The internal circuit of a ventilator allows the gas to go directly from its power source into the pa-tient. This is known as which of the following?

a. Single-circuit
b. Open loop
c. Closed loop
d. Double-circuit

ANS: A
There are two types of internal circuits, the single- and the double-circuit. The single-circuit al-lows the gas to flow from its power input source to the patient. The double-circuit utilizes a pri-mary power source to generate a gas flow that compresses a mechanism such as a bellows. The gas within the bellows will then flow to the patient. Open loop and closed loop refer to the ab-sence or presence, respectively, of a feedback loop system.