VSM/ Process Map Case ExamplesColonoscopy
A simple VSM for patients requiring a colonoscopy at an endoscopy clinic is shown in the following
graphic. Assume that patients recover in the same room where the colonoscopy is performed, and the
clinic has two colonoscopy rooms.
What is the cycle time for the process?
Cycle time for the process = longest task cycle time = patient recovery = 40 minutes.
What is the throughput time?
Total time in the system = 5 + 20 + 15 + 15 + 30 + 40 + 10 + 5 = 140 minutes.
What is the percent value added in this process?
Value added time = 5 + 15 + 30 + 40 = 90
Value added time/total time = 90/140 *100 = 64%
If the clinic operates 10 hours a day and demand is12 patients per day, what is the takt
time?
10hours day
= 0.83hours * 60 min utes hour = 50 min utes
12patients day
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If demand is 20 patients per day what is the takt time?
10hours day
= 0.5hours * 60 min utes hour = 30 min utes
20 patients day
What would you do in the second situation?
Because the takt time is smaller than the cycle time, you cannot meet demand. You need to improve
the system by decreasing cycle time or reducing demand.
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Case Study – Imaging Center
This is a relatively simple process map to evaluate and improve a process.
What is the cycle time for the process?
Cycle time for the process = longest task cycle time = patient recovery = 15 minutes.
What is the throughput time?
Total time in the system = 1 + 1 + 2 + 7 + 13 + 3 + 7 + 15 + 5 + 3 + 3 = 60 minutes.
What is the % value added in this process?
Value-added time = 2 + 3 + 15 + 5 + 3 = 28
Value added time/total time = 29/60 * 100% = 47%
Possible Improvements:
1. Pre-registration should be done online or via the phone.
2. Concierge service should be available to park car and retrieve car after the procedure. This
should be synchronized with procedure duration.
3. More attention should be paid to the takt time of the procedure and a better pull system to
reduce the time the patient stays in the exam room.
Although the parking service might be a new cost to the system, the reduction in non-valueadded time should improve total cycle time, which would allow more patients to be seen per day.