The main parameter that the ventilator manipulates for any given breath is referred to as which of the following?

a. Control circuit c. Control variable
b. Phase variable d. Cycle variable

ANS: C
The main parameter or variable controlled by the ventilator for any given breath is referred to as the control variable. A control circuit is part of the internal circuit of a mechanical ventilator and consists of mechanical devices, such as spring-loaded valves, pneumatic systems, or fluidic com-ponents. Phase variables are the variables that control the four phases of a breath. A cycle varia-ble is the variable that is being used by the ventilator to end inspiration.