Status asthmaticus medical therapy
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Initial severity assessment is evaluated using arterial blood gas and pulmonary function test and aggressive therapy is initiated to prevent progression to respiratory failure.
Medical Therapy
- Non-invasive ventilation using C-PAP or tight-fitting face mask may be used to reduce the work of breathing without intubation.
- Endotracheal intubation and mechanical ventilation should be used with caution in asthmatics who are non-responsive to medical therapy or non-invasive methods of ventilation, due to the substantial risk of barotrauma. Common indications include impending respiratory arrest, severe hypoxia non-responsive to supplemental oxygen, CO2 retention with PaCO2 greater than 50 mmHg, acidosis and/or altered mental status.
- Supplemental oxygen via nasal canula or face mask is recommended to alleviate severe hypoxia. Oxygen saturation is maintained above 92% and is monitored using pulse Oximetry
- Helium with oxygen mixture has shown to reduce airway resistance and thereby reduce the work of breathing and also improve bronchodilator efficacy.
- Use of magnesium sulphate administered either IV or nebulized in addition to β2-agonists remains controversial.[1][2][3][4]
- Mainstay drugs for the management include nebulized β2-agonists such as albuterol, salbutamol or terbutaline, parenteral steroids such as hydrocortisone or prednisolone and theophylline
- Anti-cholinergics such as ipratropium bromide may be indicated in patients who are unable to tolerate inhaled β2-agonists.
- In patients non-responsive to nebulized bronchodilator, IV-aminophylline or oral-leukotriene inhibitor may be used.[5]
Therapy Based on the Severity of the Disease Assessed by Arterial Blood Gas Analysis
Stage 1
- Hyperventilation with normal PO2
- No hypoxemia
- Patients may benefit from nebulized ipratropium used adjunctive to β2-agonist therapy
Stage 2
- Hyperventilation with hypoxemia (low PO2 and PCO2)
- Patients may require corticosteroids in addition to bronchodilator therapy
Stage 3
- CO2 retention due to respiratory muscle fatigue
- Markedly elevated PCO2 levels are an indicator for mechanical ventilation
- Aggressive β2-agonist therapy along with parenteral steroids and/or theophylline is indicated
Stage 4
- Severe hypoxia with markedly elevated PCO2
- FEV1 lower than 20% predicted is suggestive of an impending respiratory arrest that may require intubation and mechanical ventilation
- Metered-dose inhalation of β2-agonist and anticholinergics are recommended. Administration of parenteral steroids and/or theophylline has also shown to be beneficial.
Contraindicated medications
Status asthmaticus is considered an absolute contraindication to the use of the following medications:
References
- ↑ Scarfone RJ, Loiselle JM, Joffe MD, Mull CC, Stiller S, Thompson K et al. (2000) A randomized trial of magnesium in the emergency department treatment of children with asthma. Ann Emerg Med 36 (6):572-8. DOI:10.1067/mem.2000.111060 PMID: 11097697
- ↑ Bessmertny O, DiGregorio RV, Cohen H, Becker E, Looney D, Golden J et al. (2002) A randomized clinical trial of nebulized magnesium sulfate in addition to albuterol in the treatment of acute mild-to-moderate asthma exacerbations in adults. Ann Emerg Med 39 (6):585-91. PMID: 12023699
- ↑ Glover ML, Machado C, Totapally BR (2002) Magnesium sulfate administered via continuous intravenous infusion in pediatric patients with refractory wheezing. J Crit Care 17 (4):255-8. DOI:10.1053/jcrc.2002.36759 PMID: 12501154
- ↑ Blitz M, Blitz S, Beasely R, Diner BM, Hughes R, Knopp JA et al. (2005) Inhaled magnesium sulfate in the treatment of acute asthma. Cochrane Database Syst Rev (2):CD003898. DOI:10.1002/14651858.CD003898.pub2 PMID: 15846687
- ↑ Press S, Lipkind RS (1991) A treatment protocol of the acute asthma patient in a pediatric emergency department. Clin Pediatr (Phila) 30 (10):573-7. PMID: 1934839