A patient transport device is disclosed which includes a seat member, a back member, a leg supporting member, and a head supporting member. In the method, in case the receiving MPs of all of the plural MSDUs to be transmitted are identical, a transmitting MP generates an A-MSDU using the plural MSDUs and transmits the A-MSDU to the receiving MP. A buoyant light source is disposed on the sheet to provide nighttime visibility to the sheet. Two bottom portions are arranged on opposed sides of the bulge and ascend from the lower bottom toward the front wall and the corner areas adjoining the front wall or toward the front wall and the sidewalls and the corner areas adjoining the front wall and the sidewalls. The hydraulic actuator is configured, upon receipt of pressurized hydraulic fluid, to supply a second drive force.