0031-3955/92 $0.00
ASTHMA
+ .20
MANAGEMENT OF ACUTE ASTHMA David A. Stempel, MD, and Gregory J. Redding, MD
Patients with acute asthma experience increased airway obstruction, increased work of breathing, and ventilation-perfusion mismatching. When severe, acute asthma also causes hypoxia, respiratory muscle fatigue, carbon dioxide retention, and respiratory acidosis. Children with chronic asthma often experience acute exacerbations superimposed on pre-existing airway obstruction. Immediate recognition of an exacerbation and aggressive treatment of the pathophysiologic processes producing airway disease in asthma are necessary to reduce the severity and duration of acute asthma. Failure to recognize acute asthma early has been identified as an important factor contributing to fatal and near fatal asthma in adults and children. 13 Asthma flares or "attacks" are frequently noted during viral respiratory infections and allergen or irritant exposure and with exercise. Regardless of the stimulus precipitating the acute attack, therapy for acute asthma is the same. It is designed to relieve bronchospasm, reduce airway wall edema, mobilize and clear airway secretions, and reduce airway inflammation. In severe cases therapy must ensure adequate ventilation and oxygenation until pharmacologic therapy opens airways and reduces lung hyperinflation. Management of acute asthma is dictated by the setting in which it is encountered. Initially, acute asthma is identified and, ideally, treated in the home by a parent or the child. The second and often next setting is the physician's office or the emergency room, where initial medically supervised care is provided. The third setting is the hospital and, if necessary, the intensive care unit. The fourth and final setting is that From the Department of Pediatrics, University of Washington (DAS, GJR); Department of Pediatric Allergy and Immunology, Virginia Mason Clinic (DAS); and Pulmonary Medicine Service, Children's Hospital and Medical Center (GJR), Seattle, Washington
PEDIATRIC CLINICS OF NORTH AMERICA VOLUME 39 • NUMBER 6 • DECEMBER 1992
1311
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STEMPEL & REDDING
in which convalescent care is provided and patient education is stressed in order to prevent further exacerbations of asthma and to develop more effective treatment plans to prevent recurrences.
HOME THERAPY
Successful home management of acute asthma begins before symptoms develop. Children and their families must be able to recognize clinical signs of asthma and know how to respond to these changes. Too often patients and parents recognize acute asthma only as an "attack" rather than the more gradual decline in lung function that frequently precedes the onset of respiratory distress. The entire household should understand the relative importance of different physical signs. Increasing cough is a common early symptom of acute asthma. This occurs especially at night and may disrupt sleep. Although isolated viral upper respiratory infections may produce coughing and frequently precede flares of asthma, an increase in cough always should be attributed to asthma in a child with this diagnosis. It is important to stress to the families of individuals with asthma that bronchodilator or anti-inflammatory treatments should be instituted or increased for cough rather than the use of cough suppressants. Decrease in activity level, fatigue, and chest discomfort are signs that may reflect increasing disease severity. Parents should be instructed to observe their children more closely and follow peak flows when these symptoms are noted. Observation of the wheezing or coughing child with asthma to assess the work of breathing can be accomplished by most parents once they have seen and understand the significance of subcostal, intercostal, and suprasternal retractions and the use of accessory respiratory muscles. Cyanosis is a finding reflecting severe disease, but it is an insensitive marker of oxyhemoglobin desaturation during mild hypoxemia and is unreliably appreciated even when hypoxemia is moderately severe. ll Chest auscultation by the family is difficult and may frequently mislead parents who focus on wheezing rather than the degree of air movement during inspiration and expiration. Respiratory rates can be counted by parents; however, the poor correlation between respiratory rate and severity of airway obstruction precludes this finding as a sensitive indicator of the onset of acute asthma. 21 Peak flow monitoring provides a useful objective parameter to . follow in children with known asthma who may not be able to appreciate dyspnea or early increases in airway obstruction. Children over 4 years of age can frequently learn appropriate forced expiratory technique sufficiently to make home peak flow measurements useful as a monitoring index of asthma. Individual norms can be established and contingency therapy outlined varying on the degree to which peak flow rate falls below baseline values. A sliding scale for additional use
MANAGEMENT OF ACUTE ASTHMA
1313
of [3-agonists, theophylline, or steroids can be established based on the child's previous rate of decline once peak flows fall below "well" values. Peak flow meters may be insensitive when small airways disease predominates, and clinical judgments always should be factored when interpreting the peak flow rate. 9 Home treatment consists of incremental changes in medications in response to the onset or worsening of clinical signs of asthma or changes in peak flows. This contingency plan is perhaps the most important treatment phase of acute asthma in view of findings that most mortality caused by asthma occurs prior to initiation of supervised medical care. 38 Parents who have any doubts about how to treat asthma should contact their physician for advice if not a direct evaluation. Physicians, on the other hand, must accurately know an individual parent's assessment and treatment skills if home therapy for acute asthma is to be provided safely. Distance and available transportation to the nearest medical facility or emergency room must be considered in the contingency plans. With these concepts in mind, it is common practice for families to increase asthma medications in response to onset of symptoms attributable to acute asthma. Children can increase use of home [3-adrenergic agents up to every 4 hours safely. Although the National Heart, Lung, and Blood Institute Guidelines for the Diagnosis and Management of Asthma suggest that nebulized [3-adrenergic therapy every 2 hours can be used at home for acute asthma, the safe, maximal frequency and duration of this treatment has not been established in published reports. Whether increasing inhaled steroid use at the onset of an exacerbation is beneficial is also unclear. During flares of asthma, metered dose inhalers are best used through spacers because this decreases reflex cough after inhalation and may improve delivery of the medication. As with nebulized [3-agonists, the maximum frequency of safe home use for acute asthma is not known. During active wheezing the two inhalations of the bronchodilator delivered by metered dose inhaler should be separated by several minutes. This allows initial improvement in airway function, possibly mobilization of secretions, and then better deposition of the second dose of medication. Recording peak expiratory flow rate (PEFR) before and after this treatment is useful to assess the severity of this episode. The home contingency plan should respond to these parameters and help guide in the frequency of inhaled [3-agonist, institution of systemic steroids, or need for emergency room care. In infants and children unable to use metered dose inhalers or in patients with PEFR less than 50% of baseline values, the use of a nebulizer might provide more effective therapy. Dividing the treatment with 5 minutes of medication, a 10-minute rest period, and then completing the treatment might be more effective. 33 The need for these drugs more often then every 3 to 4 hours suggests that the asthma is worsening, that the addition of theophylline or corticosteroids is required, or that the acutely ill patient is using improper inhalation technique. Depending on the response and need for frequent [3-agonists, the
1314
STEMPEL & REDDING
patient's cardiopulmonary reserve, and the patient's past pattern of deterioration from acute asthma, additional medication such as oral steroids or theophylline should be administered early in the course of acute asthma at home. Some clinicians propose increasing the dose of inhaled corticosteroids with 30% declines in PEFR to restore airway function and prevent a more significant decline in lung function that would warrant the use of prednisone. 2 Subacute reductions in peak flow also deserve more aggressive treatment in order to prevent more serious deterioration when acute asthma develops. Specific criteria for using oral steroids at home for acute asthma varies with patients, but a persistent reduction in PEFR of
ASTHMA
+ .20
MANAGEMENT OF ACUTE ASTHMA David A. Stempel, MD, and Gregory J. Redding, MD
Patients with acute asthma experience increased airway obstruction, increased work of breathing, and ventilation-perfusion mismatching. When severe, acute asthma also causes hypoxia, respiratory muscle fatigue, carbon dioxide retention, and respiratory acidosis. Children with chronic asthma often experience acute exacerbations superimposed on pre-existing airway obstruction. Immediate recognition of an exacerbation and aggressive treatment of the pathophysiologic processes producing airway disease in asthma are necessary to reduce the severity and duration of acute asthma. Failure to recognize acute asthma early has been identified as an important factor contributing to fatal and near fatal asthma in adults and children. 13 Asthma flares or "attacks" are frequently noted during viral respiratory infections and allergen or irritant exposure and with exercise. Regardless of the stimulus precipitating the acute attack, therapy for acute asthma is the same. It is designed to relieve bronchospasm, reduce airway wall edema, mobilize and clear airway secretions, and reduce airway inflammation. In severe cases therapy must ensure adequate ventilation and oxygenation until pharmacologic therapy opens airways and reduces lung hyperinflation. Management of acute asthma is dictated by the setting in which it is encountered. Initially, acute asthma is identified and, ideally, treated in the home by a parent or the child. The second and often next setting is the physician's office or the emergency room, where initial medically supervised care is provided. The third setting is the hospital and, if necessary, the intensive care unit. The fourth and final setting is that From the Department of Pediatrics, University of Washington (DAS, GJR); Department of Pediatric Allergy and Immunology, Virginia Mason Clinic (DAS); and Pulmonary Medicine Service, Children's Hospital and Medical Center (GJR), Seattle, Washington
PEDIATRIC CLINICS OF NORTH AMERICA VOLUME 39 • NUMBER 6 • DECEMBER 1992
1311
1312
STEMPEL & REDDING
in which convalescent care is provided and patient education is stressed in order to prevent further exacerbations of asthma and to develop more effective treatment plans to prevent recurrences.
HOME THERAPY
Successful home management of acute asthma begins before symptoms develop. Children and their families must be able to recognize clinical signs of asthma and know how to respond to these changes. Too often patients and parents recognize acute asthma only as an "attack" rather than the more gradual decline in lung function that frequently precedes the onset of respiratory distress. The entire household should understand the relative importance of different physical signs. Increasing cough is a common early symptom of acute asthma. This occurs especially at night and may disrupt sleep. Although isolated viral upper respiratory infections may produce coughing and frequently precede flares of asthma, an increase in cough always should be attributed to asthma in a child with this diagnosis. It is important to stress to the families of individuals with asthma that bronchodilator or anti-inflammatory treatments should be instituted or increased for cough rather than the use of cough suppressants. Decrease in activity level, fatigue, and chest discomfort are signs that may reflect increasing disease severity. Parents should be instructed to observe their children more closely and follow peak flows when these symptoms are noted. Observation of the wheezing or coughing child with asthma to assess the work of breathing can be accomplished by most parents once they have seen and understand the significance of subcostal, intercostal, and suprasternal retractions and the use of accessory respiratory muscles. Cyanosis is a finding reflecting severe disease, but it is an insensitive marker of oxyhemoglobin desaturation during mild hypoxemia and is unreliably appreciated even when hypoxemia is moderately severe. ll Chest auscultation by the family is difficult and may frequently mislead parents who focus on wheezing rather than the degree of air movement during inspiration and expiration. Respiratory rates can be counted by parents; however, the poor correlation between respiratory rate and severity of airway obstruction precludes this finding as a sensitive indicator of the onset of acute asthma. 21 Peak flow monitoring provides a useful objective parameter to . follow in children with known asthma who may not be able to appreciate dyspnea or early increases in airway obstruction. Children over 4 years of age can frequently learn appropriate forced expiratory technique sufficiently to make home peak flow measurements useful as a monitoring index of asthma. Individual norms can be established and contingency therapy outlined varying on the degree to which peak flow rate falls below baseline values. A sliding scale for additional use
MANAGEMENT OF ACUTE ASTHMA
1313
of [3-agonists, theophylline, or steroids can be established based on the child's previous rate of decline once peak flows fall below "well" values. Peak flow meters may be insensitive when small airways disease predominates, and clinical judgments always should be factored when interpreting the peak flow rate. 9 Home treatment consists of incremental changes in medications in response to the onset or worsening of clinical signs of asthma or changes in peak flows. This contingency plan is perhaps the most important treatment phase of acute asthma in view of findings that most mortality caused by asthma occurs prior to initiation of supervised medical care. 38 Parents who have any doubts about how to treat asthma should contact their physician for advice if not a direct evaluation. Physicians, on the other hand, must accurately know an individual parent's assessment and treatment skills if home therapy for acute asthma is to be provided safely. Distance and available transportation to the nearest medical facility or emergency room must be considered in the contingency plans. With these concepts in mind, it is common practice for families to increase asthma medications in response to onset of symptoms attributable to acute asthma. Children can increase use of home [3-adrenergic agents up to every 4 hours safely. Although the National Heart, Lung, and Blood Institute Guidelines for the Diagnosis and Management of Asthma suggest that nebulized [3-adrenergic therapy every 2 hours can be used at home for acute asthma, the safe, maximal frequency and duration of this treatment has not been established in published reports. Whether increasing inhaled steroid use at the onset of an exacerbation is beneficial is also unclear. During flares of asthma, metered dose inhalers are best used through spacers because this decreases reflex cough after inhalation and may improve delivery of the medication. As with nebulized [3-agonists, the maximum frequency of safe home use for acute asthma is not known. During active wheezing the two inhalations of the bronchodilator delivered by metered dose inhaler should be separated by several minutes. This allows initial improvement in airway function, possibly mobilization of secretions, and then better deposition of the second dose of medication. Recording peak expiratory flow rate (PEFR) before and after this treatment is useful to assess the severity of this episode. The home contingency plan should respond to these parameters and help guide in the frequency of inhaled [3-agonist, institution of systemic steroids, or need for emergency room care. In infants and children unable to use metered dose inhalers or in patients with PEFR less than 50% of baseline values, the use of a nebulizer might provide more effective therapy. Dividing the treatment with 5 minutes of medication, a 10-minute rest period, and then completing the treatment might be more effective. 33 The need for these drugs more often then every 3 to 4 hours suggests that the asthma is worsening, that the addition of theophylline or corticosteroids is required, or that the acutely ill patient is using improper inhalation technique. Depending on the response and need for frequent [3-agonists, the
1314
STEMPEL & REDDING
patient's cardiopulmonary reserve, and the patient's past pattern of deterioration from acute asthma, additional medication such as oral steroids or theophylline should be administered early in the course of acute asthma at home. Some clinicians propose increasing the dose of inhaled corticosteroids with 30% declines in PEFR to restore airway function and prevent a more significant decline in lung function that would warrant the use of prednisone. 2 Subacute reductions in peak flow also deserve more aggressive treatment in order to prevent more serious deterioration when acute asthma develops. Specific criteria for using oral steroids at home for acute asthma varies with patients, but a persistent reduction in PEFR of
![[Management of acute asthma].](/assets/img/hold.png)
