No volunteers were enrolled, study was closed

The investigators will test whether breathing through an inspiratory resistance device will improve the ability to be upright and decrease blood pressure drops on standing in patients with orthostatic hypotension.

Orthostatic hypotension is commonly described, especially in an elderly population. Using data from a national hospital inpatient database, Shibao et al. have reported that the annual hospitalization rate for orthostatic hypotension was 233 per 100000 among patients older than 75 years. Orthostatic hypotension is associated with an increased risk of falls, increased risk of coronary heart disease and mortality.

Orthostatic hypotension is defined as a fall in systolic blood pressure of at least 20 mmHg within 3 minutes upon standing 3. Patients with orthostatic hypotension commonly experience lightheadedness or syncope. In normal individuals, changes in posture do not results in significant changes in blood pressure due to physiological compensation for the gravity-mediated pooling of blood in the lower limbs with upright posture. Unfortunately, in patients with impairments of the autonomic nervous system, one or more of these adaptive mechanisms fail, and an orthostatic fall in blood pressure results.

In this pilot study, we will test the hypothesis that breathing through an inspiratory resistance device will improve orthostatic tolerance and reduce orthostatic hypotension in patients with neurogenic orthostatic hypotension.

Inclusion Criteria:

• Diagnosed with neurogenic orthostatic hypotension by the Vanderbilt Autonomic Dysfunction Center
• Decrease in systolic blood pressure ≥ 20 mmHg with position change from supine to standing (10 minutes)
• Evidence of reproducibility suggestive of non-reversible nervous system origin for the orthostatic hypotension
• Age between 18-80 years
• Male and female subjects are eligible
• Able and willing to provide informed consent

Exclusion Criteria:

• Overt cause for orthostatic hypotension (such as acute dehydration)
• Inability to give, or withdrawal of, informed consent
• Pregnant
• Other factors which in the investigator's opinion would prevent the subject from completing the protocol