This case study first appeared in the report Committed to Safety: Ten Case Studies on Reducing Harm to Patients by Douglas McCarthy and David Blumenthal, M.D.

Organizations. The Institute for Healthcare Improvement (IHI) is a Boston-based not-for-profit that works with health care organizations worldwide to spread quality improvement. Premier, Inc., of San Diego, is an alliance of more than 200 not-for-profit hospitals and health care systems across the United States. Roger Resar, M.D., senior IHI fellow at Luther Midelfort, Mayo Health System in Eau Claire, Wis., developed the tool with assistance of IHI colleagues Carol Haraden, Ph.D., and Frances Griffin, R.R.T., M.A.

Objective. The trigger tool allows organizations to simply measure the incidence and types of adverse events occurring within the institution. This information can be used to prioritize areas for improvement, design appropriate actions for prevention, and track the impact of changes on the occurrence of adverse events over time. The trigger tool is designed to overcome the limitations of other methods like voluntary reporting systems.

Date of implementation. IHI, in partnership with Premier, developed the trigger tool for measuring adverse drug events as part of the Idealized Design of the Medication System collaborative, which began in 2000. Four additional trigger tools have since been developed to detect adverse events globally in the hospital and in intensive care units, specific kinds of adverse events such as those associated with anticoagulation treatment, and adverse events that occur as part of "life events" in the outpatient setting, such as a new diagnosis of cancer or an emergency room visit for an adverse reaction to medication.

Description. The trigger tool uses an efficient sampling technique to identify potential adverse events through a periodic audit of medical records. Each tool includes a limited number of triggers that signal the most common types of adverse events or those that are likely to cause serious harm. Triggers were included based on a literature review, expert opinion, and testing for feasibility. For example, triggers for a potential adverse drug event include orders for antidotes, abnormal laboratory values, abrupt medication stop orders, transfers to a higher level of care, and development of a rash.

The tool is applied to a small, random sample of patient records (e.g., 20 hospital charts per month for patients with a hospital stay of at least 24 hours). When a trigger is found, the chart is reviewed to determine whether an adverse event has occurred. Adverse events are defined from the perspective of the patient and require clinical judgment to distinguish those that occur as a natural course of disease process versus complications of treatment. Level of patient harm is classified using an objective scale—the National Coordinating Council for Medication Error Reporting and Prevention Index. To make the process reliable and efficient, the tool developers recommend that chart reviewers be trained by experienced users, that an initial double review be conducted to standardize the process, and that a time limit of 20 minutes be set for reviewing a single chart.

To gain maximum benefit from the trigger tool, Dr. Resar recommends the following approach:

• use the trigger tool monthly for a period of six months to one year to observe trends;
• place identified adverse drug events into "buckets" or clinically meaningful categories to determine the most common types of events occurring within the institution; and
• direct resources to understand the potential causes of commonly occurring events and design countermeasures to prevent them.

Results. A total of 86 hospitals in four medication safety collaboratives tested the original trigger tool (Rozich et al. 2003). There were 720 adverse drug events identified among 2,837 patient charts and 268,796 medication doses, yielding an adverse drug event rate of 25 percent of patients and 2.68 events per 1,000 doses. A low level of variation among hospitals (2.47 to 4.81 per 1,000 doses) suggests that the tool can be used consistently in different settings. Only 2 percent of the adverse drug events detected using the trigger tool were identified using traditional methodologies such as incident reports, pharmacy interventions, and billing codes. Commonly identified high-risk medications associated with adverse events include anticoagulants, narcotics, insulin, sedation and patient-controlled analgesia, and intravenous pumps.

Lessons learned. The trigger tool directs attention to issues that are not otherwise obvious when using traditional reporting mechanisms. By focusing on adverse events rather than the larger universe of errors, the trigger tool "eliminates wasted effort directed towards quantifying errors," noted James Rozich, M.D., Carol Haradan, Ph.D., and Roger Resar, M.D., in a journal article (2003). "Organizations that fail to recognize the difference between medication errors and [adverse drug events] may concentrate their efforts on systems that improve the accuracy of drug administration but that produce only marginal reductions in patient harm," they wrote.

The trigger tool does not assess the preventability of adverse events, because opinions differ regarding those kinds of judgments, noted Dr. Resar. "Some events are more preventable than others, but that can change tomorrow" with advances in medical technology, he said. Dr. Resar suggests that it is more productive for hospitals to focus on driving the adverse event rate as low as possible. "There's probably a basement level below which we can't go today, but we haven't found it yet," he said.

In a previously published interview with the QualityIndicator online newsletter (Neveleff 2003), Dr. Resar explained the implications of this philosophy using a hypothetical example in which a patient is mistakenly given acetaminophen.

'The chance that the acetaminophen will cause harm is virtually zero,' Resar notes. 'But that is still considered an error. As a contrasting example, if a patient is given morphine for pain and vomits for three hours afterwards, he or she may not be able to eat, which will delay recovery. Even though the morphine was not given in error, the patient is harmed by the drug, and this harm could have been mitigated by standardized antinausea protocols. Physicians and organizations should strive to prevent or mitigate situations that actually cause harm to patients, whether the harm is caused by an error or a faulty or inefficient process.'

The trigger methodology can be adapted to an automated process, although manual review of the triggered charts or events is still generally required to apply clinical judgment about adverse events. Electronic approaches can also be used as a means of detecting and mitigating potential errors in real time. Because of the time required to review all the positive triggers generated for every patient, those using automated triggers tend to limit their use to a smaller number of conditions related mostly to adverse drug events, according to Dr. Resar.

The manual trigger methodology "has the advantage of being cheap, readily available to all institutions whether they have [information] technology or not, and a real learning experience for those who do the reviews," Dr. Resar says. He sees the manual and automated approaches as two different, but complementary, tools: a retrospective sampling tool to measure the rate at which adverse events occur at given points in time, and a prospective tool to detect and mitigate potential adverse events as they occur in real time.

Implications. Measuring adverse drug events is key to their prevention. Using a trigger tool to review medical records can identify up to 50 times more adverse drug events than traditional incident reporting systems.

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This study was based on publicly available information and self-reported data provided by the case study institution(s). The aim of Fund-sponsored case studies of this type is to identify institutions that have achieved results indicating high performance in a particular area, have undertaken innovations designed to reach higher performance, or exemplify attributes that can foster high performance. The studies are intended to enable other institutions to draw lessons from the studied organizations' experiences in ways that may aid their own efforts to become high performers. The Commonwealth Fund is not an accreditor of health care organizations or systems, and the inclusion of an institution in the Fund's case studies series is not an endorsement by the Fund for receipt of health care from the institution.