Variable width hospital bed

A system for changing width of a person support apparatus is disclosed. The system comprises: a bed controller (58) configured to receive a command signal indicative of a command for width alteration; a mattress controller (64) configured to communicate with the bed controller (58); a fluid supply device (32) configured to be controlled by the mattress controller (64); and a mattress configured to be supported by the person support apparatus. The mattress comprises at least one side bolster (52) fluidly connected to the fluid supply device (32) and configured to be inflated by the fluid supply device (32) upon the fluid supply device (32) receiving a fluid supply device control signal from the mattress controller (64). The at least one side bolster (52) comprises at least one pressure transducer (74) and the at least one pressure transducer (74) is configured to communicate with the mattress controller (64) to allow the mattress controller to determine the pressure inside the at least one side bolster (52).