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Patient safety is of great interest to many regulatory groups, such as The Joint Commission, hospital administrations, health care professionals, and the general public. The interest has continued to grow since the publications of two reports by the Institute of Medicine. The first report, in 1999, focused on all medical errors and introduced measures necessary to ensure a safer health care system.85 The second report, in 2006, focused on reducing medication errors and adverse drug effects.83 These reports and others reveal that medications errors represent up to 25% of all medical errors.49 Many health care institutions address medication safety through their pharmacy and therapeutics (also commonly called drug and formulary), medication safety, patient safety, and quality improvement committees. Table 140–1 shows a timeline of some important developments in medication safety.
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Studies of medical errors, including those involving medications, are of a highly variable quality and usefulness. This occurs in large part because they address diverse populations, the definitions utilized vary, and a variety of data collection techniques, including observational studies and voluntary reporting, are employed.
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One study estimates that 180,000 people die each year of medical errors,64 and 60% of these injuries are probably preventable.17 The Institute of Medicine estimates that an additional 44,000 to 98,000 people die each year from medical errors.85 However, despite having methodologic differences, both studies establish that medical errors cause thousands of deaths each year. Studies like these illustrate the “Swiss Cheese Model of Error:”92 that is, multiple errors must align with an initial error to lead to harm.
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More than 1.5 million preventable adverse drug events (ADEs) may occur each year.83 An ADE is an untoward event or outcome associated with the use of a drug. The definition of ADEs includes medication errors as well as adverse reactions to a drug and drug interactions. A medication error is “any preventable event that may cause or lead to inappropriate medication use or patient harm while the medication is in the control of the health care professional, patient, or consumer.”81 An adverse drug reaction is a sign or symptom related to use of a medication that results in unpleasant effects when an error has not occurred. An adverse drug reaction is also an ADE.5 Those ADEs and medication errors with serious effects lead to 3.1% to 6.2% of all hospital admissions.62
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In 1997, the cost of a single ADE was estimated to be $2000 to $5000 at academic medical centers.10,22,23 Similarly, in 2012, a retrospective multi-center study of community hospitals estimated an increased cost of $3000 to overall care and increased length of stay of 3 days above expected when an ADE occurs.46 Other studies estimated that the annual cost of ADE morbidity and mortality was greater than $77 to 177 billion in the ambulatory care setting,33,50$2 billion in hospitals,10,23 and $4 billion in nursing homes.16 These costs exclude legal or other costs that accrue to the patient or their families.
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Deaths from Medication Errors and ADEs
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Although medication errors are the most common cause of iatrogenic patient injury, less than 2% result in injuries. Nevertheless, the incidence of ADEs in hospitalized patients is estimated to range from 2% to 20%22 resulting in 7000 deaths annually in the United States.85 A retrospective review of hospital death certificates by ICD 9 and ICD 10 codes from 1983 to 2004 revealed an increase of 361% in fatal medication errors and a 33% increase in deaths from ADEs occurring in a patient’s home.91 The hospital death certificate review also revealed an increase in fatal medication errors 32 times higher when prescription medications were combined with alcohol and or illicit xenobiotics.91 According to voluntary MedWatch reports to the US Food and Drug Administration (FDA), 17% of reported ADEs were associated with death, 7% were associated with permanent disability, and many others had serious complications. Women and elderly patients were at the highest risk.78
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National Coordinating Council for Medication Error Reporting and Prevention Taxonomy
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A useful medication error taxonomy, developed by the National Coordinating Council for Medication Error Reporting and Prevention (NCC MERP), classifies medication errors according to severity of outcome (Fig. 140–1).81 Importantly, the categories of least severity (A and B) describe circumstances or events in which the potential to cause error exists, or the error occurs but does not affect the patient. These “near misses” are so frequent that they serve as a critical source of information related to systems problems and education about medication error, but are typically underreported and underappreciated. In one study of 154,816 errors reported by hospitals and health systems to MEDMARX from 1999 to 2001, most of the errors were in category C (47%) and resulted in no patient injury, whereas there were 19 errors in category I, contributing to or resulting in patient death, comprising 0.01%.96 See Fig. 140–2 for a comparison of errors in the inpatient versus the emergency department (ED) setting based on the NCC MERP classification.
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FDA reports suggest that opioid analgesics and immune modulators are the most common medications in which errors resulted in death.78 The medications most frequently involved in errors and ADEs reported to MEDMARX were insulin, anticoagulants, morphine, and potassium chloride.96 These medications are considered high alert drugs according to the sentinel event alert system of The Joint Commission. Recently, The Joint Commission has focused more on all opioids (not just morphine) in order to promote safe use in the hospital setting.105 Identifying characteristics of high-risk drugs include low therapeutic index, pharmacokinetic interactions, inherent undesirable effects, newly approved or “off-label” use, and direct-to-consumer promotion.13Table 140–2 lists medications commonly reported and their classes of errors.
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The Medication Process
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The Medication Process comprises the five stages in the sequence of ordering a medication to its delivery to the patient. The stages are prescribing, transcribing, dispensing, administering, and monitoring.6 For patients discharged from the ED or hospital, discharge, and follow-up is the sixth stage.28 Although the medicating process has only six stages, there are multiple steps within each stage. The potential for error is high, increasing proportionately as the number of steps and their complexity increase. Figure 140–3 describes typical errors that occur at each stage in the process, along with prevention strategies.
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The greatest number of errors resulting in preventable ADEs (medication errors) occurs at the first prescribing stage.7 In a study of serious medication errors, 39% were found to occur at the prescribing stage, 12% at transcription, 11% at dispensing, and 38% at administration.65 In one study of 17,808 inpatient and ED medication orders, 6.2% of orders written involved a prescribing error and 30% of these were likely to harm the patient if they were not discovered.15 Another recent prospective study suggests that up to 43.8% of medications orders on hospital wards had a prescribing error discovered by ward-based pharmacists, despite the level of prescriber experience.98 In the ED, most errors occurred in either the prescribing or administration phase.89
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Transcribing errors usually involve poor communication due to illegible handwriting, the use of trailing zeroes, or inappropriate abbreviations. Poor handwriting can also lead to confusion, particularly with regard to look-alike and sound-alike medications.90 All information, whether printed, spoken, or otherwise communicated, must be transmitted in a clear, unambiguous, and timely fashion with avoidance of abbreviations. In its 2004 National Patient Safety Goals, The Joint Commission developed a minimum list of five sets of dangerous abbreviations, acronyms, and symbols that should not be used, and proposed preferred terms.104 The Institute for Safe Medication Practices (ISMP) also published a comprehensive list.48 By not using these abbreviations, the hope is that communication will be improved and that there will be no misinterpretation of poor physician handwriting.
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Dispensing errors are most commonly due to substitution and labeling errors.99 Errors at the stage of administering medications include incorrect drug, incorrect dose, incorrect route, and a drug given to the wrong patient. Computerized provider order entry (CPOE) was introduced to improve the medication process from prescribing to administering but has introduced new problems. See the Information Technology section for further discussion.
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Monitoring and discharging with follow up are associated with fewer errors. This phase involves attention to liver and kidney function, checking xenobiotic concentrations, and attention to and evaluation of drug interactions and pharmacokinetic interactions.28 Monitoring must be an ongoing process that begins when the patient receives the medication, regardless of where the patient is in the health care system, and continues as long as the individual continues to have the medication prescribed. In the acute stages of treatment, such as in the hospital or ED, the process is especially important and requires optimal three-way linkage between the pharmacy, laboratory, and physician.97 This process must be maintained throughout the individual’s continued relationship with the health care system. In the outpatient setting, providers must be aware of signs and symptoms related to adverse drug effects while they are monitoring and following up patients. In a study of 661 patients in four primary care practices, patient reports of medication side effects to their physicians led to changed therapies in 76% of cases. A failure to identify medication-related symptoms and change therapy resulted in 21% ameliorable and 2% preventable ADEs. Ameliorable ADEs were defined as those in which “the severity or duration could have been reduced substantially had different actions been taken.”112