There is provided a backrest pivoting system having a backrest and an actuator for pivoting the backrest. The actuator is pivotably connected to the backrest by a pivot defining a first pivot axis. The backrest is configured to pivot about a guide member which defines a second pivot axis coaxial with the first pivot axis. There is also provided a backrest pivoting system including an actuator and a resilient member mounted in series with the actuator. There is also provided an extendable user support assembly comprising a lower body support panel and a core support panel supported by a frame, the lower body support panel being translatable relative to the frame such that an opening is created between the lower body support panel and the core support panel when the lower body support panel is translated away from the core support panel. There is also provided a method for placing a bed in a vascular position.