QUERI – Quality Enhancement Research Initiative

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Quality Improvement Methods

8. Continuous Flow

a. Definition: Continuous flow is the concept that work can be done best where there are no stops and starts but rather a smooth and organized sequence. This reduces waste, such as waiting between Steps. Continuous flow improves quality due to ongoing focus on the necessary tasks. Doing work in batches is the opposite of continuous flow and leads to waste (see Section 48). One piece flow is deemed better because it tends to reduce inventory and makes errors more obvious. (see Section 26)

b. Literature

The concept of continuous flow comes from the manufacturing and supply chain industries but its benefits are applicable to healthcare work as well.

  • Nelson-Peterson, Dana L., and Carol J. Leppa. "Creating an environment for caring using lean principles of the Virginia Mason Production System." Journal of nursing administration 37.6 (2007): 287-294. The Virginia Mason hospital in Seattle has implemented many of the Toyota Production System ideas, including converting batch work to more continuous one piece flow.
  • Adapting lean to histology laboratories, Rene J. Buesa, Annals of Diagnostic Pathology, Volume 13, Issue 5 , Pages 322-333, October 2009. There are many published examples of successfully converting work done in batches to continuous flow. Often this is in a Lab or Pharmacy setting but successful examples occur in emergency departments, surgery, outpatient clinics and others.

c. Example: A hospital pharmacy prepares medications each day and various technicians do the work. It is a part time task for each technician. Previously the technicians would work on a batch of orders but do other tasks between the batches. By creating a workflow, a supportive work layout and appropriate staffing at a level that promotes continuous flow, a better quality and improved productivity results. The total amount of labor, with such an arrangement, is often less than in the previous arrangement.

d. Steps

The basic idea of continuous flow is to function with one-piece flow rather than batch flow. Thus providing a service or completing a product is done in a sequence of continuous workflow. Steps include:

1) Determine where continuous flow is applicable and the steps involved to create it. Continuous flow is useful where there is sufficient work to require ongoing staffing and is often helpful as part of a simplification effort

2) Determine the work, and equipment needed for each step

3) Determine "Takt time" to create a continuous flow (see Section 43)

4) Determine the staffing needed to meet the Takt time

5) Balance the work within the cell