Healthcare workflow has recently become an enabling technology in the healthcare industry to automate processes, improve care quality, and enhances patient safety. Although some work has been done on healthcare workflow for some departments of a hospital, automating processes and improving patient safety in the Sterile Processing Department (SPD) is still an open problem. The main contributions of this paper are: i) we identify the main factors and issues in the current practice of a sterile processing department that compromise patient safety; ii) we propose to address these issues using healthcare workflow and identify the key architectural requirements for a healthcare workflow system for SPDs; iii) based on these requirements, we propose a service-oriented architecture and validate it with our SPD workflow prototyping system, SPDFLOW. To our best knowledge, SPDFLOW is the first effort in exploring healthcare workflow technology in the SPD domain.