Asthma diagnosis and management

Early Prediction of Intensive Care Admission in Emergency Department Patients With Asthma

BACKGROUND

Emergency physicians must choose whether patients with asthma are admitted to a hospital ward or a higher level of care, such as an intermediate care unit (IMC) or intensive care unit (ICU).

OBJECTIVE

This study aimed to determine which variables, available early during emergency department (ED) visits, are associated with IMC/ICU admission.

METHODS

In this retrospective chart review (records from 2015-2018), two trained abstractors, blinded to study hypothesis, abstracted data on predictor variables and disposition (ward vs. IMC/ICU). Predictor variables were defined explicitly and abstracted from the periods of ED arrival and after treatment with 7.5 mg nebulized albuterol. Distress was defined as tripod positioning or speaking in broken sentences. "Arrival" and "after treatment" scoring systems were derived based on adjusted odds ratios (aOR) for predictor variables. We performed analyses using SAS^Ⓡ, version 9.4 (SAS Institute).

RESULTS

Among 273 patients, 105 required admission to an IMC/ICU. At presentation, distress (aOR 2.1, 95% confidence interval [CI] 1.1-3.9), room air SpO₂ ≥95% (aOR 0.29, 95% CI 0.14-0.62), respiratory rate > 20 breaths/min (aOR 1.9, 95% CI 1.0-3.3), and retractions (aOR 1.9, 95% CI 1.1-3.3) were associated with IMC/ICU admission. After initial bronchodilator therapy, heart rate > 120 beats/min (aOR 7.1, 95% CI 2.0-25), room air SpO₂ ≥ 95% (aOR 0.15, 95% CI 0.07-0.34), and noninvasive ventilation (aOR 6.5, 95% CI 2.5-17) were associated with IMC/ICU admission. Both scoring systems stratified risk of IMC/ICU admission into low-risk (9-10%) and high-risk (70-100%) groups.

CONCLUSIONS

Combinations of predictor variables, available early in a patient's stay, stratify risk of admission to an IMC/ICU bed.

Emergency Department Asthma "Spacing Trials": Institutional Variability and Time Cost

BACKGROUND

Some admitting physicians request a medication-free interval ("spacing trial") in the emergency department (ED) to determine whether a patient with an acute exacerbation of asthma can be safely admitted to a hospital ward bed, where bronchodilators are only available every 4 h.

OBJECTIVE

Our objectives were to estimate the frequency of ED spacing trials in different hospitals and their associated time cost.

METHODS

This multicenter retrospective cohort study examined patients admitted for asthma from 2015 to 2018. We included all university records and a random sample of records from two community hospitals in the same urban area. Two team members abstracted data from each record using recommended methods, with group consensus to resolve differences. Proportion confidence intervals were calculated using normal binomial approximation. We calculated mean differences in ED stay associated with spacing trials, using multivariable linear regression to adjust for age, hospital type, history of intubation, initial pulse, initial respiratory rate, initial signs of distress.

RESULTS

We collected data from 274 patients in the university hospital, and 71 and 70 cases from the community hospitals. An explicit spacing trial was noted in 52 of 274 (19%) university hospital records vs. 3 of 141 (2%) community hospital records, with a difference of 17% (95% confidence interval [CI] 11-23%). Delayed patient decompensation occurred in 3%, with no difference between hospitals. Spacing trials were associated with an adjusted mean of 159 min (95% CI 102-217 min) increase in ED stay.

CONCLUSIONS

The practice of spacing varies widely between hospitals and is associated with substantial delay without an apparent benefit.

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.

Near-fatal asthma in the elderly

Asthma affects the elderly as often as other age groups; however, it more often becomes fatal in the elderly. Unfortunately, asthma is often unmanaged or underdiagnosed in the older population. It is important for health care providers to recognize risk factors in the elderly and properly treat them before asthma becomes fatal. This article describes near-fatal asthma and identifies risk factors specifically for the elderly. Symptoms of asthma are reviewed as well as assessments and diagnostic tests to identify asthma severity and complications. Proper management needs to be urgently initiated to prevent worsening respiratory distress; this includes fast-acting drug treatments appropriate for elderly patients. Decompensated acute respiratory failure, secondary to severe asthma, requires the skills of an experienced anesthesiologist because these patients may rapidly deteriorate during induction and intubation. Ventilator management must include strategies to prevent worsening hyperinflation of the lungs. Elderly asthma patients have a higher mortality risk related to ventilator complications and other comorbidities.

Management of Acute Exacerbation of Asthma and Chronic Obstructive Pulmonary Disease in the Emergency Department

Acute asthma and chronic obstructive pulmonary disease (COPD) exacerbations are the most common respiratory diseases requiring emergent medical evaluation and treatment. Asthma and COPD are chronic, debilitating disease processes that have been differentiated traditionally by the presence or absence of reversible airflow obstruction. Asthma and COPD exacerbations impose an enormous economic burden on the US health care budget. In daily clinical practice, it is difficult to differentiate these 2 obstructive processes based on their symptoms, and on their nearly identical acute treatment strategies; major differences are important when discussing anatomic sites involved, long-term prognosis, and the nature of inflammatory markers.

Pharmacotherapy of critical asthma syndrome: current and emerging therapies

The critical asthma syndrome (CAS) encompasses the most severe, persistent, refractory asthma patients for the clinician to manage. Personalized pharmacotherapy is necessary to prevent the next acute severe asthma exacerbation, not just the control of symptoms. The 2007 National Asthma Education and Prevention Program Expert Panel 3 provides guidelines for the treatment of uncontrolled asthma. The patient's response to recommended pharmacotherapy is highly variable which risks poor asthma control leading to frequent exacerbations that can deteriorate into CAS. Controlling asthma symptoms and preventing acute exacerbations may be two separate clinical activities with their own unique demands. Clinicians must be prepared to use the entire spectrum of asthma medications available but must concurrently be aware of potential drug toxicities some of which can paradoxically worsen asthma control. Medications normally prescribed for COPD can potentially be useful in the CAS patient, particularly those with asthma-COPD overlap syndrome. Immunomodulation with drugs like omalizumab in IgE-mediated asthma syndromes is one important approach. New and emerging drugs address unique aspects of airway inflammation and biology but at a significant financial cost. The pharmacology and toxicities of the agents that may be used in the treatment of CAS to control asthma symptoms and prevent severe exacerbations are reviewed.

The acute management of asthma

Patients presenting to the emergency department (ED) or clinic with acute exacerbation of asthma (AEA) can be very challenging varying in both severity and response to therapy. High-dose, frequent or continuous nebulized short-acting beta2 agonist (SABA) therapy that can be combined with a short-acting muscarinic antagonist (SAMA) is the backbone of treatment. When patients do not rapidly clinically respond to SABA/SAMA inhalation, the early use of oral or parenteral corticosteroids should be considered and has been shown to impact the immediate need for ICU admission or even the need for hospital admission. Adjunctive therapies such as the use of intravenous magnesium and helium/oxygen combination gas for inhalation and for driving a nebulizer to deliver a SABA and or SAMA should be considered and are best used early in the treatment plan if they are likely to impact the patients' clinical course. The use of other agents such as theophylline, leukotriene modifiers, inhaled corticosteroids, long-acting beta2 agonist, and long-acting muscarinic antagonist currently does not play a major role in the immediate treatment of AEA in the clinic or the ED but is an important therapeutic option for physicians to be aware of and to consider initiating at the time of discharge from clinic, hospital, or ED to reduce later clinical worsening and readmission to the ED and hospital. A comprehensive summary is provided of the currently available respiratory pharmaceuticals approved for asthma and other airway syndromes. Clinicians must be prepared to use the entire spectrum of medications available for the treatment of acute asthma exacerbations and the agents that should be initiated to prevent worsening or additional exacerbations. They need to be familiar with the major potential drug toxicities associated with their use.

Molecular imaging of heparan sulfate expression with radiolabeled recombinant eosinophil cationic protein predicts allergic lung inflammation in a mouse model for asthma

Heparan sulfate proteoglycans (HSPGs) are glycoproteins consisting of a core protein to which linear heparan sulfate (HS) side chains are covalently attached. These HS side chains mediate a variety of biologic functions involved in inflammation. Radionuclide imaging of HS side chains in tissues with inflammation may be used for the stratification of patients who would most likely benefit from HSPG-targeting therapy. The goal of this study was to evaluate the feasibility of in vivo radionuclide imaging of HS side chain expression in a mouse model of asthma using the recombinant eosinophil cationic protein (rECP).

METHODS

rECP was radioiodinated with (125)I or (123)I using the Chloramine-T method. The 50% inhibitory concentration value for (125)I-labeled rECP was determined in a competitive cell-binding assay using Beas-2B cells. The binding of radiolabeled rECP to HS side chains was evaluated both in vitro and in vivo. The biodistribution of radiolabeled rECP was assessed in asthma mice or in control mice using SPECT imaging, ex vivo biodistribution measurements, and microautoradiography.

RESULTS

The 50% inhibitory concentration value for (125)I-rECP was 7.4 ± 0.1 nM. The loss of HS side chains substantially inhibited the cellular and tissue uptake of (125)I- or (123)I-rECP, indicating that HS side chains of HSPGs are required for (125)I- or (123)I-eosinophil cationic protein binding and uptake both in vitro and in vivo. SPECT imaging demonstrated an appreciably higher accumulation of radioactivity in the lungs of asthma mice than in those of control mice. Ex vivo biodistribution studies also confirmed that there was at least a 4-fold increase in the lung-to-muscle ratio of asthma mice, compared with control mice. The accumulation of radiolabeled rECP was linearly correlated with leukocyte infiltration.

CONCLUSION

This study illustrates the feasibility of using radiolabeled rECP for the visualization of HS side chains of HSPGs and the evaluation of allergic lung inflammation in living subjects. Our data indicate that radiolabeled rECP is a novel imaging agent for HS side chains of HSPGs in predicting allergic lung inflammation in living mice.