Abstract: A patient support appliance is provided of the kind formed from a plurality of inflatable air sacs, mounted on an articulating base and extending transversely of the base so as to provide, when inflated, a surface for supporting a person thereon. The base is divided into sections lengthwise of the appliance and the air sacs arranged in groups corresponding to said sections. An airblower for supplying air to the sacs is suspended from said base or mounted on a supporting frame. Air from the blower is fed to the appliance by a main air supplying conduit via a distribution chamber and individual air supply tubes lead from the distribution chamber to the groups of sacs. Pressure regulating valves are provided to regulate individually the pressure of air in the air supply tubes so that the pressure of air in each group can be regulated independently of the others. Means are provided for exhausting air rapidly from the distribution chamber, e.g.