Subjects lying face up reveal a reduced ability for 'nasal air con...( Compensating for this physiological f...)

January 3, 2002 -- Bethesda, MD -- The nose warms and humidifies air. Previous research efforts have led to an ability to measure how the nose conditions cold, dry air (CDA). The consensus is that the two most important predicting parameters of the nasal air-conditioning process are the blood temperature distribution along the airway walls, or the nasal mucosal temperature, and the volume, or perimeter, of the nasal cavity.

An increase in nasal mucosal temperature by feet warming has been previously shown to enhance the ability of the nose to warm and humidify air. How altering the other important parameter, nasal volume, affects nasal conditioning is the subject of this research.

Background
Assuming a supine position (lying face-up) has been consistently shown to increase nasal airway resistance and decrease nasal volume secondary to an increase in the volume of the capacitance vessels of the nose. Although actual blood volume in the cavernous sinusoids has not been measured in the upright and supine positions, an increase in nasal blood volume is the explanation given for the consistent changes in nasal air cavity volume and nasal airway resistance.

The only other structures within that region are the nasal mucosa with its cavernous sinusoids. Sinusoids are considered the variable responsible for the change in nasal cavity volume on changing from the upright to the supine position. Because the nasal cavity has defined anatomic limits, an increase in blood volume will lead to a reciprocal decrease in nasal cavity volume and vice versa. Supporting this notion is the effect of topical intranasal decongestants, which decrease nasal blood volume and increase nasal cavity volume.

A team of Chicago physiologists have hypothesized that decreasing nasal volume by placing subjects in the supine position would i
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Contact: Donna Krupa
djkrupa1@aol.com
703-527-7357
American Physiological Society
10-Jan-2002