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In this section, recommendations are presented for the assessment and treatment of exacerbations in the home, ED, and hospital. See section 1, "Overall Methods Used To Develop This Report," for literature search strategy and tally of results for this EPR—3: Full Report 2007 section on "Managing Exacerbations of Asthma." Four Evidence Tables were prepared: 17, Increasing the Dose of Inhaled Corticosteroids; 18, IV Aminophylline; 19, Magnesium Sulfate; and 20, Heliox. Asthma exacerbations are acute or subacute episodes of progressively worsening shortness of breath, cough, wheezing, and chest tightness—or some combination of these symptoms.

Exacerbations are characterized by decreases in expiratory airflow that can be documented and quantified by simple measurement of lung function (spirometry or PEF). These objective measures more reliably indicate the severity of an exacerbation than does the severity of symptoms. In general, milder exacerbations may be managed "at home" (i.e., outside the health care system), whereas more serious exacerbations may require an unscheduled ("urgent") office visit, an ED visit, or a hospital admission (see ). The most severe exacerbations require admission to the intensive care unit (ICU) for optimal monitoring and treatment. Although assessment and treatment of young children pose unique challenges, the management of asthma exacerbations in older children and adults is fairly similar.

Individuals who have their asthma under control with ICSs will decrease the risk of exacerbations. Nonetheless, patients in good control can still be vulnerable to exacerbations, for example, when they have clinical respiratory infections (). Diurnal variability, a marker of poor control, may not change during an exacerbation; thus, clinicians may fail to detect important changes in lung function. The striking difference between PEF variations during exacerbations, as compared with during poor asthma control, suggests differences in beta 2 -adrenoceptor function between these conditions. The decrease in responsiveness to SABA during some severe exacerbations may help to explain the benefit of ipratropium bromide and other "alternative" approaches to bronchodilation.

Based on the scientific literature and the opinion of the Expert Panel, the Panel recommends that clinicians consider the following general principles and goals for managing asthma exacerbations: early treatment, special attention to patients who are at high risk of asthma-related death, and special attention to infants (). ▪ Early treatment is the best strategy for management of asthma exacerbations. Important elements of early treatment include: — A written asthma action plan (See "Component 2: Education for a Partnership in Asthma Care," figure 3–10 ) to guide patient self-management, especially for patients who have moderate or severe persistent asthma and any patient who has a history of severe exacerbations.

— Recognition of early indicators of an exacerbation, including worsening PEF. Patients are instructed to recognize early signs and symptoms of worsening asthma and to use quick-relief medications if symptoms occur or if PEF drops below 80 percent predicted or personal best. If PEF is 50–79 percent, the patient should carefully monitor the response to quick-relief medication and, based on the response, consider contacting a clinician. If PEF is below 50 percent, immediate medical care is usually required (See sample written asthma action plans, figures 3–10a , b , and c .). In the urgent or emergency care setting, different parameters are used to classify the severity of the exacerbation and determine the clinical course; see . The Panel chose cut points of 40 percent and 70 percent of predicted (or personal best) because 40 percent denotes an exacerbation severity below which several adjunct therapies are effective, and 70 percent is a posttreatment goal for discharge from the ED or hospital. — Appropriate intensification of therapy, often including a short course of systemic corticosteroids. — Removal of or withdrawal from allergens or precipitating irritants in the environment that may be contributing to the exacerbation.

— Prompt communication between patient and clinician about any serious deterioration in symptoms or peak flow, decreased responsiveness to SABA treatment, or decreased duration of effect. ▪ Patients who are at high risk for asthma-related death require special attention— particularly intensive education, monitoring, and care. Such patients should be counseled to seek medical care early during an exacerbation and instructed about the availability of ambulance services. Such patients include those who have identifiable risk factors (See .). ▪ Infants require special attention, especially due to their greater risk for respiratory failure (See .).

The principal goals and Expert Panel recommendations for treating asthma exacerbations are: ▪ Correction of significant hypoxemia, in moderate or severe exacerbations, by administering supplemental oxygen. In rare instances, alveolar hypoventilation requires mechanically assisted ventilation (). ▪ Rapid reversal of airflow obstruction (Evidence A). This is best achieved by: — Repetitive or continuous administration of a SABA (; ; ; ) — Early in the course of treatment, administration of systemic corticosteroids to patients who have moderate or severe exacerbations or to patients who fail to respond promptly and completely to SABA treatment (; ; ). ▪ Reduction of the likelihood of relapse of the exacerbation or future recurrence of severe airflow obstruction by intensifying therapy (Evidence A). Often, a short course of systemic corticosteroids is useful (; ).

▪ Achieving these goals requires careful assessment and monitoring (Evidence B). The ability to predict care requirements, including the need for hospitalization, is based on repeated clinical assessments. In adults, repeated measurements of lung function are often helpful. The specific measurements chosen for monitoring will depend on the age of the patient and the available resources. — Children. In children, no single assessment tool appears to be the best for assessing the severity of the exacerbation or for monitoring response to treatment and predicting hospital admission (; ,; ; ; ; ; ). ♦ Serial measurements of lung function. Lung function measures using either FEV 1 or PEF may be useful for many children 5 years of age or older. However, neither maneuver may be obtainable during an exacerbation. found that only 65 percent of children 5–18 years of age could complete either measurement during an acute exacerbation, and for children less than 5 years old, the maneuvers were almost impossible.

♦ Pulse oximetry. An initial pulse oximetry in infants and young children might be useful for assessing exacerbation severity but not for predicting the need for hospital admission (; ; ; ; ). However, a repeat pulse oximetry of <92–94 percent (sea level) at 1 hour was a better predictor of need for hospitalization, and it may be useful to move those infants and children into the hospital and out of the ED at that time (; ; ).

♦ Signs and symptoms scores. Several severity assessment scores have been developed and tested in children to help predict the need for hospitalization early in the course of ED treatment (; ; ; ). None is 100 percent predictive, but the assessments may help to determine who should be transferred from the ED to the hospital after an initial 1- to 2-hour period of treatment, leaving the ED resources for those who are more likely to be able to go home after extended ED treatment and observation. These assessment scores combine physician- or nurse-observed signs and symptoms—such as shortness of breath, chest tightness, ability to speak in sentences or phrases, emotional impact, and alertness—plus respiratory rate, use of intercostals muscles, timing and volume of wheezes as well as pulse oximetry and, if available and feasible, FEV 1 or PEF. One score () has added a parental assessment of asthma control over the past several months and history of previous exacerbations requiring ED or hospital management. Others add the continuing need for hourly SABA 4 or more hours after the administration of oral systemic corticosteroids.

A recent study suggests that most children who require hospitalization can be identified by a repeat assessment 1 hour after initial treatment (). After 1 hour, those children who continue to meet the criteria for a severe exacerbation have >86 percent chance of requiring hospitalization; those who meet the criteria for moderate exacerbation at 1 hour have an 84 percent chance of requiring hospitalization; and those whose assessment has remained the same or dropped to the mild level have only an 18 percent chance of requiring hospitalization. These severity assessment studies highlight the importance of regular, multifaceted assessments and close observation of children and adolescents who present to the office or ED with acute asthma exacerbations (See and .).

— Adults ♦ Serial measurements of lung function. FEV 1 or PEF appear to be more useful in adults for categorizing the severity of the exacerbation and the response to treatment and in predicting the need for hospitalization. Repeated measurements of PEF or FEV 1 in adults at 1 hour and beyond are useful as isolated assessments in determining who will require hospitalization and who is likely to have sufficient response to treatment to allow continued ED care. Indeed, repeated FEV 1 or PEF measures at presentation to the ED and 1 hour after treatment were the strongest single predictor of hospitalization among adults who present to the ED with an asthma exacerbation (; ; ; ; ). When FEV 1 is unavailable, PEF may be substituted. Although percentage of personal best PEF or FEV 1 would be ideal for patient management, individuals may report erroneous values (). Interpretation of percentage of predicted values is complicated by differences between formulas in the literature (). Regardless of the calculation chosen, for severe exacerbations with obvious airway compromise and even cyanosis, the immediate testing of FEV 1 or PEF provides little additional information, and the maneuver can be very uncomfortable for acutely ill patients ().

♦ Pulse oximetry is indicated for patients who are in severe distress, have FEV 1 or PEF <40 percent of predicted, or are unable to perform lung function measures. ♦ Signs and symptoms scores. As in children, some multifaceted prediction models have been tested and shown to improve slightly on the accuracy of the FEV 1 or PEF alone (; and ; ; ). used multiple signs and symptoms to determine the level of the severity of the exacerbation at 1 hour after the first ED treatment as well as the duration of symptoms (either <6 hours or ≥ 6 hours) before the patient's arrival at the ED () and found the additional measures improved the prediction rate by 5–10 percent. (See paragraph above related to the same model used in children.) For EDs that have limited resources, the presence of drowsiness in a patient is a useful predictor of impending respiratory failure and reason to consider immediate transfer of the patient to a facility equipped to deal with ventilatory support (). As in the case with children, the ability to predict future care requirements is based on repeated clinical assessments, and, in adults, repeated measures of FEV 1 or PEF (See .).

Beginning treatment at home avoids treatment delays, prevents exacerbations from becoming severe, and also adds to patients' sense of control over their asthma. The degree of care provided in the home depends on the patients' (or parents') abilities and experience and on the availability of emergency care. General guidelines for managing exacerbations at home are presented in . The Expert Panel recommends preparing patients for home management of asthma exacerbations by taking the following actions (Also see "Component 1: Measures of Asthma Assessment and Monitoring," and "Component 2: Education for a Partnership in Asthma Care."). ▪ Teach all patients how to monitor signs and symptoms so they can recognize early signs of deterioration and take appropriate action (Evidence A) (See "Component 2: Education for a Partnership in Asthma Care."), particularly since many fatal asthma exacerbations occur out of hospital (). Patients should be taught how to adjust their medications early in an exacerbation () and when to call for further help or seek medical care. Patients should seek medical help earlier if the exacerbation is severe; treatment does not give rapid, sustained improvement; or there is further deterioration.

▪ Consider teaching how to monitor lung function, by using PEF to facilitate early and accurate assessment of exacerbations and response to treatment, to patients and parents of children who have moderate or severe persistent asthma or a history of severe exacerbations (Evidence B) and patients who are poor perceivers of airflow obstruction (Evidence D). Signs and symptoms imperfectly mirror airflow obstruction; therefore, other tools may be required, especially in the group of people who are "poor perceivers" and have failed to recognize previous exacerbations or symptom deteriorations early (; ). Exacerbations recognized and treated within 6 hours of onset may be less likely to result in hospitalizations (). When using PEF expressed only as a percent of personal best, the impact of any irreversible airflow obstruction must be considered. For example, in a person whose personal best is only 160 L/min, a drop to 60 percent of personal best represents life-threatening airflow obstruction.

▪ Provide to all patients a written asthma action plan that includes daily management and recognizing and handling worsening asthma, including self-adjustment of medications in response to acute symptoms or changes in PEF measures in the event of an exacerbation. A written asthma action plan is particularly recommended for patients who have moderate or severe persistent asthma and any patient who has a history of severe exacerbations or poorly controlled asthma (Evidence B). A peak-flow-based plan may be particularly useful for patients who have difficulty perceiving airflow obstruction and worsening asthma (Evidence D). See component 2—Education for a Partnership in Asthma Care, figure 3–10 for a sample plan. Children should also receive a plan appropriate to the school setting (See "Component 2: Education for a Partnership in Asthma Care," figure 3–16 .). The plan should direct the patient to adjust medications in response to particular signs, symptoms, and peak flow measurements and should state when to seek medical help. Review the plan with the patient and family. The clinician should tailor the plan to the needs of individual patients. Patients who are at risk for asthma death (See .) require especially close monitoring.

▪ Advise patients who have moderate or severe persistent asthma or a history of severe exacerbations to have the medication (e.g., corticosteroid tablets or liquid) and equipment (e.g., peak flow meter, compressor-driven nebulizer for young children) for treating exacerbations at home (Evidence A). The Expert Panel recommends the following pharmacologic therapy for home management of exacerbations: ▪ Increase the frequency of SABA treatment (Evidence A). ▪ Initiate oral systemic corticosteroid treatment under certain circumstances (Evidence A). Short courses or "bursts" of oral corticosteroids reduce the duration and may prevent hospitalizations and relapse following an acute exacerbation (; ; ). The Expert Panel recommends that, unless working from a defined action plan, individuals contact their health care provider before instituting a course of oral systemic corticosteroids (Evidence D).

▪ Doubling the ICS dose is not sufficient (Evidence B) (See Evidence Table 17, Increasing the Dose of Inhaled Corticosteroids.). Doubling the dose of an ICS in those patients already receiving ICS therapy has not been effective at reducing the severity or preventing progression of exacerbations (; ; ; ). However, higher doses of an ICS may be effective in the ED management of acute asthma exacerbations. For example, preliminary evidence indicates that quadrupling the dose of an ICS for 7 days, starting at the first appearance of worsening symptoms, may prevent exacerbations requiring oral systemic corticosteroids (). For patients who experience substantial adverse effects with oral systemic corticosteroids (e.g., mood changes, worsening diabetes), high-dose ICS may be an effective alternative for mild to moderate exacerbations.

▪ Continue more intensive treatment for several days (). Recovery from an exacerbation varies, with symptom relief in 1–2 days for moderate exacerbations but in 3 or more days for severe exacerbations (See .). For many persons, the improvement is quite gradual. Even when symptoms have resolved, evidence of inflammation in the airways may continue for up to 2–3 weeks (). In managing an exacerbation at home, patients' greater use of SABA should be continued until symptoms and PEF are stable. That said, patients should seek medical care rather than rely on bronchodilator therapy in excessive doses or for prolonged periods (e.g., >12 puffs/day for more than 24 hours). The Expert Panel does not recommend the following home management techniques, because no studies have demonstrated effectiveness, and it is the opinion of the Panel that these techniques may delay patients from obtaining necessary care (). ▪ Drinking large volumes of liquids or breathing warm, moist air (e.g., the mist from a hot shower). ▪ Using over-the-counter products such as antihistamines or cold remedies. Over-the-counter bronchodilators may provide transient bronchodilation, but their use should not delay seeking medical care.

The Expert Panel also notes that although pursed-lip and other forms of controlled breathing may help to maintain calm during respiratory distress, these methods do not bring about improvement in lung function.

The Expert Panel recommends that emergency medical services (EMS) providers administer supplemental oxygen and SABA to patients who have signs or symptoms of an asthma exacerbation (Evidence A). Prehospital administration of SABA reduces airflow obstruction and relieves symptoms (; ; ). Ideally, all EMS providers would receive a standing order to allow them to provide albuterol to their patients who have asthma exacerbations. Such an order would be consistent with their legally authorized scope of practice and local medical direction (). In such settings, EMS providers should have available a nebulizer and/or an inhaler plus spacer/holding chamber for SABA administration (see for dosages). If these are not available, subcutaneous epinephrine or terbutaline should be given for severe exacerbations (See .) (; ).

When initiating bronchodilatory use, EMS personnel should not delay transport of the patient to the appropriate medical facility. The treatment, however, may be repeated while transporting the patient. Prolonged transport times (e.g., in a rural setting or during transport on congested urban streets) may necessitate multiple inhaled SABA treatments before arrival at the medical facility (). Patients should receive a maximum of three inhaled SABA treatments in the first hour, and then one per hour thereafter (consistent with practice in the ED setting; see and ). After each treatment, EMS personnel should reassess and record the patient's vital signs and lung sounds. Ambulance services should develop prehospital protocols for the treatment of acute asthma in children and adults (; ). With medical oversight, these protocols can allow for more frequent administration of several established acute asthma treatments, such as ipratropium bromide and oral systemic corticosteroids (). The latter medication is particularly important during prolonged transport times. All prehospital providers should receive training in how to respond to the clinical signs and symptoms of severe airway obstruction and imminent respiratory failure ().

Severe exacerbations of asthma are potentially life threatening. Care must be prompt. Effective initial therapies (i.e., SABA and the means of giving it by aerosol and a source of supplemental oxygen) should be available in a physician's office. Serious exacerbations, however, require close observation for deterioration, frequent treatment, and repetitive measurement of lung function. Therefore, most severe exacerbations of asthma require prompt transfer to an ED for more complete therapy (; ). Despite appropriate therapy, approximately 10–25 percent of ED patients who have acute asthma will require hospitalization (; ). In the hospital, multidisciplinary (e.g., nursing and respiratory care) clinical pathways for asthma appear to be effective in reducing hospital length-of-stay and inpatient costs, but they have less clear impact on clinical outcomes (). An overview of the treatment strategies in EDs and hospitals is presented in and detailed below.

The Expert Panel recommends the following activities to assess exacerbations: ▪ All clinicians treating patients who have asthma should be prepared to treat an asthma exacerbation, be familiar with the symptoms and signs of severe and life-threatening exacerbations (, , and ), and have procedures for facilitating immediate patient transfer to an emergency care facility (). ▪ Initial assessment should include a brief history, brief physical examination, and, for most patients, objective measures of lung function. Initial laboratory studies may be helpful, but they are not required for most patients, and they should not delay initiation of asthma treatment (). ▪ In the ED, all patients presenting with a reported asthma exacerbation must be evaluated and triaged immediately, based on at least vital signs and an overall physical assessment (e.g., ability to breathe well enough to talk). Treatment should begin immediately following recognition of a moderate, severe, or life-threatening exacerbation by assessment of symptoms, signs, or, when possible, lung function (). ▪ While treatment is given, obtain a brief, focused history and physical examination pertinent to the exacerbation (See .). Take a more detailed history and complete physical examination and perform laboratory studies only after initial therapy has been completed (Evidence D).

▪ The objectives of functional assessment (the frequency and number of measurements) will depend on the severity of the exacerbation and the response to treatment (See .) are to: — Obtain objective lung function measurements. ♦ FEV 1 or PEF values provide important information about the level of airflow obstruction both initially and in response to treatment. Because low PEF values cannot distinguish between poor effort, restrictive ventilatory disorders (e.g., neuromuscular weakness, pneumonia), and obstructive ventilatory disorders (e.g., asthma), FEV 1 measurements are preferable if they are readily available (Evidence D). ♦ In the initial assessment of a life-threatening asthma exacerbation, FEV 1 or PEF are not indicated (Evidence D). ♦ Very severe exacerbations may preclude performance of a maximal expiratory maneuver and, in such cases, the clinical presentation should suffice for clinical assessment and prompt initiation of therapy (Evidence D). ♦ In less severe exacerbations, in the office or ED, FEV 1 or PEF should be obtained on arrival and 30–60 minutes after initial treatment (Evidence B). ♦ In the hospital, FEV 1 or PEF should be measured on admission and 15–20 minutes after bronchodilator therapy during the acute phase and at least daily thereafter until discharge (Evidence C).

♦ Any FEV 1 or PEF value <25 percent of predicted that improves by <10 percent after treatment or values that fluctuate widely are potential indications for ICU admission and close monitoring for respiratory failure (Evidence C). ♦ Flow-volume loops should be obtained to distinguish between upper and lower airway obstruction in patients who have atypical asthma symptoms (e.g., dysphonia) or findings on exam (e.g., stridor) or if response to therapy is inadequate (Evidence D). — Monitor oxygen saturation. ♦ Pulse oximetry is indicated for children unable to perform FEV 1 or PEF or for any patient who is in severe distress or has an FEV 1 or PEF <40 percent of predicted to assess the adequacy of arterial oxygen saturation (SaO 2 ) (; ; ; ) (Evidence C). ♦ Serial pulse oximetry measurements can be useful to assess both the severity of the exacerbation and improvement with treatment (Evidence B). By contrast, a single pulse oximetry value on admission is of relatively little value for predicting hospital admission (; ; ). ▪ Objectives of the brief history are to determine (): — Time of onset and any potential causes of current exacerbation. — Severity of symptoms, especially compared with previous exacerbations, and response to any treatment given before admission to ED. — All current medications and time of last dose, especially of asthma medications.

— Estimate of number of previous unscheduled office visits, ED visits, and hospitalizations for asthma, particularly within the past year. — Any prior episodes of respiratory insufficiency due to asthma (loss of consciousness or intubation and mechanical ventilation). — Other potentially complicating illness, especially other pulmonary or cardiac disease or diseases that may be aggravated by systemic corticosteroid therapy (such as diabetes, peptic ulcer, hypertension, and psychosis). ▪ Objectives of the initial brief physical examination are to (): — Assess the severity of the exacerbation, as indicated by the findings listed in . — Assess overall patient status, including level of alertness, fluid status, and presence of cyanosis, respiratory distress, and wheezing. Wheezing can be an unreliable indicator of obstruction; in rare cases, extremely severe obstruction may be accompanied by a "silent chest" (). — Identify possible complications (e.g., pneumonia, pneumothorax, or pneumomediastinum); although rare, these will influence management of the asthma exacerbation.

— Rule out upper airway obstruction. Both intrathoracic and extrathoracic central airway obstruction can cause severe dyspnea and may be diagnosed as asthma. ♦ Causes include upper airway foreign bodies, epiglottitis, organic diseases of the larynx, vocal cord dysfunction, and extrinsic and intrinsic tracheal narrowing (See "Component 1: Measures of Asthma Assessment and Monitoring."). ♦ Clues to the presence of alternative reasons for dyspnea include dysphonia, inspiratory stridor, monophonic wheezing loudest over the central airway, normal values for PO 2 , and unexpectedly complete resolution of airflow obstruction with intubation. ♦ When upper airway obstruction is suspected, further evaluation is indicated by flow-volume curves and by referral for laryngoscopy (See "Component 1: Measures of Asthma Assessment and Monitoring.").

▪ Laboratory studies. Most patients who have an asthma exacerbation do not require any initial laboratory studies. If laboratory studies are ordered, they must not delay initiation of asthma treatment (). The most important objective of laboratory studies is detection of actual or impending respiratory failure. Other objectives include detection of theophylline toxicity or conditions that complicate the treatment of asthma exacerbations (such as cardiovascular disease, pneumonia, or diabetes). For example: — Consider arterial blood gas (ABG) measurement for evaluating arterial carbon dioxide tension (PCO 2 ) in patients who have suspected hypoventilation, severe distress, or FEV 1 or PEF ≤25 percent of predicted after initial treatment. (Note: Respiratory drive is typically increased in asthma exacerbations, so a "normal" PCO 2 of 40 mmHg indicates severe airflow obstruction and a heightened risk of respiratory failure.) — Venous levels of PCO 2 have been tested as a substitute for arterial measurements, and a venous PCO 2 of >45 mmHg may serve as a screening test but cannot substitute for the ABG evaluation of respiratory function ().

— Complete blood count (CBC) is not required routinely but may be appropriate in patients who have fever or purulent sputum. Keep in mind that modest leukocytosis is common in asthma exacerbations and that corticosteroid treatment causes a further outpouring of polymorphonuclear leukocytes within 1–2 hours of administration. — Measure serum theophylline concentration in patients who have taken theophylline before presentation. — It may be prudent to measure serum electrolytes in patients who have been taking diuretics regularly and in patients who have coexistent cardiovascular disease, because frequent SABA administration can cause transient decreases in serum potassium, magnesium, and phosphate. — Chest radiography is not recommended for routine assessment but should be obtained for patients suspected of a complicating cardiopulmonary process, such as congestive heart failure, or another pulmonary process such as pneumothorax, pneumomediastinum, pneumonia, or lobar atelectasis. — Electrocardiograms are not required routinely, but a baseline electrocardiogram and continual monitoring of cardiac rhythm are appropriate in patients older than 50 years of age and in those who have coexistent heart disease or chronic obstructive pulmonary disease (COPD). The electrocardiogram may show a pattern of right ventricular strain that reverses promptly with treatment of airflow obstruction.