When determining the time of onset for a stroke, what is the critical reference point?

The time patient was last seen normal serves as the critical reference point when determining the time of onset for a stroke. This timestamp is vital because it helps clinicians assess the appropriate course of treatment, including the eligibility for thrombolytic therapy, which is most effective when administered within a specific window of time from the onset of symptoms.

Identifying when the patient was last seen normal allows medical providers to estimate how long the brain has been without adequate blood flow, guiding interventions to minimize neurological damage. This reference assists in the decision-making process regarding the urgency and type of care needed upon hospital arrival and the potential for recovery outcomes. Other timing scenarios, such as when symptoms first appeared, the time of hospital arrival, or the time of first emergency contact, do not provide as clear a baseline for assessing stroke progression and treatment options.