Reduction of Patients’ Reduction of Patients’ Total Turn Around TimeTotal Turn Around Time

A System Design Project conducted on Department of Diagnostic Imaging (DDI) By ISE-DDI team: Chong Jun Xiong, Fan Jiafang, Liu Xufeng, Wu Zhe

Problem DescriptionProblem DescriptionDepartment of Diagnostic Imaging (DDI) provides radiography services to in-patients (IP) and out-patients (OP) in NUH.

This project focuses on two most important modalities: X-ray and CT, attempting to reduce the total turn around time (TAT) of patients, which comprises a large portion for waiting.

Problem DescriptionProblem DescriptionDepartment of Diagnostic Imaging (DDI) provides radiography services to in-patients (IP) and out-patients (OP) in NUH.

This project focuses on two most important modalities: X-ray and CT, attempting to reduce the total turn around time (TAT) of patients, which comprises a large portion for waiting.

ObjectiveObjectiveReduce the total Turn around time through1. Improvements on X-Ray processes and resource utilization2. Modify CT appointment scheduling3. Lean service & process standardization

ObjectiveObjectiveReduce the total Turn around time through1. Improvements on X-Ray processes and resource utilization2. Modify CT appointment scheduling3. Lean service & process standardization

Process MappingProcess MappingProcess MappingProcess Mapping

TAT Factors GenerationTAT Factors GenerationTAT Factors GenerationTAT Factors Generation

Solutions (X-Ray)Solutions (X-Ray)

1. Assign SupervisorDevote one radiographer for cassettes handling, including transfer cassettes between X-ray rooms and processor; cassette developing, film & database entry checking. He also serve as a supervisor to X-ray corridor to handle coordinationamong radiographers and patients .

The use of “supervisor” is expected to reduce total TAT by up to 20-40%.

2. “express-queue” Nursing assistants direct all chest x-ray patients to Room 3 during peak hour uponsupervisor’s signal. Assign an experienced radiographer to achieve highest efficiency to ensure fast scans for short procedures, so as to reduce total TAT through reduction of machine setup time.

The “express-queue” is expected to reduce total TAT by 8-13%.

3. Process standardizationBy standardizing the process will results in the variation in service time, which leads to significant reduction of TAT for about 15-25%.

Solutions (X-Ray)Solutions (X-Ray)

1. Assign SupervisorDevote one radiographer for cassettes handling, including transfer cassettes between X-ray rooms and processor; cassette developing, film & database entry checking. He also serve as a supervisor to X-ray corridor to handle coordinationamong radiographers and patients .

The use of “supervisor” is expected to reduce total TAT by up to 20-40%.

2. “express-queue” Nursing assistants direct all chest x-ray patients to Room 3 during peak hour uponsupervisor’s signal. Assign an experienced radiographer to achieve highest efficiency to ensure fast scans for short procedures, so as to reduce total TAT through reduction of machine setup time.

The “express-queue” is expected to reduce total TAT by 8-13%.

3. Process standardizationBy standardizing the process will results in the variation in service time, which leads to significant reduction of TAT for about 15-25%.

Solutions (CT)Solutions (CT)Long waiting for CT is largely due to disruption of add-ons and unpunctual arrival of appointment patients. Hence more flexible appointment scheduling rules is suggested:

1. Assign different appointment interval times for patients of different process type and stage.

2. Give buffer of 10 mins for each hour. 20 mins buffers are given at 9:40 am and 1:40pm.

3. Extend the schedule hour to 4pm4. Advise patients arrive 5-10 mins earlier5. Avoid scheduling consecutive long

procedures in one CT room6. Avoid long procedures scheduled after 3pm.

The diagram is an illustration with Excel VBA, different appointment intervals are calculated with different combination of patients type and stage, base on current data analysis.

Solutions (CT)Solutions (CT)Long waiting for CT is largely due to disruption of add-ons and unpunctual arrival of appointment patients. Hence more flexible appointment scheduling rules is suggested:

1. Assign different appointment interval times for patients of different process type and stage.

2. Give buffer of 10 mins for each hour. 20 mins buffers are given at 9:40 am and 1:40pm.

3. Extend the schedule hour to 4pm4. Advise patients arrive 5-10 mins earlier5. Avoid scheduling consecutive long

procedures in one CT room6. Avoid long procedures scheduled after 3pm.

The diagram is an illustration with Excel VBA, different appointment intervals are calculated with different combination of patients type and stage, base on current data analysis.

Current Queue Length Improved Queue Length

Fig. 4.1 Comparison of queue length with a supervisor

Process time variance = 2 min Process time variance = 1 min

Fig.4.3 Comparison of queue length with different process time variance

Lean service & process standardizationLean service & process standardizationLean service & process standardizationLean service & process standardization

Special thanks to Department of Diagnostic Imaging, National University Hospital for the kind help and support, Dr Yap Chee Meng and Dr Chai Kah Hin for the inspiring guidance and assistance.

Total TAT

X-Ray CT

OP Registration Counter

IP Registration Counter

Others…

Patients

Work Flow

Queuing discipline

Preparation

Facility layout

No. of staff

No. of cassette

Others…

Contrast

Add on

Work Flow

Facility layout

Open hours

Others…

Appointment Schedule

Queuing discipline Work

Flow

Tray location

No. of terminals

Disruption IT system

Others…

Porter coordination

Others…

Porter scheduling

Waiting bay design

Appointment handling

Arrival rate

Type

Stage Age

Education

Others…

Other modalities

Others…

Out-Patient

In-Patient

2

18%

53%

0

30%

1

8

70%43%

10% 32%15%23%12%

12%6%

CT

20

103

49

10

X-Ray

X-Ray

Waiting Time

32%15%23%

12%12%6%

7%37%48%7%

1.5

6

2.03.5

2.52.5

6.515.0

26.0

16.0

13.06.0

12.09.0

3.55.55.5

3.5

Waiting Time

Registration Counter

Waiting Time before leave

Scan TimeRegistration Time

Registration Floor

Corridor A & E

Corridor C & E

Waiting bay, A, C &

E

Performance control &Continuous Improvements!

Categorize activity

Internal system standardization

External system standardization Reduce external factor variations

(patients arrival pattern & behavior)

Standardize serviceprocedures

Standardize individual performance actions

Standardize overall performances

Take form From the tray

DevelopCassette

Give patient Instruction

Issue queue Number

Form Processing

ComputerData entry

Fetchcassettes

FeedbackTo patient

Scan

Instruct patient

Collection &Process form

AnalyzeFilm

Scan

Take oneForm

ScanPreparation

Call inPatient

FormProcessing

Take PatientOut

Registration X-Ray CT

Identify wastes

Value adding activities

No value, can eliminate

Categorize activity

Internal system standardization

External system standardization Reduce external factor variations

(patients arrival pattern & behavior)

Standardize serviceprocedures

Standardize individual performance actions

Standardize overall performances

Take form From the tray

DevelopCassette

Give patient Instruction

Issue queue Number

Form Processing

ComputerData entry

Fetchcassettes

FeedbackTo patient

Scan

Instruct patient

Collection &Process form

AnalyzeFilm

Scan

Take oneForm

ScanPreparation

Call inPatient

FormProcessing

Take PatientOut

Registration X-Ray CT

Take form From the tray

DevelopCassette

Give patient Instruction

Issue queue Number

Form Processing

ComputerData entry

Fetchcassettes

FeedbackTo patient

Scan

Instruct patient

Collection &Process form

AnalyzeFilm

Scan

Take oneForm

ScanPreparation

Call inPatient

FormProcessing

Take PatientOut

Registration X-Ray CT

Identify wastes

Value adding activities

No value, can eliminate

No value, cannot eliminate

Scheduled slots

Reserved slots

Available slots