What is hypotension defined as in terms of systolic blood pressure?

Hypotension is generally defined as a systolic blood pressure that is less than 90 mm Hg. This threshold is significant because blood pressure below this level can indicate inadequate perfusion of vital organs, leading to potential complications such as shock. When systolic blood pressure drops below this limit, it raises concern for the body's ability to maintain blood flow to the heart and brain, which is essential for their proper function.

Understanding this definition is crucial in emergency medicine, as it helps guide the evaluation and management of patients presenting with low blood pressure. In a clinical setting, recognizing hypotension allows healthcare professionals to promptly investigate its causes and initiate appropriate treatment to stabilize the patient and prevent adverse outcomes.