Traditional efforts to detect adverse events* (AEs) have focused on voluntary reporting and tracking of errors. However, public health researchers have established that only 10 to 20 percent of errors are ever reported and, of those, 90 to 95 percent cause no harm to patients. Hospitals need a more effective way to identify events that do cause harm to patients, in order to select and test changes to reduce harm.

Tracking the percentage of admissions with an AE over time is a useful way to tell if changes are leading to improvement.

*An adverse event is defined as any harm that occurs to the patient from medical care, whether or not it is the result of an error.

Decrease the percentage of admissions with an AE by 75 percent.

Every month, select a random sample of at least 20 closed patient records, each with a minimum stay of 24 hours. Review the records, looking for “triggers” — certain medications, laboratory values, or events — that often provide clues that an AE has occurred. Investigate each trigger further to determine if an AE did in fact occur. Patients who experienced multiple AEs should be counted only once in the numerator, although the details of every AE should be reviewed.

The Global Trigger Tool for Measuring AEs provides instructions for conducting a retrospective review of patient records using triggers to identify possible AEs. This tool includes a list of known AE triggers and instructions for measuring the number and degree of harmful events.