Mapping the Flexible Endoscope Disinfection Cycle indicates the Need for Risk Reduction Strategies for Task Complexity and Environmental Stressors

Highlights

•
75 consecutive tasks are required to sterilize an endoscope.
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This series of 75 tasks is termed the Endoscope Sterilization Cycle.
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The majority of risk of error (94.6 %) in this cycle maps to the sterile processing space.
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Reduction in task complexity and environmental stress will be critical for reducing errors in this cycle.

Abstract

Introduction

Endoscopes carry a significant infectious risk if not properly sterilized. We mapped the total tasks required to properly sterilize an endoscope and conducted theoretical risk modeling to define tasks at greatest risk for error in this process.

Methods

observations were conducted on a hospital campus in the following spaces: operating room, sterile processing pre-washer side, sterile processing post-washer side, and storage. The total number of tasks and the stress level in each space were determined. Each task was assigned an error rate based on a complexity scale in Smith’s textbook Reliability, Maintainability and Risk , 7th Ed. Tasks in low stress spaces were assigned the lowest possible error rate per task type and those in high stress environments were assigned the highest error rate per task type. Risk of error score (RES) for each space and an overall RES was calculated by adding up all the assigned task error rates.

Results

observations were conducted on 22 flexible endoscopes. Seventy-five tasks were identified. Each was performed by a human. Fifty-two tasks were performed in sterile processing which had the highest stress score and highest number of complicated, non-routine tasks. The aggregate RES per endoscope. was 3.0832 The majority of risk (94.%) mapped to sterile processing (RES of 2.918).

Conclusions

proper sterilization of endoscopes involves 75 tasks. The majority of the RES maps to the high stress SPD environment. Strategies that reduce stress levels and the complexity of tasks in this space would significantly reduce the risk of errors in sterilization.

1 Introduction

Flexible endoscopes are unique as instruments for invasive procedures because they are not subjected to high pressure, steam sterilization. The endoscopic disinfection cycle, the series of tasks required to disinfect an endoscope between patients has not been well mapped and the risk for error for all tasks in this cycle has never been risk modeled. However, breakdown in task performance and contamination have been reported via direct observational studies. ^, ^, We have previously mapped and modeled the theoretical risk of errors in sterile processing for simple, non-laparoscopic surgical instruments which we termed the Surgical Instrument Cycle. Our modeling indicated that complexity of task and stress in the work environment presented the greatest challenges in limiting risk of errors and that the majority of risk mapped to the Sterile processing department (SPD) as indicated through a metric termed Risk of Error Score or RES. With our previous experience in mind, we set out to map the number of steps required to sterilize an endoscope and map the RES in a process which we term the Flexible Endoscope Sterilization Cycle.

2 Methods

Observations were conducted in the following spaces: operating room, sterile processing pre-washer side, sterile processing post-washer side, and storage. Task categorization has been described previously. Briefly tasks in the Endoscope Sterilization Cycle were compared to similar tasks in Smith’s textbook Reliability, Maintainability and Risk , 7th Ed. and assigned an error score identical to a cognate or equivalent sample tasks in the textbook. Tasks fell into one of four categories: simplest possible, simple routine, routine with care and complicated non-routine. Error rates were adjusted to the highest or lowest error rate for a given task based on the stress level in the environment. Assessing stress levels in the environment has been described previously. Briefly, the following variables were scored in decimals from 0 to 1: Physical Work Environment (temperature/noise/light/humidity), Organizational (layout), Workforce health (percent full FTE compliment), Employee experience (percent fully trained), Circumstantial (time pressures, etc.). Aggregate variable scores greater than 2 in any space were considered high stress and anything below 1 was considered low stress.

RES was determined by adding up all the assigned error scores in each space after adjusted for stress levels.

3 Results

We observed 22 pediatric endoscopes (1 upper, 4 bronchoscopes, 17 colonoscopes) passing through the Endoscope Sterilization Cycle. Seventy-five tasks were identified in this cycle. Each task was performed by a human. Most tasks (Fifty-two) were performed in sterile processing. Stress scores varied considerably between the spaces with the OR, and OR storage having a stress score of 0.3 and the entirety of sterile processing having a stress score of 3.3 ( Table 1 ). There were 7 tasks in the OR space ( Table 2 ) after the endoscope had been used. Five of these were “routine with care” tasks. The RES for this space was 0.0052. The RES for SPD ( Table 3 , Table 4 52 tasks) was 2.918. Six of the seven “complicated non-routine” tasks were performed in pre-washer SPD space which had 37 tasks. Interestingly, only one of these had to do with inspection. The post-washer SPD space had 15 tasks (7 “routine simple” and 8 “routine with care”). OR Storage and OR Prior to Use had a total of 16 tasks with one “complicated non-routine” task of inspecting the endoscope prior to use (RES of 0.16). The aggregate RES for the endoscope sterilization cycle was 3.0895. Most risk (94.6 %) mapped to the sterile processing space (RES of 2.918).

Table 1

Stress scores of the spaces in the Endoscope Sterilization Cycle.

	Stress Scores
Space	Phys. Environ.	Organizational	W.F. Health	Employee Exp.	Circumstantial	Total Stress Score
OR after use	0	0	0.1	0.2	0	0.3
SPD pre-washer	1	1	0.2	0.3	0.8	3.3
SPD post-washer	1	1	0.2	0.3	0.8	3.3
OR Storage	0	0	0.1	0.2	0	0.3
OR before use	0	0	0.1	0.2	0	0.3

*W.F.=Workforce.

*SPD= Sterile Processing Department.

Table 2

Tasks in operating room after use.

Task#	Task	Task complexity	Adjusted Task RES	Space RES
1	Received from surgeon	routine with care	0.0001
2	Put back in pan	routine with care	0.001
3	Instruments sprayed	routine with care	0.001
4	Recover pan	routine simple	0.001
5	Pan bagged	routine with care	0.001
6	Pan put on cart	routine simple	0.0001
7	Cart bagged	routine with care	0.001	0.0052

Table 3

Tasks in sterile processing.

Task #	Task (Pre-Washer side)	Task complexity	Adjusted Task RES	Space RES
8	Cart wheeled to dirty room	simple	0.0005
9	Cart unbagged	routine with care	0.05
10	Pans put on rack	routine with care	0.05
11	Put on PPE gear	routine with care	0.05
12	Fill sink with water	simple	0.0005
13	Take instrument case off rack	routine with care	0.05
14	Unbag case	routine with care	0.05
15	Open case	routine simple	0.005
16	Take out endoscope	routine with care	0.05
17	Throw any remaining caps on scope ports away	routine with care	0.05
18	Fill bucket of water on clean side of sink	simple	0.0005
19	Turn on Olympus leak checker	routine simple	0.005
20	Check for pressure	routine with care	0.05
21	Hook up to endoscope	routine with care	0.05
22	Place endoscope in water	routine with care	0.05
23	Inspection for leaks	Complicated	0.25
24	Turn off Olympus leak checker	routine simple	0.005
25	Release pressure and wait 10 ss	routine with care	0.05
26	Add enzymatic detergent to sink	routine with care	0.05
27	Open endoscopic scrub brush/wire	routine simple	0.005
28	Scrub endoscope	Complicated	0.25
29	Throw away brush	simple	0.0005
30	Wipe entire scope with rag	routine with care	0.05
31	Add plugs to certain ports for Scope Buddy	Complicated	0.25
32	Add SPECIFIC hose attachment for scope buddy	Complicated	0.25
33	Start scope buddy using enzymatic solution	routine with care	0.05
34	Move hose to pure water bucket	routine simple	0.005
35	Start scope buddy again	routine with care	0.05
36	Remove hose from bucket	routine simple	0.005
37	Pull sink drain	routine simple	0.0005
38	Rinse scope under water	routine with care	0.05
39	Place scope in DSD machine	Complicated	0.25
40	Add leak tester plug and connect to DSD	Complicated	0.25
41	Close inside lid	routine with care	0.05
42	Close outside lid	routine with care	0.05
43	Start machine	routine with care	0.05
44	Get new gloves	simple	0.0005
	(Post -washer side)
45	Open outside lid	routine simple	0.005
46	Open container with indicator strips	routine simple	0.005
47	Place strip into specific compartment and wait 40 ss	routine with care	0.05
48	Confirm test clear and input into machine	routine with care	0.05
49	Fully de-gown from all dirty material	routine with care	0.05
50	Have someone pass clean gloves over	routine simple	0.005
51	Open inside lid	routine simple	0.005
52	Remove leak tester	routine with care	0.05
53	Remove endoscope from DSD and place on towel in clean room	routine simple	0.005
54	Detach plugs and hose	routine simple	0.005
55	Return plugs and hose to location	routine with care	0.05
56	In clean room, get new gloves	routine simple	0.005
57	Air brush endoscope until dry	routine with care	0.05
58	Hang on rack in immediate proximity	routine with care	0.05
59	Place in a separately washed endoscope bin	routine with care	0.05	2.918