OH is a sustained reduction of systolic blood pressure (SBP) of ≥ 20 mm Hg or diastolic BP ≥ 10 mm Hg within 3 min of standing or head-up tilt to at least 60° on a tilt table (1); symptoms are not part of the criteria. In patients with supine hypertension, a reduction in SBP of 30 mm Hg has been suggested (1).
The Centers for Disease Control and Prevention (CDC) recommends BP measurements when patient is supine for 5 min, and after standing for 1 and 3 min (2). Preference for mercury column sphygmomanometer due to its reliability and simplicity, with arm at the level of the heart has been stressed (3).
OH is more common and more severe during mornings and after meals, and is exacerbated by large meals, meals high in carbohydrate, and alcohol intake (1). In some patients symptomatic OH occurs beyond 3 minutes of standing (1).
- Freeman R, Wieling W, Axelrod FB, et al. Consensus statement on the definition of orthostatic hypotension, neurally mediated syncope and the postural tachycardia syndrome. Autonomic Neuroscience: Basic and Clinical 2011;161: 46–48. https://www.ncbi.nlm.nih.gov/pubmed/21431947
- http://www.cdc.gov/steadi/pdf/measuring_orthostatic_blood_pressure-a.pdf , accessed Dec 13, 2015.
- Naschitz J, Rosner I. Orthostatic hypotension: framework of the syndrome . Postgrad Med J 2007; 83:568-574. http://pmj.bmj.com/content/83/983/568