Orthostatic hypotension is an abnormal drop in blood pressure when standing from a seated or lying down position and is common in elderly patients. It is defined as a reduction in blood pressure of at least 20mm Hg systolic or 10mm Hg diastolic within 3 minutes of standing. There are complex regulatory mechanisms that prevent a reduction in blood pressure when in the upright position, however in orthostatic hypotension a component of this complex system does not allow the vascular system to compensate for the gravity-induced drop in blood-pressure.
The symptoms occur when standing from a seated or supine position and can be associated with:
The episodes last for seconds to minutes and improve with sitting, lying down, or standing with support.
There are many causes of orthostatic hypotension that can be separated into two categories, neurogenic and non-neurogenic.
Neurogenic causes of orthostatic hypotension:
Non-neurogenic causes of orthostatic hypotension:
Iatrogenic etiologies (medications):
Medications can cause orthostatic hypotension by interfering with autonomic pathways or their target end-organs, or by affecting intravascular volume.
Tilt test – The patient’s blood pressure is taken when lying down and then again within 1-3 minutes after standing.
Tilt table test – The patient is secured with straps on a table that is able to move from a horizontal to vertical position. While lying down on the table the patient’s blood pressure and heart rhythm are monitored by a blood pressure cuff and EKG respectively. Then, the table is raised into an upright position where the patient is kept for approximately 45 minutes while the blood pressure and heart rhythm are monitored. The patient is then returned to the lying down position.
The goal of management of orthostatic hypotension is to raise the patient’s standing blood pressure without also raising the blood pressure while lying down, and specifically to reduce orthostatic symptoms, increase the time the patient can stand, and improve his or her ability to perform daily activities (1). Figueroa et al recommended an A-F mnemonic to highlight management strategies. The alphabetical order does not represent a sequential approach to management(1).
A: Abdominal compression – Wearing an abdominal binder helps to decrease orthostatic hypotension. Moving from the supine to upright position causes immediate pooling of up to 1 liter of blood in the dependent regions of the abdomen and legs (2). Wearing compression stockings alone is not as beneficial as abdominal compression because there is more venous capacity in the abdomen, specifically the splanchic mesenteric bed. The abdominal binder should be put on prior to getting out of bed and then taken off when going to bed. Compression stockings can provide additional benefit when abdominal compression is not enough. Compression garments should extend to the waist or at least to the proximal thigh.
B: Boluses of water – Drinking water can provide a rapid relief of symptoms resulting from orthostatic hypotension in autonomic failure patients. This intervention is particularly useful in the morning (when orthostatic hypotension tends to be more severe) and can bridge the time required for oral medications to start working (3).
B: Bed up – Sleeping with the head of the bed elevated to the maximal tolerated angle encourages local autoregulation of blood flow by cerebral vessels, adapting them over the long term to low perfusion pressures; it also avoids the sudden pooling of blood upon arising in the morning (4).
C: Countermaneuvers – Isometric contractions of the lower extremities for 30 seconds at a time can help increase blood flow to the heart. These techniques can be performed to help maintain blood pressure during daily activities and include (5):
D: Drugs – fludrocortisone (Florinef) and midodrine (ProAmantine). A review of the patient’s current medications is also important to identify possible drugs that could be causing orthostatic hypotension. Discontinuing the medication or replacing it with another medication should be discussed thoroughly with the patient’s primary care physician and/or Cardiologist.
E: Education – The patient should be taught the symptoms or orthostatic hypotension and learn the conditions that can lower blood pressure. For example, prolonged standing, drinking alcohol, eating carbohydrate-heavy meals, heat exposure, standing quickly from a seated or lying down position, and lying down for a prolonged time period.
E: Exercise – Mild exercise can help reduce pooling of blood. Recumbent biking and swimming are preferred to upright exercise.
F: Fluid and Salt – Maintaining an adequate plasma volume is crucial (1). Patients should drink five to eight 8-ounce glasses (1.25 to 2.5 L) of water or other fluid per day.(1) Patients should have 10-20 grams of salt intake per day. Caution should be taken with increasing sodium intake in patients with hypertension.