An improved patient support structure comprises an articulatable frame, a plurality of elongated inflatable sacks, a low pressure compressed air blower and a plurality of pipes for carrying gas from the blower to the sacks. The sacks rest atop a neoprene membrane which covers a planar upper surface of the frame. A variable autotransformer supplies power to the air blower and is adjustable by an electric motor mechanically connected to the autotransformer. Operation of the motor is controlled by an electronic circuit which balances the autotransformer voltage against a voltage output from a preset variable resistor. A multi-outlet, variable flow, gas valve comprises a housing defining an inlet and a passageway. The sacks can be rapidly deflated via a plurality of solenoid valves, and the pipes from the blower can be directed alternatively to different sacks by opening and closing a plurality of manually operated valves. A plurality of pressure sensitive switches indicates when a substantially deflated condition exists in one or more of the sacks. A plurality of fabric panels is attached via a plurality of snap members to the ends of the sacks and to a portion of the frame.