Quality Improvement Methods
30. One Piece Flow
a. Definition: Consistent with Continuous Flow (see Section 8), for many processes it is more efficient to do one piece of work at a time rather than in batches. This tends to reduce waste in the form of waiting for a batch, additional inventory in process and the wasted use of space. Cycle time is generally reduced with one piece flow. One piece flow may not be feasible in certain areas such as where resources are not always available.
There are several related concepts, including Heijunka or production leveling. Heijunka means to do work at a steady pace in conjunction with demand. Heijunka, one piece flow, Takt time (see Section 49), and continuous production all tend to reduce waste in established processes as compared to batch workflow where work arrives in lumps and otherwise waits until the prior batch is completed. One-piece flow may not make sense in some situations. For Example, a lab may not run each specimen one at a time, if the laboratory test is not extremely time-sensitive, because the test set up time may mean it is more efficient to run the lab test with batches of specimens rather than as they arrive. However, other work may benefit from one piece flow such as completing all the work for one patient before moving on to the next. This often improves quality, patient satisfaction and productivity. So-called flow rounding means that all work for a patient is completed by an intern or resident before they move to the next patient.
Also related to these ideas is SMED (Single-Minute Exchange of Dies) or reducing the changeover time between different processes or changes in equipment. This is done by moving as many changeover tasks as possible so that they occur when a process or equipment is running. Thus, there is less idle time (waste) required for the changeover. The benefits are often lower costs and more responsiveness.
- Murray, Mark, and Donald M. Berwick. "Advanced access: reducing waiting and delays in primary care." JAMA 289.8 (2003): 1035-1040.
- Stapleton, F. Bruder, et al. "Modifying the Toyota Production System for continuous performance improvement in an academic children's hospital." Pediatric Clinics of North America 56.4 (2009): 799-813.
- Leslie, Marshall, et al. "Using lean methods to improve OR turnover times." AORN journal 84.5 (2006): 849-855.
One piece flow has been used on ambulatory care centers where as each patient arrives they are greeted, vital signs taken promptly, meet with a provider, procedure done and then moved to a recovery area. Similarly, rapid response to each arrival has been effective in Emergency Department patient flow as well as individual clinics. Very little waiting occurs, which is appreciated by the patient. Flow is achieved by careful coordination among staff. Patients' value for their visit is increased.
1. Break down the process to individual parts sufficient to maintain productive work using Takt time (see Section 49). Reduce, or eliminate, patient flow or other activities where the work is done in batches.
2. Assure that the physical layout minimizes travel for both patients and staff
3. Train and assign staff and implement flow as designed
4. Cross train the staff involved regarding the various steps, where possible
5. Document the process with Standard Work (see Section 47)