| 释义 |
DictionarySeeactionball-valve action
ball-valve actionIntermittent obstruction of a passageway or opening so that the flow of fluid or air is prevented from moving in and out in equal amounts. A common example is a mucus plug in a distal airway. During inspiration the airway widens allowing gas to flow past the plug. During expiration the airway narrows and gas is trapped. This mechanism can be responsible for a pneumothorax in ventilated patients. See also: action |