Severity and Mortality Predictors of Pediatric Acute Respiratory Distress Syndrome According to the Pediatric Acute Lung Injury Consensus Conference Definition

Severity and mortality of acute respiratory failure in pediatrics: A prospective multicenter cohort in Bogotá, Colombia

Background and Aims

Acute respiratory failure (ARF) is the most frequent cause of cardiorespiratory arrest and subsequent death in children worldwide. There have been limited studies regarding ARF in high altitude settings. The aim of this study was to calculate mortality and describe associated factors for severity and mortality in children with ARF.

Methods

The study was conducted within a prospective multicentric cohort that evaluated the natural history of pediatric ARF. For this analysis three primary outcomes were studied: mortality, invasive mechanical ventilation, and pediatric intensive care unit (PICU) length of stay. Eligible patients were children older than 1 month and younger than 18 years of age with respiratory difficulty at the time of admission. Patients who developed ARF were followed at the time of ARF, 48 h later, at the time of discharge, and at 30 and 60 days after discharge. It was conducted in the pediatric emergency, in-hospital, and critical-care services in three hospitals in Bogotá, Colombia, from April 2020 to June 2021.

Results

Out of a total of 685 eligible patients, 296 developed ARF for a calculated incidence of ARF of 43.2%. Of the ARF group, 90 patients (30.4%) needed orotracheal intubation, for a mean of 9.57 days of ventilation (interquartile range = 3.00-11.5). Incidence of mortality was 6.1% (n = 18). The associated factors for mortality in ARF were a history of a neurologic comorbidity and a higher fraction of inspired oxygen at ARF diagnosis. For PICU length of stay, the associated factors were age between 2 and 5 years of age, exposure to smokers, and respiratory comorbidity. Finally, for mechanical ventilation, the risk factors were obesity and being unstable at admission.

Conclusions

ARF is a common cause of morbidity and mortality in children. Understanding the factors associated with greater mortality and severity of ARF might allow earlier recognition and initiation of prompt treatment strategies.

The death risk of pediatric patients with cancer-related sepsis requiring continuous renal replacement therapy: a retrospective cohort study

OBJECTIVE

To assess the outcome of patients with cancer-related sepsis requiring continuous renal replacement therapy (CRRT) in a single-center pediatric intensive care unit (PICU).

METHOD

Children with sepsis who necessitate CRRT from January 2017 to December 2021 were enrolled. The patients with leukemia/lymphoma or solid tumors were defined as underlying cancer. Multivariate logistic regression analysis was performed to identify the death risk factors in patients with cancer-related sepsis.

RESULTS

A total of 146 patients were qualified for inclusion. Forty-six (31.5%) patients with cancer-related sepsis and 100 (68.5%) non-cancer-related sepsis. The overall PICU mortality was 28.1% (41/146), and mortality was significantly higher in cancer-related sepsis patients compared with non-cancer patients (41.3% vs. 22.0%, p = 0.016). Need mechanical ventilation, p-SOFA, acute liver failure, higher fluid overload at CRRT initiation, hypoalbuminemia, and high inotropic support were associated with PICU mortality in cancer-related sepsis patients. Moreover, levels of IL-6, total bilirubin, creatinine, blood urea nitrogen, and international normalized ratio were significantly higher in non-survivors than survivors. In multivariate logistic regression analysis, pediatric sequential organ failure assessment (p-SOFA) score (OR:1.805 [95%CI: 1.047-3.113]) and serum albumin level (OR: 0.758 [95%CI: 0.581 -0.988]) were death risk factors in cancer-related sepsis receiving CRRT, and the AUC of combined index of p-SOFA and albumin was 0.852 (95% CI: 0.730-0.974).

CONCLUSION

The overall PICU mortality is high in cancer-related sepsis necessitating CRRT. Higher p-SOFA and lower albumin were independent risk factors for PICU mortality.

Echinatin attenuates acute lung injury and inflammatory responses via TAK1-MAPK/NF-κB and Keap1-Nrf2-HO-1 signaling pathways in macrophages

Echinatin is an active ingredient in licorice, a traditional Chinese medicine used in the treatment of inflammatory disorders. However, the protective effect and underlying mechanism of echinatin against acute lung injury (ALI) is still unclear. Herein, we aimed to explore echinatin-mediated anti-inflammatory effects on lipopolysaccharide (LPS)-stimulated ALI and its molecular mechanisms in macrophages. In vitro, echinatin markedly decreased the levels of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-stimulated murine MH-S alveolar macrophages and RAW264.7 macrophages by suppressing inducible nitric oxide synthase and cyclooxygenase-2 (COX-2) expression. Furthermore, echinatin reduced LPS-induced mRNA expression and release of interleukin-1β (IL-1β) and IL-6 in RAW264.7 cells. Western blotting and CETSA showed that echinatin repressed LPS-induced activation of mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) pathways through targeting transforming growth factor-beta-activated kinase 1 (TAK1). Furthermore, echinatin directly interacted with Kelch-like ECH-associated protein 1 (Keap1) and activated the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway to enhance heme oxygenase-1 (HO-1) expression. In vivo, echinatin ameliorated LPS-induced lung inflammatory injury, and reduced production of IL-1β and IL-6. These findings demonstrated that echinatin exerted anti-inflammatory effects in vitro and in vivo, via blocking the TAK1-MAPK/NF-κB pathway and activating the Keap1-Nrf2-HO-1 pathway.

Mechanical power and normalized mechanical power in pediatric acute respiratory distress syndrome

Background

Mechanical power (MP) refers to the energy transmitted over time to the respiratory system and serves as a unifying determinant of ventilator-induced lung injury. MP normalization is required to account for developmental changes in children. We sought to examine the relationship between mechanical energy (MEBW), MP normalized to body weight (MPBW), and MP normalized to respiratory compliance (MPCRS) concerning the severity and outcomes of pediatric acute respiratory distress syndrome (pARDS).

Method

In this retrospective study, children aged 1 month to 18 years diagnosed with pARDS who underwent pressure-control ventilation for at least 24 h between January 2017 and September 2020 were enrolled. We calculated MP using Becher's equation. Multivariable logistic regression analysis adjusted for age, pediatric organ dysfunction score, and oxygenation index (OI) was performed to determine the independent association of MP and its derivatives 24 h after diagnosing pARDS with 28-day mortality. The association was also studied for 28 ventilator-free days (VFD-28) and the severity of pARDS in terms of OI.

Results

Out of 246 admitted with pARDS, 185 were eligible, with an overall mortality of 43.7%. Non-survivors exhibited higher severity of illness, as evidenced by higher values of MP, MPBW, and MEBW. Multivariable logistic regression analysis showed that only MEBW but not MP, MPBW, or MPCRS at 24 h was independently associated with mortality [adjusted OR: 1.072 (1.002-1.147), p = 0.044]. However, after adjusting for the type of pARDS, MEBW was not independently associated with mortality [adjusted OR: 1.061 (0.992-1.136), p = 0.085]. After adjusting for malnutrition, only MP at 24 h was found to be independently associated. Only MPCRS at 1-4 and 24 h but not MP, MPBW, or MEBW at 24 h of diagnosing pARDS was significantly correlated with VFD-28.

Conclusions

Normalization of MP is better related to outcomes and severity of pARDS than non-normalized MP. Malnutrition can be a significant confounding factor in resource-limited settings.

Integrated Proteomics and Metabolomics Analysis to Explore the Amelioration Mechanisms of Rosa roxburghii Tratt Fruit Polyphenols on Lipopolysaccharide-Induced Acute Lung Injury Mice

Acute lung injury (ALI) is the main cause of death for the elderly and children due to its high morbidity and mortality rates. Plant-derived functional foods are becoming increasingly important to the healthcare and food industries for adjunctive and alternative treatments of ALI. Polyphenols have been regarded to be beneficial to the prevention and amelioration of ALI. Rosa roxburghii Tratt fruit polyphenols (RRTP) has potential to prevent ALI, but mechanism remains unclear. This study was set up to systematically analyze the RRTP extract active ingredients, comprehensively evaluate its protective effects via lung histopathological examination, protein concentration, and cytokines production in ALI mice induced by lipopolysaccharide (LPS), and finally revealed alleviation mechanisms of the regulatory effects of RRTP by proteomics and metabolomics approach. The results demonstrated RRTP could synergistically exert significant preventive effects against ALI by notably ameliorating lung histopathological damage and pulmonary capillary permeability in ALI mice, inhibiting lung tissue inflammatory response and acute phase proteins and S-100 calcium binding proteins, suppressing excessive activation of complement and coagulation cascades, and regulating disordered lipids metabolism and amino acid metabolism. This study illustrated that RRTP has obvious advantages in ALI adjunctive therapy and revealed the complicated amelioration mechanisms, which provides a breakthrough for the development and demonstration of RRTP as a nutritional compound additive for complementary therapy of ALI.

Definition, Incidence, and Epidemiology of Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference

OBJECTIVES

In 2015, the Pediatric Acute Lung Injury Consensus Conference (PALICC) provided the first pediatric-specific definitions for acute respiratory distress syndrome (pediatric acute respiratory distress syndrome [PARDS]). These definitions have since been operationalized in cohort and interventional PARDS studies. As substantial data have accrued since 2015, we have an opportunity to assess the construct validity and utility of the initial PALICC definitions. Therefore, the Second PALICC (PALICC-2) brought together multiple PARDS experts and aimed to identify and summarize relevant evidence related to the definition and epidemiology of PARDS and create modifications to the definition of PARDS.

DATA SOURCES

MEDLINE (Ovid), Embase (Elsevier), and CINAHL Complete (EBSCOhost).

STUDY SELECTION

We included studies of subjects with PARDS, or at risk for PARDS, excluding studies pertaining primarily to adults except as specified for identifying age-specific cutoffs.

DATA EXTRACTION

Title/abstract review, full-text review, and data extraction using a standardized data collection form.

DATA SYNTHESIS

The Grading of Recommendations Assessment, Development, and Evaluation approach was used to identify and summarize evidence and develop recommendations. A total of 97 studies were identified for full-text extraction addressing distinct aspects of the PARDS definition, including age, timing, imaging, oxygenation, modes of respiratory support, and specific coexisting conditions. Data were assessed in a Patient/Intervention/Comparator/Outcome format when possible, and formally summarized for effect size, risk, benefit, feasibility of implementation, and equity. A total of 17 consensus-based definition statements were made that update the definition of PARDS, as well as the related diagnoses of "Possible PARDS" and "At-Risk for PARDS." These statements are presented alongside a summary of the relevant epidemiology.

CONCLUSIONS

We present updated, data-informed consensus statements on the definition for PARDS and the related diagnoses of "Possible PARDS" and "At-Risk for PARDS."

Pathobiology, Severity, and Risk Stratification of Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference

OBJECTIVES

To review the literature for studies published in children on the pathobiology, severity, and risk stratification of pediatric acute respiratory distress syndrome (PARDS) with the intent of guiding current medical practice and identifying important areas for future research related to severity and risk stratification.

DATA SOURCES

Electronic searches of PubMed and Embase were conducted from 2013 to March 2022 by using a combination of medical subject heading terms and text words to capture the pathobiology, severity, and comorbidities of PARDS.

STUDY SELECTION

We included studies of critically ill patients with PARDS that related to the severity and risk stratification of PARDS using characteristics other than the oxygenation defect. Studies using animal models, adult only, and studies with 10 or fewer children were excluded from our review.

DATA EXTRACTION

Title/abstract review, full-text review, and data extraction using a standardized data collection form.

DATA SYNTHESIS

The Grading of Recommendations Assessment, Development, and Evaluation approach was used to identify and summarize relevant evidence and develop recommendations for clinical practice. There were 192 studies identified for full-text extraction to address the relevant Patient/Intervention/Comparator/Outcome questions. One clinical recommendation was generated related to the use of dead space fraction for risk stratification. In addition, six research statements were generated about the impact of age on acute respiratory distress syndrome pathobiology and outcomes, addressing PARDS heterogeneity using biomarkers to identify subphenotypes and endotypes, and use of standardized ventilator, physiologic, and nonpulmonary organ failure measurements for future research.

CONCLUSIONS

Based on an extensive literature review, we propose clinical management and research recommendations related to characterization and risk stratification of PARDS severity.

Protective Effects of Atractylodis lancea Rhizoma on Lipopolysaccharide-Induced Acute Lung Injury via TLR4/NF-κB and Keap1/Nrf2 Signaling Pathways In Vitro and In Vivo

Acute lung injury (ALI) is a syndrome caused by an excessive inflammatory response characterized by intractable hypoxemia both inside and outside the lung, for which effective therapeutic drugs are lacking. Atractylodis rhizoma, a traditional Chinese medicine, has excellent anti-inflammatory and antiviral properties in addition to protecting the integrity of the cellular barrier. However, few studies of Atractylodis rhizoma for the treatment of ALI have been published, and its mechanism of action remains unclear. In the present study, the chemical composition of the ethanolic extract of Atractylodis rhizoma (EEAR) was initially clarified by high performance liquid chromatography (HPLC), after which it was studied in vivo using a lipopolysaccharide (LPS)-induced ALI rat model. Treatment with EEAR significantly reduced the lung wet/dry (W/D) ratio, neutrophil infiltration, and malondialdehyde (MDA) and myeloperoxidase (MPO) formation, and enhanced superoxide dismutase (SOD) and glutathione (GSH) depletion in rats with ALI, thereby improving lung barrier function and effectively reducing lung injury. In addition, EEAR significantly reduced histopathological changes, decreased the expression of inflammatory factors (such as tumor necrosis factor-α (TNF-α), interleukin-1 beta (IL-1β), inducible nitric oxide synthase (INOS), and cyclooxygenase-2 (COX-2)), and inhibited the activation of the NF-κB signaling pathway, thus reducing inflammation. In addition, EEAR was found to also reduce oxidative stress in ALI by upregulating the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream proteins heme oxygenase-1 (HO-1) and NADPH quinone acceptor oxidoreductase 1 (NQO-1). EEAR also reduced LPS-induced inflammatory factor expression in THP-1 cells in vitro by inhibition of the NF-κB signaling pathway, and reduced damage from lipopolysaccharide (LPS)-induced oxidative stress in THP-1 cells by promoting the expression of Nrf2 and its downstream targets HO-1 and NQO-1, the molecular mechanism of which was consistent with in vivo observations. Therefore, we conclude that EEAR attenuates oxidative stress and inflammatory responses via TLR4/NF-κB and Keap1/Nrf2 signaling pathways to alleviate LPS-induced ALI, suggesting that Atractylodis rhizoma is a potential drug candidate for the treatment of ALI.

Analysis of protective effects of Rosa Roxburghii Tratt fruit polyphenols on lipopolysaccharide-induced acute lung injury through network pharmacology and metabolomics

Acute lung injury (ALI) is a respiratory disease with high morbidity and mortality rates and is the primary cause of death in children and the elderly around the world. The use of Chinese foods in the complementary and alternative treatment of ALI has attracted more and more attention. This study aimed to explore the anti-ALI activity of Chinese functional foods Rosa roxburghii Tratt fruit polyphenols (RRTP). RRTP was administered to lipopolysaccharide-induced ALI mice, and its protective effects were comprehensively evaluated by lung histopathological examination, wet/dry (W/D) ratio, and cytokine production. Metabolomics analysis was used to identify the differential metabolites and metabolic pathways in plasma, and molecular docking and systemic biology-based network pharmacology assay were performed to explore the active components and potential therapeutic targets. The results indicated that RRTP significantly attenuated the severity of pathological changes and pulmonary capillary permeability. Furthermore, RRTP limited the increase in tumor necrosis factor alpha (TNF-α), interleukin 1β (IL-1β), and interleukin 6 (IL-6) levels and the decrease in interleukin 10 (IL-10) levels in ALI mice. Metabolomics studies revealed that RRTP markedly affected 19 different metabolites, three amino acid metabolism pathways, and sphingolipid metabolism. Moreover, network pharmacology identified AKT1 (AKT serine/threonine kinase 1), TP53, IL-6, VEGFA (vascular endothelial growth factor A), and TNF (tumor necrosis factor) as the most promising target proteins, while quercetin, luteolin, and kaempferol were the core active components of RRTP. This study investigated the complex mechanisms of RRTP against ALI for the first time, and provided a foundation for the application of RRTP as a functional food, facilitating the research of nutritional food additives for the adjuvant treatment of ALI.

Epidemiology of Acute Respiratory Distress Syndrome in Pediatric Intensive Care Unit: Single-center Experience

Background

Acute respiratory distress syndrome (ARDS) is characterized by dysregulated inflammation resulting in hypoxemia and respiratory failure and causes both morbidity and mortality.

Objectives

To describe the clinical profile, outcome, and predictors of mortality in ARDS in children admitted to the Pediatric intensive care unit.

Materials and methods

This is a single-center retrospective study conducted at a tertiary referral hospital in a 12-bed PICU involving children (1 month to 18 years) with ARDS as defined by Pediatric Acute Lung Injury Consensus Conference (PALICC) guidelines, over a period of 5 years (2016–2020). Demographic, clinical, and laboratory details at onset and during PICU stay were collected. Predictors of mortality were compared between survivors and non-survivors.

Results

We identified 89 patients with ARDS. The median age at presentation was 76 months (12–124 months). The most common precipitating factor was pneumonia (66%). The majority of children (35.9%) had moderate ARDS. Overall mortality was 33% with more than half belonging to severe ARDS group (58%). On Kaplan–Meier survival curve analysis, the mean time to death was shorter in the severe ARDS group as compared to other groups. Multiorgan dysfunction was present in 46 (51.6%) of the cases. Non-survivors had higher mean pediatric logistic organ dysfunction (PELOD2) on day 1. PRISM III at admission, worsening trends of ventilator and oxygenation parameters (OI, P/F, MAP, and PEEP) independently predicted mortality after multivariate analysis.

Conclusion

High PRISM score predicts poor outcome, and worsening trends of ventilator and oxygenation parameters (OI, P/F, MAP, and PEEP) are associated with mortality.

How to cite this article

Pujari CG, Lalitha AV, Raj JM, Kavilapurapu A. Epidemiology of Acute Respiratory Distress Syndrome in Pediatric Intensive Care Unit: Single-center Experience. Indian J Crit Care Med 2022;26(8):949–955.

Paediatric acute respiratory distress syndrome: consider the role of lymphatics

We present a case of a 7-day-old male infant with severe respiratory disease requiring venoarterial extracorporeal membrane oxygenation therapy with evidence of lymphangiectasia on lung biopsy. Differentiating primary versus secondary lymphangiectasis in this patient remains a riddle despite extensive investigations including an infective screen, lung biopsy and whole-genome sequencing. In addition to the standard therapies used in paediatric acute respiratory distress syndrome, such as lung-protective ventilation, permissive hypoxaemia and hypercarbia, nursing in the prone position, early use of muscle relaxants, rescue intravenous corticosteroids and broad-spectrum antibiotics, the patient was also given octreotide despite the absence of a chylothorax based on the theoretical benefit of altering the lymphatic flow. His case raises an interesting discussion around the role of lymphatics in the pathophysiology of paediatric and adult respiratory distress syndrome and prompts the exploration of novel agents which may affect lymphatic vessels used as an adjunctive therapy.

The Association Between Oxygenation Status at 24 h After Diagnosis of Pulmonary Acute Respiratory Distress Syndrome and the 30-Day Mortality among Pediatric Oncological Patients

BACKGROUND

Pediatric oncology patients with acute respiratory distress syndrome (ARDS) secondary to pneumonia are at high risk of mortality. Our aim was to describe the epidemiology of ARDS in this clinical population and to identify the association between the oxygenation status at 24 h after diagnosis and the 30-day mortality rates, stratified by the severity of ARDS.

METHODS

This was a retrospective cohort study of 82 pediatric oncology patients, with a median age of 4 years, admitted to our pediatric intensive care unit with a diagnosis of ARDS between 2013 and 2021. Demographic and clinical factors were compared between the survivor (n = 52) and non-survivor (n = 30) groups. Univariate and multivariate Cox proportional hazards regression models were used to determine the association between the oxygenation status at 24 h after diagnosis and the 30-day mortality rates.

RESULTS

The mean airway pressure at ARDS diagnosis, PaO₂/FiO₂ (P/F) ratio, oxygenation index (OI) value, peak inspiratory pressure, and lactate level at 24 h after ARDS diagnosis, as well as complications (i.e., septicemia and more than two extrapulmonary organ failures) and adjunctive continuous renal replacement therapy, were significant mortality risk factors. After adjusting for other covariates, the oxygenation status P/F ratio (Hazard ratio [HR] = 0.98, 95% confidence interval [CI] = 0.96-1.00, P = 0.043) and OI value (HR = 1.12, 95% CI = 1.02-1.23, P = 0.016) at 24 h remained independent mortality risk factors. According to the Kaplan-Meier survival curve, a low P/F ratio (≤ 150) and high OI (>10) were associated with a higher risk of 30-day mortality (50.9 and 52.9%, respectively; both P < 0.05).

CONCLUSION

The P/F ratio and OI value measured at 24 h after ARDS diagnosis can provide a better stratification of patients according to ARDS disease severity to predict the 30-day mortality risk.

Extracorporeal membrane oxygenation for severe acute respiratory distress syndrome in children with leukemia/lymphoma: A retrospective case series

OBJECTIVE

The cancer patients with severe acute respiratory distress syndrome (ARDS) benefit from extracorporeal membrane oxygenation (ECMO) remains unanswered. We analyzed clinical characteristics and outcomes of pediatric patients with leukemia/lymphoma who developed ARDS and treated with ECMO.

METHODS

Pediatric leukemia or lymphoma patients with ARDS who underwent ECMO between August 2017 and December 2021 were retrospectively analyzed in a tertiary pediatric intensive care unit (PICU).

RESULTS

Seven patients with median age 53 (IQR 42-117) months and 4 males were included. Six cases of leukemia [5 of acute lymphocytic leukemia (ALL) and 1 of acute myelogenous leukemia (AML, M5)] and 1 of non-Hodgkin lymphoma with severe ARDS received ECMO on chemotherapy period. The etiology of ARDS is community or chemotherapy-associated bacterial or/and fungal or viral infection. All the patients received chemotherapy in the 2 weeks prior to ECMO and five were neutropenic at initial ECMO. Six cases underwent veno-arterial ECMO (VA ECMO) and 1 for veno-venous ECMO (VV-ECMO). The median duration of ECMO support was 122 (IQR 56-166) hours. Overall, 42.9% (three of seven) survived to hospital discharge and 6 months survival rate was 28.6% (two of seven). Bleeding was the main ECMO-associated complication occurring in 7 patients, followed by nosocomial infection in 4 cases. All the patients required vasopressor support, and 6 received continuous renal replacement therapy (CRRT).

CONCLUSION

Our experiences suggest that rescue ECMO provides a selective treatment strategy in childhood hematologic malignancies with severe ARDS.

Role of Sildenafil in Management of Pediatric Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) has high mortality and multiple therapeutic strategies have been used to improve the outcome. Inhaled nitric oxide (INO), a pulmonary vasodilator, is used to improve oxygenation. This study was conducted to determine the role of sildenafil, an oral vasodilator, to improve oxygenation and mortality in pediatric ARDS (PARDS). The prevalence of pulmonary hypertension in PARDS was studied as well. Inclusion criteria included children (1–18 years) with ARDS requiring invasive ventilation admitted to the pediatric intensive care unit of a teaching hospital in Northern India over a 1-year period of time. Thirty-five patients met the inclusion criteria. Cardiologist performed a detailed echocardiogram to determine pulmonary arterial pressure (PAP). Patients with persistent hypoxemia were started on oral sildenafil. The majority (77%) patients had a primary pulmonary etiology of PARDS. Elevated PAP (>25 mm Hg) was detected in 54.3% patients at admission. Sildenafil was given to 20 patients who had severe and persistent hypoxemia. Oxygenation improved in most patients after the first dose with statistically significant improvement in PaO2/FiO2 ratios at both 12 and 24 hours following initiation of therapeutic dosing of sildenafil. Improvement in oxygenation occurred irrespective of initial PAP. Outcomes included a total of 57.1% patients discharged, 28.6% discharged against medical advice (DAMA), and a 14.3% mortality rate. Mortality was related to the severity of PARDS and not the use of sildenafil. This is the first study to determine the effect of sildenafil in PARDS. Sildenafil led to improvement in oxygenation in nearly all the cases without affecting mortality. Due to unavailability of INO in most centers of developing countries, sildenafil may be considered as an inexpensive alternative in cases of persistent hypoxemia in PARDS. We recommend additional randomized controlled trials to confirm the effect of sildenafil in PARDS as determined in this study.

Natural product derived phytochemicals in managing acute lung injury by multiple mechanisms

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) as common life-threatening lung diseases with high mortality rates are mostly associated with acute and severe inflammation in lungs. With increasing in-depth studies of ALI/ARDS, significant breakthroughs have been made, however, there are still no effective pharmacological therapies for treatment of ALI/ARDS. Especially, the novel coronavirus pneumonia (COVID-19) is ravaging the globe, and causes severe respiratory distress syndrome. Therefore, developing new drugs for therapy of ALI/ARDS is in great demand, which might also be helpful for treatment of COVID-19. Natural compounds have always inspired drug development, and numerous natural products have shown potential therapeutic effects on ALI/ARDS. Therefore, this review focuses on the potential therapeutic effects of natural compounds on ALI and the underlying mechanisms. Overall, the review discusses 159 compounds and summarizes more than 400 references to present the protective effects of natural compounds against ALI and the underlying mechanism.

Protective effect of Chrysanthemum morifolium Ramat. ethanol extract on lipopolysaccharide induced acute lung injury in mice

BACKGROUND

To evaluate the effect of Chrysanthemum morifolium Ramat. ethanol extract (CEE) on lipopolysaccharide induced acute lung injury in mice.

METHODS

The ninety C57BL/6 J male mice randomly divided into five groups: control, model and CEE (50, 100, 200 mg/kg) groups for 7 days oral administration. At the last administration, all mice except control were intratracheal instilled with lipopolysaccharide (LPS, 3 mg/kg) for establish the acute lung injury. Then lung histopathologic, lung wet/dry weight, white blood cells, lymphocytes, neutrophils were detected. The pro-inflammation cytokine tumor necrosis factor-α (TNF-α), interleukin (IL)-6, anti-inflammatory cytokine transforming growth factor-β1 (TGF-β1), IL-10 and the marker of antioxides ability total-antioxidant capacity (T-AOC), malondialdehyde (MDA) in lung tissue were measured.

RESULTS

The result showed that CEE could improve lung histopathological injury, reduce the ratio of wet/dry lung weight and lung index, inhibit the increased number of white blood cells, lymphocytes and neutrophils, and reduce the increased levels of TNF-α and IL-6. While CEE also significantly increased the levels of TGF-β1 and IL-10. Furthermore, CEE also markedly increased the activity of T-AOC, and decreased the contents of MDA with a dose-dependent manner.

CONCLUSIONS

The study exhibited that CEE has a potential protective effect on lipopolysaccharide induced acute lung injury in mice, the action mechanism of CEE may through balance of the pro-inflammatory and anti-inflammatory factors, and the oxygen free radicals inhibition.