The victim was bound upon this wheel, on his knees, with his hands behind his back.
A continuous positive airway pressure (CPAP) machine was initially used mainly by patients for the treatment of sleep apnea at home, but now is in widespread use across intensive care units as a form of ventilation.
Like other PAP (Positive Airway Pressure) machines, the APAP machine is a device that is connected with a non-invasive mask to a pressure generator that is designed to deliver air pressure to keep your airways open while you sleep.