available to determine whether a difference exists in those with severe disease. For delivering short-acting beta-agonists in acute asthma in children, spacers may have advantages compared to nebulisers, but children with life-threatening asthma have not been studied. There is no strong evidence for the use of intravenous LABA for adults or children who have acute asthma. There is insufficient evidence to directly compare the effectiveness of a metered-dose inhaler attached to a homemade spacer compared to commercially available spacer for treating children with asthma. Adverse effects Long-term use of inhaled corticosteroids at conventional doses carries a minor risk of adverse effects. Risks include thrush, the development of cataracts, and a slightly slowed rate of growth. Rinsing the mouth after the use of inhaled steroids can decrease the risk of thrush. Higher doses of inhaled steroids may result in lower bone mineral density. Others Inflammation in the lungs can be estimated by the level of exhaled nitric oxide. The use of exhaled nitric oxide levels (FeNO) to guide asthma medication dosing may have small benefits for preventing asthma attacks but the potential benefits are not strong enough for this approach to be universally recommended as a method to guide asthma therapy in adults or children. When asthma is unresponsive to usual medications, other options are available for both emergency management and prevention of flareups. Additional options include: Humidified Oxygen to alleviate hypoxia if saturations fall below 92%. Corticosteroid by mouth are recommended with five days of prednisone being the same 2 days of dexamethasone. One review recommended a seven-day course of steroids. Magnesium sulfate intravenous treatment increases bronchodilation when used in addition to other treatment in moderate severe acute asthma attacks. In adults intravenous treatment results in a reduction of hospital admissions. Low levels of evidence suggest that inhaled (nebulised) magnesium sulfate may have a small benefit for treating acute asthma in adults. Overall, high quality evidence do not indicate a large benefit for combining magnesium sulfate with standard inhaled treatments for adults with asthma. Heliox, a mixture of helium and oxygen, may also be considered in severe unresponsive cases. Intravenous salbutamol is not supported by available evidence and is thus used only in extreme cases. Methylxanthines (such as theophylline) were once widely used, but do not add significantly to the effects of inhaled beta-agonists. Their use in acute exacerbations is controversial. The dissociative anesthetic ketamine is theoretically useful if intubation