Overview
Introduction
A patient who becomes light headed after standing may have dehydration, medication effect, autonomic failure, impaired cardiac output, or a more urgent problem such as bleeding...
A patient who becomes light-headed after standing may have dehydration, medication effect, autonomic failure, impaired cardiac output, or a more urgent problem such as bleeding or sepsis. Orthostatic hypotension (OH) is therefore a sign to interpret, not a final diagnosis. Standing normally shifts roughly 500–1,000 mL of blood into the abdominal and lower-limb venous beds. Venous return and stroke volume fall briefly; baroreceptors respond by increasing sympathetic activity, vascular tone, and heart rate. OH develops when that response fails or when volume loss, vasodilation, or low cardiac output overwhelms it. The bedside priorities follow from this model: protect the patient from a fall, confirm the pressure change correctly, identify the precipitant, and improve upright tolerance without provoking dangerous hypertension while the patient is supine.