Which of the following is an example of a sentinel event?

A sentinel event is defined as an unexpected occurrence involving death or serious physical or psychological injury, or the risk thereof. Incompatible blood type issues represent a significant risk to patient safety and could lead to severe consequences, including death. This makes it a clear example of a sentinel event, as it indicates a failure in the system that must be addressed to prevent future occurrences.

Other options do not represent sentinel events because they either describe appropriate and safe practices, such as properly labeled fluids and timely diagnoses, or gather feedback on experiences, like patient satisfaction surveys, which do not involve directly adverse clinical outcomes. These choices focus more on aspects of quality improvement and patient safety rather than actual events that trigger severe adverse effects.