Müller's maneuver

Müller's Manoeuvre

After a forced expiration, an attempt at inspiration is made with closed mouth and nose, whereby the negative pressure in the chest and lungs is made very subatmospheric; the reverse of Valsalva manoeuvre.

This technique is designed to look for collapsed sections of airways such as the trachea and upper airways. In this maneuver, the patient attempts to inhale with his mouth closed and his nostrils plugged, which leads to a collapse of the airway. Introducing a flexible fiberoptic scope into the hypopharynx to obtain a view, the examiner may witness the collapse and identify weakened sections of the airway. Müller's maneuver is used to help determine the cause of sleep apnea. A positive test results means the site of upper airway obstruction is likely below the level of the soft palate, and the patient will probably not benefit from a uvulopalatopharyngoplasty alone. This maneuver is very helpful in doing MRI for sleep apnoea, when sedation to patient can be avoided.

Reference

Textbook of Medical Physiology p784 - Arthur C. Guyton