Clinical meaning
The nurse must differentiate types of orthostatic hypotension and implement appropriate management strategies. OH is classified as: (1) Initial OH -- transient BP drop within 15 seconds of standing with quick recovery (common, benign); (2) Classic OH -- sustained BP drop within 3 minutes of standing (standard definition); (3) Delayed OH -- BP drop occurring after 3 minutes of standing, often missed with standard testing (requires prolonged standing test or tilt-table). Neurogenic OH (nOH) is distinguished from non-neurogenic causes by the heart rate response: nOH shows absent or blunted HR increase (less than 15 bpm) because the autonomic nervous system cannot generate a compensatory tachycardia. Non-neurogenic OH (hypovolemia, medication-related) shows an appropriate HR increase of 20+ bpm. The nurse also assesses for postural orthostatic tachycardia syndrome (POTS): HR increase of 30+ bpm (or HR above 120) within 10 minutes of standing WITHOUT significant BP drop; more common in young women; symptoms include palpitations, lightheadedness, exercise intolerance, fatigue. The head-up tilt-table test (HUT) is the gold standard for evaluating orthostatic intolerance, performed at 60-70 degrees for 20-45 minutes with continuous BP and HR monitoring.