AKI was related to the patient’s underlying disease and the severity of hospital admission, while late AKI was related to the application of nephrotoxic drugs. The mortality rate of ARDS combined with AKI was 57.1%, which was independently associated with shock (OR 54.943, 95%CI 9.751–309.573).

Conclusion

A significant number of patients with ARDS developed AKI, and the mortality rate for ARDS patients was significantly higher when combined with AKI. Therapeutic drug monitoring should be routinely used to avoid drug toxicity during treatment.

Development and validation of the MMCD score to predict kidney replacement therapy in COVID-19 patients

BACKGROUND

Acute kidney injury (AKI) is frequently associated with COVID-19, and the need for kidney replacement therapy (KRT) is considered an indicator of disease severity. This study aimed to develop a prognostic score for predicting the need for KRT in hospitalised COVID-19 patients, and to assess the incidence of AKI and KRT requirement.

METHODS

This study is part of a multicentre cohort, the Brazilian COVID-19 Registry. A total of 5212 adult COVID-19 patients were included between March/2020 and September/2020. Variable selection was performed using generalised additive models (GAM), and least absolute shrinkage and selection operator (LASSO) regression was used for score derivation. Accuracy was assessed using the area under the receiver operating characteristic curve (AUC-ROC).

RESULTS

The median age of the model-derivation cohort was 59 (IQR 47-70) years, 54.5% were men, 34.3% required ICU admission, 20.9% evolved with AKI, 9.3% required KRT, and 15.1% died during hospitalisation. The temporal validation cohort had similar age, sex, ICU admission, AKI, required KRT distribution and in-hospital mortality. The geographic validation cohort had similar age and sex; however, this cohort had higher rates of ICU admission, AKI, need for KRT and in-hospital mortality. Four predictors of the need for KRT were identified using GAM: need for mechanical ventilation, male sex, higher creatinine at hospital presentation and diabetes. The MMCD score had excellent discrimination in derivation (AUROC 0.929, 95% CI 0.918-0.939) and validation (temporal AUROC 0.927, 95% CI 0.911-0.941; geographic AUROC 0.819, 95% CI 0.792-0.845) cohorts and good overall performance (Brier score: 0.057, 0.056 and 0.122, respectively). The score is implemented in a freely available online risk calculator ( https://www.mmcdscore.com/ ).

CONCLUSIONS

The use of the MMCD score to predict the need for KRT may assist healthcare workers in identifying hospitalised COVID-19 patients who may require more intensive monitoring, and can be useful for resource allocation.

Missed diagnosis of acute kidney injury in older patients with invasive mechanical ventilation: a multicenter retrospective study

OBJECTIVES

Patients who undergo mechanical ventilation (MV) are at higher risk of suffering from acute kidney injury (AKI). However, whether AKI is diagnosed in all patients and the association between AKI and mortality are unclear.

METHODS

This was a retrospective, observational, multicenter cohort study conducted from January 2008 to December 2020 that included 3271 consecutive older patients (≥ 75 years) who received invasive MV from four medical centers in Chinese PLA General Hospital. AKI was diagnosed according to the serum creatinine (Scr)-based Kidney Disease: Improving Global Outcomes guidelines by an absolute increase in Scr of ≥ 26.5 µmol/L within the first 48 h of MV. The outcomes of patients with and without AKI and whether AKI was recognized were compared.

RESULTS

A total of 1292 patients were included in the final evaluation. Three hundred seventy-six patients (29.1%) fulfilled the diagnostic criteria. Among the 376 AKI patients, the recognition rate and nonrecognition rate were 62.8% (236/376) and 37.2% (140/376), respectively. The overall 90-day mortality rate was 45.2% (584/1,292), which was dramatically increased in unrecognized AKI patients and recognized AKI compared to non-AKI patients (70.7% vs. 54.7% vs. 38.9%, respectively, P < 0.001). The survival of patients with recognized AKI was better than that of patients with unrecognized AKI. Multivariate logistic regression analysis revealed that recognized AKI was significantly associated with mean arterial pressure, positive end-expiratory pressure, uric acid, baseline Scr, and peak Scr. AKI was identified as an independent predictor of all-cause 90-day mortality (recognized AKI vs. non-AKI: HR = 1.722; 95% CI = 1.399-2.119; P < 0.001 and unrecognized AKI vs. non-AKI: HR = 2.632; 95% CI = 2.081-3.329; P < 0.001).

CONCLUSIONS

AKI is a common complication in older patients undergoing MV, with substantial underdiagnosis and undertreatment. Interventions for improving the diagnosis of AKI are urgently needed.

ARDS associated acute brain injury: from the lung to the brain

A complex interrelation between lung and brain in patients with acute lung injury (ALI) has been established by experimental and clinical studies during the last decades. Although, acute brain injury represents one of the most common insufficiencies in patients with ALI and acute respiratory distress syndrome (ARDS), the underlying pathophysiology of the observed crosstalk remains poorly understood due to its complexity. Specifically, it involves numerous pathophysiological parameters such as hypoxemia, neurological adverse events of lung protective ventilation, hypotension, disruption of the BBB, and neuroinflammation in such a manner that the brain of ARDS patients-especially hippocampus-becomes very vulnerable to develop secondary lung-mediated acute brain injury. A protective ventilator strategy could reduce or even minimize further systemic release of inflammatory mediators and thus maintain brain homeostasis. On the other hand, mechanical ventilation with low tidal volumes may lead to self-inflicted lung injury, hypercapnia and subsequent cerebral vasodilatation, increased cerebral blood flow, and intracranial hypertension. Therefore, by describing the pathophysiology of ARDS-associated acute brain injury we aim to highlight and discuss the possible influence of mechanical ventilation on ALI-associated acute brain injury.

A genetic model for in vivo proximity labelling of the mammalian secretome

Organ functions are highly specialized and interdependent. Secreted factors regulate organ development and mediate homeostasis through serum trafficking and inter-organ communication. Enzyme-catalysed proximity labelling enables the identification of proteins within a specific cellular compartment. Here, we report a BirA*G3 mouse strain that enables CRE-dependent promiscuous biotinylation of proteins trafficking through the endoplasmic reticulum. When broadly activated throughout the mouse, widespread labelling of proteins was observed within the secretory pathway. Streptavidin affinity purification and peptide mapping by quantitative mass spectrometry (MS) proteomics revealed organ-specific secretory profiles and serum trafficking. As expected, secretory proteomes were highly enriched for signal peptide-containing proteins, highlighting both conventional and non-conventional secretory processes, and ectodomain shedding. Lower-abundance proteins with hormone-like properties were recovered and validated using orthogonal approaches. Hepatocyte-specific activation of BirA*G3 highlighted liver-specific biotinylated secretome profiles. The BirA*G3 mouse model demonstrates enhanced labelling efficiency and tissue specificity over viral transduction approaches and will facilitate a deeper understanding of secretory protein interplay in development, and in healthy and diseased adult states.

The predictors of mortality in patients with methyl alcohol intoxication

Aim: Methanol intoxication is a worldwide public health problem. Mortality rates are quite high unless there is early intervention and diagnosis. The aim of this study was to investigate the predictors of mortality in patients with methyl alcohol intoxication. Material and Method: The study included 18 patients admitted to emergency department of our hospital in 2019-2020, who were diagnosed with methanol intoxication. Laboratory parameters and basic features of the patients were recorded. According to the criteria of 2012 Clinical Practice Guideline for Acute Kidney Injury (AKI), patients were diagnosed with AKI. Results: The mean age of the patients was 45.7±15.21 years and 72.2% of those were male. The mortality and AKI rate were 38.9% and 44.4%, respectively. In regression analyses, delay in admission to hospital, low Glasgow coma scale score, AKI development and high lactate level were independent predictors of mortality. According to ROC analyses when lactate level was more than 5.75 mmol/L, mortality rate increased more rapidly. Conclusion: Mortality rate is very high in methanol intoxication. Patients with AKI and high lactate levels should be intervened faster.

Internal and external validation of machine learning-assisted prediction models for mechanical ventilation-associated severe acute kidney injury

BACKGROUND

Currently, very few preventive or therapeutic strategies are used for mechanical ventilation (MV)-associated severe acute kidney injury (AKI).

OBJECTIVES

We developed clinical prediction models to detect the onset of severe AKI in the first week of intensive care unit (ICU) stay during the initiation of MV.

METHODS

A large ICU database Medical Information Mart for Intensive Care IV (MIMIC-IV) was analysed retrospectively. Data were collected from the clinical information recorded at the time of ICU admission and during the initial 12 h of MV. Using univariate and multivariate analyses, the predictors were selected successively. For model development, two machine learning algorithms were compared. The primary goal was to predict the development of AKI stage 2 or 3 (AKI-23) and AKI stage 3 (AKI-3) in the first week of patients' ICU stay after initial 12 h of MV. The developed models were externally validated using another multicentre ICU database (eICU Collaborative Research Database, eICU) and evaluated in various patient subpopulations.

RESULTS

Models were developed using data from the development cohort (MIMIC-IV: 2008-2016; n = 3986); the random forest algorithm outperformed the logistic regression algorithm. In the internal (MIMIC-IV: 2017-2019; n = 1210) and external (eICU; n = 1494) validation cohorts, the incidences of AKI-23 were 154 (12.7%) and 119 (8.0%), respectively, with areas under the receiver operator characteristic curve of 0.78 (95% confidence interval [CI]: 0.74-0.82) and 0.80 (95% CI: 0.76-0.84); the incidences of AKI-3 were 81 (6.7%) and 67 (4.5%), with areas under the receiver operator characteristic curve of 0.81 (95% CI: 0.76-0.87) and 0.80 (95% CI: 0.73-0.86), respectively.

CONCLUSIONS

Models driven by machine learning and based on routine clinical data may facilitate the early prediction of MV-associated severe AKI. The validated models can be found at: https://apoet.shinyapps.io/mv_aki_2021_v2/.

Multi-Omics Techniques Make it Possible to Analyze Sepsis-Associated Acute Kidney Injury Comprehensively

Sepsis-associated acute kidney injury (SA-AKI) is a common complication in critically ill patients with high morbidity and mortality. SA-AKI varies considerably in disease presentation, progression, and response to treatment, highlighting the heterogeneity of the underlying biological mechanisms. In this review, we briefly describe the pathophysiology of SA-AKI, biomarkers, reference databases, and available omics techniques. Advances in omics technology allow for comprehensive analysis of SA-AKI, and the integration of multiple omics provides an opportunity to understand the information flow behind the disease. These approaches will drive a shift in current paradigms for the prevention, diagnosis, and staging and provide the renal community with significant advances in precision medicine in SA-AKI analysis.

In-hospital mortality of critically Ill patients with interactions of acute kidney injury and acute respiratory failure in the resource-limited settings: Results from SEA-AKI study

PURPOSE

Our goal was to describe clinical outcomes and explore the physiological interactions between acute kidney injury (AKI) and acute respiratory failure (ARF) in critically ill patients.

MATERIALS AND METHODS

Data were retrieved from the SEA-AKI study, a multinational multicenter database of adult ICUs from Thailand, Laos, and Indonesia. AKI was defined using KDIGO criteria stage 2-3. ARF was defined by being mechanically ventilated. Patients were assigned into 6 patterns based on AKI and ARF sequence: "no AKI/ARF", "ARF alone", "AKI alone", "ARF first", "AKI first", and "Concurrent AKI-ARF". The primary outcome was in-hospital mortality of each pattern.

RESULTS

A final cohort of 5468 patients were eligible for the analysis. The "Concurrent AKI-ARF" had the highest in-hospital mortality of 69.6%. The "AKI first" and the "ARF first" had in-hospital mortality of 54.4% and 53%, respectively. Among patients with single organ failure, in-hospital mortality was 14.6% and 31.5% in the "AKI alone" and the "ARF alone", accordingly. In-hospital mortality was 12.4% in patients without AKI and ARF.

CONCLUSION

Critically ill patients with ARF and AKI are at higher risk of in-hospital death. Different patterns of AKI and ARF interaction result in unique clinical outcomes as well as risk factors.

Multidisciplinary basic and clinical research of acute kidney injury with COVID-19: Pathophysiology, mechanisms, incidence, management and kidney transplantation

Acute kidney injury (AKI) linked to coronavirus disease 2019 (COVID-19) has been identified in the course of the disease. AKI can be mild or severe and that is dependent on the presence of comorbidities and the severity of COVID-19. Among patients who had been hospitalized with COVID-19, some were admitted to intensive care unit. The etiology of AKI associated with COVID-19 is multifactorial. Prevention of severe AKI is the prime task in patients with COVID-19 that necessitates a battery of measurements and precautions in management. Patients with AKI who have needed dialysis are in an increased risk to develop chronic kidney disease (CKD) or a progression of their existing CKD. Kidney transplantation patients with COVID-19 are in need of special management to adjust the doses of immunosuppression drugs and corticosteroids to guard against graft rejection but not to suppress the immune system to place the patient at risk of developing a COVID-19 infection. Immunosuppression drugs and corticosteroids for patients who have had a kidney transplant has to be adjusted based on laboratory results and is individualized aiming at the protection of the transplanted from rejection.

Lung-kidney interactions and their role in chronic kidney disease-associated pulmonary diseases

Chronic illnesses rarely present in a vacuum, devoid of other complications, and chronic kidney disease is hardly an exception. Comorbidities associated with chronic kidney disease lead to faster disease progression, expedited dialysis dependency, and a higher mortality rate. Although chronic kidney disease is most commonly accompanied by cardiovascular diseases and diabetes, there is clear cross talk between the lungs and kidneys pH balance, phosphate metabolism, and immune system regulation. Our present understanding of the exact underlying mechanisms that contribute to chronic kidney disease-related pulmonary disease is poor. This review summarizes the current research on kidney-pulmonary interorgan cross talk in the context of chronic kidney disease, highlighting various acute and chronic pulmonary diseases that lead to further complications in patient care. Treatment options for patients presenting with chronic kidney disease and lung disease are explored by assessing activated molecular pathways and the body's compensatory response mechanisms following homeostatic imbalance. Understanding the link between the lungs and kidneys will potentially improve health outcomes for patients and guide healthcare professionals to better understand how and when to treat each of the pulmonary comorbidities that can present with chronic kidney disease.

[Acute kidney injury and COVID-19: lung-kidney crosstalk during severe inflammation]

Eine mit der Coronaviruserkrankung 2019 (COVID-19) assoziierte Nierenschädigung ist vor allem bei Intensivpatient:innen ein häufiges Phänomen. Das Virus selbst dürfte im Sinne eines direkten Befalls der Niere nur in geringem Ausmaß eine Rolle spielen, die mit einer schweren COVID-19-Erkrankungen assoziierte pathologische Entzündungsreaktion dagegen sehr wohl. Einen wesentlichen Einfluss haben die Folgen der invasiven Beatmung und das durch COVID-19 verursachte Acute Respiratory Distress Syndrome (ARDS). Hohe Beatmungsdrücke wirken sich negativ auf die Nierenperfusion aus und können so zur Entstehung einer AKI beitragen. Die durch das ARDS verursachte Entzündungsreaktion sowie die für COVID-19 typische endotheliale Dysfunktion in Kombination mit einer Hyperkoagulabilität sind weitere Faktoren, die die Nierenfunktion negativ beeinflussen können.

When the Renal (Function) Begins to Fall: A Mini-Review of Acute Kidney Injury Related to Acute Respiratory Distress Syndrome in Critically Ill Patients

Acute kidney injury (AKI) is one of the most frequent causes of organ failure encountered in patients in the intensive care unit (ICU). Because of its predisposition to occur in the most critically ill patients, it is not surprising to observe a high frequency of AKI in patients with acute respiratory distress syndrome (ARDS). However, few studies have been carried out to assess the epidemiology of AKI in subgroups of ARDS patients using recommended KDIGO criteria. Moreover, the mechanisms involved in the physio-pathogenesis of AKI are still poorly understood, in particular the impact of mechanical ventilation on the kidneys. We carried out a review of the literature, focusing on the epidemiology and physiopathology of AKI in patients with ARDS admitted to the ICU. We addressed the importance of clinical management, focusing on mechanical ventilation for improving outcomes, on AKI. Finally, we also propose candidate treatment strategies and management perspectives. Our literature search showed that AKI is particularly common in ICU patients with ARDS. In association with the classic risk factors for AKI, such as comorbidities and iatrogeny, changes in mechanical ventilation parameters, which have been exclusively evaluated for their outcomes on respiratory function and death, must be considered carefully in terms of their impact on the short-term renal prognosis.

Physiological and Pathophysiological Consequences of Mechanical Ventilation

Mechanical ventilation is a life-support system used to ensure blood gas exchange and to assist the respiratory muscles in ventilating the lung during the acute phase of lung disease or following surgery. Positive-pressure mechanical ventilation differs considerably from normal physiologic breathing. This may lead to several negative physiological consequences, both on the lungs and on peripheral organs. First, hemodynamic changes can affect cardiovascular performance, cerebral perfusion pressure (CPP), and drainage of renal veins. Second, the negative effect of mechanical ventilation (compression stress) on the alveolar-capillary membrane and extracellular matrix may cause local and systemic inflammation, promoting lung and peripheral-organ injury. Third, intra-abdominal hypertension may further impair lung and peripheral-organ function during controlled and assisted ventilation. Mechanical ventilation should be optimized and personalized in each patient according to individual clinical needs. Multiple parameters must be adjusted appropriately to minimize ventilator-induced lung injury (VILI), including: inspiratory stress (the respiratory system inspiratory plateau pressure); dynamic strain (the ratio between tidal volume and the end-expiratory lung volume, or inspiratory capacity); static strain (the end-expiratory lung volume determined by positive end-expiratory pressure [PEEP]); driving pressure (the difference between the respiratory system inspiratory plateau pressure and PEEP); and mechanical power (the amount of mechanical energy imparted as a function of respiratory rate). More recently, patient self-inflicted lung injury (P-SILI) has been proposed as a potential mechanism promoting VILI. In the present chapter, we will discuss the physiological and pathophysiological consequences of mechanical ventilation and how to personalize mechanical ventilation parameters.

Association Between the Severity of Early Acute Kidney Injury and Subsequent in-Hospital Complications and 90-Day Mortality in Geriatric Patients Receiving Invasive Mechanical Ventilation

Purpose

Acute kidney injury (AKI) in elderly patients is associated with higher hospital mortality. However, the relationship between AKI and peri-intubation complications is unclear.

Methods

This retrospective, observational, multicenter cohort study enrolled 3271 consecutive elderly patients (≥75 years) who received invasive mechanical ventilation (MV) in four medical centers of Chinese PLA General Hospital from 2008 to 2020. AKI was diagnosed according to the 2012 KDIGO criteria by an absolute increase in serum creatinine of ≥26.5 µmol/L within the first 48 hours of MV. We recorded subsequent in-hospital complications, including incident gastrointestinal bleeding, new-onset electrolyte imbalances, severe hypoxemia, hypoalbuminemia, cardiovascular instability and all-cause 90-day mortality.

Results

A total of 1292 patients were included in the final evaluation, with 29.1% presenting AKI (stage 1: 31.4%, stage 2: 35.1%, stage 3: 33.5%). Multiple regression analyses show that more advanced AKI increased the risk of MAP <65 mmHg (stage 1: OR=1.833, P=0.002; stage 2: OR= 4.653, P<0.001; stage 3: OR=4.834, P<0.001) and SBP <90 mmHg (stage 1: OR=1.644, P=0.014; stage 2: OR=3.701, P<0.001; stage 3: OR=5.750, P<0.001), a new need for or requiring an increased dose of vasopressors (stage 1: OR=1.623, P=0.014; stage 2: OR=3.250, P<0.001; stage 3: OR=12.132, P<0.001), gastrointestinal bleeding (stage 1: OR=1.102, P=0.669; stage 2: OR=1.471, P=0.060; stage 3: OR=2.377, P<0.001), severe hypoxia (stage 1: OR=1.213, P=0.399; stage 2: OR=1.449, P=0.077; stage 3: OR=2.214, P<0.001) and all-cause 90-day mortality (stage 1: OR =0.935; P=0.741; stage 2: OR=1.888; P=0.001; stage 3: OR=12.584; P<0.001).

Conclusion

Our study suggests that the presence of AKI within the first 48 hours of MV in geriatric patients is associated with a higher risk for postintubation complications and 90-day mortality. Moreover, the risk of complications was greater for patients with more severe AKI.

The mechanism underlying extrapulmonary complications of the coronavirus disease 2019 and its therapeutic implication

The coronavirus disease 2019 (COVID-19) is a highly transmissible disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that poses a major threat to global public health. Although COVID-19 primarily affects the respiratory system, causing severe pneumonia and acute respiratory distress syndrome in severe cases, it can also result in multiple extrapulmonary complications. The pathogenesis of extrapulmonary damage in patients with COVID-19 is probably multifactorial, involving both the direct effects of SARS-CoV-2 and the indirect mechanisms associated with the host inflammatory response. Recognition of features and pathogenesis of extrapulmonary complications has clinical implications for identifying disease progression and designing therapeutic strategies. This review provides an overview of the extrapulmonary complications of COVID-19 from immunological and pathophysiologic perspectives and focuses on the pathogenesis and potential therapeutic targets for the management of COVID-19.

Timeline of Multi-Organ Plasma Extravasation After Bleomycin-Induced Acute Lung Injury

Acute lung injury (ALI) is characterized by the abrupt onset of clinically significant hypoxemia in the context of non-hydrostatic pulmonary edema. Acute lung injury is associated with cytokine release and plasma extravasation (PEx) that can cause pulmonary edema and subsequently acute respiratory distress syndrome (ARDS). Therefore, it is critical we understand the relationship between ALI and lung PEx. In addition, it is also important to assess PEx in the lungs and other organs post-ALI since ALI/ARDS often causes multi-organ failure. We hypothesized that ALI induces time-dependent lung PEx, which promotes extravasation in the heart, liver, kidney, spleen, pancreas, and gastrointestinal (GI) tract, in a time-dependent manner. To test our hypothesis, we administered bleomycin or saline via tracheal intubation in 8-week-old Sprague Dawley rats. At the terminal experiments, Evans Blue was injected (IV) through the femoral vein to allow for the visualization of PEx. Plasma extravasation of desired organs was evaluated at 3-, 7-, 14-, 21-, and 28-days after bleomycin or saline treatment by evaluating Evans Blue concentrations calorimetrically at fluorescence excitation wavelength of 620 nm (bandwidth 10 nm) and an emission wavelength of 680 nm (bandwidth 40 nm). Data show that ALI induces lung PEx beginning at day 3 and peaking between 7 and 21 days. Extravasation was also seen in all organs at varying degrees beginning at day 3 and peaking between days 7 and 14. Resolution appears to start after day 21 and continues past day 28. We conclude that ALI caused by bleomycin incites a time-dependent PEx of the lungs and multiple other organs.

Complications associated with long-term positive-pressure ventilation in dogs and cats: 67 cases

OBJECTIVES

To determine the complications associated with positive-pressure ventilation (PPV) in dogs and cats.

DESIGN

Retrospective study from October 2009 to September 2013.

SETTING

University Teaching Hospital.

ANIMALS

Fifty-eight dogs and 9 cats.

MEASUREMENTS AND MAIN RESULTS

Medical records were retrospectively reviewed; signalment, complications associated with PPV, duration of PPV, and outcome were recorded. Complications most commonly recorded during PPV included hypothermia 41/67 (61%), hypotension 39/67 (58%), cardiac arrhythmias 33/67 (49%), a positive fluid balance 31/67 (46%), oral lesions 25/67 (37%), and corneal ulcerations 24/67 (36%). A definition of ventilator-associated events (VAE) extrapolated from the Center of Disease Control's criteria was applied to 21 cases that received PPV for at least 4 days in this study. Ventilator-associated conditions occurred in 5 of 21 (24%) of cases with infection-related ventilator-associated conditions and ventilator-associated pneumonia identified in 3 of 21 (14%) cases.

CONCLUSIONS

Complications are common and diverse in dogs and cats receiving long-term PPV and emphasizes the importance of intensive, continuous patient monitoring and appropriate nursing care protocols. Many of the complications identified could be serious without intervention and suggests that appropriate equipment alarms could improve patient safety. Development of veterinary specific surveillance tools such as the VAE criteria would aid future investigations and allow for effective multicenter studies.

Hypercapnia from Physiology to Practice

Acute hypercapnic ventilatory failure is becoming more frequent in critically ill patients. Hypercapnia is the elevation in the partial pressure of carbon dioxide (PaCO₂) above 45 mmHg in the bloodstream. The pathophysiological mechanisms of hypercapnia include the decrease in minute volume, an increase in dead space, or an increase in carbon dioxide (CO₂) production per sec. They generate a compromise at the cardiovascular, cerebral, metabolic, and respiratory levels with a high burden of morbidity and mortality. It is essential to know the triggers to provide therapy directed at the primary cause and avoid possible complications.

Lesión renal aguda en COVID-19: puesta al día y revisión de la literatura

Los coronavirus humanos son virus que se asocian a varias patologías respiratorias como el síndrome respiratorio agudo severo y el síndrome respiratorio del Medio Oriente. Esto ha puesto a esta familia de virus en el centro de atención de la comunidad científica debido a la alta patogenicidad en humanos, especialmente ahora con la nueva pandemia por la enfermedad por coronavirus del 2019 (COVID-19). La COVID-19 se manifiesta principalmente como enfermedad respiratoria aguda con compromiso respiratorio bajo, pero puede afectar múltiples órganos como lo es el riñón, lo cual a conlleva a peores desenlaces. En este manuscrito revisaremos el compromiso renal por los diferentes coronavirus, en especial en la COVID-19, al igual que las terapias que juegan algún papel en el tratamiento de esta.

Factors associated with prolonged weaning from mechanical ventilation in medical patients

BACKGROUND

Patients who need prolonged mechanical ventilation (MV) have high resource utilization and relatively poor outcomes. The pathophysiologic mechanisms leading to weaning failure in this group may be complex and multifactorial. The aim of this study was to investigate the factors associated with prolonged weaning based on the Weaning Outcome according to a New Definition (WIND) classification.

METHODS

This is a prospective observational study with consecutive adult patients receiving MV for at least two calendar days in medical intensive care units from 1 November 2017 to 30 September 2020. Eligible patients were divided in a non-prolonged weaning group, including short and difficult weaning, and in a prolonged weaning group according to the WIND classification. The risk factors at the time of first separation attempt associated with prolonged weaning were analyzed using a multivariable logistic regression model.

RESULTS

Of the total 915 eligible patients, 172 (18.8%) patients were classified as prolonged weaning. A higher proportion of the prolonged weaning group had previous histories of endotracheal intubation, chronic lung disease, and hematologic malignancies. When compared with the non-prolonged weaning group, the median duration of MV before the first spontaneous breathing trial (SBT) was longer and the proportion of tracheostomized patients was higher in prolonged weaning group. In addition, the prolonged weaning group used higher peak inspiratory pressures and yielded lower PaO₂/FiO₂ ratios at the day of the first SBT compared with the non-prolonged weaning group. In multivariate analyses, the duration of MV before first SBT (adjusted odds ratio [OR] = 1.14, 95% confidence interval [CI] = 1.06-1.22, p < 0.001), tracheostomy state (adjusted OR = 1.95, 95% CI = 1.04-3.63, p = 0.036), PaO₂/FiO₂ ratio (adjusted OR = 1.00, 95% CI = 0.99-1.00, p = 0.023), and need for renal replacement therapy (adjusted OR = 2.68, 95% CI = 1.16-6.19, p = 0.021) were independently associated with prolonged weaning. After the exclusion of patients who underwent tracheostomy before the SBTs, similar results were obtained.

CONCLUSION

Longer duration of MV before the first SBT, tracheostomy status, poor oxygenation, and need for renal replacement therapy at the time of first SBT can predict prolonged weaning.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT05134467.

Interaction of Acute Respiratory Failure and Acute Kidney Injury on in-Hospital Mortality of Patients with Acute Exacerbation COPD

Purpose

Both acute respiratory failure (ARF) and acute kidney injury (AKI) are two common complications in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Moreover, both ARF and AKI are reported as increasing the risk of mortality of patients with AECOPD. However, the interaction of ARF and AKI on the mortality of patients with AECOPD remains unknown. Therefore, the aim of this study is to investigate the joint effect of ARF and AKI on in-hospital mortality in AECOPD patients.

Patients and Methods

We performed a retrospective, observational cohort study of data from Nanjing First Hospital. The effect of AKI and ARF on in-hospital mortality was assessed using a multivariate logistic regression model. Additive interaction was assessed with the relative excess risk due to interaction.

Results

A total of 1647 participants were enrolled. ARF and AKI occurred in 515 (31.3%) and 357 (21.7%) patients, respectively. Overall, in-hospital mortality was 5.7%. The in-hospital mortality of the neither ARF nor AKI group, the ARF only group, the AKI only group, and both the ARF and AKI group were 0.8%, 7.0%, 7.5%, and 29.9%, respectively. After multivariate logistic regression analysis, the independent factors for in-hospital death included: albumin (OR 0.88, 95% CI 0.83–0.93, P < 0.001), ARF only (OR 8.53, 95% CI 3.64–19.99, P < 0.001), AKI only (OR 8.99, 95% CI 3.58–22.55, P < 0.001), and both ARF and AKI (OR 39.13, 95% CI 17.02–89.97, P < 0.001). The relative excess risk due to interaction was 22.62 (95% CI, 0.31 to 44.93), the attributable proportion due to interaction was 0.59 (95% CI, 0.36 to 0.79), and the synergy index was 2.46 (95% CI, 1.44 to 4.20), indicating ARF and AKI had a significant synergic effect on in-hospital mortality.

Conclusion

ARF and AKI had a synergistic effect on in-hospital mortality in AECOPD patients.

[Acute kidney injury in intensive care unit: A review]

Acute kidney injury is a common complication in intensive care unit. Its incidence is variable according to the studies. It is considered to occur in more than 50 % of patients. Acute kidney injury is responsible for an increase in morbidity (length of hospitalization, renal replacement therapy) but also for excess mortality. The commonly accepted definition of acute kidney injury comes from the collaborative workgroup named Kidney Disease: Improving Global Outcomes (KDIGO). It made it possible to standardize practices and raise awareness among practitioners about monitoring plasma creatinine and also diuresis. Acute kidney injury in intensive care unit is a systemic disease including circulatory, endothelial, epithelial and cellular function involvement and an acute kidney injury is not accompanied by ad integrum repair. After prolonged injury, inadequate repair begins with a fibrotic process. Several mechanisms are involved (cell cycle arrest, epithelial-mesenchymal transition, mitochondrial dysfunction) and result in improper repair. A continuum exists between acute kidney disease and chronic kidney disease, characterized by different renal recovery phenotypes. Thus, preventive measures to prevent the occurrence of kidney damage play a major role in management. The nephrologist must be involved at every stage, from the prevention of the first acute kidney injury (upon arrival in intensive care unit) to long-term follow-up and the care of a chronic kidney disease.

Acute kidney injury in ventilated patients with coronavirus disease-2019 pneumonia: A single-center retrospective study

Background:

Acute kidney injury (AKI) is repeatedly observed in ventilated critically ill patients with coronavirus disease-2019 (COVID-19) pneumonia. This study aimed to determine the incidence, risk factors, and consequences of AKI in the ventilated critically ill adult patients with COVID-19 pneumonia.

Methods:

This retrospective study included all the ventilated critically ill adult patients with COVID-19 pneumonia from March 1, 2020, to June 1, 2020. Data were collected from the electronic medical system. AKI was diagnosed using the Kidney Disease: Improving Global Outcomes 2012 Clinical Practice definition. Patients were followed 90 days from the intensive care unit (ICU) admission time or to the date when they were discharged from the hospital.

Results:

AKI occurred in 65.1% of patients, with 26.6% of these started on continuous renal replacement therapy (CRRT). Patients with AKI had higher comorbidity and illness severity scores (P < 0.001). Age and the vasopressor requirements were predictors of AKI (P= 0.016 and P = 0.041) and hypertension predicted AKI (P = 0.099) and its progression (P = 0.05). The renal recovery rate was 86.7% and was associated with the mean arterial pressure on ICU admission in the no-CRRT group (P = 0.014) and the hypoxic index in the CRRT group (P = 0.019). AKI was associated with higher mortality (P = 0.017) and significantly longer ICU length-of-stay (P = 0.001). Additionally, AKI patients were more often discharged to a long-term skilled nursing facility (P = 0.005).

Conclusion:

COVID-19-associated AKI was common and associated with poor outcome, with the specific mechanisms being the main driving factors.

Impact of Permissive Hypoxia and Hyperoxia Avoidance on Clinical Outcomes in Septic Patients Receiving Mechanical Ventilation: A Retrospective Single-Center Study

BACKGROUND

Septic patients often require mechanical ventilation due to respiratory dysfunction, and effective ventilatory strategies can improve survival. The effects of the combination of permissive hypoxia and hyperoxia avoidance for managing mechanically ventilated patients are unknown. This study examines these effects on outcomes in mechanically ventilated septic patients.

METHODS

In a retrospective before-and-after study, we examined adult septic patients (aged ≥18 years) requiring mechanical ventilation at a university hospital. On April 1, 2017, our mechanical ventilation policy changed from a conventional oxygenation target (SpO2: ≥96%) to more conservative targets with permissive hypoxia (SpO2: 88-92% or PaO2: 60 mmHg) and hyperoxia avoidance (reduced oxygenation for PaO2 > 110 mmHg). Patients were divided into a prechange group (April 2015 to March 2017; n = 83) and a postchange group (April 2017 to March 2019; n = 130). Data were extracted from clinical records and insurance claims. Using a multiple logistic regression model, we examined the association of the postchange group (permissive hypoxia and hyperoxia avoidance) with intensive care unit (ICU) mortality after adjusting for variables such as Sequential Organ Failure Assessment (SOFA) score and PaO2/FiO2 ratios.

RESULTS

The postchange group did not have significantly lower adjusted ICU mortality (0.67, 0.33-1.43; P = 0.31) relative to the prechange group. However, there were significant intergroup differences in mechanical ventilation duration (prechange: 11.0 days, postchange: 7.0 days; P = 0.01) and ICU stay (prechange: 11.0 days, postchange: 9.0 days; P = 0.02).

CONCLUSIONS

Permissive hypoxia and hyperoxia avoidance had no significant association with reduced ICU mortality in mechanically ventilated septic patients. However, this approach was significantly associated with shorter mechanical ventilation duration and ICU stay, which can improve patient turnover and ventilator access.

Exosomal CD63 in critically ill patients with sepsis

CD63 is one of the tetraspanin protein family members that is ubiquitously expressed on exosomes and is involved in the signal transduction of various types of immune cells. It may thus contribute to immunometabolic mechanisms of cellular and organ dysfunction in sepsis. Nonetheless, the association of exosomal CD63 with the severity and mortality of sepsis is not well known. Therefore, in the present study, the overall levels of exosomal CD63 were evaluated to ascertain whether they were associated with organ failure and mortality in patients with sepsis. Exosomal CD63 was measured from prospectively enrolled critically-ill patients with sepsis (n = 217) and healthy control (n = 20). To detect and quantify exosomes in plasma, a commercially available enzyme-linked immunosorbent assay kit was used according to the manufacturer's protocol. The total number of exosomal CD63 was determined by quantifying the immunoreactive CD63. The association between plasma levels of exosomal CD63 and sequential organ failure assessment (SOFA) score was assessed by a linear regression method. The best cut-off level of exosomal CD63 for 28-day mortality prediction was determined by Youden's index. Among 217 patients with sepsis, 143 (66%) patients were diagnosed with septic shock. Trends of increased exosomal CD63 levels were observed in control, sepsis, and septic-shock groups (6.6 µg/mL vs. 42 µg/mL vs. 90 µg/mL, p < 0.001). A positive correlation between exosomal CD63 and SOFA scores was observed in patients with sepsis (r value = 0.35). When patients were divided into two groups according to the best cut-off level, the group with higher exosomal CD63 levels (more than 126 µg/mL) was significantly associated with 28-day and in-hospital mortality. Moreover, the Kaplan-Meier survival method showed a significant difference in 90-day survival between patients with high- and low-exosomal CD63 levels (log-rank p = 0.005). Elevated levels of exosomal CD63 were associated with the severity of organ failure and predictive of mortality in critically ill patients with sepsis.

Betel Nut Chewing Was Associated with Obstructive Lung Disease in a Large Taiwanese Population Study

The prevalence of betel nut chewing in Taiwan is high at approximately 7%, however, few studies have evaluated the relationship between betel nut chewing and lung disease. Therefore, the aim of this study was to investigate associations between betel nut chewing and lung function in 80,877 participants in the Taiwan Biobank (TWB). We further investigated correlations between betel nut chewing characteristics such as years of use, frequency, daily amount, and accumulative dose, with obstructive lung disease. We used data from the TWB. Lung function was assessed using spirometry measurements of forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). The participants were classified into normal lung function and obstructive lung function (FEV1/FVC < 70%) groups. The participants were asked questions about betel nut chewing, including years of use, frequency, and daily amount. After multivariable analysis, betel nut chewing (odds ratio [OR] = 1.159; p < 0.001) was significantly associated with FEV1/FVC < 70% in all participants (n = 80,877). Further, in the participants who chewed betel nut (n = 5135), a long duration of betel nut chewing (per 1 year; OR = 1.008; p = 0.012), betel nut use every day (vs. 1–3 days/month; OR = 1.793; p = 0.036), 10–20 quids a day (vs. <10 quids; OR = 1.404; p = 0.019), 21–30 quids a day (vs. <10 quids; OR = 1.662; p = 0.010), ≥31 quids a day (vs. <10 quids; OR = 1.717; p = 0.003), and high cumulative dose (per 1 year × frequency × daily score; OR = 1.001; p = 0.002) were significantly associated with FEV1/FVC < 70%. In this large population-based cohort study, chewing betel nut was associated with obstructive lung disease. Furthermore, a long duration of betel nut chewing, more frequent use, higher daily amount, and high cumulative dose were associated with obstructive lung disease. This suggests that preventing betel nut chewing should be considered to reduce obstructive lung disease in Taiwan.

Risk factors and mortality of acute kidney injury within 1 month after lung transplantation

After lung transplantation (LT), some patients are at risk of acute kidney injury (AKI), which is associated with worse outcomes and increased mortality. Previous studies focused on AKI development from 72 h to 1 week within LT, and reported main risk factors for AKI such as intraoperative hypotension, need of ECMO support, ischemia time or longer time on waiting list. However, this period interval rarely reflects medical risk factors probably happen in longer post-operative period. So, in this study we aimed to describe the incidence and risk factor of AKI within post-operative 1 month, which is longer follow up duration. Among 161 patients who underwent LT at Severance hospital in Seoul, Korea from October 2012 to September 2017, 148 patients were retrospectively enrolled. Multivariable logistic regression and Cox proportional hazard models were utilized. Among 148 patients, 59 (39.8%) developed AKI within 1-month after LT. Stage I or II, and stage III AKI were recorded in 26 (17.5%) and 33 (22.2%), respectively. We also classified AKI according to occurrence time, within 1 week as early AKI, from 1 week within 1 month was defined as late AKI. AKI III usually occurred within 7 days after transplantation (early vs. late AKI III, 72.5% vs 21.1%). Risk factor for AKI development was pre-operative anemia, higher units of red blood cells transfused during surgery, colistin intravenous infusion for treating multi drug resistant pathogens were independent risk factors for AKI development. Post-operative bleeding, grade 3 PGD within 72 h, and sepsis were more common complication in the AKI group. Patients with AKI III ([24/33] 72.7%) had significantly higher 1-year mortality than the no-AKI ([18/89] 20.2%), and AKI I or II group ([9/26] 34.6%), log-rank test, P < 0.001). AKI was associated with worse post-operative outcome, 3-month, and 1-year mortality after LT. Severity of AKI was usually determined in early post op period (ex. within 7 days) after LT, so optimal post-operative management as well as recipients selection should be considered.

Acute respiratory distress syndrome: focusing on secondary injury

Acute respiratory distress syndrome (ARDS) is one of the most common severe diseases seen in the clinical setting. With the continuous exploration of ARDS in recent decades, the understanding of ARDS has improved. ARDS is not a simple lung disease but a clinical syndrome with various etiologies and pathophysiological changes. However, in the intensive care unit, ARDS often occurs a few days after primary lung injury or after a few days of treatment for other severe extrapulmonary diseases. Under such conditions, ARDS often progresses rapidly to severe ARDS and is difficult to treat. The occurrence and development of ARDS in these circumstances are thus not related to primary lung injury; the real cause of ARDS may be the “second hit” caused by inappropriate treatment. In view of the limited effective treatments for ARDS, the strategic focus has shifted to identifying potential or high-risk ARDS patients during the early stages of the disease and implementing treatment strategies aimed at reducing ARDS and related organ failure. Future research should focus on the prevention of ARDS.

Long covid-mechanisms, risk factors, and management

Since its emergence in Wuhan, China, covid-19 has spread and had a profound effect on the lives and health of people around the globe. As of 4 July 2021, more than 183 million confirmed cases of covid-19 had been recorded worldwide, and 3.97 million deaths. Recent evidence has shown that a range of persistent symptoms can remain long after the acute SARS-CoV-2 infection, and this condition is now coined long covid by recognized research institutes. Studies have shown that long covid can affect the whole spectrum of people with covid-19, from those with very mild acute disease to the most severe forms. Like acute covid-19, long covid can involve multiple organs and can affect many systems including, but not limited to, the respiratory, cardiovascular, neurological, gastrointestinal, and musculoskeletal systems. The symptoms of long covid include fatigue, dyspnea, cardiac abnormalities, cognitive impairment, sleep disturbances, symptoms of post-traumatic stress disorder, muscle pain, concentration problems, and headache. This review summarizes studies of the long term effects of covid-19 in hospitalized and non-hospitalized patients and describes the persistent symptoms they endure. Risk factors for acute covid-19 and long covid and possible therapeutic options are also discussed.

Extracorporeal carbon dioxide Removal (ECCO2 R) with the Advanced Organ Support (ADVOS) system in critically ill COVID-19 patients

Disturbed oxygenation is foremost the leading clinical presentation in COVID‐19 patients. However, a small proportion also develop carbon dioxide removal problems. The Advanced Organ Support (ADVOS) therapy (ADVITOS GmbH, Munich, Germany) uses a less invasive approach by combining extracorporeal CO₂‐removal and multiple organ support for the liver and the kidneys in a single hemodialysis device. The aim of our study is to evaluate the ADVOS system as treatment option in‐COVID‐19 patients with multi‐organ failure and carbon dioxide removal problems. COVID‐19 patients suffering from severe respiratory insufficiency, receiving at least two treatments with the ADVOS multi system (ADVITOS GmbH, Munich, Germany), were eligible for study inclusion. Briefly, these included patients with acute kidney injury (AKI) according to KDIGO guidelines, and moderate or severe ARDS according to the Berlin definition, who were on invasive mechanical ventilation for more than 72 hours. In total, nine COVID‐19 patients (137 ADVOS treatment sessions with a median of 10 treatments per patient) with moderate to severe ARDS and carbon dioxide removal problems were analyzed. During the ADVOS treatments, a rapid correction of acid‐base balance and a continuous CO₂ removal could be observed. We observed a median continuous CO₂ removal of 49.2 mL/min (IQR: 26.9‐72.3 mL/min) with some treatments achieving up to 160 mL/min. The CO₂ removal significantly correlated with blood flow (Pearson 0.421; P < .001), PaCO₂ (0.341, P < .001) and HCO3‐ levels (0.568, P < .001) at the start of the treatment. The continuous treatment led to a significant reduction in PaCO₂ from baseline to the last ADVOS treatment. In conclusion, it was feasible to remove CO₂ using the ADVOS system in our cohort of COVID‐19 patients with acute respiratory distress syndrome and multiorgan failure. This efficient removal of CO₂ was achieved at blood flows up to 300 mL/min using a conventional hemodialysis catheter and without a membrane lung or a gas phase.

Clinical factors associated with composition of lung microbiota and important taxa predicting clinical prognosis in patients with severe community-acquired pneumonia

Few studies have described the key features and prognostic roles of lung microbiota in patients with severe community-acquired pneumonia (SCAP). We prospectively enrolled consecutive SCAP patients admitted to ICU. Bronchoscopy was performed at bedside within 48 h of ICU admission, and 16S rRNA gene sequencing was applied to the collected bronchoalveolar lavage fluid. The primary outcome was clinical improvements defined as a decrease of 2 categories and above on a 7-category ordinal scale within 14 days following bronchoscopy. Sixty-seven patients were included. Multivariable permutational multivariate analysis of variance found that positive bacteria lab test results had the strongest independent association with lung microbiota (R² = 0.033; P = 0.018), followed by acute kidney injury (AKI; R² = 0.032; P = 0.011) and plasma MIP-1β level (R² = 0.027; P = 0.044). Random forest identified that the families Prevotellaceae, Moraxellaceae, and Staphylococcaceae were the biomarkers related to the positive bacteria lab test results. Multivariable Cox regression showed that the increase in α-diversity and the abundance of the families Prevotellaceae and Actinomycetaceae were associated with clinical improvements. The positive bacteria lab test results, AKI, and plasma MIP-1β level were associated with patients’ lung microbiota composition on ICU admission. The families Prevotellaceae and Actinomycetaceae on admission predicted clinical improvements.

Comparison of early postoperative cytokine changes in patients undergoing intubated and non-intubated thoracic surgery: a randomized controlled trial

OBJECTIVES

The inflammatory response after surgery is associated with patient prognosis. Patients who undergo thoracic surgery exhibit a profound systemic inflammatory response due to the surgical procedures used and application of one-lung ventilation. The aim of this study was to compare perioperative inflammatory changes in patients after intubated and non-intubated thoracic surgery for primary lung cancer resection.

METHODS

This prospective randomized controlled study included forty patients who underwent surgical resection for stage I non-small-cell lung cancer. Blood samples for cytokine analysis were collected just before induction, at 1 and 24 h after surgery. Levels of the pro-inflammatory cytokine and anti-inflammatory cytokines were measured using quantitative sandwich enzyme immunoassay kits.

RESULTS

The basal values of cytokines were comparable between 2 groups. Within each group, the postoperative levels of interleukin (IL)-1, IL-6 and tumour necrosis factor-α increased, while those of IL-4 and IL-10 did not change significantly. The levels of IL-6 and tumour necrosis factor-α were significantly lower in group NI at 1 and 24 h postoperatively. Other cytokines did not differ in both groups during postoperative period. The IL-6/IL-10 ratio at 1 h after surgery was lower in non-intubated patients than in intubated patients, but there was no difference at 24 h after surgery.

CONCLUSIONS

Non-intubated thoracic surgery may attenuate the early inflammatory cytokine changes following major resection for primary lung cancer compared with intubated conventional surgery.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov registry number NCT04007354.

Acute Kidney Injury and Early Predictive Factors in COVID-19 Patients

Objectives: Our objective was to explore the incidence and early predictive factors of acute kidney injury in coronavirus disease 2019 (COVID-19) patients. Method: We established a retrospective cohort of 408 patients who were admitted to Shenzhen Third People's Hospital in Shenzhen, China, between January 1 and March 31, 2020. Clinical outcomes and renal function were monitored until April 12, 2020, with a median follow-up duration of 21 days [interquartile range (IQR) = 14-33]. Results: When first admitted to hospital (baseline), 19.36% (79/408) presented renal dysfunction [estimated glomerular filtration rate (eGFR) <90 ml/min/1.73 m2]. During follow-up, 3.9% (16/408) developed acute kidney injury (AKI). Age ≥60 years [hazard ratio (HR) = 4.78, 95% CI = 1.10-20.69], PaO2/FiO2 ratio <300 (HR = 3.48, 95% CI = 1.04-11.62), and higher creatinine (HR = 1.04, 95% CI = 1.01-1.07) at baseline independently predicted the risk of AKI. Respectively, 25.0% (102/408), 3.9% (16/408), 0.5% (2/408), 1.0% (4/408), and 0.2% (1/408) experienced G2, G3a, G3b, G4, and G5 as their most severe category during hospitalization, while 69.4% (283/408) had normal eGFRs throughout the follow-up period. When finally discharged from hospital, there were 12.5% (51/408) of patients with abnormal eGFRs. Conclusions: COVID-19 patients can be at risk of AKI and continuous eGFR decline during hospitalization, which can be early predicted by baseline factors. Some individuals still had renal dysfunction when finally discharged from hospital.

The influence of assisted ventilation and recumbency on cardiorespiratory physiology in the anesthetized freshwater turtle Trachemys scripta scripta

The use of assisted ventilation is required in anesthetized reptiles as their respiratory drive is lost at surgical depths of anesthesia. The minute volume of the assisted ventilation influences arterial blood gases and acid-base regulation. Meanwhile, the ventilatory pattern may also affect hemodynamics in chelonians, which, given their large capacity for cardiac shunts, may impact the efficacy of the ventilation in terms of gas exchange. Hence, there is a need for primary information on the influence of assisted ventilation on chelonian physiology, and we, therefore, performed a randomized study into the effects of recumbency and maximum airway pressure on pressure-cycled ventilation in nine female Trachemys scripta scripta. Pronounced effects of ventilation pressure on arterial PCO₂ and pH regardless of recumbency were revealed, whilst dorsal recumbency led to a larger Arterial-alveolar (A-a) O₂ difference, suggesting compromised pulmonary gas exchange. Plasma [Na⁺] and [K⁺] balance was also significantly correlated with maximum airway pressure. Computed tomography (CT) scanning at a range of end-inspiratory pressures and ventral and dorsal recumbencies in eight T. scripta scripta showed that lung volumes increase with maximum ventilatory pressure, while recumbency did not influence volume at pressures above 5 cmH₂O. Static compliance of the lungs was influenced by recumbency at neutral pressures. In conclusion, dorsal recumbency reduces pulmonary efficacy during positive pressure ventilation and tends to lower lung volume when ventilation is not provided. However, lung volumes and function - even in dorsal recumbency - can be adequately supported by assisted ventilation, and an end inspiratory pressure of 10 cmH₂O at 4 breaths min^-1 provided the most physiologically appropriate ventilation of anesthetized T. scripta scripta.