Acute severe asthma

Opioid use disorder's impact on asthma hospitalizations: A propensity-matched nationwide study

BACKGROUND

Patients with asthma and opioid use disorder (OUD) experience higher rates of acute exacerbation, but the effects of OUD on asthma hospitalizations have been poorly described.

OBJECTIVE

To explore how concurrent OUD may affect the clinical outcomes of adult patients hospitalized for asthma.

METHODS

Using the National Inpatient Sample, adult patients admitted for asthma with concomitant OUD were identified and compared with those without OUD. Cohorts were matched in a 1:1 ratio using propensity score matching, with mortality as primary outcome of interest.

RESULTS

A total of 491,990 patients were hospitalized for asthma, and 3.49% had a concomitant diagnosis of OUD. Patients with asthma and OUD were younger, with a mean age of 41 years (SD ± 12.2) vs 51 years (SD ± 17.2) in those without OUD. After matching, both cohorts had 17,125 patients. There was no significant difference regarding in-hospital mortality (odds ratio [OR] 0.92, 95% CI 0.51-1.63, P = .77) between the cohorts. Patients with asthma with OUD had significantly higher rates of mechanical ventilation (OR 1.52, 95% CI 1.23-1.87, P < .001), noninvasive mechanical ventilation (OR 1.37, 95% CI 1.15-1.62, P < .001), and mean length of stay (3.18 vs 2.92 days, P < .001) compared with patients with asthma without OUD. Patients with OUD had no difference in mean total hospitalization costs ($33,514 vs $31,529, P = .054) compared with patients without OUD. Compared with a routine hospital discharge, patients with OUD were more likely to leave against medical advice (relative risk [RR] 2.67, 95% CI 2.28-3.13, P < .001), be discharged to a long-term facility (RR 1.40, 95% CI 1.01-1.95, P = .045), and be discharged with home health care (RR 1.56, 95% CI 1.22-1.99, P < .001) than patients without OUD.

CONCLUSION

Concomitant OUD has no impact on mortality in asthma hospitalizations, but patients with asthma with OUD have worse secondary outcomes compared with those without OUD.

High-flow nasal cannula and in-line aerosolised bronchodilator delivery during severe exacerbation of asthma in adults: a feasibility observational study

BACKGROUND

Asthma is a common chronic respiratory disease affecting 1-29% of the population in different countries. Exacerbations represent a change in symptoms and lung function from the patient's usual condition that requires emergency department (ED) admission. Recently, the use of a High-Flow Nasal Cannula (HFNC) plus an in-line vibrating mesh nebulizer (VMN) for aerosol drug delivery has been advocated in clinical practice. Thus, this pilot observational study aims to investigate the feasibility of HFNC treatment with VMN for in-line bronchodilator delivery in patients with severe asthma.

METHODS

This study was conducted from May 2022 to May 2023. Subjects ≥18 years old with a previous diagnosis of asthma who were admitted to the ED during severe exacerbation were included. The primary endpoint was the change in peak expiratory flow ratio (PEFR) after 2-h of treatment with bronchodilator delivered by HFNC with in-line VMN. Additional outcomes were changes in forced expiratory volume in 1 s (FEV1) and clinical variables before treatment.

RESULTS

30 patients, mean age of 43 (SD ± 16) years, mostly female (67%) were studied. A significant change in PEFR (147 ± 31 L/m vs. 220 ± 38 L/m; p < 0.001) was observed after treatment with HFNC and in-line VMN with significant improvement in clinical variables. And no subjects required invasive mechanical ventilation (IMV) during the study.

CONCLUSIONS

HFNC treatment with in-line VMN for bronchodilator delivery appears feasible and safe for patients with severe asthma exacerbation. These preliminary promising results should be confirmed with appropriately large-designed studies.

Risk prediction model construction for asthma after allergic rhinitis by blood immune T effector cells

BACKGROUND

Allergic rhinitis (AR) and asthma (AS) are prevalent and frequently co-occurring respiratory diseases, with mutual influence on each other. They share similar etiology, pathogenesis, and pathological changes. Due to the anatomical continuity between the upper and lower respiratory tracts, allergic inflammation in the nasal cavity can readily propagate downwards, leading to bronchial inflammation and asthma. AR serves as a significant risk factor for AS by potentially inducing airway hyperresponsiveness in patients. Currently, there is a lack of reliable predictors for the progression from AR to AS.

METHODS

In this exhaustive investigation, we reexamined peripheral blood single cell RNA sequencing datasets from patients with AS following AR and healthy individuals. In addition, we used the bulk RNA sequencing dataset as a validation lineup, which included AS, AR, and healthy controls. Using marker genes of related cell subtype, signatures predicting the progression of AR to AS were generated.

RESULTS

We identified a subtype of immune-activating effector T cells that can distinguish patients with AS after AR. By combining specific marker genes of effector T cell subtype, we established prediction models of 16 markers. The model holds great promise for assessing AS risk in individuals with AR, providing innovative avenues for clinical diagnosis and treatment strategies.

CONCLUSION

Subcluster T effector cells may play a key role in post-AR AS. Notably, ACTR3 and HSPA8 genes were significantly upregulated in the blood of AS patients compared to healthy patients.

Critical Care Management of Severe Asthma Exacerbations

Severe asthma exacerbations, including near-fatal asthma (NFA), have high morbidity and mortality. Mechanical ventilation of patients with severe asthma is difficult due to the complex pathophysiology resulting from severe bronchospasm and dynamic hyperinflation. Life-threatening complications of traditional ventilation strategies in asthma exacerbations include the development of systemic hypotension from hyperinflation, air trapping, and pneumothoraces. Optimizing pharmacologic techniques and ventilation strategies is crucial to treat the underlying bronchospasm. Despite optimal pharmacologic management and mechanical ventilation, the mortality rate of patients with severe asthma in intensive care units is 8%, suggesting a need for advanced non-pharmacologic therapies, including extracorporeal life support (ECLS). This review focuses on the pathophysiology of acute asthma exacerbations, ventilation management including non-invasive ventilation (NIV) and invasive mechanical ventilation (IMV), the pharmacologic management of acute asthma, and ECLS. This review also explores additional advanced non-pharmacologic techniques and monitoring tools for the safe and effective management of critically ill adult asthmatic patients.

Single-institution experience of extracorporeal membrane oxygenation for near-fatal asthma

Near-fatal asthma (NFA) is the most severe presentation of asthma. It is characterized by hypoxemic and hypercapnic respiratory failure requiring ventilatory assistance, including non-invasive ventilation and mechanical ventilation. However, NFA has a high mortality rate despite conventional therapy. Extracorporeal membrane oxygenation (ECMO) is a treatment modality that is increasingly being utilized as rescue therapy in patients with NFA that is refractory to mechanical ventilation. Prior analyses of the international Extracorporeal Life Support Organization (ELSO) registry data showed a survival rate of over 83% in patients placed on venovenous (VV) ECMO for NFA, but with notable rate of hemorrhagic complications. We report seven cases of adults with NFA requiring ECMO support at our large quaternary care institution between the years 2019 and 2022. All seven patients presented with respiratory failure in the setting of asthma exacerbation that progressed despite standard pharmacotherapy and mechanical ventilation. All patients survived to hospital discharge after ECMO support without hemorrhagic complications, highlighting the effectiveness and safety of ECMO when appropriately used in this population.

Severe Acute Bronchial Asthma with Sepsis: Determining the Status of Biomarkers in the Diagnosis of the Disease

Bronchial asthma is a widely prevalent illness that substantially impacts an individual's health standard worldwide and has a significant financial impact on society. Global guidelines for managing asthma do not recommend the routine use of antimicrobial agents because most episodes of the condition are linked to viral respiratory tract infections (RTI), and bacterial infection appears to have an insignificant impact. However, antibiotics are recommended when there is a high-grade fever, a consolidation on the chest radiograph, and purulent sputum that contains polymorphs rather than eosinophils. Managing acute bronchial asthma with sepsis, specifically the choice of whether or not to initiate antimicrobial treatment, remains difficult since there are currently no practical clinical or radiological markers that allow for a simple distinction between viral and bacterial infections. Researchers found that serum procalcitonin (PCT) values can efficiently and safely minimize antibiotic usage in individuals with severe acute asthma. Again, the clinical manifestations of acute asthma and bacterial RTI are similar, as are frequently used test values, like C-reactive protein (CRP) and white blood cell (WBC) count, making it harder for doctors to differentiate between viral and bacterial infections in asthma patients. The role and scope of each biomarker have not been precisely defined yet, although they have all been established to aid healthcare professionals in their diagnostics and treatment strategies.

Acute severe asthma and its predictors of mortality in rural Southwestern Nigeria: a-five year retrospective observational study

OBJECTIVES

There is an observed paucity of data regarding the predictors of asthma mortality in Nigeria. This study aimed to ascertain the clinical presentations and predictors of acute severe asthma mortality in rural Southwestern Nigeria.

METHODS

A retrospective observational study using a data form and a standardized questionnaire was used to review the 124 patients admitted at Emergency Department between January 2015 and December 2019. The data were analyzed using SPSS Version 22.0. The results were presented in descriptive and tabular formats. Binary logistic regression analysis was used to determine the predictors of asthma mortality and a p-value <.05 was considered statistically significant.

RESULTS

A total of 124 patients were studied. The acute severe asthma mortality was 4.8% and its predictors were older age (Crude odds Ratio (COR), 14.857; 95% CI: 2.489-88.696, p < .001), Tobacco smoking (COR, 6.741; 95% CI: 1.170-38.826, p = .016), more than three co-morbidities (COR, 2.750; 95% CI: 1.147-26.454, p = 0.012), diabetes mellitus (COR, 13.750; 95% CI: 2.380-79.433, p < .001), Human Immunodeficiency virus (COR, 117.000; 95% CI: 9.257-1479.756, p < .001), ≥2 days before presentation (COR, 7.440; 95% CI: 1.288-42.980, p = .039), and Short-acting-B2-agonists overuse (COR, 7.041; 95% CI: 1.005-62.165, p = .044).

CONCLUSION

The mortality rate was 4.8% and its predictors were older age patients, tobacco smoking, multiple co-morbidities, diabetes mellitus, HIV, SP02 <90%, delay presentation, and Short-acting-B2-agonists over use, The study showed that there is high prevalence of asthma mortality in rural Southwestern Nigeria. The findings may be used to plan for asthma preventions and control programs in rural settings, and may also provide an impetus for prospective research on these outcomes.

A bibliometric and scientific knowledge map study of the drug therapies for asthma-related study from 1982 to 2021

Objective: Asthma drug research has been increasing yearly, and its clinical application value has increasingly attracted attention. This study aimed to analyze the development status, research hotspots, research frontiers, and future development trends of the research works on drugs for patients with asthma, especially severe asthma.

Methods: Asthma drug-related articles published between 1982 and 2021 were retrieved from the Web of Science Core Collection (WOSCC) database, and only articles published in English were included. CiteSpace and VOSviewer software were utilized to conduct collaborative network analysis of countries/regions, institutions, keywords, and co-citation analysis of references.

Results: A total of 3,234 asthma drug-related eligible articles were included. The United States was in a leading position, and Karolinska Institute (Sweden) was the most active institution. The most prolific journal in this field was Journal of Asthma, and the most cited journal was Journal of Allergy and Clinical Immunology. Keyword co-occurrence studies suggested that the current hotspots and frontiers were as follows: ① asthma: fully revealing the potential of existing conventional asthma drugs, determining the best drug delivery system, and indicating the best combination. To continue to explore potential targets for severe asthma or other phenotypes. Inhaled glucocorticoids and budesonide are still one of the important aspects of current asthma drug research and ② severe asthma: the research and development of new drugs, especially monoclonal antibodies including omalizumab, mepolizumab, and benralizumab to improve asthma control and drug safety, have become a research hotspot in recent years, highlighting the importance of “target” selection.

Conclusion: This study demonstrates the global research hotspots and trends of the research works on drugs for patients with asthma/severe asthma. It can help scholars quickly understand the current status and hotspots of research in this field.

Glucocorticoid therapy in respiratory illness: bench to bedside

Each year, hundreds of millions of individuals are affected by respiratory disease leading to approximately 4 million deaths. Most respiratory pathologies involve substantially dysregulated immune processes that either fail to resolve the underlying process or actively exacerbate the disease. Therefore, clinicians have long considered immune-modulating corticosteroids (CSs), particularly glucocorticoids (GCs), as a critical tool for management of a wide spectrum of respiratory conditions. However, the complex interplay between effectiveness, risks and side effects can lead to different results, depending on the disease in consideration. In this comprehensive review, we present a summary of the bench and the bedside evidence regarding GC treatment in a spectrum of respiratory illnesses. We first describe here the experimental evidence of GC effects in the distal airways and/or parenchyma, both in vitro and in disease-specific animal studies, then we evaluate the recent clinical evidence regarding GC treatment in over 20 respiratory pathologies. Overall, CS remain a critical tool in the management of respiratory illness, but their benefits are dependent on the underlying pathology and should be weighed against patient-specific risks.

Asthma in paediatric intensive care in England residents: observational study

Despite high prevalence of asthma in children in the UK, there were no prior report on asthma admissions in paediatric intensive care units (PICU). We investigated the epidemiology and healthcare resource utilisation in children with asthma presenting to PICUs in England. PICANet, a UK national PICU database, was queried for asthma as the primary reason for admission, of children resident in England from April 2006 until March 2013. There were 2195 admissions to PICU for a median stay of 1.4 days. 59% were males and 51% aged 0–4 years. The fourth and fifth most deprived quintiles represented 61% (1329) admissions and 73% (11) of the 15 deaths. Deaths were most frequent in 10–14 years age (n = 11, 73%), with no deaths in less than 5 years age. 38% of admissions (828/2193) received invasive ventilation, which was more frequent with increasing deprivation (13% (108/828) in least deprived to 31% (260/828) in most deprived) and with decreasing age (0–4-year-olds: 49%, 409/828). This first multi-centre PICU study in England found that children from more deprived neighbourhoods represented the majority of asthma admissions, invasive ventilation and deaths in PICU. Children experiencing socioeconomic deprivation could benefit from enhanced asthma support in the community.

Leukocytes in Critical Patients With Asthma Exacerbation

Background Asthma exacerbations, defined as acute or subacute progressive worsening of airway spasm, are a significant cause of disease morbidity. Risk factors for exacerbation include sex, age, race, socioeconomic status, baseline lung function, smoking history, and exposure to respiratory viruses. It is believed that white cells play an essential role in the pathogenesis of such attacks; however, the current understanding of the relationship between cell lines during an asthma attack is minimal. Methods This report represents a retrospective study for patients admitted to ICU for asthma exacerbations. The Medical Information Mart for Intensive Care iii (MIMIC iii) version 1.4 database was used to identify patients admitted for asthma exacerbations. The demographics, laboratory data gathered in addition, to clinical variables and outcomes were determined. Results The length of stay increased with the increase in WBC (p = 0.001). Intubated patients had an increased white blood cell (WBC) count when compared with non-intubated patients (p-value 0.009). In addition, patients with normal basophil counts on presentation were less likely to need intubation than those presenting with low basophils (p-value 0.015, adjusted odds ratio = 0.074, CI [0.009-0.620]) and those presenting with basophilia (p-value 0.001, adjusted odds ratio = 0.025, CI [0.003-0.225]). Furthermore, prolonged intubation (for three days or more) was positively correlated with eosinophil counts. On the other hand, there was no statistically significant association between the length of ICU and the patient's age, smoking status, or gender (p-values 0.611; 0.761; and 0.201, respectively). Conclusion Asthma exacerbation is a disease of heterogeneous pathophysiology. The leukocyte count is associated with the length of stay and the need for mechanical ventilation.

The use of non- invasive ventilation in asthma exacerbation - a two year retrospective analysis of outcomes

Background: The use of Non-Invasive Ventilation (NIV) in acute asthma exacerbation remains controversial. Comparative data on patient characteristics that benefit from NIV in asthma exacerbation to those patients that fail NIV remains limited. Our study compares some of these patient characteristics and examines if NIV is safe and effective in carefully selected patients.

Methods: Following institutional review board approval, we extracted from the electronic medical record and conducted a retrospective chart-based review of those patients who received NIV in the emergency room for a diagnosis of asthma exacerbation from January 2017 to December 2018.

Results and Conclusion: The rate of failure of NIV overall was low, at 9.17%, with younger patients more likely to fail NIV (P = 0.03) and need invasive mechanical ventilation. Surprisingly, baseline asthma severity did not impact NIV failure rate, and neither did body mass index, smoking history, and a host of clinical characteristics. Understandably, the length of stay was significantly longer in the group of patients that failed NIV. There were no adverse events, such as an increased rate of barotrauma events in either group. In conclusion, this study contributes to the growing body of evidence that NIV is a safe and effective adjunct to routine care in the management of patients with asthma exacerbation.

Health disparities of critically ill children according to poverty: the Korean population-based retrospective cohort study

Background

There is a lack of nationwide studies on critically ill patients’ health disparity under the National Health Insurance (NHI) system. We evaluated health disparities in intensive care unit (ICU) admission, outcomes, and readmission in impoverished children.

Methods

We conducted a retrospective cohort study using a national database from the Korean NHI and Medical Aid Program (MAP). MAP supports the population whose household income is lower than 40% of the median Korean household income. We defined poverty as being a MAP beneficiary and compared the poverty and non-poverty groups. Patients between 28 days and 18 years old who were admitted to the ICU were included. Hospital mortality and readmission were analyzed with adjustment for patient characteristics, hospital type, and management procedures.

Results

Out of 17,893 patients, 1153 (6.4%) patients were in poverty. The age-standardized ICU admission rate was higher in the poverty group (126.9 vs. 80.2 per 100,000 person-years). There was more age-standardized mortality in the poverty group (11.8 vs. 4.3 per 100,000 person-years). Patients in the poverty group did not have a statistically different risk of adjusted in-hospital mortality to those in the non-poverty group (odds ratio: 1.15, confidence interval [CI]: 0.84–1.55) but had a higher readmission rate (hazard ratio 1.25, CI 1.09–1.42).

Conclusion

Under the NHI system, the disparity in pediatric critical care outcomes according to poverty is not definite, but the healthcare disparity in pre- and post-hospital care is a concern. Further studies are required to improve pre- and post-hospital healthcare quality of impoverished children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11324-4.

Decapneization as supportive therapy for the treatment of status asthmaticus: a case report

Background

Acute severe asthma is a life-threatening medical emergency. Characteristics of asthma include increased airway resistance and dynamic pulmonary hyperinflation that can manifest in dangerous levels of hypercapnia and acidosis, with significant mortality and morbidity. Severe respiratory distress can lead to endotracheal intubation followed by mechanical ventilation, which can cause increased air trapping with dynamic hyperinflation, predisposing the lungs to barotraumas.

Case presentation

The present case report describes the use of the minimally invasive ECCO₂R ProLUNG^® (Estor) with protective low-tidal-volume ventilation, in a Caucasian patient with near-fatal asthma and with no response to conventional therapy.

Conclusions

Since hypercarbia rather than hypoxemia is the primary abnormality in status asthmaticus, a rescue therapeutic strategy combining the ECCO₂R membrane ProLUNG^® (Estor) with ultra-protective low-tidal-volume ventilation can be successfully applied to limit the risk of severe barotrauma during invasive mechanical ventilation. ECCO₂R ProLUNG^® is a partial respiratory support technique that, based on the use of an extracorporeal circuit with a gas-exchange membrane, achieves relevant CO₂ clearance directly from the blood using double-lumen venous-venous vascular access, at blood flow in the range of 0.4–1.0 L/minute.

Emergency department treatment of asthma in children: A review

Asthma is the most common chronic illness in children, with >700,000 emergency department (ED) visits each year. Asthma is a respiratory disease characterized by a combination of airway inflammation, bronchoconstriction, bronchial hyperresponsiveness, and variable outflow obstruction, with clinical presentations ranging from mild to life-threatening. Standardized ED treatment can improve patient outcomes, including fewer hospital admissions. Informed by the most recent guidelines, this review focuses on the optimal approach to diagnosis and treatment of children with acute asthma exacerbations who present to the ED.

Physiologically variable ventilation in a rabbit model of asthma exacerbation

BACKGROUND

Mechanical ventilation during status asthmaticus is challenging and increases the risk of severe complications. We recently reported the value of physiologically variable ventilation (PVV) in healthy and acutely injured lungs. We investigated whether PVV provides benefits compared with pressure-controlled ventilation (PCV) in an experimental model of severe acute asthma.

METHODS

Allergen-sensitised rabbits were anaesthetised and randomised to either PCV (n=10) or PVV (n=12) during sustained bronchoconstriction induced by allergen and cholinergic stimuli for 6 h. The PVV pattern was generated from pre-recorded spontaneous breathing. Ventilation parameters, oxygenation index (PaO₂/FiO₂), and respiratory mechanics were measured hourly. Histological injury and inflammation were quantified after 6 h of ventilation.

RESULTS

PVV resulted in lower driving pressures (13.7 cm H₂O [12.5-14.9], mean [95% confidence interval]), compared with pressure-controlled ventilation (17.6 cm H₂O [15.4-19.8]; P=0.002). PVV improved PaO₂/FiO₂ (PVV: 55.1 kPa [52-58.2]; PCV: 45.6 kPa [39.3-51.9]; P=0.018) and maintained tissue elastance (PVV: +8.7% [-0.6 to 18]; PCV: -11.2% [-17.3 to -5.1]; P=0.03). PVV resulted in less lung injury as assessed by lower histological injury score (PVV: 0.65 [0.62-0.65]; PCV: 0.71 [0.69-0.73]; P=0.003), cell count (PVV: 247 10⁴ ml^-1 [189-305]; PCV: 447 10⁴ ml^-1 [324-570]; P=0.005), and protein concentration in bronchoalveolar lavage fluid (PVV: 0.14 μg ml^-1 [0.10-0.18]; PCV: 0.21 μg ml^-1 [0.15-0.27]; P=0.035).

CONCLUSIONS

Applying physiological variable ventilation in a model of asthma exacerbation led to improvements in gas exchange, ventilatory pressures, and respiratory tissue mechanics, and reduced lung injury. A global reduction in lung shear stress and recruitment effects may explain the benefits of PVV in status asthmaticus.

Acute severe asthma requiring invasive mechanical ventilation in the era of modern resuscitation techniques: A 10-year bicentric retrospective study

Purpose

Patients with acute severe asthma (ASA) may in rare cases require invasive mechanical ventilation (IMV). However, recent data on this issue are lacking.

Materials and methods

In this retrospective and bicentric study conducted on a 10 year period, we investigate the in-hospital mortality in patients with ASA requiring IMV. We compare this mortality to that of patients with other types of respiratory distress using a standardized mortality ratio (SMR) model.

Results

Eighty-one episodes of ASA requiring IMV were evaluated. Factors significantly associated with in-hospital mortality were cardiac arrest on day of admission, cardiac arrest as the reason for intubation, absence of decompensation risk factors, need for renal replacement therapy on day of admission, and intubation in pre-hospital setting. Non-survivors had higher SAPS II, SOFA, creatinine and lactate levels as well as lower blood pressure, pH, and HCO₃ on day of admission. In-hospital mortality was 15% (n = 12). Compared to a reference population of 2,670 patients, the SMR relative to the SAPS II was very low at 0.48 (95% CI, 0.25–0.84). The only factor independently associated with in-hospital mortality was cardiac arrest on day of admission. In-hospital mortality was 69% in patients with cardiac arrest on day of admission and 4% in others (p < 0.01). Salvage therapies were given to 7 patients, sometimes in combination with each other: ECMO (n = 6), halogenated gas (n = 1) and anti-IL5 antibody (n = 1). Death occurred in only 2 of these 7 patients, both of whom had cardiac arrest on day of admission.

Conclusion

Nowadays, the mortality of patients with ASA requiring IMV is low. Death is due to multi-organ failure, with cardiac arrest on day of admission being the most important risk factor. In patients who did not have cardiac arrest on day of admission the mortality is even lower (4%) which allows an aggressive management.

Clinical Phenotypes of Patients Hospitalized for an Asthma Exacerbation: Prognostic Implications

BACKGROUND

Hospitalization due to acute asthma exacerbation (AE) is a highly detrimental situation requiring critical management to prevent further deterioration, including mechanical ventilation, intensive care unit (ICU) admission, and death. However, patients hospitalized for AEs are highly heterogeneous and remain largely unexplored.

OBJECTIVE

To identify clinical and inflammatory phenotypes of AE requiring hospitalization associated with in-hospital outcomes.

METHODS

We performed a hierarchical cluster analysis of 825 consecutively recruited patients hospitalized for AEs. Logistic regressions were conducted to quantify the independent associations of the identified phenotypes with in-hospital outcomes. Decision tree analysis was developed to predict cluster assignment.

RESULTS

We identified 3 clusters of patients, which had significantly different characteristics associated with in-hospital adverse outcomes. Cluster 1 (n = 526, 63.8%) was a late-onset phenotype, cluster 2 (n = 97, 11.8%) was an early-onset phenotype, and cluster 3 (n = 202, 24.5%) was a phenotype with fewer eosinophils and more comorbidities. Clusters 2 and 3 had an elevated risk of death (relative ratio [RR_adj], 18.10 and 19.17, respectively) and mechanical ventilation (RR_adj, 2.56 and 5.71, respectively) than did cluster 1. Individuals in cluster 3 had an extended length of hospital stay (11 days), increased hospitalization direct costs (13,481.57 Chinese Yuan), and a higher risk of ICU admission (RR_adj, 2.14) than individuals in clusters 1 and 2. The decision tree assigned 90.8% of the participants correctly.

CONCLUSIONS

We identified 3 phenotypes with differential clinical and inflammatory characteristics associated with in-hospital adverse outcomes. These new phenotypes might have important and clinically relevant implications for the management of patients hospitalized for AEs.

Evaluation and management of the critically ill adult asthmatic in the emergency department setting

INTRODUCTION

Asthma is a common reason for presentation to the Emergency Department and is associated with significant morbidity and mortality. While patients may have a relatively benign course, there is a subset of patients who present in a critical state and require emergent management.

OBJECTIVE

This narrative review provides evidence-based recommendations for the assessment and management of patients with severe asthma.

DISCUSSION

It is important to consider a broad differential diagnosis for the cause and potential mimics of asthma exacerbation. Once the diagnosis is determined, the majority of the assessment is based upon the clinical examination. First line therapies for severe exacerbations include inhaled short-acting beta agonists, inhaled anticholinergics, intravenous steroids, and magnesium. Additional therapies for refractory cases include parenteral epinephrine or terbutaline, helium‑oxygen mixture, and consideration of ketamine. Intravenous fluids should be administered, as many of these patients are dehydrated and at risk for hypotension if they receive positive pressure ventilatory support. Noninvasive positive pressure ventilation may prevent the need for endotracheal intubation. If mechanical ventilation is required, it is important to avoid breath stacking by setting a low respiratory rate and allowing permissive hypercapnia. Patients with severe asthma exacerbations will require intensive care unit admission.

CONCLUSIONS

This review provides evidence-based recommendations for the assessment and management of severe asthma with a focus on the emergency clinician.

Extracorporeal carbon dioxide removal in heart-beating donor with acute severe asthma: A case report

Status asthmaticus is a life-threatening disorder that can manifest in dangerous levels of hypercapnia and acidosis. The use of extracorporeal carbon dioxide removal (ECCO2R) has been used successfully to control pH and PaCO₂ in patients with acute severe asthma. The present report describes the use of this technology in near-fatal asthma with brain death, and awaiting organ harvest. The ProLUNG® system consists of a veno-venous hemoperfusion circuit with an artificial lung polymethylpentene membrane coated with phosphorylcholine with a surface of 1.81 m². The system can reach a blood flow of 450 ml/min trough a double-lumen central venous catheter (13.0 Fr) placed in femoral, subclavian or jugular vein. The platform is provided with automated management of airflow and VCO₂ monitoring during treatment. The patient was maintained on extracorporeal treatment ensuring stable arterial pH control and PaCO₂ control. In acute status asthmaticus, complicated with cardiac arrest, mini-invasive ECCO2R was an effective method of controlling pH and PaCO₂, for optimizing hemodynamic and aerobic metabolism and for performing protective ventilation for an optimal organ donor preservation until the organ harvest occurs.

Volatile anaesthetic for treatment of respiratory failure from status asthmaticus requiring extracorporeal membrane oxygenation

A 37-year-old male smoker with asthma presented with status asthmaticus refractory to terbutaline, intravenous magnesium, continuous bronchodilators, steroids, heliox and theophylline infusion. He was intubated on hospital day 2 and cannulated for veno-venous extracorporeal membrane oxygenation (V-V ECMO) on hospital day 3 for refractory respiratory acidosis secondary to hypercapnia and hypoxemia despite maximum medical management over 4 days. He was started on inhaled isoflurane with improvement in peak airway pressures and respiratory acidosis, allowing for prompt weaning from V-V ECMO and extubation. Inhaled volatile anaesthetics exert a direct action on bronchiole smooth muscle causing relaxation with significant effect despite severely impaired pulmonary function. This treatment in patients on ECMO may allow for earlier decannulation and decreased risk of coagulopathy, ECMO circuit failure, infection, renal failure, pulmonary haemorrhage and central nervous system haemorrhage. However, major limitations exist in delivering volatile anaesthetics, which may make use inefficient and costly despite efficacy.

Blood eosinophil count correlates with severity of respiratory failure in life-threatening asthma and predicts risk of subsequent exacerbations

BACKGROUND

An elevated blood eosinophil count when asthma is stable predicts exacerbations and therapeutic response to corticosteroids or biologics targeting eosinophils. Few studies have examined the prognostic value of blood eosinophils measured at exacerbation.

AIM

To elucidate the relationship between a spot blood eosinophil count-measured at the onset of a life-threatening asthma exacerbation-with indices of exacerbation severity and risk of subsequent exacerbations.

METHODS

Real-world, retrospective review of all life-threatening asthma cases admitted at 4 public hospitals in Singapore between 2011-2015. We assessed the trends and correlations between blood eosinophil count on admission with arterial blood gas values, duration of mechanical ventilation, and risk of death, hypoxic ischemic encephalopathy or respiratory arrest. Risk of future exacerbations among survivors was modelled using Cox regression and survival curves.

RESULTS

There were 376 index life-threatening exacerbations with median blood eosinophil count (5-95th percentiles) of 0.270 × 10⁹ /L (0-1.410 × 10⁹ /L). Arterial pH decreased and PCO₂ increased with increasing eosinophil count. Duration of mechanical ventilation and risk of death, hypoxic ischaemic encephalopathy or respiratory arrest did not vary with eosinophils. Among 329 survivors who were followed-up over a median of 52 months, blood eosinophils ≥1.200 × 10⁹ /L was associated with an increased hazard of emergency visits and/or admissions for asthma (hazard ratio 1.8, 95% confidence interval 1.1-2.9, P = .02).

CONCLUSION

In this study of life-threatening asthma, we found that a spot blood eosinophil count correlates with severity of respiratory failure and predicts risk of subsequent exacerbations.

Symptoms and perception of airway obstruction in asthmatic patients: Clinical implications for use of reliever medications

BACKGROUND

Asthma causes the unpleasant sensation of breathlessness (dyspnea) caused by airway obstruction. Patients with poor perception of airway obstruction are at risk of delay in seeking medical attention and undertreatment, which can lead to avoidable deaths. Conversely, those with heightened perception are at risk of overtreatment and iatrogenic adverse effects with reliever medications, anxiety, and unnecessary use of health care resources.

OBJECTIVE

We sought to review evidence about symptom misperception in asthmatic patients and how to identify and manage affected patients, particularly with regard to reliever medications.

METHODS

We conducted a systematic literature search for studies of perception of airway function in asthmatic patients. We searched the OVID (Medline and Medline [R] in process [PubMed]), Embase, and Adisearch/Odyssey databases, restricting our search to human studies published in English from 1990-2018, with no restrictions on age, sex, or racial origin.

RESULTS

We found that both underperception and overperception assessed during induced bronchoconstriction or bronchodilation or during changes in airway resistance were common across all age groups and that aging, disease severity, smoking, sex, ethnicity, psychologic factors, and medication are all associated with differences in perception. Importantly, airway inflammation was associated with impaired perception and a history of severe or near-fatal asthma. We also identified knowledge gaps, such as whether an individual patient's perception varies over time and the influence perception has on patients' use of reliever medication.

CONCLUSION

We found that abnormal perception of airway obstruction has important clinical implications for the management of patients with asthma.

Acid-Base Disturbances in Patients with Asthma: A Literature Review and Comments on Their Pathophysiology

Asthma is a common illness throughout the world that affects the respiratory system function, i.e., a system whose operational adequacy determines the respiratory gases exchange. It is therefore expected that acute severe asthma will be associated with respiratory acid-base disorders. In addition, the resulting hypoxemia along with the circulatory compromise due to heart–lung interactions can reduce tissue oxygenation, with a particular impact on respiratory muscles that have increased energy needs due to the increased workload. Thus, anaerobic metabolism may ensue, leading to lactic acidosis. Additionally, chronic hypocapnia in asthma can cause a compensatory drop in plasma bicarbonate concentration, resulting in non-anion gap acidosis. Indeed, studies have shown that in acute severe asthma, metabolic acid-base disorders may occur, i.e., high anion gap or non-anion gap metabolic acidosis. This review briefly presents studies that have investigated acid-base disorders in asthma, with comments on their underlying pathophysiology.

Development of a pediatric asthma predictive index for hospitalization

BACKGROUND

Variation in emergency department (ED) management for asthma exacerbation leads to disparities in care. Current asthma severity scores are insufficient to be used for hospitalization decisions.

OBJECTIVE

To develop and internally validate an asthma predictive index for hospitalization (APIH) to guide practitioners in their admission decision for children with asthma exacerbations.

METHODS

Data were collected from 12,066 children between 5 and 18 years old diagnosed with asthma exacerbation in the ED. Epidemiologic findings, number of inhaled corticosteroid canisters, short-acting β-blocker canisters, oral steroids, coexisting atopy, family history of atopy, insurance, and prior asthma ED visits or hospitalizations were compared between patients hospitalized and discharged. We used univariate analysis and multivariate analysis to determine the best predictor variables for hospitalization. Our study internally validated the prediction index to estimate future performance of the prediction rule.

RESULTS

The highest risk factors associated with asthma hospitalization from the ED are oxygen saturation less than 94%, respiratory rate greater than 31/min, history of pneumonia, and asthma ED visits in past 12 months. With a reduced predictive model that combined these risk factors, the odds ratio was 44.9 (95% CI, 32.8-61.4), which is extremely significant. Our C index of discrimination of 0.77 was similar to the validation C index of 0.78, which confirms a solid prediction model.

CONCLUSION

We have developed and internally validated a pediatric hospitalization prediction index for acute asthma exacerbation in the ED. Further studies are needed to externally validate the APIH before its implementation into clinical practice.

Critical Care Interventions for Asthmatic Patients Admitted From the Emergency Department to the Pediatric Intensive Care Unit

OBJECTIVES

The aim of this study was to assess the frequency and predictors of critical interventions in asthmatic patients admitted to the pediatric intensive care unit (PICU) at a tertiary-care pediatric hospital.

METHODS

We conducted a retrospective chart review of patients admitted from our emergency department (ED) to the PICU for treatment of status asthmaticus between January 1, 2008, and March 31, 2013. Patients with concomitant medical conditions and those who received a critical intervention, other than continuously aerosolized albuterol, in the ED before admission were excluded. Data collected included patient demographics, clinical characteristics including clinical asthma scores (CASs), hospital course, and adverse events.

RESULTS

A total of 384 patients were included in the analyses (mean age, 8.2 ± 4.5 years). Thirty-four patients (8.9%) received at least 1 critical intervention. No patients were intubated, had central venous catheter placement, and developed circulatory collapse or pneumothoraxes. Independent predictors associated with an increased likelihood of receiving a critical intervention included age above 8 years (odds ratio [OR], 4.3; 95% confidence interval [CI], 1.9-9.4), previous PICU admission (OR, 3.2; 95% CI, 1.5-6.6), altered mental status on ED arrival (OR, 4.5; 95% CI, 1.5-13.4), CAS on ED arrival of 5 or greater (OR, 3.4; 95% CI, 1.3-9.1), and CAS on PICU admission of 5 or greater (OR, 4.3; 95% CI, 1.8-10.2).

CONCLUSIONS

Patients admitted to the PICU for status asthmaticus infrequently require critical interventions if they have not been initiated in the ED. Patients with a CAS of less than 5 may be safely managed with continuously aerosolized albuterol on non-critical care units with low risk for clinical deterioration.

Characteristics and Outcomes of Children with Clinical History of Atopic Versus Non-atopic Asthma Admitted to a Tertiary Pediatric Intensive Care Unit

Background:

Children admitted to the Pediatric Intensive Care Unit (PICU) with status asthmaticus have variable clinical courses, and predicting their outcomes is challenging. Identifying characteristics in these patients that may require more intense intervention is important for clinical decision-making.

Objective:

This study sought to determine the characteristics and outcomes, specifically length of stay and mortality, of atopic versus non-atopic asthmatics admitted to a PICU with status asthmaticus.

Methods:

A retrospective study was conducted at a children’s hospital from November 1, 2008 to October 31, 2013. A total of 90 children admitted to the PICU were included in the analysis. Patients were divided into two groups based on the presence of specific historical data indicative of a clinical history of atopy. Children were considered to be atopic if they had a parental history of asthma, a personal history of eczema, or a combined history of wheezing (apart from colds) and allergic rhinitis (diagnosed by a medical provider). The median hospital Length Of Stay (LOS), PICU LOS, cardiopulmonary arrest, and mortality were compared between atopic and non-atopic asthma groups. Regression models were used to estimate the LOS stratified by atopic or non-atopic and by history of intubation in present hospitalization.

Results:

Median hospital LOS for atopic children was 5.9 days (IQR of 3.8-8.7) and 3.5 days (IQR of 2.2-5.5) for non-atopic asthmatics (z = 2.9, p = 0.0042). The median PICU LOS was 2.5 days (IQR 1.4-6.1) for atopic asthmatics and 1.6 days (IQR 1.1-2.4) for non-atopic asthmatics (z = 2.5, p = 0.0141). The median LOS was significantly higher for atopic intubated patients compared to non-atopic intubated patients (p=0.021). Although there was an increased tendency towards intubation in the atopic group, the difference was not significant. There was no significant difference in cardiopulmonary arrest or mortality.

Conclusion:

A clinical history of atopic asthma in children admitted to the PICU with status asthmaticus was associated with longer length of stays The longest LOS was observed when atopic patients required intubation.

Variable ventilation decreases airway responsiveness and improves ventilation efficiency in a rat model of asthma

The optimal ventilation strategy in patients receiving mechanical ventilation for severe asthma remains unclear. The effect of conventional ventilation (with constant tidal volume and respiratory rate) and variable ventilation (with the same average but variable tidal volume and respiratory rate) on peak airway pressure and airway exacerbation induced by increasing doses of methacholine was compared in a rat model of asthma. The respiratory rate and tidal volume data were obtained from a spontaneously breathing intact rat during immobility using a whole-body plethysmograph. Peak airway pressure and airway responsiveness to cumulative doses of methacholine were significantly affected by ventilation mode and they were lower in variable ventilation group than in the conventional ventilation group. Also, variable ventilation improved oxygen saturation compared to conventional ventilation. Our results indicate that variable ventilation decreases airway responsiveness and enhances ventilation efficiency in a rat model of asthma. We suggest further investigations on beneficial effects of variable ventilation strategy in mechanically ventilated patients with severe asthma.

Outcomes of Noninvasive and Invasive Ventilation in Patients Hospitalized with Asthma Exacerbation

RATIONALE

Little is known about the effectiveness of noninvasive ventilation for patients hospitalized with asthma exacerbation.

OBJECTIVES

To assess clinical outcomes of noninvasive (NIV) and invasive mechanical ventilation (IMV) and examine predictors for NIV use in patients hospitalized with asthma.

METHODS

This was a retrospective cohort study at 97 U.S. hospitals using an electronic medical record database. We developed a hierarchical regression model to identify factors associated with the choice of initial ventilation and used the Laboratory Acute Physiological Score to adjust for differences in the severity of illness. We assessed the outcomes of patients treated with initial NIV or IMV in a propensity-matched cohort.

MEASUREMENTS AND MAIN RESULTS

Among 13,930 subjects, 73% were women and 54% were white. The median age was 53 years. Overall, 1,254 patients (9%) required ventilatory support (NIV or IMV). NIV was the initial ventilation method for 556 patients (4.0%) and IMV for 668 (5.0%). Twenty-six patients (4.7% of patients treated with NIV) had to be intubated (NIV failure). The in-hospital mortality was 0.2, 2.3, 14.5, and 15.4%, and the median length of stay was 2.9, 4.1, 6.7, and 10.9 days among those not ventilated, ventilated with NIV, ventilated with IMV, and with NIV failure, respectively. Older patients were more likely to receive NIV (odds ratio, 1.06 per 5 yr; 95% confidence interval [CI], 1.01-1.11), whereas those with higher acuity (Laboratory Acute Physiological Score per 5 units: odds ratio, 0.85; 95% CI, 0.82-0.88) and those with concomitant pneumonia were less likely to receive NIV. In a propensity-matched sample, NIV was associated with a lower inpatient risk of dying (risk ratio, 0.12; 95% CI, 0.03-0.51) and shorter lengths of stay (4.3 d less; 95% CI, 2.9-5.8) than IMV.

CONCLUSIONS

Among patients hospitalized with asthma exacerbation and requiring ventilatory support (NIV or IMV), more than 40% received NIV. Although patients successfully treated with NIV appear to have better outcomes than those treated with IMV, the low rate of NIV failure suggests that NIV was being used selectively in a lower risk group. The increased risk of mortality for patients who fail NIV highlights the need for careful monitoring to avoid possible delay in intubation.

Extracorporeal membrane oxygenation for life-threatening asthma refractory to mechanical ventilation: analysis of the Extracorporeal Life Support Organization registry

Background

The use of extracorporeal membrane oxygenation (ECMO) in cases of near-fatal asthma (NFA) has increased, but the benefits and potential complications of this therapy have yet to be fully investigated.

Methods

Cases were extracted from the Extracorporeal Life Support Organization Registry between March 1992 and March 2016. All patients with a diagnosis of asthma (according to the International Classification of Diseases 9th edition), who also received ECMO, were extracted. Exclusion criteria included patients who underwent multiple courses of ECMO; those who received ECMO for cardiopulmonary resuscitation or cardiac dysfunction; and those with another primary diagnosis, such as sepsis. We analyzed survival to hospital discharge, complications, and clinical factors associated with in-hospital mortality, in patients with severe life-threatening NFA requiring ECMO support.

Results

In total 272 patients were included. The mean time spent on ECMO was 176.4 hours. Ventilator settings, including rate, fraction of inspired oxygen (FiO₂), peak inspiratory pressure (PIP), and mean airway pressure, significantly improved after ECMO initiation (rate (breaths/min), 19.0 vs. 11.3, p < 0.001; FiO₂ (%), 81.2 vs. 48.8, p < 0.001; PIP (cmH₂O), 38.2 vs. 25.0, p < 0.001; mean airway pressure (cmH₂O): 21.4 vs. 14.2, p < 0.001). In particular, driving pressure was significantly decreased after ECMO support (29.5 vs. 16.8 cmH₂O, p < 0.001). The weaning success rate was 86.7%, and the rate of survival to hospital discharge was 83.5%. The total complication rate was 65.1%, with hemorrhagic complications being the most common (28.3%). Other complications included renal (26.8%), cardiovascular (26.1%), mechanical (24.6%), metabolic (22.4%), infection (16.5%), neurologic (4.8%), and limb ischemia (2.6%). Of the hemorrhagic complications, cannulation site hemorrhage was the most common (13.6%). Using multivariate logistic regression analysis, it was found that hemorrhage was associated with increased in-hospital mortality (odds ratio, 2.97; 95% confidence interval, 1.07–8.24; p = 0.036). Hemorrhage-induced death occurred in four patients (1.5%). The most common reason for death was organ failure (37.8%).

Conclusions

ECMO can provide adequate gas exchange and prevent lung injury induced by mechanical ventilation, and may be an effective bridging strategy to avoid aggressive ventilation in refractory NFA. However, careful management is required to avoid complications.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1886-8) contains supplementary material, which is available to authorized users.

Mechanically Ventilating the Severe Asthmatic

The management of the critically ill patients with asthma can be rather challenging. Potentially devastating complications relating to this presentation include hypoxemia, worsening bronchospasm, pulmonary aspiration, tension pneumothorax, dynamic hyperinflation, hypotension, dysrhythmias, and seizures. In contrast to various other pathologies requiring mechanical ventilation, acute asthma is generally associated with better outcomes. This review serves as a practical guide to the physician managing patients with severe acute asthma requiring mechanical ventilation. In addition to specifics relating to endotracheal intubation, we also discuss the interpretation of ventilator graphics, the recommended mode of ventilation, dynamic hyperinflation, permissive hypercapnia, as well as the role of extracorporeal membrane oxygenation and noninvasive mechanical ventilation.

Sensing and responding to allergic response cytokines through a genetically encoded circuit

While constantly rising, the prevalence of allergies is globally one of the highest among chronic diseases. Current treatments of allergic diseases include the application of anti-histamines, immunotherapy, steroids, and anti-immunoglobulin E (IgE) antibodies. Here we report mammalian cells engineered with a synthetic signaling cascade able to monitor extracellular pathophysiological levels of interleukin 4 and interleukin 13, two main cytokines orchestrating allergic inflammation. Upon activation of transgenic cells by these cytokines, designed ankyrin repeat protein (DARPin) E2_79, a non-immunogenic protein binding human IgE, is secreted in a precisely controlled and reversible manner. Using human whole blood cell culturing, we demonstrate that the mammalian dual T helper 2 cytokine sensor produces sufficient levels of DARPin E2_79 to dampen histamine release in allergic subjects exposed to allergens. Hence, therapeutic gene networks monitoring disease-associated cytokines coupled with in situ production, secretion and systemic delivery of immunomodulatory biologics may foster advances in the treatment of allergies.

The standard treatment for an allergic response is anti-histamines, steroids and anti-IgE antibodies. Here the authors present a genetic circuit that senses IL-4 and IL-13 and responses with DARPin production to bind IgE.

Prognostic nomogram for inpatients with asthma exacerbation

Background

Asthma exacerbation may require a visit to the emergency room as well as hospitalization and can occasionally be fatal. However, there is limited information about the prognostic factors for asthma exacerbation requiring hospitalization, and no methods are available to predict an inpatient’s prognosis. We investigated the clinical features and factors affecting in-hospital mortality of patients with asthma exacerbation and generated a nomogram to predict in-hospital death using a national inpatient database in Japan.

Methods

We retrospectively collected data concerning hospitalization of adult patients with asthma exacerbation between July 2010 and March 2013 using the Japanese Diagnosis Procedure Combination database. We recorded patient characteristics and performed Cox proportional hazards regression analysis to assess the factors associated with all-cause in-hospital mortality. Then, we constructed a nomogram to predict in-hospital death.

Results

A total of 19,684 patients with asthma exacerbation were identified; their mean age was 58.8 years (standard deviation, 19.7 years) and median length of hospital stay was 8 days (interquartile range, 5–12 days). Among study patients, 118 died in the hospital (0.6%). Factors associated with higher in-hospital mortality included older age, male sex, reduced level of consciousness, pneumonia, and heart failure. A nomogram was generated to predict the in-hospital death based on the existence of seven variables at admission. The nomogram allowed us to estimate the probability of in-hospital death, and the calibration plot based on these results was well fitted to predict the in-hospital prognosis.

Conclusion

Our nomogram allows physicians to predict individual risk of in-hospital death in patients with asthma exacerbation.

Pneumologie

Die Pneumologie und Beatmungsmedizin gehört zur Basis der Intensivmedizin. Die Abklärung der Dyspnoe, das Management des Asthma bronchiale, der akuten COPD-Exazerbation und des akuten Lungenversagens (ARDS) bilden die Säulen dieses Kapitels. Im Rahmen der bettseitigen Abklärung der Dyspnoe gewinnt die Lungen- bzw. Thoraxsonographie zunehmend an Bedeutung.

Improving Guideline-Based Care of Acute Asthma in a Pediatric Emergency Department

BACKGROUND AND OBJECTIVE

Rapid repetitive administration of short-acting β-agonists (SABA) is the most effective means of reducing acute airflow obstruction in asthma. Little evidence exists that assesses process measures (ie, timeliness) and outcomes for asthma. We used quality improvement (QI) methods to improve emergency department care in accordance with national guidelines including timely SABA administration and use of asthma severity scores.

METHODS

The Model for Improvement was used and interventions were targeted at 4 key drivers: knowledge, engagement, decision support, and workflow enhancement. Time series analysis was performed and outcomes assessed on statistical process control charts.

RESULTS

Asthma severity scoring increased from 0% to >95% in triage and to >75% for repeat scores. Time to first SABA (T1) improved by 32.8 minutes (47%). T1 for low severity patients improved by 17.6 minutes (28%). T1 for high severity patients improved by 3.1 minutes to 18.1 minutes (15%). Time to third SABA (T3) improved by 30 minutes (24%). T3 for low severity patients improved by 42.5 minutes (29%) and T3 for high severity patients improved by 21 minutes (23%). Emergency department length of stay for low severity patients discharged to home improved by 29.3 minutes (15%). The number of asthma-related visits between 48-hour return hospitalizations increased from 114 to 261. The admission rate decreased 6.0%.

CONCLUSIONS

We implemented standardized asthma severity scoring with high rates of compliance, improved timely administration of β-agonist treatments, demonstrated early improvements in Emergency department length of stay, and reduced admission rates without increasing unplanned return admissions.

Low-flow veno-venous extracorporeal carbon dioxide removal in the management of severe status asthmatics: a case report

Status asthmaticus is a life-threatening condition that requires intensive care management. Most of these patients have severe hypercapnic acidosis that requires lung protective mechanical ventilation. A small proportion of these patients do not respond to conventional lung protective mechanical ventilation or pharmacotherapy. Such patients have an increased mortality and morbidity. Successful use of extracorporeal membrane oxygenation (ECMO) is reported in such patients. However, the use of ECMO is invasive with its associated morbidity and is limited to specialised centres. In this report, we report the use of a novel, minimally invasive, low-flow extracorporeal carbon dioxide removal device in management of severe hypercapnic acidosis in a patient with life threatening status asthmaticus.

Investigation of the anti‑asthmatic activity of Oridonin on a mouse model of asthma

Oridonin is an extract obtained from a traditional Chinese medicinal herb, Xihuangcao. Previous studies have demonstrated that Oridonin exerts various pharmaceutical effects, such as anti-tumor and immunosuppressive effects, as well as modulating cytokine balance. The present study identified that Oridonin could regulate the T_h1/T_h2 cytokine balance in mice. However, as the anti-asthmatic effect of Oridonin is currently unknown a mouse model of asthma was used in the present study. BALB/c mice were sensitized using ovalbumin (OVA), then the sensitized mice were treated with Oridonin prior to OVA challenge. The in vivo study indicated that Oridonin decreased the OVA-induced airway hyper-responsiveness significantly (P<0.05). In addition, the results indicated that in Oridonin-treated mice, the eosinophil number and total inflammatory cell number in bronchoalveolar lavage (BAL) fluid decreased significantly in the Oridonin group when compared with the control group. Further study indicated that Oridonin significantly decreased the level of inflammatory cytokines, which were induced by OVA, in BAL fluid. Histological studies were performed to evaluate the effect of Oridonin on eosinophilia and mucus in the airway, the results indicated that Oridonin significantly inhibited the eosinophilia and mucus production in the lungs. Therefore the present study demonstrated that Oridonin regulates T_h1/T_h2 balance in mice and exhibited anti-asthmatic effects in a mouse model of asthma. These findings indicate that Oridonin may serve as a potential therapeutic compound for the treatment of asthma in future.

Severe or life-threatening asthma exacerbation: patient heterogeneity identified by cluster analysis

BACKGROUND

Severe or life-threatening asthma exacerbation is one of the worst outcomes of asthma because of the risk of death. To date, few studies have explored the potential heterogeneity of this condition.

OBJECTIVES

To examine the clinical characteristics and heterogeneity of patients with severe or life-threatening asthma exacerbation.

METHODS

This was a multicentre, prospective study of patients with severe or life-threatening asthma exacerbation and pulse oxygen saturation < 90% who were admitted to 17 institutions across Japan. Cluster analysis was performed using variables from patient- and physician-orientated structured questionnaires.

RESULTS

Analysis of data from 175 patients with severe or life-threatening asthma exacerbation revealed five distinct clusters. Cluster 1 (n = 27) was younger-onset asthma with severe symptoms at baseline, including limitation of activities, a higher frequency of treatment with oral corticosteroids and short-acting beta-agonists, and a higher frequency of asthma hospitalizations in the past year. Cluster 2 (n = 35) was predominantly composed of elderly females, with the highest frequency of comorbid, chronic hyperplastic rhinosinusitis/nasal polyposis, and a long disease duration. Cluster 3 (n = 40) was allergic asthma without inhaled corticosteroid use at baseline. Patients in this cluster had a higher frequency of atopy, including allergic rhinitis and furred pet hypersensitivity, and a better prognosis during hospitalization compared with the other clusters. Cluster 4 (n = 34) was characterized by elderly males with concomitant chronic obstructive pulmonary disease (COPD). Although cluster 5 (n = 39) had very mild symptoms at baseline according to the patient questionnaires, 41% had previously been hospitalized for asthma.

CONCLUSIONS & CLINICAL RELEVANCE

This study demonstrated that significant heterogeneity exists among patients with severe or life-threatening asthma exacerbation. Differences were observed in the severity of asthma symptoms and use of inhaled corticosteroids at baseline, and the presence of comorbid COPD. These findings may contribute to a deeper understanding and better management of this patient population.

Pediatric acute asthma exacerbations: Evaluation and management from emergency department to intensive care unit

OBJECTIVE

The goal of this report is to review available modalities for assessing and managing acute asthma exacerbations in pediatric patients, including some that are not included in current expert panel guidelines. While it is not our purpose to provide a comprehensive review of the National Asthma Education and Prevention Program (NAEPP) guidelines, we review NAEPP-recommended treatments to provide the full range of treatments available for managing exacerbations with an emphasis on the continuum of care between the ER and ICU.

DATA SOURCES

We searched PubMed using the following search terms in different combinations: asthma, children, pediatric, exacerbation, epidemiology, pathophysiology, guidelines, treatment, management, oxygen, albuterol, β2-agonist, anticholinergic, theophylline, corticosteroid, magnesium, heliox, BiPAP, ventilation, mechanical ventilation, non-invasive mechanical ventilation and respiratory failure. We attempted to weigh the evidence using the hierarchy in which meta-analyses of randomized controlled trials (RCTs) provide the strongest evidence, followed by individual RCTs, followed by observational studies. We also reviewed the NAEPP and Global Initiative for Asthma expert panel guidelines.

RESULTS AND CONCLUSIONS

Asthma is the most common chronic disease of childhood, and acute exacerbations are a significant burden to patients and to public health. Optimal assessment and management of exacerbations, including appropriate escalation of interventions, are essential to minimize morbidity and prevent mortality. While inhaled albuterol and systemic corticosteroids are the mainstay of exacerbation management, escalation may include interventions discussed in this review.

Pulse Oximeter Plethysmograph Estimate of Pulsus Paradoxus as a Measure of Acute Asthma Exacerbation Severity and Response to Treatment

OBJECTIVES

Pulsus paradoxus is one of the few objective bedside measures of acute asthma exacerbation severity but is difficult to measure in tachypneic and tachycardic patients and in noisy clinical environments. Our primary objective was to examine whether pulse oximeter plethysmograph estimate of pulsus paradoxus (PEP) is associated with physiologic and symptom measures of acute exacerbation severity (airway resistance by impulse oscillometry [%IOS] and the Acute Asthma Intensity Research Score [AAIRS]). Secondary objectives were to validate the previous association of PEP with percent predicted forced expiratory volume in 1 second (%FEV1 ) and to examine associations of change of PEP with change of these outcomes after 2 hours of treatment.

METHODS

This was a secondary analysis of data from a prospective observational study of patients aged 5-17 years with acute asthma exacerbations. The predictor variable, PEP, was measured using a dedicated pulse oximeter and waveform analysis program. Outcome measures included the AAIRS, %IOS, and %FEV1 at baseline and after 2 hours of treatment. We examined associations of PEP with %IOS and the AAIRS at baseline using multiple linear regression models adjusted for age, sex, and race. As secondary analyses we similarly examined the association of PEP with %FEV1 at baseline and change of PEP with change of %IOS, the AAIRS, and %FEV1 after 2 hours of treatment using multiple linear regression models adjusted for the baseline value of the outcome measure and the AAIRS.

RESULTS

Among 684 participants (61% males; 61% African American) there were associations of baseline PEP with %IOS, the AAIRS, and %FEV1 (p < 0.001). Change of PEP after 2 hours of treatment was associated with change of %FEV1 (p < 0.001) and change of the AAIRS (p = 0.01) but not with change of %IOS (p = 0.60).

CONCLUSIONS

PEP demonstrates criterion validity in predicting baseline %IOS, the AAIRS, and %FEV1 , and responsiveness to change of the AAIRS and %FEV1 . Data contained in the oximeter plethysmograph waveform might be utilized as a continuous, objective measure of acute asthma exacerbation severity and real-time response to treatment.

Mechanical ventilation for severe asthma

Acute exacerbations of asthma can lead to respiratory failure requiring ventilatory assistance. Noninvasive ventilation may prevent the need for endotracheal intubation in selected patients. For patients who are intubated and undergo mechanical ventilation, a strategy that prioritizes avoidance of ventilator-related complications over correction of hypercapnia was first proposed 30 years ago and has become the preferred approach. Excessive pulmonary hyperinflation is a major cause of hypotension and barotrauma. An appreciation of the key determinants of hyperinflation is essential to rational ventilator management. Standard therapy for patients with asthma undergoing mechanical ventilation consists of inhaled bronchodilators, corticosteroids, and drugs used to facilitate controlled hypoventilation. Nonconventional interventions such as heliox, general anesthesia, bronchoscopy, and extracorporeal life support have also been advocated for patients with fulminant asthma but are rarely necessary. Immediate mortality for patients who are mechanically ventilated for acute severe asthma is very low and is often associated with out-of-hospital cardiorespiratory arrest before intubation. However, patients who have been intubated for severe asthma are at increased risk for death from subsequent exacerbations and must be managed accordingly in the outpatient setting.