The original Valsalva manoeuvre (VM) was described in detail by the Italian anatomist, physician and surgeon Antonio Maria Valsalva (1666-1723). The VM consists of a voluntary forced expiratory effort against a closed upper airway. It was used tradionally in otolaryngology for testing the openess of the eustachian tubes and expelling pus/fluid from the middle to the external ear. VM is associated with increased intrathoracic and -abdominal pressure and leads to hemodynamic changes. The use of VM for cardiovascular purposes was first described by Eduard Friedrich Weber, a German physiologist. The M��ller manoeuvre (MM) represents the opposite of the VM by forced inspiration against a closed upper airway. Negative intrathoracic and abdominal pressure (ITP) with direct effects on cardiac function and hemodynamics can be generated by the MM. MM has also been used to simulate the hemodynamic effects of negative ITP in obstructive sleep apnea patients. The M��ller manoeuvre was first described by the German anatomist and physician Johannes M��ller (1801-1858).
