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 Continuous Positive Airways Pressure. It is the most effective way to treat sleep apnoea. If you have Obstructive Sleep Apnea, your Sleep Specialists may give you a range of treatment choices and CPAP may be one of these.