Which of the following intermittent positive-pressure breathing machines can deliver 100% oxy-gen?

a. Bird Mark 10 c. Puritan Bennett AP-5
b. Bird Mark 14 d. Puritan Bennett PR-2

ANS: D
The Puritan Bennett PR-2 can deliver either 100% source gas or air-diluted source gas. The Bird Mark 10 and Mark 14 ventilators do not have an air-mix control, which means that they can op-erate only in the air-dilution mode. The gas in the Puritan Bennett AP-5 unit is provided by an air compressor and a Venturi jet that entrains additional air; there is no means to attach a gas source.