“Can’t Rather than Don’t” Saves Lives

July/August 2011

Human Factors

“Can’t Rather than Don’t” Saves Lives

A recent article in The New York Times, “U.S. Inaction Lets Look-Alike Tubes Kill Patients,” (Harris, 2010) shows that American hospitals are 80 or more years behind manufacturing industries in basic safety. This inexcusable situation deserves zero tolerance from patients, insurers, healthcare professionals, and other healthcare stakeholders.

As reported in the article, Robin Rogers and her unborn baby were killed when a nurse attached a liquid food bag to an intravenous line. The article continues:
Tubes intended to inflate blood-pressure cuffs have been connected to intravenous lines, leading to deadly air embolisms. Intravenous fluids have been connected to tubes intended to deliver oxygen, leading to suffocation. …In the meantime, FDA reviewers have begun to question whether feeding tubes that could mistakenly be connected to intravenous tubes should be declared fundamentally unsafe.

It is astounding that the Food and Drug Administration has only now begun to question a situation that factory managers would have recognized as unsafe more than 90 years ago. Norwood reported in 1931 that the Ford Motor Company’s River Rouge plant used the safety principle “can’t rather than don’t” and devoted an entire chapter to this subject. Resnick (1920) shows, however, that Ford implemented this approach no later than 1920, and he credits safety director Robert A. Shaw with many specific safety initiatives.

“Can’t Rather than Don’t” Makes Tragedies Impossible
Consider for example a sign that says, “Don’t put your hand into the punch press when it closes.” Resnick wrote that this sign’s equivalent, including systems that used red and green lights (visual controls) and tap signaling between operators, cost thousands of fingers and hundreds of hands every year. It was, however, impossible for a worker to lose a hand in one of Henry Ford’s punch presses no matter how inattentive, exhausted, or even drunk he might have been.

Resnick (1920) states, “To trip a press equipped with this device, the operator must press two buttons, about a foot apart, so that it is necessary for him to use both hands.” If the worker’s hands were on the buttons, they were obviously not inside the press or near any other moving parts (which were covered with guards). A two-man press required four buttons to be pressed simultaneously, so one worker could not close it without knowing where the other’s limbs were. This is consistent with the principle of lockout-tagout for maintenance work, which Norwood shows was in fact practiced at the River Rouge plant. “Don’t close the press if you see a red light” was obviously far less effective in preventing injuries than “You can’t close the press unless the hands of every worker involved are where they belong.”

“Can’t rather than don’t” applies directly to the issue of interchangeable connections for liquid food, intravenous solutions, and gases such as oxygen for breathing and compressed air for blood pressure cuffs. It is easy to imagine what might happen if somebody mistakenly connected an oxygen tank to a pipe that carried hydrogen or another flammable gas, or vice versa. Such accidents are rare if they happen at all, and with good reason. The threads of oxygen cylinders are designed NOT to fit connections for flammable gases, and the threads of an acetylene tank will not fit connections for an oxygen line. It is similarly impossible to connect a 110-volt appliance or tool to a 220 or 440 volt electrical line.

A diesel fuel nozzle is too large to fit a gasoline-powered car but it has until recently been possible to put gasoline in a diesel vehicle, which can cause serious damage to the engine. BMW’s “Incorrect Fuelling Protection System” however now makes it impossible to put a gasoline nozzle into a diesel-powered BMW vehicle. This is another example of “can’t rather than don’t.”

Nestlé’s advertisement for its Spikeright™ port for enteric feeding bags in Patient Safety & Quality Healthcare (November/December 2010, pg. 9) drew our immediate attention as an application of “can’t rather than don’t” to healthcare. Nestlé’s success in developing this product makes the ongoing use of interchangeable or universal connections for intravenous, feeding tube, and oxygen lines inexcusable. As described by Nestlé on a web page devoted to the product, The SpikeRight port uses a threaded design that connects with specifically designed screw-top enteral spike sets to reduce the risk of misconnection with intravenous equipment. Only Nestlé offers an enteral-specific port built into the closed system container—it is not an optional add-on.

“Enteral-specific port” means it is not necessary for nurses to remember, “Don’t connect a feeding bag to an IV line” because the nurse can’t connect the feeding bag to an IV line.

Do Not Rely on Worker Vigilance to Prevent Mistakes
SpikeRight makes it impossible to attach an enteric feeding bag to an IV line but the nurse must still check the product’s expiration date—and the same applies to medications and other perishable medical products. The Japanese quality expert Shigeo Shingo said that no job should rely on worker vigilance to prevent mistakes. The best solution is error-proofing (poka-yoke to the Japanese) that makes the mistake impossible, and the second best is a prominent visual control that makes the mistake or defect obvious before it can cause trouble.

The concept that comes to mind immediately is a label that changes color with time, and a fairly extensive Google search located a product that might be suitable. The Timestrip® company (www.timestrip.com) manufactures labels that can “monitor anything from a few hours up to twelve months” and indicate the item’s status by means of a color change. This seems to be a relatively new concept, with labels that change color as a function of both time and temperature (to indicate the freshness of groceries) being more common. Labels also are available that undergo irreversible color changes when a temperature-sensitive item exceeds its specified maximum temperature.

Another example of “can’t rather than don’t” was implemented by Baxter Healthcare after an accidental overdose of heparin endangered the children of actor Dennis Quaid (Jablon, 2007). The company spokesperson’s statement, “While we strive to clearly differentiate our products and dosages, no amount of differentiation will replace the value of clinicians carefully reviewing and reading a drug name and dose before dispensing and administering it,” goes completely against the principle that worker vigilance is not a substitute for “can’t rather than don’t”—especially in environments where doctors and nurses work excessive hours. The same article shows, in fact, that Baxter made it almost impossible to administer high-concentration heparin by accident:
This fall, the company changed its heparin packaging by adding a red caution label that must be torn off before the vial can be opened.

It is relatively easy for a nurse or pharmacist to pick up the wrong vial of heparin, especially if the high concentration and low concentration ones are stored in the same place. It is almost impossible for a healthcare practitioner, no matter how fatigued, to use the high concentration by mistake if he or she must actually tear off a red caution label.

Closed Loop Corrective Action Must Follow All Medical Mishaps
Another question that comes immediately to mind, at least to anybody who works in industrial quality, is whether a closed loop corrective action process (Corrective Action Request, Quality Action Request) followed each of the tragedies reported above. This does not mean identifying a nurse to blame and discipline as an example to others. It means a root cause analysis (RCA) with tools such as the cause and effect or “fishbone” diagram, fault tree analysis, and so on to find out how the system allowed it to happen. An incident in which a nurse or other healthcare professional catches a mistake before it harms a patient should be treated with equal diligence. Worker vigilance should never be the only obstacle to a harmful or fatal event.

We are in all cases talking about failure modes that would carry a 9 or 10 severity rating on a 1 to 10 scale in a failure mode effects analysis (FMEA). These ratings are reserved almost exclusively for events that can endanger human life or safety. It is difficult to envision any excuse for failure to pursue closed loop corrective action to remove the potential causes of incidents of this severity.

William Levinson is the principal of Levinson Productivity Systems, P.C., in Wilkes-Barre, Pennsylvania. He is an ASQ-Certified quality engineer, quality auditor, quality manager, reliability engineer, and Six Sigma Black Belt. Levinson may be contacted at wlevinson@verizon.net.

References
Harris, G. (2010, August 20). U.S. inaction lets look-alike tubes kill patients. The New York Times.

Jablon, R. (2007, December 4).  Dennis Quaid and wife sue drug maker. USA Today. Available at http://www.usatoday.com/
life/people/2007-12-04-quaid-lawsuit_N.htm

Nestle Nutrition. Spikeright closed systems. Available at http://www.nestle-nutrition.com/products/Product.aspx?ProductId=7E85F376-4EA6-429C-B470-9FCC2293043A

Norwood, E. P. (1931). Ford: Men and methods. New York: Doubleday, Doran and Co., chapter VI.

Resnick, L. (1920, September 13). How Henry Ford saves men and money. National Safety News.

Disclaimer
Neither the author nor Levinson Productivity Systems P.C. has any financial interest in Nestlé, Baxter, BMW, or TimeStrip.