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Chapter 8. More Examples of Mistake-Proofing in Health Care

Mistake-Proofing the Design of Health Care Processes -

Chapter 8. More Examples of Mistake-Proofing in Health Care


This chapter features 34 additional examples of mistake-proofing in health care. The examples in this chapter are more expensive and technology-based than those described in Chapters 5-7, although some very simple examples are also included. They are provided as both a catalog and a catalyst for reducing human errors in health care.

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Example 8.1—Infant Abduction Prevention

Mistake-proofing often involves electronic sensors to ensure high-quality industrial production. Electronic sensors are also used in health care applications. In this example (Figure 8.1), an electronic device, or "tag," is designed to be clamped to the infant's umbilical cord. The arrow in the photo points to the cord clamp, which secures the tag to the infant. The tag ensures that the infant is not removed from the nursery. If the infant is removed without authorization, alarms sound, specified doors lock, and the elevators automatically return to the secured maternity floor; the elevator doors remain open.

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Example 8.2—Bar Coding

Bar coding is one of the more common and effective information enhancement and mistake-proofing devices. It is particularly useful in ensuring a match between a patient and their treatment, medicines, and supplies (Figures 8.2 and 8.3).

One of the contributors to this example emphasized the importance of radiologists matching the film they are reading to the right patient:

Bar codes are attached to every order so that the radiologist can electronically identify the patient and be sure that the correct patient [information] has been entered into the digital dictation system.

Another contributor stated:

Each specimen is labeled with a bar code that is specific to that patient and the test that has been ordered. The instruments in the laboratory are programmed to identify the bar code that ensures positive patient identification and to verify that the correct test is performed.

Bar coding, however, is a setting function. Therefore, it is only as effective as the regulatory function to which it is linked. Many of the control methods used with bar coding are warnings or sensory alerts. The control methods of shutdown and forced control are infrequently used.

AuBuchon discussed this shortcoming of bar coding systems for patient identification:

A disadvantage that we ran into when we began using the system on a trial basis is that the system doesn't have to be used... ultimately, our anesthesiologist said, 'You know, this is a really neat system, but I won't use it. He said [that with] the Bloodloc™, I have got to use it, I have got to do something, we have got to take it off, and that's the whole idea. It's a barrier. It prevents the transfusionist from getting to a unit of blood that they are not supposed to get to.' So we have continued using that older system rather than the new, fancy system.1

The use of bar codes does not automatically prevent errors from occurring. Staff should check that assigned bar codes match. In Figure 8.3, a line of red laser light is hovering in the gap between two bar codes, increasing the odds of reading the wrong bar code by mistake.

Given the prevalence of patient identification errors, bar coding is a very promising direction in mistake-proofing.

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Example 8.3—Computer-Aided Nutrition and Mixing

Software is used to profile total parenteral nutrition (TPN) solutions (Figure 8.4). A patient's nutritional needs (protein, sugar, fat, vitamins, and electrolytes) are entered into the software application. The software sends a message to an automixer that compounds the ingredients to create the base solution. The software issues a warning if certain concentrations of ingredients are exceeded based on literature values.

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Example 8.4—Equipment Collisions

In hospital operating suites full of large, expensive equipment, there is always the danger that units of equipment will collide with each other. Equipment requires a wide range of motion while in operation. Collision detection systems warn and, in some cases, can lock if they sense an impending collision. The equipment in Figure 8.5 is situated in an angiographic suite and outfitted with electronic and manual locks to prevent collisions.

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Example 8.5—Flawless Equipment Setup

When creating x-ray film, it is very important that the tube is centered to the film and is situated the correct distance from the film. The position locks (Figure 8.6) enable the tube to be centered quickly and correctly by only locking at the correct positions.

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Example 8.6—Mistake-Proof Mistake-Proofing

Transport monitors, which employ flashing and audible alarms, warn all health care workers of high/low heart or breathing rates. A misplaced blood pressure cuff on the lower arm below the elbow, as in Figure 8.7, would result in inaccurate blood pressure readings and trigger flashing and audible misplacement alarms.

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Example 8.7—Private Files

Often, mistake-proofing is accomplished by providing barriers that prevent people from taking the wrong action. In Figure 8.8, a portion of the file cabinet drawer can be locked. This mistake-proofing is neither mysterious nor subtle.

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Example 8.8—Computer Drug Interaction Checker

Software that checks for drug interactions (Figure 8.9) falls under Shingo's concept of a successive-check.2 A successive-check is a mistake-proofing device that facilitates checking work previously performed by others and that, in a low-cost, relatively automatic way, notifies the user that something is wrong. Shingo was of the opinion that defect detection and rapid feedback following a mistake are nearly as effective as not making the mistake at all. Even after an initial mistake, staff can recover before substantial harm occurs. In this case, the pharmacist double-checks the prescriptions submitted by doctors. It is clear that there is no resultant harm if an error can be caught by the pharmacist before the patient receives the medicine, thereby avoiding, at the very least, significant difficulties for the pharmacist, doctor, and patient.

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Example 8.9—Computerized Physician Order Entry

According to Poon, Blumenthal, Jaggi, et al;3

Medication errors are the most common cause of preventable injuries in hospitals. Computerized physician order entry (CPOE) systems can reduce the incidence of serious medication errors by 55 percent, but only 10 percent to 15 percent of hospitals use them.

CPOE is computer software that physicians and other health care providers use to issue and record patient orders for diagnostic and treatment services such as medications, laboratory tests, and diagnostic tests. Computers on wheels (COWs) are available throughout hospitals so that staff can enter information without having to go to a central location (Figure 8.10). CPOE provides several mistake-proofing features:

  1. Informs providers of common dosages and overdose warnings via drop-down menus.
  2. Eliminates the issue of legible handwriting.
  3. Conducts drug interaction and allergy checking routines.
  4. Employs sophisticated systems that function as a clinical decision support system (CDSS).a CDSSs are "active knowledge systems that use two or more items of patient data to generate case-specific advice."4

a. Go to

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Example 8.10—Sponge-Counter Bag

In aviation, significant effort is exerted to ensure that no foreign objects are left inside fighter planes. This is done to prevent foreign object damage (FOD). Changing G forces can make objects weightless. Subsequently, they could fly through the cockpit and cause serious damage to people and equipment. FOD is also a problem in surgery. Failing to remove foreign objects (tools or supplies) from inside a patient can cause serious harm.

The sponge-counter bag (Figure 8.11) assists in keeping track of sponges removed from a patient. Accounting for the sponges put into the patient is easier because the sponges are not discarded immediately or put in a random pile.

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Example 8.11—Notebook Switches

Galsworth5 endorses the mantra that workers should be able to "know by looking." The notebooks in Figures 8.12 and 8.13 enable users to do that. The dial on the notebook in Figure 8.12 and the switches on the notebook in Figure 8.13 enable everyone to know the status of the paperwork inside.

Colors indicate when medical staff have made entries that need to be processed by administrative staff. A different color notifies the nurse when the work is finished. No color is displayed when the work is completed, and no further action is needed.

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Example 8.12—Plug Protection

In May 2004, a National Patient Safety Foundation (NPSF) LISTSERV® participant inquired about the safest height for electrical wall outlets in pediatric rooms. In his response, Matthew Rosenblum stated that he believes that other matters are probably more important:

For example, how the cord is secured to the outlet and to the wall and how the outlet is covered when no devices are plugged in. In this regard, there are numerous products on the market for securing electrical cords to the outlets and to walls. Also, many secure socket covers are available.6

When an outlet is used properly, the plug fits without slowing the process. The process is slowed only when an error occurs; then the mistake-proofing device brings the process to a halt. Figures 8.14-8.18 illustrate various mistake-proofing methods employed to make wall sockets safer.

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Example 8.13—Instructions Getting in the Way

The card shown in Figure 8.19 is not the strongest example of mistake-proofing. It does, however, put knowledge in the world. Also, it is designed to stand out against a noisy background. At a minimum, someone (a patient or family member, perhaps) will have to move it out of the way in order to use the table space.

A card on the overbed table (Figure 8.20) provides information to patients about what patient safety behaviors to expect from staff and encourages them to hold staff accountable for complying with those behaviors.

This example is similar to the time-out example (Chapter 7, Example 7.4). It also has some common features with a proxy ballot that was mailed to a retirement fund (Figure 8.21). The ballot was designed so that it would not fit in the envelope until a small portion of the page containing the mailing instructions/checklist was torn off.

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Example 8.14—Monitoring Glucose

In the past, glucose monitoring required that patients follow strict clinical procedures to determine their blood glucose levels. Today, most of the precise actions and calculations are designed into a portable glucose monitor that is user-friendly and more mistake-proof.

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Example 8.15—Unit Dosing

Robotics, bar coding, and packaging medicines in plastic bags containing a single dose, or "unit dose," form a powerful combination of mistake-proofing devices. Individually, none of them would be very effective. The unit dose package enables the machine to select a single dose to be delivered to a patient. The unit dose package also provides a convenient way to associate bar codes to a specific pill for use in the pharmacy and throughout the medication delivery system. Bar codes make the packages containing the pills machine readable (Figure 8.22). The machine in Figure 8.23 provides the automation that makes converting bottled medicines into unit doses less expensive, less labor intensive, and more reliable.

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Example 8.16—Kits

The Massachusetts team from the Patient Safety Improvement Corps (PSIC) reported their efforts in reducing central line infections.7 They recommended a variety of changes to the central line insertion process. Included in their recommendations is a customized kit (Figure 8.24) that standardizes available supplies, including drapes and other site preparation materials.

Table 8.1. Cost comparison between two methods of reducing central line infections

Savings will equal the difference in total episodic costs of the two methods:

([B]$6,525,000- [A]$3,240,000 minus the difference in equipment costs ([A]$147,840-[B]$55,552=$92,288)

Method A: Previous Method

Annual equipment cost
2,240 cases x $24.80/kit = $55,552.

Annual infection cost
$45,000/episode x 145 expected episodes = $6,525,000

Total Cost = $6,580,552

Method B: Using Custom Kit

Annual equipment cost
2,240 cases x $66/kit =$147,840

Annual infection cost
$45,000/episode x 72 expected episodes = $3,240,000

Total Cost = $3,387,840

Net Savings = $3,192,712

According to the calculations in Table 8.1, the annual cost increase is substantial: $92,288. Yet, if the number of infections can be reduced by only 3 episodes out of 145 (a 2 percent decrease), the change will be cost-justified. The team forecasted infection rates would be cut in half, a result that was supported in their preliminary findings. The net savings appeared to be far more substantial than the cost increase.

Source: Example and photos courtesy of an anonymous contributor. Used with permission.

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Example 8.17—Bacteria-Detecting Bandages

Benjamin Miller8 developed the technology to produce "smart bandages" that indicate an infection by changing color (Figure 8.25). The "smart bandage" is in the early stages of development, so actual commercial products may still be years away. In its current form, the technology is in a chip that reveals the existence of different bacteria by changing colors. As a consumer product, a small chip would be embedded in a regular bandage. Computer connectivity is another future possibility.

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Example 8.18—Urinalysis Test Strips

The old method of reading urinalysis test strips required health care workers to make subjective decisions. Timing and color perception were critical to error-free results. The machine in Figure 8.26 analyzes urine test strips and prints out the results. In addition to the obvious mistake-proofing associated with the automatic nature of the machine, the strip can be inserted in only one direction, and the results can be printed out and placed in the patient's medical chart. A transcription of the results is not necessary.

Improperly handled or inadequately maintained samples can result in inaccurate diagnosis and treatment. The sample transport kit in Figure 8.27 maintains urine specimen integrity without refrigeration for up to 72 hours at room temperature.

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Example 8.19—Controlled by Connections

In Figure 8.28, a benign failure protects patients. Only rubberized specula will fit as attachments to this loop electrosurgical excision procedure (LEEP)b machine. Standard metal specula cannot be attached. If a metal speculum could be inadvertently attached to the machine and used, it would result in burns or electrocution.

b LEEP is "a way to test and treat abnormal cell growth on the surface tissue of the cervix. LEEP is prescribed after abnormal changes in the cervix are confirmed by Pap tests and colposcopy." Go to:

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Example 8.20—Child-proofing

Child-proofing is mistake-proofing. Since the bottle in the foreground of Figure 8.29 is not child-proofed, it is kept inside a child-proofed medication container when not in use to prevent accidents. In this example, an entire demographic group is unable to open a container, the exact benign failure for which it was designed.

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Example 8.21—Hemoglobin Testing

Precision in hemoglobin testing is important. Appropriate diagnosis and treatment are based on the results. Automatic hemoglobin testing devices (Figure 8.30), which perform the analyses in under 1 minute, have replaced analyses that relied on visual judgment or time-consuming, complicated methods for their precision.

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Example 8.22—Auto Shut-Off Treadmills

The treadmill in Figures 8.31 is used in rehabilitative therapy. It is equipped with an emergency stop button and automatically slows to a stop if the patient trips or falls.

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Example 8.23—Visual Systems

Figures 8.32 and 8.33 are more examples of how to "know by looking."5 Visual systems make a system's status visible to all. Norman9 encourages visibility to reduce errors: "make relevant parts visible." In Figure 8.32, the goal was to encourage employee donations in a workplace. The visibility of the status of the blood supply made a dramatic difference. Employee donations grew 300 percent. The sign served as a simple gauge to indicate inventory levels and mitigated the human perception, or error, of believing that the blood supply was more than adequate. The gas gauge depicted in Figure 8.33 is another visual cue to the status of a machine.

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Example 8.24—Needleless Systems

Needleless systems are used throughout the hospital to prevent needle sticks. The display panel in Figure 8.34 informs the nurse if there is air in the system.

Safety-engineered products for intravenous (IV) therapy have proven effective in protecting health care workers from exposure to bloodborne pathogens (Figure 8.35). In a retrospective review, the Exposure Prevention Information Network (EPINet) at the International Health Care Worker Safety Center at the University of Virginia in Charlottesville showed that the rate of percutaneous injuries among nurses declined from 19.5 per 100 occupied beds in 1993 to 9.6 per 100 occupied beds in 2001, a decrease of nearly 51 percent.10

Because these figures only include the first few months of legally mandated safety device use, they don't fully reflect the effect of the Needlestick Safety and Prevention Act,11 which mandated the use of needleless IV systems in all health care settings.

Safety-engineered devices prevent accidental needle sticks in two ways: primary prevention and secondary prevention. The most direct method of preventing needle stick injuries is through primary prevention techniques that eliminate the need to introduce sharps into the workplace, reducing the total number of sharps used.

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Example 8.25—Dress Code Cued by Floor Tile

The patterned tile in the hallway (Figure 8.36) is a sensory alert that surgical attire must be worn past this point. The tile adds a visual cue about what to do, but it only works for those who have been taught what the tiles mean. Patients, visitors, or new staff members will not be aware of this convention, thereby limiting its effectiveness. Fortunately, patients are usually sedated and recumbent in this hall, and visitors are prohibited.

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Example 8.26—Internet-Aware Refrigerator

Undergraduate engineering students at Virginia Military Institute (VMI)—advised by a biomedical engineer, a computer engineer, and a physician—designed a medical, Internet-aware, insulin refrigerator for patients living alone. The small refrigerator (Figure 8.37) is monitored by a microcontroller that is connected to a standard telephone outlet. If the refrigerator door is not opened in a 16-hour period, the microcontroller sends an E-mail or a pager alert to a designated caregiver. The system has battery backup in case of a power outage. The system can be retrofitted to standard refrigerators.

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Example 8.27—Resources with Which to Err

Sometimes, mistake-proofing can be thought of as the removal of the materials required to make errors. In the United Kingdom, the National Patient Safety Agency, in its first patient safety alert, warned that potassium chloride solution in its concentrated form should be removed from all general wards and replaced by diluted products. Go to Chapter 7, Example 7.7.

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Example 8.28—Keeping Time

Mistake prevention in the work environment involves reducing ambiguity. As far as time is concerned, variation is ambiguity. Clock systems (Figure 8.38) eliminate variation. A receiver takes signals from global positioning system (GPS) satellites and communicates the signals to other clocks in the system, including those in computers.

The clocks in Figure 8.39, produced by different manufacturers, set themselves accurately. When observed, the variation between them was approximately one-half second.

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Example 8.29—Distinct Labeling

Businesses try to build an image for their product lines by using similar packaging. Figure 8.40 illustrates a consistent image that leads to brand awareness but may also lead to packaging that offers minimal distinctions between products. Figure 8.41 shows that, while patterns and graphics can unify a company's product line, individual product packaging can be visually distinct. Even within the same product line, different dosages can be made distinct.c

c Information design for patient safety. A guide to the graphic design of medication packaging is available from the UK's National Patient Safety Agency at

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Example 8.30—Free-Flow/No-Flow Protection

Infusing too much or too little fluid can lead to problems. The free-flow protection on the IV pump in Figure 8.42 causes a benign failure. It is a simple V-shaped piece of plastic (Figure 8.43) loaded on the machine. The flow of medication to the patient stops if a tube is removed from the machine.

Some infusion pumps also offer downstream occlusion alarms that alert staff that the tubes are blocked or that the clamp has not been opened, preventing the fluid from infusing.

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1. AuBuchon J. Practical considerations in the implementation of measures to reduce mistransfusion. Best practices for reducing transfusion errors—OBRR/CBER/FDA Workshop. Food and Drug Administration, Center for Biologics Evaluation and Research and Office of Blood Research and Review. Bethesda, MD; 2002 Feb 15. Accessed: Sept. 2005.

2. Shingo S. Zero quality control: source inspection and the poka-yoke system. New York: Productivity Press; 1985.

3. Poon EG, Blumenthal D, Jaggi T, et al. Overcoming barriers to adopting and implementing computerized physician order entry systems in U.S. hospitals. Health Affairs 2004 July;23(4):184-90.

4. Wyatt J, Spiegelhalter D. Field trials of medical decision-aids: Potential problems and solutions. In: Clayton P, ed. Proceedings of the 15th symposium on computer applications in medical care, Washington, 1991. New York: McGraw Hill; 1991.

5. Galsworth GD. Visual workplace: visual thinking. Presentation at 16th annual Shingo Prize Conference. Lexington, KY: May 2004.

6. Rosenblum M. Written correspondence. NPSF LISTSERV®; 2004 27 May.

7. Alper E, Brush K, McHale E, et al. Prevention of central line infections. Public-private collaboration,

8. Smart bandages. Popular Mechanics 2002 May; 179(5):30.

9. Norman DA. The design of everyday things. New York: Doubleday; 1989.

10. Jagger J, Perry J. Comparison of EPINet data for 1993 and 2001 shows marked decline in needlestick injury rates. Adv Exposure Prev 2003;6(3):25-27.

11. Needlestick Safety and Prevention Act. Public Law 106-430, 106th Congress; 2000 Jan 24.

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Page last reviewed May 2007
Internet Citation: Chapter 8. More Examples of Mistake-Proofing in Health Care: Mistake-Proofing the Design of Health Care Processes -. May 2007. Agency for Healthcare Research and Quality, Rockville, MD.