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 stands for continuous positive airway pressure. It is the most popular treatment for obstructive sleep apnea (OSA). It uses air pressure generated by a machine, delivered through a tube into a mask that fits over the nose or mouth.