According to Health Care Risk Management standards supported by ASHRM and The Joint Commission’s sentinel event policy, a sentinel event is defined as a patient safety event that results in death, permanent harm, or severe temporary harm. Severe temporary harm is harm that is critical, life-threatening, or requires major intervention to sustain life, even if the patient ultimately recovers.

Sentinel events signal the need for immediate investigation and response because of the seriousness of the outcome. The Joint Commission requires completion of a root cause analysis and development of an action plan within specified timeframes following awareness of such an event. The focus is on identifying system vulnerabilities and preventing recurrence.

Temporary or moderate harm alone does not meet the sentinel event threshold unless it rises to the level of severe temporary harm. Increased length of stay, without death or significant harm, does not qualify as a sentinel event under the formal definition.

Clinical and patient safety objectives emphasize accurate event classification, structured investigation, and corrective action. Therefore, a sentinel event is one that results in death, permanent harm, or severe temporary harm.