Part I
Understanding the Causes and Costs of Medication Errors
Numerous factors in the health care system contribute to medication safety and errors. Some of these factors can be attributed directly to provider organizations, while others can be attributed to the medication-use system itself. In many cases, multiple factors are involved. The following case study, discussed in Hospital Pharmacy (Smetzer and Cohen, 1998), illustrates the complexity of the health care system and the medication-use process and the interrelatedness of the factors involved in medication safety and quality.
In 1996, a Denver hospital acknowledged that a medication error had led to the death of a day-old infant, born to a mother with a prior history of syphilis. Because the infant’s parents spoke only Spanish, communication was difficult, and treatment of the disease could not be verified easily. Despite incomplete information about the mother’s past treatment for syphilis and the current status of both mother and child, a decision was made to treat the infant for congenital syphilis. After telephone consultation with infectious disease specialists and the health department, an order was written for one dose of “Benzathine penicillin G 150,000U IM.”
The hospital physicians, nurses, and pharmacists, unfamiliar with the treatment of congenital syphilis, had limited knowledge about this drug. The pharmacist filling the order consulted both the infant’s progress notes (where a nurse practitioner had documented a recommendation from the health department) and a drug reference book to determine the usual dose of penicillin G benzathine for an infant. However, the pharmacist misread the dose in both sources as 500,000 units/kilogram (kg), a typical adult
dose, instead of 50,000 units/kg. Consequently, she misread the order as 1,500,000 units, especially since the “U” for units appeared to add a zero to the dose. She prepared the order accordingly—a 10-fold overdose. Because there was no consistent pharmacy procedure for independent double-checking, the error was not detected. A pharmacy label on the bag that was dispensed indicated that 2.5 milliliters (ml) of medication was to be administered IM (intramuscularly) to equal a dose of 1,500,000 units.
After glancing at the medication sent from the pharmacy, one of the nurses expressed concern to her colleagues about the number of injections required to give the infant the medication. Normally, because a baby’s muscles are so tiny, a maximum of 0.5 ml per injection is allowed in infants. The labeled dose would require five injections. Wishing to prevent any unnecessary pain to the infant, two of the nurses decided to investigate the possibility of administering the medication IV (intravenously) instead of IM. They checked with a popular medication reference book to determine whether penicillin G benzathine could be administered IV. However, the reference did not mention penicillin G benzathine specifically; instead, it referred to aqueous crystalline penicillin G IV slow push or penicillin G procaine IM. Nowhere in the two-page text in the reference book was penicillin G benzathine mentioned, nor were there any specific warnings regarding “IM use only” for penicillin G procaine and penicillin G benzathine.
Unfamiliar with the various forms of penicillin G, the nurse practitioner believed that “benzathine” was a brand name for penicillin G. This misconception was reinforced by the fact that the physician had written the order with benzathine capitalized and placed on a line above “penicillin G” rather than after it on the same line. In addition, many texts use ambiguous synonyms when referring to various forms of penicillin. For example, penicillin G benzathine is frequently associated with the terms “crystalline penicillin” and “aqueous suspension” in texts. Believing that aqueous crystalline penicillin G and penicillin G benzathine were the same drug, the nurse practitioner concluded that the drug could be safely administered IV. The nurses knew that, while having been taught that only clear liquids can be injected IV, certain milky-looking substances, such as lipid-based drug products, can be given IV. Therefore, they did not recognize the problem with giving penicillin G benzathine, a milky-white substance, IV.
While hospital policies and practices gave prescribing authority to nurse practitioners, they did not clearly define such authority in terms of the ability to change prescription orders. However, the neonatal nurse practitioner assumed that she was operating under a national protocol that allows neonatal nurse practitioners to plan, direct, implement, and change drug therapy. Consequently, the nurse practitioner, not wanting to cause pain to the infant with the large IM injection dose, made the decision to administer the drug IV.
While preparing for drug administration, neither of the nurses noticed the 10-fold overdose or the manufacturer’s label on the syringe “IM use only.” They had no idea that IV administration would be lethal because the drug is insoluble and obstructs blood flow in the lungs required for the transfer of oxygen from the baby’s airways. The manufacturer’s warning is very difficult to see because it is not prominently placed; it can be viewed only if the syringe is rotated 180 degrees away from the drug name. The nurses began to administer the first syringe of Permapen slow IV push. After about 1.8 ml had been administered, the infant became unresponsive, and resuscitation efforts were unsuccessful. Later, upon autopsy, it was confirmed that the baby had not had congenital syphilis, and therefore never needed treatment.
The three nurses involved in this medication error were later indicted by a grand jury for negligent homicide. Two of the nurses agreed to legal sanctions before the trial, but a third pled not guilty, and a trial ensued. Expert testimony presented during the trial served as convincing evidence that, while the nurse and her colleagues had played a part in the tragedy, more than 50 latent1 and active failures had occurred throughout the medication-use process (see Table I-1), most of which, such as the poor syringe labeling, the pharmacist’s mistake, and the confusing drug information, had not been under the control of the nurses. It was these failures that had set the stage for the nurses’ tragic mistakes. The experts advised against the tendency to focus on the errors of the providers. Had even one of these failures not occurred, either the accident would not have happened, or the error would have been detected and corrected before reaching the infant. Since most of what people do is governed by the system within which they act, the causes of errors belong to the system and often lie outside the control of individuals, despite their best efforts. This case illustrates that medication errors are almost never the fault of a single practitioner or caused by the failure of a single element. The analysis presented during the trial had a powerful influence on the jury, which acquitted the nurse in the one case that was tried. The lesson learned from this case study is that we must look beyond blaming individuals and focus on the multiple underlying system failures that shape individual behavior and create the conditions under which medication errors occur.
TABLE I-1 Latent and Active Failures Associated with Key Elements of the Medication-Use System, Denver Case Study
Key Element |
Latent Failures |
Active Failures |
1. Prescribing Phase |
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Patient Information |
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Patient Education |
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Communication Dynamics |
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Drug Information |
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Key Element |
Latent Failures |
Active Failures |
2. Ordering Phase |
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Drug Information |
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Staff Education and Staffing Patterns |
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Quality Control |
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3. Drug Dispensing Phase |
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Quality Control |
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Labeling, Packaging, and Nomenclature of Drug |
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Staff Education |
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Key Element |
Latent Failures |
Active Failures |
Drug Information |
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4. Drug Administration Phase |
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Drug Information |
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Key Element |
Latent Failures |
Active Failures |
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warn that drug can be administered IM only.
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Competency |
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Labeling, Packing, and Nomenclature |
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SOURCE: Smetzer and Cohen, 1998. |
REFERENCES
Reason, J. 1990. The contribution of latent human failures to the breakdown of complex systems. Philosophical Transactions of the Royal Society of London, Series B 327, 475–484.
Smetzer JL, Cohen MR. 1998. Lessons from the Denver medication error/criminal negligence case: Look beyond blaming individuals. Hospital Pharmacy 33(6):640–657.