Acute asthma exacerbation (peds)
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For adult patients see Asthma
Background
- An estimated 6 million children in the US have asthma
- In 2007, asthma lead to >700,000 ED visits
- Asthma is part of the atopy triad (asthma, allergies, eczema)
- A history of eczema or allergies maybe helpful in making a new diagnosis of asthma
- Wheezing in an infant is more often bronchiolitis than asthma
- Viral URI, allergen exposure, and respiratory irritants(ie smoke)are common precipitants for pediatric asthma exacerbations
Clinical Features
- Wheezing
- Cough
- Accessory muscle use
- Dyspnea
- Prolonged expiration
- Sign of impending ventilatory failure
- Paradoxical respiration
- Chest deflation and abdominal protrusion during inspiration
- Altered mental status
- "Silent chest"
- Paradoxical respiration
Differential Diagnosis
- Upper Airway diseases
- Allergic rhinitis and sinusitis
- Large Airway Obstruction
- Foreign body aspiration
- Vascular ring or laryngeal webs
- Laryngotracheomalacia
- Enlarged lymph node or tumor
- Vocal cord dysfunction
- Small Airway Obstruction
- Viral bronchiolitis
- Cystic Fibrosis
- Bronchopulmnary dysplasia
- Cardiac Disease
- Other causes
Evaluation
- Clinical diagnosis
Consider CXR
- 1st wheezing episode
- Asymmetric lung auscultation findings, after treatment with albuterol
- Poor response to medications/treatment, if history and exam are not consistent with bronchiolitis
- Worsening symptoms
Clinical Scores
- Diagnosis and treatment can be guided by clinical scores
- Modified Pulmonary Index Score (MPIS - Utilized at CCMC)
- Pediatric Asthma Score (PAS)
- Pulmonary Score (PS)
- Pediatric Respiratory Assessment Measure (PRAM)
Modified Pulmonary Index Score (MPIS)
Age <3 Years | ||||||
---|---|---|---|---|---|---|
Points | SpO2 | Acces Musc Use | I:E | Wheeze | HR | RR |
0 | >95% | None | 2:1 | None; Good Aeration | ≤120 | ≤30 |
1 | 93-95% | Mild | 1:1 | End Exp | 121-140 | 31-45 |
2 | 90-92% | Moderate | 1:2 | Insp/Exp; Good Aeration | 141-160 | 46-60 |
3 | <90% | Severe | 1:3 | Insp/Exp; Poor Aeration | >160 | >60 |
Age 3-6 Years | ||||||
---|---|---|---|---|---|---|
Points | SpO2 | Acces Musc Use | I:E | Wheeze | HR | RR |
0 | >95% | None | 2:1 | None; Good Aeration | ≤100 | ≤30 |
1 | 93-95% | Mild | 1:1 | End Exp | 101-120 | 31-45 |
2 | 90-92% | Moderate | 1:2 | Insp/Exp; Good Aeration | 121-140 | 46-60 |
3 | <90% | Severe | 1:3 | Insp/Exp; Poor Aeration | >140 | >60 |
Age ≥6 Years | ||||||
---|---|---|---|---|---|---|
Points | SpO2 | Acces Musc Use | I:E | Wheeze | HR | RR |
0 | >95% | None | 2:1 | None; Good Aeration | ≤100 | ≤20 |
1 | 93-95% | Mild | 1:1 | End Exp | 101-120 | 21-35 |
2 | 90-92% | Moderate | 1:2 | Insp/Exp; Good Aeration | 121-140 | 36-50 |
3 | <90% | Severe | 1:3 | Insp/Exp; Poor Aeration | >140 | >50 |
- MPIS <7 - Mild exacerbation
- MPIS 7-10 - Moderate exacerbation
- MPIS ≥10 - Severe exacerbation
Management
Albuterol
- Nebulizer
- Intermitent: 2.5-5mg q20min, three doses are tradionally given back to back, then repeat as needed.
- Continuous: 0.5mg/kg/hr (max 15mg/hr)[1]
- MDI
- 4-8 puffs q20min given in first hour, then q1-4hr as needed
Favor continuous nebulization to decrease the chance of admission when compared to intermittent dosing[2]
Ipratropium
- 0.5mg q20min, given with the first three doses of albuterol, it is shown to reduce admission.
Steroids
Should be given in the first hour with effects to reduce admission[3]
- Dexamethasone
- 0.6mg/kg PO or IV (max 16mg); 2nd dose 24-36hrs later.
- PO and IV have equal efficacy
- Both 1 and 2 dose regimens as effective as prednisone in children [4]
- 0.6mg/kg PO or IV (max 16mg); 2nd dose 24-36hrs later.
- Prednisone
- 1-2mg/kg/day(60mg max) in one or two divided doses for 3-5 days
- Methylprednisolone
- 1mg/kg IV q 4–6hr
- Only use IV if cannot tolerate PO since equal effectiveness between dosing routes[5]
Magnesium
- Dose: 50mg/kg IV, max 2-4 g
- Smooth muscle relaxant
- Duration of action approx 20 min
- In patients with moderate to severe asthma there is a decreased rate of admission with an NNT of 2[3]
Epinephrine
- 1:1000 0.01mg/kg (max 0.3mg) IM, repeat as needed
Terbutaline
- Given SQ, usual dose 0.01mg/kg up to 0.3mg.
- Longer-acting beta2-agonist promoting bronchodilation
Assisted Ventilation
- Non-invasive ventilation
- Consider as alternative to intubation
- Alleviates muscle fatigue which leads to larger tidal volumes
- Maximize inspiratory support
- Inspiratory pressure 10
- PEEP 0-5
- Heliox
- 60 to 80% helium is blended with 20 to 40% oxygen
- Heliox improves non laminar flow and may increases the diffusion of carbon dioxide by improving ventilation[6]
Intubation
- Consider induction with Ketamine
- Provides bronchodilation and sedation however it does promote secretions
- Ketamine is the preferred induction agent for intubation in an asthmatic.
- Dosing 1-2mg/kg
- Ventilation of asthmatic patients requires deep sedation
- Ventilation settings
- Assist-control ventilation
- Resp rate
- Start slow to avoid air-trapping and allow for longer expiration time
- Consider I:E ratio of 1:2 or 1:3
- Make sure plateau pressure <30
- May require "permissive hypoventilation" and permissive hypercarbia and acidosis
- Low peak pressure/avoidance of breath stacking more important than correcting CO2 [7]
- Tidal volume 6-8cc/kg ideal wt
- PEEP 0-5
- Flow rate 80-100L/min
- Keep FiO2 minimum to achieve SpO2 > 90%
- Use bronchodilators even when intubated
Outpatient Treatment
Severity | Day Sx | Night Sx | Treatment (WHO 2008 Formulary)[8] |
Mild intermittent, > 80% peak flow | < 2/wk | < 2/mo | Albuterol MDI 100-200 mcg prn qid |
Mild persistent, > 80% peak flow | >2/wk | >2/mo | Albuterol MDI 100-200 mcg prn qid
PLUS Beclometasone 100-250 mcg bid |
Moderate persistent, 60-80% peak flow | Daily with exacerbations weekly | > 1/wk | Albuterol MDI 100-200 mcg prn qid
PLUS Beclometasone 100-500 mcg bid PLUS Salmeterol inhaled 50 mcg bid |
Severe persistent, < 60% peak flow | Continuous daily | Frequent | Albuterol MDI 100-200 mcg prn qid
PLUS Beclometasone 1mg bid (high dose) PLUS Salmeterol inhaled 50 mcg bid PLUS (if needed) SR theophylline, leukotriene antagonist, or PO prednisolone with taper |
Disposition
- Discharge
- Often, patients will still have mild wheezing, but should have complete resolution of tachypnea, hypoxia, and improved work of breathing
- A short course of glucocorticoids decreases chance of relapse [9])
- Patient should generally continue albuterol at home q6hrs for at least the first 24hrs after discharge
- A spacer should be prescribed to be used with the MDI to improve medication delivery to the lungs
- Admit
- If symptoms do not significantly improve or for severe exacerbations
- Peak flow measurements maybe helpful when deciding disposition
- Predicted = (30 x age (yrs)) + 30
- PEF >70% predicted → high likelihood of successful discharge
- PEF <40% predicted → should be admitted
See Also
External Links
References
- ↑ National Asthma Education and Prevention Program (NAEPP), “Expert Panel Report 3 (EPR-3): Guidelines for the Diagnosis and Management of Asthma,” Clinical Practice Guidelines, National Institutes of Health, National Heart, Lung, and Blood Institute, NIH Publication No. 08-4051, prepublication 2007; available at http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.htm.
- ↑ Camargo CA et al. Continuous versus intermittent beta- agonists for acute asthma. Cochrane Database Syst Rev. 2003;(4):CD001115. PMID: 14583926.
- ↑ 3.0 3.1 Rowe BH et al. Magnesium sulfate for treating exac- erbations of acute asthma in the emergency depart- ment. Cochrane Database Syst Rev. 2000;(2):CD001490. PMID: 10796650.
- ↑ Keeney, et al. Dexamethasone for Acute Asthma Exacerbations in Children: A Meta-analysis. Pediatrics. 2013-2273
- ↑ Rowe BH, Keller JL, Oxman AD. Effectiveness of steroid therapy in acute exacerbations of asthma: a meta-analysis. Am J Emerg Med. Jul 1992;10(4):301-10
- ↑ Kass JE: Heliox redux. Chest 2003; 123:673.
- ↑ Darioli, et al. Mechanical Controlled hypoventilation in status asthmaticus. Am Rev Respir Dis. 1984; 129 (3) 385-7
- ↑ Stuart MC et al. WHO Model Formulary 2008. http://www.who.int/selection_medicines/list/WMF2008.pdf.
- ↑ Chapman K. Effect of a short course of prednisone in the prevention of early relapse after the emergency room treatment of acute asthma. NEJM. 1991;324(12):788