Patient isn’t responding? Try IV magnesium
For patients who don't respond to corticosteroids and albuterol treatments, IV magnesium sulfate (usual dose, 25-75 mg/kg/d; maximum dose, 2000 mg/d) has been shown to improve respiratory function, but not necessarily decrease admission rates.31 Inhaled magnesium sulfate hasn't been shown to be more effective than IV administration and isn'trecommended.32
Evidence doesn’t support use of heliox
Heliox, which consists of 80% helium, is theorized to be effective in the treatment of asthma by increasing laminar flow and increasing the delivery of medications to the alveoli.32 Overall, the evidence does not support the use of heliox, which is typically restricted to patients with severe asthma exacerbations.33
Is it worth considering noninvasive positive pressure ventilation?
If patients don't improve with medical treatment, noninvasive positive pressure ventilation can be considered. A recent meta-analysis suggests that there is no definitive benefit or harm from this treatment, although several studies have indicated a decrease in symptom severity.34
Intubation should be considered for hypoxemia unresponsive to medications, or in cases of exhaustion, worsening mental status, or respiratory acidosis unresponsive to medication. Ventilation should allow for a permissive respiratory acidosis (pH, 7.2), while maintaining adequate oxygenation.35
Reducing the burden of asthma
Due to the complex task of reducing triggers and providing effective controller medications, working with parents and children is integral to improving the quality of life for patients with asthma. Although there is an obvious genetic predisposition, family physicians can help reduce the risk of developing asthma by encouraging healthy behaviors at home before the child is born. In the prenatal period, this includes avoiding tobacco-smoke exposure, lessening maternal obesity, decreasing maternal antibiotic and acetaminophen use, and curtailing stress.
Evidence suggests that after birth, breastfeeding and reducing childhood obesity can help lower the risk of asthma.36 Atopic disease, in general, can be reduced by breastfeeding until at least 4 months, as well as encouraging a varied diet that does not restrict potential allergens during pregnancy or lactation, and introducing foods (including potential allergens) after the age of 4 months.
The risk of atopic disease can also be lowered by lessening potential triggers at home. These include restricting exposure to cats (but not dogs), reducing home mold by decreasing humidity and ensuring adequate ventilation, avoiding volatile organic compounds, such as chlorine, and curtailing exposure to vehicle emissions. Although often marketed to be effective in reducing allergies, dust-mite covers and soy-based formulas don't prevent or minimize allergies and are often costly.37,38 In addition, there is no evidence that vaccinations areassociated with allergies.39
Douglas M. Maurer, 9040A Jackson Ave, Joint-Base Lewis-McChord, WA 98431; [email protected].