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.
CPAP is the most common treatment for sleep apnea. A CPAP machine uses mild air pressure to keep your airway open while you sleep. If your doctor thinks that you have sleep apnea, he or she may schedule a split-night sleep study. During the first half of the night, your sleep will be checked without a CPAP machine.