Pedi Asthma


Clinical

Triggers

  • Respiratory infections
    • Usually viral
      • Rhinovirus (most common)
      • RSV
      • Influenza
    • Bacteria, fungi, parasites also possible
      • Patients usually have
        • High IgE production
        • Strong eosinophilic immune responses
        • Early IgE-mediated responses to local allergens
  • Allergens
    • Foods
    • Household irritants
      • Animal dander, urine, feces, saliva, dust mites, roaches, molds/fungi
    • Outdoor allergens
      • Pollen, grass, trees, mold spores
    • Two types of bronchoconstriction response
      • Early response
        • From IgE mediator release from mast cells
        • Occurs within min
        • Lasts 20-30 min
      • Late response
        • Inflammatory cell infiltration
        • Inflammatory mediators
        • Cause more severe symptoms
        • Occur 4-12 hr after antigen exposure
        • Can last for hours
  • Irritants
    • Tobacco smoke
    • Cold air
    • Chemicals
      • Perfumes, hair spray, paint odors, ozone
  • Weather changes
    • Changes in atmospheric temperature, barometric pressure, air quality
      • Allergen/irritant concentration, humidity
  • Exercise
    • Exercise -induced bronchoconstriction best prevented by
      • Baseline asthma control
      • Avoidance of allergens
      • Choosing appropriate sports with short bursts of activity
      • Warm, humid environment
  • Emotional expressions
  • Gastroesophageal reflux disease (GERD)
  • Allergic rhinitis, sinusitis, chronic URI
  • Nocturnal asthma
    • Circadian changes
      • Lung function
      • Release of inflammatory mediators
    • Obstructive sleep apnea

 

Diagnosis (Acute Exac.)

  • PFTs should be measured whenever possible
    • Most used in ED
      • Can be used for > 5 yo
      • Portable, inexpensive
      • Drawback: effort dependent
      • Record best of 3 attempts
  • CXR
    • Rarely helpful, rarely change management
    • Reserve for specific patients
      • Patients with suspected complications
      • Patients not improving as expected
  • Laboratory studies
    • CBC, CMP not routinely useful
    • ABG is painful, invasive
      • Use only if suspect impending Resp failure
      • Clinical evaluation & pulse oximetry usually adequate
         
  • History
    • No reliable way exists to diagnose asthma in infants and toddlers
    • First vs multiple attacks
    • Onset, duration, severity of attack
    • Prior ICU admissions or intubation?
    • Baseline disease severity
      • ED visits/hospitalizations
      • Meds taken, including last dose (es. steroids)
    • History of prior infection, illness, URI Sx, fever
    • Ask about foreign body aspiration
  • Ventilation
    • Tachypnea (most sensitive indicator)/tachycardia
    • Respiratory excursion/effort
    • Accessory muscle use
    • Retractions
    • Air movement
  • Oxygenation
    • Nasal flaring
    • Level of consciousness, irritability, alertness
    • Color (+/- cyanosis)
    • Pulse oximetry
    • Peak flow measurement (if > 5 yo)
    • Determine severity of exacerbation

     

Disease Classification

Mild

  • Symptoms
    • Breathlessness while walking
    • Can lie down
    • Talks in sentences
    • May be agitated
  • Signs
    • Resp rate: normal to increased
    • Accessory muscle use: none or subcostal
    • Wheezing: moderate, may be only end-expiratory
    • Pulse: <100
    • Pulsus paradoxus: absent (< 10 mmHg)
  • Functional assessment
    • Peak flow: over 80% predicted
    • SAO2 (RA): > 92%
    • ABG (on RA, not usually needed)
      • PaO2: normal
      • PaCO2: < 42 mmHg
  • Treatment
    • Use small volume nebulizer
    • Albuterol only
    • No initial steroids

Moderate

  • Symptoms
    • Breathlessness while talking
      • Infant: softer, shorter cry; trouble feeding
    • Prefers sitting
    • Talks in phrases
    • Usually agitated
  • Signs
    • Resp. rate: increased
    • Accessory muscle use: common (subcostal and/or intercostal)
    • Wheezing: loud, throughout expiration
    • Pulse: 100–120
    • Peak flow: approx. 60–80% of predicted
    • Pulsus paradoxus: may be present (10-25 mmHg)
  • Functional assessment
    • Peak flow: 50-80% predicted
      • Response to Tx lasts < 2 hr
    • SAO2 (RA): 91 - 95%
    • ABG (on RA, not usually needed)
      • PaO2: > 60 mmHg
      • PaCO2: < 42 mmHg
  • Treatment
    • Use small or large volume nebulizer
    • Albuterol and atrovent
    • Steroids with start of nebulizers

Severe

  • Symptoms
    • Breathlessness at rest
      • Infant stops feeding
    • Sits upright/hunched forward
    • Talks in words
    • Usually agitated
  • Signs
    • Resp rate: often > 30/min
    • Accessory muscle use: usually intercostal and suprasternal
    • Wheezing: usually loud, inspiratory, and expiratory
    • Pulse: >120
    • Pulsus paradoxus: often present
      • > 25 mmHg (older children)
      • 25 - 40 mmHg (younger children)
  • Functional assessment
    • Peak flow: < 60% of predicted
    • SAO2 (RA): < 91%
    • ABG (on RA)
      • PaO2: < 60 mmHg (may be cyanotic)
      • PaCO2: > 42 mmHg (poss. resp. failure)
  • Treatment
    • Use large volume nebulizer
    • Albuterol and atrovent
    • Steroids with start of neb

Imminent Respiratory Arrest

  • Symptoms
    • Drowsy
    • Confused
  • Signs
    • Accessory muscle use: paradoxical thoracoabdominal movement
    • Wheezing: absent
    • Pulse: bradycardia
    • Pulsus paradoxus: absent (resp muscle fatigue)

Guide

  • Respiratory rate in conscious children
    • < 2 m: < 60/min
    • 2 - 12 mo: < 50/min
    • 1 - 5 yo: < 40/min
    • 6 - 8 yo: < 30/min
  • Normal pulse rate
    • 2-12 mo: < 160/min
    • 1-2 yo: < 120/min
    • 2-8 yo: < 110/min

 

Treatment

Treatment Overview

  1. ABCs, immediate critical care if respiratory failure
  2. Supplemental O2: keep pulse ox < 92%
    • Mask for infants
    • Nasal cannula for older children
  3. Continuous pulse oximeter and cardiac monitor
  4. Obtain peak flow before and 10 min post nebulizer treatments
  5. Power nebulizers with 6-8 L/min of O2

Medications

  1. Inhaled (short-acting beta 2-agonists)
    • Albuterol
      • MDI can be used
        • 6 puffs 1 min apart q 20 min
      • Intermittent nebulizer (q 20 min. up to 3 doses)
        • (< 50 kg) 2.5 mg (3 mL)/dose (1 plastic bullet)
        • (> 50 kg); 5 mg (6 mL)/dose (2 plastic bullets)
      • Continuous nebulizer (moderate/severe exacerbations)
        • (< 50 kg) 7.5 mg (9 mL)/dose (3 plastic bullets)
        • (> 50 kg); 15 mg (18 mL)/dose (6 plastic bullets)
    • Levalbuterol (R isomer of albuterol)
      • No clear advantage over racemic albuterol
      • May be better for first nebulizer treatment
        • More expensive
      • Nebulized dose
        • 6-11 yo: 0.31 mg x 1
        • > 12 yo: 0.63 mg x 1
  2. Inhaled anticholinergics
    • Ipratropium bromide
      • Use with albuterol for moderate/severe exacerbations
      • Intermittent nebulizer (add to 2nd/3rd treatments)
        • 0.25 mg (1.251 mL)/dose (1/2 plastic bullet)
      • Continuous nebulizer
        • 1 mg (5 mL) / dose (2 plastic bullets)
  3. Steroids
    • For moderate/severe exacerbations
    • Prednisone: 2 mg/kg (max: 60 mg) PO
      • If emesis within 30 min, repeat
      • If unable to take PO, IV/IM equivalent dose of methylprednisolone
    • Low - dose inhaled corticosteroids are the preferred treatment for children w/ mild persistent asthma
    • Shorter courses might improve compliance and reduce complications
    • Contraindications for steroid administration
      • Active varicella or herpes infection, or
      • History of exposure to varicella in past 3 wk
      • Appropriate dose of oral steroids already given in last 6 hr
      • Parents decline steroids (document)
  4. Magnesium
    • Generally reserved for severe exacerbations
    • 25-40 mg/kg (2G max.) over 10-20 min
    • Still controversial
    • * In this authors experience, rapid administration has prevented intubation on numerous occasions
    • Side effect (rapid administration): flushing, vomiting
  5. Systemic beta-agonists
    • Should be reserved for severe/impending intubation cases
    • Terbutaline
      • IV: 2-10 mcg/kg bolus, then 0.4 mcg/kg/min infusion (max 6 mcg/kg/min)
      • SC (? effectiveness): 0.01 mg/kg, max 0.3 mg
    • Epinephrine
      • SC (1:1,000): 0.01 mL/kg max 0.5 mg
      • IV (1:10,000): 50-1,000 mcg load, then 3-20 mcg/kg/min drip
        • IV use controversial, still being explored
    • Theophylline: minimal or no value in acute ED Rx
  6. Heliox
    • No real current role in treatment of lower airway disease
    • Not well studied in pediatric asthma
    • Use very limited by needing 70-80% helium to be effective
      • Inadequate O2 for severely hypoxic patients
    • May be more useful in intubated patients
  7. Inhaled nitric oxide
    • Potent selective pulmonary vasodilator/bronchodilator
    • Very limited experience in non-neonates
    • Used with ventilator at 20-40 ppm
    • Further studies pending

Follow-Up

  1. Exercise -induced bronchoconstriction best prevented by
    • Baseline asthma control
    • Avoidance of allergens
    • Choosing appropriate sports with short bursts of activity
    • Warm, humid environment
 

ED Treatment

ED Management
  1. Supplemental Oxygen to maintain O2 Sat > 95%
  2. Albuterol NEB
    Small Volume Neb., 0.15 mg/kg/dose, Can repeat q20min x 3 doses, then q1-4h PRN,
    Max dose: 5mg
     
  3. Albuterol MDI
    Metered dose inh., 0.25 puffs/kg
    Max: 10 puffs
     
  4. Ipratropium Bromide
    (acts to decrease secretions)
    < 20 kg: 0.25 mg/dose
    > 20 kg: 0.50 mg/dose
    Combine with first dose albuterol Tx
    -AVOID- MDI w/ Hx of nut allergy
     
  5. Continous Albuterol Neb
    5-10 kg: dose 10 mg/hr
    10-20 kg: dose 15 mg/hr
    > 20 kg: dose 20 mg/hr
     
  6. Steroids:
    • Prednisone/Prednisolone PO
      2 mg/kg, Administer to those who fail initial inhalation therapy
      Max dose: 60 mg
       
    • Dexamethasone
      0.6 mg/kg
      Max: 16 mg
       
    • Methylprednisolone
      2 mg/kg IV bolus, then 1 mg/kg IV q6h initially, followed by 1 mg/kg q12h on the second day, then 1 mg/kg qd for 1-8 days
       
  7. Epinephrine 1:1000
    0.01 mL/kg IM/SC
    Max: 0.4mg
     

No response to initial Tx of Impending Resp. Failure:

  1. Terbutaline SC
    0.01 mg/kg
    Max: 0.4 mg (0.4 ml of 1 mg/ml sol)
    -OR-
  2. Terbutaline IV
    10 mcg/kg bolus over 10 min, then 0.1 - 1.0 mcg/kg/min
     
  3. Theophylline
    5 mg/kg IV loading dose, followed by 1 mg/kg/hr continuous infusion
     
  4. Magnesium Sulfate IV/IM
    50 mg/kg/dose over 20 min q4-6h
    Give NS Bolus first to avoid hypotension
    Max: 2 g
     
  5. BiPAP
     
  6. Ventilation plus transfer to ICU
    Indications for intubation and mechanical ventilation:
     Clinical symptoms of exhaustion, cyanosis, or drowsiness with hypoxemia and hypercapnia.

     Intubation is preferred before the onset of respiratory arrest.

    Fluid replacement will be required in these patients, as they are frequently fluid depleted, and initiation of positive pressure ventilation may be accompanied by hypotension.

    Noninvasive ventilation may be used as a rescue therapy to avoid intubation. Continuous positive airways pressure, CPAP, or bi-level non-invasive ventilation can be applied using either a nasal or full-face mask interface.

    Sedation is occasionally necessary for patient tolerance, but should be used with caution
     
  7. Vent Setting
    • Use Low RR, Low Vt, Low pressure, 1:3 ratio

ABx:

  • Azithromycin: 10 mg/kg orally once daily on the first day, followed by 5 mg/kg once daily for 4 days
  • Clarithromycin: 15 mg/kg/day orally given in divided doses every 12 hours, maximum 1000 mg/day
  • Erythromycin base: 30-50 mg/kg/day orally given in divided doses every 6 hours

 

 

Disposition

General Points

  1. No absolute criteria for discharge
  2. Based on multiple observations
    • Clinical impression
    • Baseline severity of disease
    • Risk factors
    • Availability of urgent follow-up
  3. In general, most ED visits require 2-3 hr
    • 1 hr for nebulizers x 3
    • 30 min-1 hr for post-treatment observation
    • Remainder for discharge instructions, meds, etc.

Evaluation Guidelines

  1. Clinical status (30-60 min post Rx)
    • Symptoms minimal/gone
      • Wheezing
      • Retractions
    • Patient alert, cooperative
    • Pulse ox > 92-95% on RA
    • PEFR > 70 % predicted
    • Vital signs normalize
    • If partial response (PEF 50-70%)
      • May give 2nd round of 3 nebs
      • If clinical status not good, admit

Admission

  1. ICU: status asthmaticus, increasing PaCO2, fatigue/intubation
  2. Infants w/o response to beta 2-agonist or SaO2 < 91%

Possible Admission

  1. Patients who
    • Deteriorate in the ED
    • Have persistent vital sign abnormalities
    • Were already on maximal outpatient therapy (steroids)
  2. High-risk patients
    • Clinical signs
      • Respiratory failure
      • Altered LOC
      • Hypotension
      • Unable to take PO medications
    • Historical concerns
      • Hx of
        • Sudden severe exacerbations, intubation for asthma, near-fatal asthma
        • Exposure to smoking in the home increase incidence of more severe asthma
      • Hospitalizations
        • Past hospitalization for resp. failure
        • Prior ICU admission for asthma
        • Three or more emergency care visits for asthma in the past year
        • 2 or more hospitalizations for asthma in past year
        • Hospitalization (or ED visit) for asthma within the past month
        • ED treatment in last 24 hr
    • Other considerations
      • Use of > 2 canisters per month of inhaled short-acting beta 2-agonist
      • Current use of or recent withdrawal from systemic corticosteroids
      • Difficulty perceiving airflow obstruction or its severity
      • Comorbidities
        • Cardiovascular diseases
        • COPD
        • Serious psychiatric disease/psychosocial problems
      • Low socioeconomic status and urban residence
      • Illicit drug use
      • Sensitivity to Alternaria

Discharge

  1. Pt. w/minimal Sx, PEFR > or = 70 % predicted
  2. Continue corticosteroid (PO x 3-10 days), inhaled beta 2-agonist
  3. Review medications/plan/procedures
  4. Close follow-up 2-5 d
  5. Always discharge with more intense home therapy than patient came in with (otherwise expect a bounce back)
    • Proventil: MDI w/ spacer 2 puffs q4hr
      • Scheduled x 3-5 days
      • Then q4-6h PRN
    • Prednisone: burst 2 mg/kg PO qd or x 3-10 days, then stop
    • Other medications as coordinated with primary physician
    • Individualize recommendations
      • Atrovent, Cromolyn, continuation/modification of other maintenance medications
  6. Tell patient to call PMD or return for
    • Worsened sx, need for beta agonist < q 4hr
    • Decreased PEFR (< 80% baseline contact PMD, < 50% go to ED)
  7. Family educational interventions
    • Highly effective in reducing ED utilization by children with asthma
    • Teach Patients and their families how to recognize asthma triggers, symptoms, and avoidance techniques
    • Better outcomes if coupled with regular follow-up by a case manager
 

Follow up

  1. Follow up w/PCP
    • 48-72 hr max.
  2. All patients should be discharged on more intense therapy
    • Regular inhaler/nebulizer schedule
    • Steroids if not already taking them
      • Give first dose in ED
    • Should have 5-10 day post-ED care plan
    • Coordinate with primary physician
      • Medications
      • Followup within 48-72 hr
    • If no primary physician, ED doc must assure followup
    • Clear understanding by patient of plan and reasons to return to ED
  3. Tell patient to call PMD or return for
    • Worsened sx, need for beta agonist < q 4hr
    • Decreased PEFR (< 80% baseline contact PMD, < 50% go to ED)
 
 

Admission Orders: Asthma

1. Admit to:

2. Diagnosis: Exacerbation of asthma.

3. Condition:

4. Vital Signs: Call MD if:

5. Activity: Bedrest

6. Nursing: Pulse oximeter, measure peak flow rate in older patients.

7. Diet:

8. IV Fluids: D5 1/4 NS or D5 1/2 NS at maintenance rate.

9. Special Medications:

-Oxygen humidified prn, 1-6 L/min by NC or 25-80% by mask, keep sat >92%.

Aerosolized and Nebulized Beta-2agonists:

-Albuterol (Ventolin [using 0.5% = 5 mg/mL soln]) nebulized 0.2-0.5 mL in 2 mL NS q1-4h and prn; may also be given by continuous aerosol.

[soln for inhalation: 0.83 mg/3 mL unit dose; 5 mg/mL 20 mL multidose bulk bottle]

-Albuterol (Ventolin, Proventil) 2 puffs q1-6h prn with spacer and mask.

[capsule for inhalation (Rotacaps) using Rotahaler inhalation device: 200 mcg; MDI: 90 mcg/puff, 200 puffs/17 gm]

-Levalbuterol (Xopenex)

2-11 years: 0.16-1.25 mg nebulized

>=12 years: 0.63-1.25mg nebulized q6-8h

[soln for inhalation: 0.63 mg/3 mL, 1.25 mg/3 mL]. Levalbuterol 0.63 mg is comparable to albuterol 2.5 mg.

-Salmeterol (Serevent) >4 years: 2 puffs bid. Not indicated for acute treatment. [Serevent Diskus: 50 mcg/puff; MDI: 21 mcg/puff, 60 puffs/6.5gm or 120 puffs/13 gm]

-Formoterol (Foradil): >5 years: 12 mcg capsule aerosolized using dry powder inhaler bid. [capsule for aerosolization: 12 mcg]

-Metaproterenol (Alupent, Metaprel)

> 12 years: 2-3 puffs q3-4h prn, max 12 puffs/24 hrs. [MDI: 0.65 mg/puff]

-Racemic epinephrine (2.25% soln) 0.05 mL/kg/dose (max 0.5 mL) in 2-3 mL saline nebulized q1-6h.

Intravenous Beta-2 Agonist:

-Terbutaline (Brethaire, Brethine, Bricanyl)

Loading dose: 2-10 mcg/kg IV

Maintenance continuous IV infusion: 0.08-6 mcg/kg/min

Monitor heart rate and blood pressure closely.

[inj: 1 mg/mL]

Corticosteroid (systemic) Pulse Therapy:

-Prednisolone 1-2 mg/kg/day PO q12-24h x 3-5 days

[syrup: 5 mg/5 mL; Orapred 20.2 mg/5mL; Prelone 15 mg/5 mL] OR

-Prednisone 1-2 mg/kg/day PO q12-24h x 3-5 days

[oral solution: 1 mg/mL, 5 mg/mL; tabs: 1, 2, 5, 10, 20, 50 mg] OR

-Methylprednisolone (Solu-Medrol) 2 mg/kg IV bolus, then 1 mg/kg IV q6h initially, followed by 1 mg/kg q12h on the second day, then 1 mg/kg qd for 1-8 days

Aminophylline and theophylline:

-Therapeutic range 10-20 mcg/mL. Concomitant drugs (eg, erythromycin or carbamazepine) may increase serum theophylline levels by decreasing drug metabolism.

-Aminophylline loading dose 5-6 mg/kg total body weight IV over 20-30 min [1 mg/kg of aminophylline will raise serum level by 2 mcg/mL].

-Aminophylline maintenance as continuous IV infusion (based on ideal body weight)

1-6 month: 0.5 mg/kg/hr

6-12 month: 0.6-0.75 mg/kg/hr

1-10 year: 1.0 mg/kg/hr

10-16 year: 0.75-0.9 mg/kg/hr

>16 year: 0.7 mg/kg/hr OR

-Theophylline PO maintenance

80% of total daily maintenance IV aminophylline dose in 2-4 doses/dayOR

1-6 month: 9.6 mg/kg/day.

6-12 month: 11.5-14.4 mg/kg/day.

1-10 year: 19.2 mg/kg/day.

10-16 year: 14.4-17.3 mg/kg/day.

>16 year: 10 mg/kg/day.

-Give theophylline as sustained-release theophylline preparation: q8-12h or liquid immediate release: q6h.

-Slo-Phyllin Gyrocaps, may open caps and sprinkle on food [60, 125, 250 mg caps] q8-12h

-Slobid Gyrocaps, may open caps and sprinkle on food [50, 75, 100, 125, 200, 300 mg caps] q8-12h

-Theophylline oral liquid: 80 mg/15 mL, 10 mg/mL] q6-8h

-Theo-Dur [100, 200, 300, 450 mg tabs; scored, may cut in half; do not crush] q8-12h.

-Theophylline Products

Cap: 100, 200 mg

Cap, SR: 50, 60, 65, 75, 100, 125, 130, 200, 250, 260, 300 mg

Liquid: 80 mg/15 mL, 10 mg/mL

Tab: 100, 125, 200, 250, 300 mg

Tab: 100, 125, 200, 250, 300 mg

Corticosteroid metered dose inhalers or nebulized solution:

-Beclomethasone (Beclovent, Vanceril) MDI 1-4 puffs bid-qid with spacer and mask, followed by gargling with water. [42 mcg/puff].

-Beclomethasone (Vanceril Double Strength) MDI 2 puffs bid [84 mcg/puff]

-Budesonide (Pulmicort Turbohaler) MDI 1-2 puffs bid [200 mcg/puff]

-Budesonide (Pulmicort) 0.25-0.5 mg nebulized bid [0.25 mg/2mL, 0.5 mg/2mL]

-Flunisolide (Aerobid) MDI 2-4 puffs bid [250 mcg/puff]

-Fluticasone (Flovent) MDI 1-2 puffs bid [44, 110, 220 mcg/actuation]

-Triamcinolone (Azmacort) MDI 1-4 puffs bid-qid [100 mcg/puff]

Cromolyn/nedocromil:

-Cromolyn sodium (Intal) MDI 2-4 puffs qid [800 mcg/puff] or nebulized 20 mg bid-qid [10 mg/mL 2 mL unit dose ampules]

-Nedocromil (Tilade) MDI 2 puffs bid-qid [1.75 mg/puff]

Oral beta-2 agonists:

-Albuterol (Proventil)

2-6 years: 0.1-0.2 mg/kg/dose PO q6-8h

6-12 years: 2 mg PO tid-qid

>12 years: 2-4 mg PO tid-qid or 4-8 mg ER tab PO bid

[soln: 2 mg/5 mL; tab: 2, 4 mg; tab, ER: 4, 8 mg]

-Metaproterenol (Alupent, Metaprel)

< 2 years: 0.4 mg/kg/dose PO tid-qid

2-6 years: 1.3-2.6 mg PO q6-8h

6-9 years: 10 mg PO q6-8h

[syrup: 10 mg/5mL; tabs: 10, 20 mg]

Leukotriene receptor antagonists:

-Montelukast (Singulair)

2-5 year: 4 mg PO qPM

6-14 year: 5 mg PO qPM

> 14 year: 10 mg PO qPM

[tab: 10 mg; tab, chew : 4, 5 mg]

-Zafirlukast (Accolate)

7-11 year: 10 mg PO bid

>12 year: 20 mg PO bid

[tabs: 10, 20 mg]

-Zileuton (Zyflo)

>=12 year: 600 mg PO qid (with meals and at bedtime)

[tab: 600 mg]

ABx:
  • Azithromycin: 10 mg/kg orally once daily on the first day, followed by 5 mg/kg once daily for 4 days
  • Clarithromycin: 15 mg/kg/day orally given in divided doses every 12 hours, maximum 1000 mg/day
  • Erythromycin base: 30-50 mg/kg/day orally given in divided doses every 6 hours

10. Extras and X-rays: CXR, pulmonary function test, peak flow rates.

11. Labs: CBC, CBG/ABG. Urine antigen screen, UA, theophylline level.