<Ul> <Li> Oxygen to alleviate hypoxia if saturations fall below 92% . </Li> <Li> 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 . </Li> <Li> Magnesium sulfate intravenous treatment increases bronchodilation when used in addition to other treatment in moderate severe acute asthma attacks . In adults it results in a reduction of hospital admissions . </Li> <Li> Heliox, a mixture of helium and oxygen, may also be considered in severe unresponsive cases . </Li> <Li> Intravenous salbutamol is not supported by available evidence and is thus used only in extreme cases . </Li> <Li> 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 . </Li> <Li> The dissociative anesthetic ketamine is theoretically useful if intubation and mechanical ventilation is needed in people who are approaching respiratory arrest; however, there is no evidence from clinical trials to support this . </Li> <Li> For those with severe persistent asthma not controlled by inhaled corticosteroids and LABAs, bronchial thermoplasty may be an option . It involves the delivery of controlled thermal energy to the airway wall during a series of bronchoscopies . While it may increase exacerbation frequency in the first few months it appears to decrease the subsequent rate . Effects beyond one year are unknown . </Li> <Li> Evidence suggests that sublingual immunotherapy in those with both allergic rhinitis and asthma improve outcomes . </Li> <Li> Omalizumab may also be useful in those with poorly controlled allergic asthma . </Li> <Li> It is unclear if non-invasive positive pressure ventilation in children is of use as it has not been sufficiently studied . </Li> </Ul> <Li> Oxygen to alleviate hypoxia if saturations fall below 92% . </Li> <Li> 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 . </Li> <Li> Magnesium sulfate intravenous treatment increases bronchodilation when used in addition to other treatment in moderate severe acute asthma attacks . In adults it results in a reduction of hospital admissions . </Li>

Which measure is the single best determinant of asthma severity