Domino96 Therapy Thread

[Sleeprider]

It happens all the time. A CA is simply a 70% or more reduction in respiratory flow where the airway is determined to be open by the Resmed FOT pulse algorithm. So if flow limitation is severe enough, it can reduce flow enough to cause hypopnea (30% to 50% of normal flow) or CA (less than 30% of normal flow), and because you're still breathing with effort through the airway flow limit, the airway probes as clear and CA is flagged. CA events should be a reduction of respiratory flow based on effort or drive, but the machine has no means to measure that, so it is a "clear airway" event, and may be central of flow-limited obstructive. A fully obstructed airway usually occurs when the airway obstructs at the end of expiration as inspiration begins. This registers by FOT as a closed or obstructed airway, and is usually a full-obstruction as respiratory effort can create vacuum in the airway locking it tight. That's why it's important to look closely at the flow wave. When CA occurs together with flow limitation, that is kind of a red-flag to me to check what we're really looking at.