Back-up plans and business continuity protocols worked as expected during a period yesterday when South Australia's Enterprise Patient Administration System (EPAS) was out of action, with the glitch affecting all hospitals using the system until it was restored at midnight last night, SA Health says.

The doctors' and nurses' unions were hopping mad at the glitch, which saw a small piece of software malfunction and slow down the whole system so much that some hospitals reverted to documenting on paper.