Journal of clinical monitoring
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Anesthesia ventilators with bellows that rise on expiration (standing bellows) are favored over ventilators with bellows that descend during expiration (hanging bellows). Standing bellows will not rise if there is a disconnection, and thus they facilitate detection of disconnections. ⋯ Thus, spirometers that measure tidal volume (VT) in the expiratory limb of the breathing system may falsely indicate an expiratory VT after a disconnection of the breathing system at the Y-piece or the endotracheal tube. Existing low-pressure alarms and capnography alarms provide redundant warning of disconnection, however, should the ventilator continue to deliver small VTs after a disconnection.