Theory of Constraints Handbook - James Cox Iii [601]
Step 1: Identify the System’s Constraint
In a complex health care system, there is one constraint that most influences the patients’ flow. It is usually the most expensive resource: human, machine, or physical space. For example, in a small practice the constraint is usually the physician, dentist, chiropractor, or veterinary surgeon. In a larger system, it could be operating rooms, recovery rooms, emergency rooms, or CT/MRI machines. Ideally, the physician or surgeon performing the services (without whom the patients cannot flow) should be the constraint. However, due to the high investment in operating rooms, government regulations, and nursing or anesthesiology shortages, the constraint might be in one of these areas. The first challenge in the 5FS is to identify the constraint. To that end, a high-level value stream map (VSM) can help clarify the key obstruction or constraint to the flow of patients and information. The current or as-is VSM is provided in Figs. 31-3a and b and shows the flow of the patient, the value-added time (41 minutes), the wait time (52 minutes), the value-added quotient of 44 percent (the value-added time/total time in system), and the constraint (doctor) location in the system.
FIGURE 31-3 High level and lower value stream maps of health care systems.
Once we understand the relationship of the constraint to Throughput and the achievement of the system’s goal, we can develop protection (a buffer for the constraint), and policies and procedures for the constraint and supporting staff to maximize the system Throughput.
In Fig. 31-4, the VSM can be drawn showing the complete value chain of health care businesses for a patient treatment. The flow of the patient through the supply chain will be dependent upon the dentist or lab when viewed from the larger system view. Similarly, the constraint to the flow of the patient in the hospital might be the capacity of the imaging department, the blood lab, or the recovery room nurses.
FIGURE 31-4 Value stream map of a series of businesses providing a patient treatment.
Step 2: Decide How to Exploit the System’s Constraint
Once we have identified the constraint, we can determine how to make the constraint both effective and efficient. In our case, this is done by determining the best use of the doctor’s time measured as Throughput/doctor time unit. Here we begin to see how combining TOC with other tools can be effective.
Example: Let us examine my practice—a dental surgeons’ practice. We identify the dental surgeon as the constraint (the scarcest and most expensive resource). We next exploit the doctor’s (dental surgeon’s) time by using the Lean tools to effectively and efficiently use the doctor’s time. We can implement the total kit concept, which ensures that all the documents, medical clearance, lab results, and imaging information are available to the doctor prior to seeing the patient. The Lean tools such as standard workflow and 5 S are useful in organizing our work-place to ensure everything is in its assigned place and is visually available for the doctor. Total preventive maintenance and mistake proofing ensure that the doctor’s time is never wasted.
Six Sigma measures are implemented to ensure that processes are capable of achieving the desired results. DMAIC methodology is used to ensure the control of the system that protects doctor time utilization. DFSS (Design for Six Sigma) methodology can be helpful in redesigning certain processes where system capability is too low and new services have to be started to stay competitive. An example might be the use of patient focus groups to develop new services through quality function deployment (QFD). QFD methods can be utilized as in Fig. 31-5 to identify the needs of potential patients, referring doctors, and other healthcare stakeholders. Once the needs have been identified, the functional requirements