Pathophysiology of the Upper Airway in Patients With COPD and Concomitant OSA

This is a physiologic study to assess the effects of lower airway and lung tissue changes of
COPD on upper airway collapsibility. Increased in lung volume and destruction of alveolar
wall in COPD may have opposite and various effects on the upper airway collapsibility, which
is an important factor of OSA development.

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are very
common disorders associated with considerable morbidity, mortality, and healthcare costs.
The prevalence of both co-existing conditions is estimated to be ~4% of the general
population. This COPD-OSA "overlap" syndrome causes more severe hypoxemia than either COPD
or OSA alone and has important clinical consequences, including death. COPD is usually
excluded in OSA research and OSA is typically excluded or not assessed in studies of COPD;
thus, available information about the "overlap" syndrome is limited. Therefore, it is
important to identify patients with both COPD and OSA and determine the mechanisms of poor
outcomes for these patients in order to optimize therapy. The pathophysiology of the
COPD-OSA syndrome is not well understood. The investigators propose to investigate upper
airway (UA) anatomic characteristics and collapsibility as potential underlying mechanisms
that may help to explain the negative additive effect of having both conditions. The
objectives are to study CT measures of airway anatomy and the critical closing pressure of
the upper airway (Pcrit), a gold standard measure of upper airway collapsibility, in
patients with COPD-OSA compared with COPD only and normal controls. CT scan of upper airway
and chest will allow precise measures of upper airway characteristics and COPD associated
alveolar and lower airway ch. angesMeasures of upper airway collapsibility will provide us
information about the mechanical nature of the airway and if the patients are more likely to
have OSA. Subjects with COPD-OSA may exhibit more upper airway inflammation possibly due to
their pre-existing COPD disease and the reoccurring opening and closing of the upper airway
due to the OSA. Therefore the investigators would like to assess the degree of inflammation
in these patients compared to normal controls.

Inclusion Criteria for COPD Subjects:

- Age range 40-70 years.

- Demonstrated moderate to severe COPD as determined by spirometry (post-bronchodilator
spirometry FEV1/FVC < 0.70 for diagnosing CODP and FEV1<80% predicted for staging)

- Smoking history of ≥ 10 pack-years

Inclusion Criteria for Control Subjects

- Age range 40-70 years

- Demonstrated no COPD as determined by normal spirometry (post-bronchodilator
spirometry FEV1/FVC > 0.70 for diagnosing CODP and FEV1<80% predicted for staging)

- No smoking history as defined by less than 100 cigarettes smoked in a lifetime

Exclusion Criteria for both COPD and Control Subjects:

- Metal objects that may interfere with chest CT quantification including presence of a
cardiac pacemaker, defibrillator, metal prosthetic heart valve, metal projectile or
metal weapon fragment (bullet, shrapnel, shotgun shot) or metal shoulder prosthesis

- Subjects unable to perform spirometry due to:

- chest or abdominal surgery in the past three months

- a heart attack in the last three months

- detached retina or eye surgery in the past three months

- hospitalization for any other heart problem in the past month

- History of hypersensitivity to Afrin, Lidocaine or albuterol

- A psychiatric disorder, other than mild depression; e.g. schizophrenia, bipolar
disorder, major depression, panic or anxiety disorders.

- More than 10 cups of beverages with caffeine (coffee, tea, soda/pop) per day

- Pregnancy or suspected pregnancy