Coughing is a vital reflex consisting of two steps: firstly, the simultaneous closure of the glottis and the rise of the intrathoracic pressure to 150–180 torr by maximum contraction of the abdominal muscles; and secondly, the quick opening of the glottis valve within 0.03 seconds. Consequently a small amount of air is pushed out of the lungs with a velocity as high as 5–8 liters/sec, carrying with it secretions or foreign materials. Under pathological conditions or in special medical situations such as general anesthesia with muscle relaxation—this physiological reflex mechanism is blocked or interrupted, possibly resulting in more or less severe pulmonary complications or even deadly asphyxia.