Management Of Asthma With Acute Exacerbation In Pediatric Patients Speaker : Dr. Meng-Shu Wu

Clinical Decision Making 1. How sick is the child? 2. Which drugs should be used for treatment? 3. What are the optimal doses and delivery routes? 4. When is more aggressive management necessary?

ASSESSMENT OF SEVERITY Clinical findings Pulmonary index Peak flow rate – poor cooperation by children aged less than 6. Chest radiograph – only performed to exclude other diagnosis Arterial blood gas – rarely necessary Clinical evaluation should be repeated frequently during the management of an acute asthma exacerbation to assess response to therapy.

ASSESSMENT OF SEVERITY Clinical findings: The history should include: 1) The time of onset of exacerbation. 2) Current medications and allergies. 3) Recent use of beta 2-agonists. 4) Risk factors for severe, uncontrolled disease, such as emergency department visits, hospital and intensive care unit admissions, repeated courses of oral glucocorticoids, and history of intubation, rapidly progressive episodes, or food allergy.

ASSESSMENT OF SEVERITY Clinical findings: The focused examination should include: 1) Vital signs and pulse oximetry. 2) Assessment of level of consciousness, anxiety, and agitation. 3) Assessment of breathlessness, wheezing, air entry, accessory muscle use, and retractions.

ASSESSMENT OF SEVERITY Pulmonary index score ScoreRespiratory rate Inspiratory/ expiratory ratio WheezingAccessory muscle use Oxygen saturation 0 ≦ 30 2:1None :1End expiration :2Entire expiration ＞ 60 1:3Inspiration and expiration +++ ＜ 93 ﹡ In general, a score of less than 7 indicates a mild attack, a score of 7 to 11 indicates a moderately severe attack, and a score of 12 or greater indicates a severe attack. ﹡ If no wheezing due to minimal air entry, score 3.

Goals Rapid reversal of airflow obstruction. Correction of hypoxemia and/or severe hypercapnia. Reduction of likelihood of recurrence by intensifying baseline therapy.

General Approach Oxygen therapy Monitoring Beta 2 agonist therapy - mainstay Glucocorticoids - mainstay

Mild Asthma Exacerbation [PSI < 7] Albuterol inhalation therapy administered via small volume nebulizer (SVN) at a dose of 0.15 mg/kg (maximum 5 mg) or metered dose inhaler (MDI-S) at a dose of one-quarter to one-third puff/kg (maximum 10 puffs). If repeated doses are needed, they should be given every 20 to 30 minutes for three doses. Administration of systemic glucocorticoids to those who fail to improve after one inhalation therapy.

Moderate Asthma Exacerbation [PSI 7-11] Administration of supplemental oxygen if oxygen saturation 92 percent in room air. Albuterol nebulization combined with ipratropium bromide every 20 to 30 minutes for three doses or continuously. Albuteraol nebulization maybe repeat after 3 doses of albuteral inhalation combined with ipratropium bromide. Administration of systemic glucocorticoids after the first inhalation therapy. Administration of IV magnesium sulfate if there is clinical deterioration despite formal treatment.

* Consider IM methylpredisolone or nebulized or oral dexamethasone if the child vomits prednisone. Management of Moderate Asthma

Management of Severe Asthma [PSI ≧ 12 ] O 2 and IVF and monitors as necessary. Albuterol nebulization combined with ipratropium bromide therapy. Alternatively, terbutaline administered subcutaneously. Reevaluation and making decision. For patients with a poor response to initial treatment: - Administration of IV methylprednisolone. - Administration of IV magnesium sulfate. For patients who do not respond to these interventions, administration of IV terbutaline may be indicated. Considering ET+MV anytime.

Management of Severe Asthma

PHARMACOTHERAPY – Inhaled β2- agonists Inhaled short-acting beta 2-agonists are the mainstay of emergent treatment of acute asthma exacerbations. Ssmall volume nebulizers (SVNs) vs MDI-S: equally effective. Advantages of SVN delivery: simultaneously deliver humidified oxygen and ipratropium bromide and to passively administer drug therapy to a child in respiratory distress. Continuous delivery — similar outcomes and side effect profiles as intermittent nebulized delivery.

PHARMACOTHERAPY – Inhaled β2- agonists Dosing and administration:  Albuterol by nebulizer mg/kg/dose (minimum 2.5 mg; maximum 5 mg) every 20 minutes for 3 doses then every 1-4 hours as needed.  Continuous albuterol by nebulizer mg/kg/hr.  Albuterol by MDI with spacer -- Dose is not well-established. Reasonable starting points: 1/4-1/3 puff/kg, max 10 puffs.  Side effects, such as tachycardia, hypertension, or tremors.  Patients who have shown little or no improvement after three doses and who are not experiencing significant adverse effects may be treated every 30 to 45 minutes or switched to continuous therapy.

Nebulizer use with mouthpiece Drug delivery is maximized by having a total solution volume of 3 to 4 mL and an oxygen flow rate of 6 to 8 L/min, tapping the sides of the reservoir to renebulize droplets, and having older children use a mouthpiece (as depicted above) to avoid nasal deposition of drug.

Use of spacer with mask To maximize drug delivery, a spacer should be employed by all patients. Infants and young children should use a spacer with a facemask (as depicted above), low dead space, and a low resistance valve.

PHARMACOTHERAPY – Glucocorticoids Anti-inflammatory action Reduced admission rates. The benefit was more pronounced in those not receiving systemic glucocorticoids before ED presentation and in those with more severe. Oral versus IV/IM — The NAEPP guidelines suggest that oral administration of glucocorticoids is preferred to intravenous administration because oral administration is less invasive and the effects are equivalent. Intramuscular administration of glucocorticoids may be warranted in patients who vomit orally administered glucocorticoids, yet do not require an intravenous line for other purposes.

PHARMACOTHERAPY – Glucocorticoids Oral prednisone - 2mg/kg (maximum 60 mg). Dexamethasone phosphate - 0.6mg/kg (maximum dose 16 mg). Methylprednisolone - 1 to 2mg/kg (maximum 60 mg). Inhaled glucocorticoids — The use of inhaled glucocorticoids to treat children with acute asthma is an area of ongoing clinical research.

PHARMACOTHERAPY – Ipratropium bromide An anticholinergic agent. Indicated in the treatment of children with moderate to severe asthma exacerbations. 250 microgram per dose for children who weigh 20 kg.

PHARMACOTHERAPY – MgSO 4 Used in children with severe asthma exacerbation and in children with moderate asthma exacerbations who have clinical deterioration despite treatment with beta 2- agonists, ipratropium bromide, and systemic glucocorticoids. 75 mg/kg (maximum 2.5 g) IV administered over 20 minutes.

PHARMACOTHERAPY – Parenteral β2-agonist Epinephrine and terbutaline. Administered subcutaneously or intravenously. Severe exacerbations Poor inspiratory flow Anxious young children who are uncooperative with or have suboptimal response to initial aerosolized therapy.

PHARMACOTHERAPY – Parenteral β2-agonist The dose of subcutaneous terbutaline for bronchodilation is 0.01 mg/kg per dose with a maximum dose of 0.4 mg; the dose may be repeated every 20 minutes for three doses. The dose of subcutaneous epinephrine for bronchodilation is 0.01 mg/kg, with a maximum dose of 0.4 mL; the dose may be repeated every 20 minutes for three doses, then every 2 to 6 hours as needed.

Nonstandard Therapies Heliox — A mixture of helium and oxygen theoretically may enhance beta 2-agonist delivery because the lower gas density would result in decreased flow resistance. Ketamine Leukotriene receptor antagonists

DISPOSITION - Discharge Discharge to home — diminished or absent wheezing and retracting and increased aeration that is sustained at least 60 minutes after the most recent albuterol dose. Discharge meds — Beta 2-agonists and oral systemic glucocorticoids for 3 to 10 days. Discharge education — 1) Review of discharge medications, with respect to purpose, side effects, and proper technique for administration. 2) A written asthma action plan should be reviewed or initiated. 3) Risk factors for asthma. 4) Prevention of acute exacerbations.

DISPOSITION - Admission Inpatient therapy — 1) Inhaled beta 2-agonists may be administered continuously or every 2 to 4 hours, depending upon the patient's degree of illness. 2) Supplemental oxygen as necessary to maintain oxygen saturation 92 percent. 3) Systemic glucocorticoids — Prednisone, prednisolone, or methylprednisolone (1 mg/kg every 6 to 12 hours for 48 hours, then 1 to 2 mg/kg [maximum 60 mg] once per day for a total of 5 days). 4) Continuation or initiation of controller agents, based upon classification of severity of chronic asthma and degree of control.

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