The Case Study: Hospital Sterile Services
Part 1: Core Scenario
The sterile services department of a large hospital manages the cleaning and sterilisation of surgical and other medical instruments used at various medical procedures such as medical operations in the hospital. The surgical instrument is organised in trays, each identified by a unique identification number. A medical procedure (operation) will typically use one or more of trays of surgical instruments. There are many types of medical operations which use several types of trays. The tray id is recorded in the procedure notes so that the history of any instruments used can be traced at any time in the future and cross-referenced to individual patients and medical personnel. The instruments do not have an ID, as it would be not cost effective to try to engrave codes on each of them (i.e. their alloy is too hard, instruments have various shapes, etc). Each procedure type requires a prescribed number of trays, each with a predetermined list of contents, specific for this type of operation.After a procedure, some or all of the instruments used may need to be disposed of. Any individual instruments disposed of are replaced by brand new ones. The trays are then loaded on trolleys and taken through a series of cleansing and sterilisation procedures.
Typically, each tray is washed to remove any organic matter and then put through a series of operations to sterilise them. Sterilisation destroys all microorganisms on the surface of an article or in a fluid to prevent disease transmission associated with the use of that item.
The series of required sterilisation operations depend on the tray instrument list type. For example, trays may require one or more of the following: gravity displacement autoclave operation, high-speed vacuum steriliser operation, steam flush-pressure pulsing operation, etc For each sterilisation operation, the operator name, sterilisation machine identification, date and time need to be recorded.
Your software consultancy company has been approached to automate the current process that is largely paper-based. The aim is to create a software system that can automate the process and allow integration with other hospital information systems.
You are required to model the current business system and propose a new, integrated software system that will include all current functionality and enhancements needed.
Your job is to elicit the exact requirements from the client (the case study). Further clarifications regarding requirements can be done in Q and A sessions during class and on the ESED discussion forum. However, you will (as good software engineers) confirm in writing any conclusions you make from these discussions, by including any assessments you make your report.
Part B: Scenario Extension
After the successful delivery of the “first cut” design of the Sterile Services system and prototype database specified in coursework Part 1, you have been retained to work on a more detailed design of the system.
However, the management of Sterile Services Ltd has come up with some changes in the specifications. Since now Sterile Services Ltd is a fully private company, it can bid for external contracts. Changes requested are a result of discussions between Sterile Services Ltd sales managers and new potential business customers carrying lucrative new accounts.
The changes are summarised in the following points:
1. Sterile Services will clean and sterilise trays of medical instruments coming from more than one hospitals and clinics, including private ones. The system must keep track of consignments of batches of trays sent for sterilisation from customers including pick-ups and deliveries.
2. A public facing web interface is to be created to allow customers to order pickups of trays and check the sterilisation status of any of their trays. The web interface is to be hosted on an ISP. The main database is to be hosted at the Sterile Services HQs.
3. Pick-ups of instrument trays from the customer are ordered and scheduled individually. For transporting trays to and from customers, Sterile Services will use a subcontractor company.
4. The system should have the ability to provide billing information. Each customer has a separately negotiated charging schedule stipulating the charge for each sterilisation process on a tray and a charge for a pick-up or a delivery.
You have also been given some new information about the technical specifications of the system: Sterile Services has a contract with an ISP that can provide a selection of web servers and server-side software platforms and database back ends. The Sterile Services HQ has a dedicated high-end server for this project.
You are required to design a new, integrated software system that will also include all Part 1 functionality and enhancements needed by Part 2.
Requirements for Component B
Part 1
Produce a preliminary design using traditional, structured methodologies, covering the functionality of the proposed new system described in the Core Scenario. The design should include:
1) Entity Relationship Diagram and attribute analysis which represents the Data Model of the System described in the coursework specification.
You are required to:
● Distinctly show all entity types, attributes (including primary key attributes) and relationships.
● Determine the structural constraints (cardinality and participation constraints) of each relationship.
2) Data Flow Diagram which represents the Process Model of the same specific functional area that you modelled for the Entity Relationship Diagram.
● Include the DFD levels 0 (context diagram) and, optional, level 1 only.
3) A prototype system that follows your structured design above. You can use any appropriate technologies, such a DB using SQL Server, etc.
Part 2
After completing the initially structured design, it was decided to design and build the system using object-oriented methodologies, to allow for more flexible design/build iterations and re-use of design and code. You have therefore now been asked to produce a “first cut” design of the new system described in the Core Scenario and Scenario Extension (Part1 +Part2) using object-oriented analysis and design principles and UML. The UML design should include:
1) Use Case Analysis - A UML Use Case diagram identifying all actors and their Use Cases.
2) Interaction Diagrams. Using UML sequence (interaction) diagrams perform an analysis of the main Use Case scenarios.
3) Design UML Class Diagram - Show all attributes, methods and associations for all main classes.
4) Statechart diagrams for all major classes (approx. THREE classes).
A prototype system can be built using any appropriate technology/tools you are familiar with. The prototype system will need to have enough business and UI functionality to test the competence of the design for TWO main functionality of the system (TWO main use cases).
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