Patient Safety Tip of the Week

October 30, 2007    

Using IHI's Global Trigger Tool


 Those of us who have been involved with mandatory incident reporting systems know that underreporting has been a significant problem. Voluntary reporting systems typically identify more opportunities for improvement by identifying near-miss events in addition to adverse events where harm has occurred. Yet voluntary systems still miss significant numbers of adverse outcomes, too. One of our biggest issues, then, is knowing whether we are getting any better at reducing adverse outcomes over time. Quite frankly, over the years we have seen the numbers of reported incidents in both types of system increase. Rather than being of sign of worsening care, that usually means that hospitals and other facilities have actually been doing a much better job at identifying incidents and adverse events. That’s where IHI’s Global Trigger Tool for Measuring Adverse Events comes in. It provides a mechanism that can help us both measure performance over time and help us identify those system issues that need the most attention in our organizations.



The concept of the IHI Global Trigger Tool is that there are certain events or items that can be gleaned from chart review that are often associated with adverse events (with adverse events being defined as harm being caused). Those events/items are looked for in the charts and, if found, the chart is further reviewed to determine if an adverse event did occur. Again, there is a big difference between a trigger and an adverse event: a trigger simply raises a flag that there might be an associated adverse event. The adverse events are recorded. The charts are chosen for review in a truly random fashion and a finite number of charts are reviewed periodically, typically 10 charts reviewed every two weeks. This sampling methodology allows calculation of a crude rate of adverse events that can be charted and compared (within the same organization) over the long run to determine whether the organization is seeing improvement. Just as important, however, is that the pattern of adverse events identified allows the organization to prioritize where it will spend more of performance improvement and patient safety resources.



The triggers themselves have been carefully selected (and refined) to reflect both the frequency and severity of adverse events encountered in a typical hospital. Though the triggers are extensive, they do not uncover all the types of adverse events found in a healthcare system. And keeping the tool and its definitions consistent is what allows the organization to track performance over time.



The process, as adopted by most organizations, typically involves having two clinical reviewers (nurses, pharmacists, etc.) each review 10 charts every two weeks. Review of each chart is limited to 20 minutes. The reviewers then meet with a designated physician, who reviews the summary sheets assembled by the clinical reviewers and confirms whether an adverse event occurred and adds his/her expertise to answer any questions that may have arisen about the case. Some organizations have chosen to review more charts or do the reviews less often, but the model of 10 charts every two weeks lends itself to some nice run charts. The real key is consistency of the reviews. IHI strongly recommends that the two clinical reviewers and the physician reviewer of the team be the same reviewers for extended periods of time (eg. for one full year or more). Obviously the reviewers need to be experienced clinicians and their time needs to be freed up so they can do these chart reviews. The other key is maintaining consistency in the chart selection. IHI provides guidelines for the criteria to be used in chart selection. Some hospital charts are contained in several volumes but don’t worry – the 20-minute rule means you just go through that chart for a maximum of 20 minutes. You need not identify all the adverse events that occurred in every case.



IHI provides good guidelines on how to best review the charts and actually provides sample charts for training. They give good guidelines on how the training should be done (typically as a team).



Some issues have arisen about use of the Global Trigger Tool. Since it requires by definition that “harm” occurred, it does not identify near-misses that may be important sources of learning. Similarly, it does not include acts of omission in defining adverse events, only events arising from commission. But remember, this is only one tool of many your organization will be using in its patient safety/quality improvement activities. You should have many other mechanisms for identifying those sorts of events.



Some have noted that the tool has never been scientifically “validated”, such as one would require in a tool being used for screening a population for a certain condition. That’s probably true but multiple diverse organizations have now used this tool over the years and found it to be very helpful in the two primary purposes: identifying trends over time and helping to prioritize areas for improvement. Issues about consistency and inter-rater reliability are minimized by using the same reviewers and training as a team.



Others have developed tools that use electronic triggers. Such tools have been used now for many years to identify adverse drug events1. Szekendi et al2 developed such a system at Northwestern University using certain abnormal laboratory results and pharmacy data as triggers and demonstrated the system can such a identify many adverse events that might have otherwise gone unreported. In addition, it has the more important feature of being able to identify issues in real-time or near-real-time. That allows for reviewers to speak to clinicians involved in the patient’s care to get more accurate details and context about the case. Is also can lead to an intervention to prevent harm. That makes electronic trigger surveillance a powerful tool of the present for some and the near future for others3. But for most, electronic surveillance will be only one prong of a multi-pronged strategy to identify opportunities to intervene.



IHI also provides several other excellent trigger tools (eg. for adverse events related to drugs, ICU’s, perioperative, neonatal and outpatient settings). But we think you’ll find the IHI Global Trigger Tool for Measuring Adverse Events an excellent addition to your patient safety program. Remember, this is only one of several mechanisms you need to employ to identify patient safety areas that need improvement. Use it as one source of data to help identify and prioritize areas for investment of resources and use it as a rough gauge of  progress over time.




1 Classen DC, Pestotnik SL, Evans RS, et al. Computerized surveillance of adverse drug events in hospital patients. JAMA 1991; 266: 2847-51


2 Szekendi, M K; Sullivan, C; Bobb, A; Feinglass, J; Rooney, D; Barnard, C; Noskin, G A Active surveillance using electronic triggers to detect adverse events in hospitalized patients. Quality & Safety in Health Care. 15(3):184-190, June 2006


3Kilbridge, P M 1; Classen, D C 2 Automated surveillance for adverse events in hospitalized patients: back to the future. Quality & Safety in Health Care. 15(3):148-149, June 2006





Update: See also our April 15, 2008 Patient Safety Tip of the Week “Computerizing Trigger Tools







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