Ver el código de «Acute asthma exacerbation (peds)»

{{Peds top}} [[asthma]]
==Background==
[[File:Asthma attack-illustration NIH.jpg|thumb|Comparison of normal airway (B) to airway during asthma symptoms (C).]]
[[File:Features of airway remodeling in asthma.jpg|thumb|Features of remodeling in asthma.]]
*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]] associated with copious rhinorrhea, allergen exposure, and respiratory irritants (i.e. smoke) are common precipitants for pediatric asthma exacerbations

==Clinical Features==
*[[Wheezing]]
*[[Cough]]
*Accessory muscle use
*[[Dyspnea]]
*Prolonged expiration
*Severity of retractions occurs in caudal to cephalad direction
**Scalene muscle contractions more severe than subcostal and intercostal retractions
*Sign of impending ventilatory failure
**Paradoxical respiration
***Chest deflation and abdominal protrusion during inspiration
**[[Altered mental status]]
**"Silent chest"

==Differential Diagnosis==
{{Pediatric wheezing DDX}}

==Evaluation==
[[File:CXR3354 IM-1609-1001.png|thumb|[[CXR]] with hyperinflated lungs consistent with broncoconstriction.]]
*Clinical diagnosis
*Can consider a blood gas if there are fears that the patient is getting tired (sleepy baby vs [[hypercapnia|elevated CO2]]?)
**A CO2 >45 is abnormal in a patient hyperventilating and warrants close monitoring

===Consider [[CXR]]===
*Asymmetric lung auscultation findings, after treatment with albuterol
*Poor response to medications/treatment, if history and exam are not consistent with [[bronchiolitis]]
*Worsening symptoms
*Fever not explained by apparent viral illness

''Obtaining a [[CXR]] in pediatric patients presenting with their first episode of wheezing was previously common,<ref>Patel NH, et al. The Practice of Obtaining a Chest X-Ray in Pediatric Patients Presenting With Their First Episode of Wheezing in the Emergency Department - A Survey of Attending Physicians. Pediatric Emergency Care 36(1):p 16-20, January 2020. | DOI: 10.1097/PEC.0000000000002015</ref> however is no longer considered standard practice.<ref>Ralston SL, et al. Clinical Practice Guideline: The Diagnosis, Management, and Prevention of Bronchiolitis. Pediatrics (2014) 134 (5): e1474–e1502. https://doi.org/10.1542/peds.2014-2742.</ref>''

===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}}

==Management==
===[[Albuterol]]===
''Favor continuous nebulization to decrease the chance of admission when compared to intermittent dosing''<ref>Camargo CA et al. Continuous versus intermittent beta- agonists for acute asthma. Cochrane Database Syst Rev. 2003;(4):CD001115. PMID: 14583926.</ref>
*Nebulizer
**Intermittent: 2.5-5mg q20min, three doses are traditionally given back to back, then repeat as needed.
**Continuous: 0.5mg/kg/hr (max 15mg/hr)<ref>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.</ref>
*MDI
**4-8 puffs q20min given in first hour, then q1-4hr as needed

===[[Ipratropium]]===
*0.25-0.5mg 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<ref name="Rowe">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.</ref>''
*[[Dexamethasone]]
**0.6 mg/kg PO or IV (max 16 mg); consider 2nd dose 24-36hrs later.<ref>Cross KP, et al. Single-dose dexamethasone for mild-to-moderate asthma exacerbations. Can Fam Physician. 2011 Oct; 57(10): 1134–1136.</ref><ref>Shenoi RP, Timm N; Committee on Drugs; Committee on Pediatric Emergency Medicine. Drugs used to treat pediatric emergencies. Pediatrics. 2020;145(1):e20193450. [PubMed 31871244]</ref><ref>Dexamethasone versus prednisone for children receiving asthma treatment in the paediatric inpatient population: protocol for a feasibility randomised controlled trial. BMJ Open. http://dx.doi.org/10.1136/bmjopen-2018-025630</ref>
***PO and IV have equal efficacy. Giving the IV form by mouth is typically better tolerated by young children (same dosing)
**Both 1 and 2 dose regimens as effective as [[prednisone]] or [[prednisolone]] in children <ref>Keeney, et al. Dexamethasone for Acute Asthma Exacerbations in Children: A Meta-analysis. Pediatrics. 2013-2273</ref><ref>Cronin et al. "A Randomized Trial of Single-Dose Oral Dexamethasone Versus Multidose Prednisolone for Acute Exacerbations of Asthma in Children Who Attend the Emergency Department." Annals of EM. May 2016. 67(5):593-601</ref>
*[[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<ref>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</ref>

===[[Magnesium]]===
*Dose: 50mg/kg IV, max 2-4 g over 20 mins with close blood pressure monitoring
*Smooth muscle relaxant
*Duration of action approximately 20 min
*In patients with moderate to severe asthma there is a decreased rate of admission with an NNT of 2<ref name="Rowe"></ref>

===Beta-agonist===
*[[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
***Delta pressure 10
***PEEP >4
**May benefit from [[ketamine]] or [[dexmedetomidine]] to mildly sedate and allow the interface

===[[Intubation]]===
*Push pull (bolus) [[IVF|fluids]] prior to intubation to maximize the patient's preload and ideally decrease the chance of the patient arresting
*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 1-2 mg/kg
*Ventilation of asthmatic patients requires deep sedation
**[[Benzos]], [[ketamine]] (1 mg/kg/hr)
*[[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
**Plateau pressure ideally <30
**May require "permissive hypoventilation" and permissive hypercarbia and acidosis
***Low peak pressure/avoidance of breath stacking more important than correcting CO2 <ref> Darioli, et al. Mechanical Controlled hypoventilation in status asthmaticus. Am Rev Respir Dis. 1984; 129 (3) 385-7 </ref>
**Tidal volume 6-8cc/kg ideal wt
**PEEP >4
**Flow rate 80-100L/min
**Keep FiO2 minimum to achieve SpO2 > 90%
*Use bronchodilators even when intubated
*Many patients require a continuous [[neuromuscular blocking agents|paralytic]] infusion for the first 24+ hrs of intubation

==Outpatient Treatment==
{|class="wikitable"
| align="center" style="background:*f0f0f0;"|'''Severity'''
| align="center" style="background:*f0f0f0;"|'''Day Sx'''
| align="center" style="background:*f0f0f0;"|'''Night Sx'''
| align="center" style="background:*f0f0f0;"|'''Treatment (WHO 2008 Formulary)<ref>Stuart MC et al. WHO Model Formulary 2008. http://www.who.int/selection_medicines/list/WMF2008.pdf.</ref>'''
|-
| 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 '''AND'''
*[[Beclometasone]] 100-250 mcg BID
|-
| Moderate persistent, 60-80% peak flow||Daily with exacerbations weekly||> 1/wk||
*[[Albuterol]] MDI 100-200 mcg PRN QID '''AND'''
*[[Beclometasone]] 100-500 mcg BID '''AND'''
*[[Salmeterol]] inhaled 50 mcg BID
|-
| Severe persistent, < 60% peak flow||Continuous daily||Frequent||
*[[Albuterol]] MDI 100-200 mcg PRN QID '''AND'''
*[[Beclometasone]] 1mg BID (high dose) '''AND'''
*[[Salmeterol]] inhaled 50 mcg BID '''AND'''
*[[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 <ref>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</ref>)
**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==
*[[Asthma]]
*[[Modified pulmonary index score]]
*[[Ventilation settings]]
*[[Deterioration after intubation]]
*[[Shortness of breath]]

==External Links==
*[http://emcrit.org/podcasts/severe-asthmatic/ EMCrit Podcast - The Severe Asthmatic]

==References==
<references/>

[[Category:Pulmonary]]
[[Category:Pediatrics]]