What is the definition of "adverse event" in healthcare?

In healthcare, an "adverse event" refers specifically to an unexpected negative outcome that arises as a result of medical care, which aligns precisely with the third choice. These events can include complications, errors in treatment, or any unintended injury that occurs during the process of providing care, whether due to a lapse in safety protocols, a side effect of treatment, or a system error. The key points are that the outcome is negative and unexpected, highlighting the importance of monitoring and improving safety practices in healthcare settings to prevent such occurrences.

In contrast, other options do not fit the definition of an adverse event. Positive outcomes are not considered adverse, and outcomes that are expected do not align with the nature of unexpected adverse events. Additionally, events that occur without medical intervention do not qualify as they are outside the realm of healthcare-related occurrences.