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



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Preventing Medication Errors 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

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Preventing Medication Errors 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.

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Preventing Medication Errors 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. 1 Weaknesses in the structure of an organization, such as faulty information management, ineffective personnel training, or faulty drug labeling. By themselves, latent failures are often subtle and may cause no problems. Their consequences are hidden, becoming apparent only when they occur in proper sequence and combine with active failures of individuals to penetrate or bypass the system’s safety nets (Reason, 1990). Providing an optimal level of medication safety requires that we recognize and correct the latent failures in the system.

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Preventing Medication Errors 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 Patient Information Incomplete clinical information on prior treatment and current status of mother for syphilis. Incomplete clinical information on current status of infant for congenital syphilis. Lack of systematic method of communicating mother’s prenatal care to infant’s physicians. Decision made to treat infant for congenital syphilis. Patient Education Inefficient education of parents regarding the possibility of congenital syphilis in the infant and their treatment options. Decision made to treat the infant prior to discharge from the hospital without informing the mother, who later said she would have refused therapy because she had been treated previously and had two other children at home without congenital syphilis. Communication Dynamics Lack of efficient means of communicating with parents when a language barrier was present. Incomplete communication of drug information. Nonstandard method of communicating drug order. Health department recommendation documented in progress notes only as “penicillin G,” not “penicillin G benzathine;” route of administration not documented. Failure to question a seemingly excessive number of IM injections. Drug Information Insufficient drug information (rarely used in practice, nonformulary drug). Order for the drug written with “Benzathine” capitalized and placed above “penicillin G;” “IM” written over “IV.” “U” used to denote units, making it look like added zero or 1,500,000 instead of 150,000.

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Preventing Medication Errors Key Element Latent Failures Active Failures 2. Ordering Phase Drug Information Insufficient drug information (rarely used in practice, nonformulary drug). Misread both health department recommendation and drug resource in determining units/kg dose for infant; consequently misread order, resulting in a 10-fold overdose. Staff Education and Staffing Patterns Lack of specialized training/education in neonatal/ pediatric pharmacy. Failure to staff pharmacy with neonatal/pediatric pharmacist in a hospital providing these services.   Quality Control Lack of maximum-dose warning system on phar-macy computer. Ten-fold overdose not detected. 3. Drug Dispensing Phase Quality Control Inconsistent pharmacy procedure for independent double-check of doses prior to dispensing. Ten-fold overdose prepared and dispensed. Labeling, Packaging, and Nomenclature of Drug Lack of unit dose system for dispensing medications in neonatal unit. Communication of dose in the millions numerically instead of phonically. Dispensed two full syringes of drug labeled “1,200,000 units” and “1,500,000 units” (instead of “1.2 million units” and “1.5 million units”), with “note dosage strength” stickers on plungers. Pharmacy label and syringes did not carry an auxiliary warning of “for IM use only.” Staff Education No procedure for educating staff prior to dispensing a nonformulary drug. Nonformulary drug dispensed without briefing of staff responsible for administering it.

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Preventing Medication Errors Key Element Latent Failures Active Failures Drug Information Insufficient information on volume of medication that can be safely administered IM to neonates (maximum of 0.5 ml per injection). Insufficient drug information regarding significant serious effects of IM injection of the drug in neonates. Dispensed medication with directions to administer 2.5 ml of drug IM to neonate, requiring five IM injections. 4. Drug Administration Phase Drug Information Insufficient drug information about various forms of penicillin G (never used penicillin G benzathine in practice, nonformulary drug). Inadequate drug references: penicillin G benzathine is frequently referred to in texts with the ambiguous synonyms “crystalline penicillin” and “aqueous suspension.” Inadequate drug reference: Neofax’95 does not mention penicillin G benzathine in monograph, but notes aqueous crystalline penicillin G IV push is used to treat congenital syphilis; no specific warnings that penicillin G benzathine (or procaine) can be administered IM only. Inadequate drug reference: NICU Medication Administration does not mention penicillin G benzathine in monograph on penicillin G. Inadequate resource text: 1994 Red Book does not Misunderstood benzathine to be brand name for aqueous penicillin G. Incorrectly thought that aqueous crystalline penicillin G and penicillin G benzathine were the same drug; consequently, problem with IV administration went unrecognized. Made decision to administer the drug IV to avoid pain from multiple IM injections.

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Preventing Medication Errors Key Element Latent Failures Active Failures   warn that drug can be administered IM only. Conflicting information about IV use of milky-white substances. Lack of FDA requirement for “black box” or other vivid warning regarding IV administration of penicillin G benzathine in drug monographs.   Competency Hospital had an unclear definition of prescriptive authority for nonphysicians. Nurse practitioner assumed authority to change route of administration based on national protocol and current practice in hospital. Labeling, Packing, and Nomenclature Manufacturer’s warning for “IM use only” not prominently placed on syringe: syringe had to be rotated 180 degrees away from drug name to view the warning; plunger obscured the view after syringe prepared; “1,200,000” used instead of “1.2 million” units (errors occur when comma is misread). Warning on syringe for “IM use only” not seen. Ten-fold overdose not recognized. Penicillin G benzathine administered intravenously. 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.