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 largest multi-center study of lung function in people with PCD across many European countries found strong evidence refuting a common assumption that it is a mild disease. This study found that lung function of people with PCD is comparable to those with cystic fibrosis in childhood but is better in young adulthood. Both diseases, however, are progressive and lung function declines with age relative to peer groups. Survey data indicate that respiratory symptoms increase progressively and continuously beginning in the mid-20s relative to the population norm. History
The classic symptom combination associated with PCD was first described in 1904 by A. K. Siewert, while Manes Kartagener published his first report on the subject in 1933. The disorder is often now referred to as Siewerts syndrome or Siewert-Kartagener syndrome. References
Further reading
GeneReview/NCBI/NIH/UW entry on Primary Ciliary Dyskinesia


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