Patients with lung disease experiencing difficulty breathing can be treated with oxygen
therapy. This involves the delivery of "extra" oxygen by a face-mask or through small tubes
placed in the nose called nasal prongs. This extra oxygen can have concentrations as high as
100% pure oxygen. The concentration of oxygen in normal air is only 21%. The high
concentration of oxygen can help to provide enough oxygen for all of the organs in the body.
Unfortunately, breathing 100% oxygen for long periods of time can cause changes in the
lungs, which are potentially harmful. Researchers believe that by lowering the concentration
of oxygen therapy to 40% patients can receive it for longer periods of time without the risk
of side effects.
This study is designed to evaluate the effects of oxygen therapy at 100% and 40% for 12 18
hours on the lungs of normal volunteers. Results of this study will help to determine if
levels of oxygen therapy currently accepted as being "safe" may actually be damaging to the
Stress such as high oxygen or inflammation can result in damage to proteins by processes
such as oxidation or alternative regulation of signaling pathways by post-translational
modification of proteins (e.g., phosphorylation). Delivery of oxygen in high concentrations
to the lungs can result in damage, which is mediated in large part by reactive oxygen
species. Inflammation can result in activation of intracellular signaling pathways. This
study will evaluate modification of proteins and nucleic acids in bronchoalveolar lavage
fluid, bronchial epithelial cells, and peripheral blood of individuals exposed to oxygen or
who are smokers. In doing so, it will determine the effects of hyperoxia or inflammation on
- INCLUSION CRITERIA:
History - good overall health without history of recent (within 3 months) acute disease;
Physical examination within normal limits;
Laboratory evaluation; including complete blood count (CBC), serum electrolyte
determinations, clotting times, chest x-ray, pulmonary function testing, and an
electrocardiogram (EKG) - within normal limits;
Non-smokers defined as having never smoked or not smoked in the past 2 years;
Smokers defined as moderate (1 pack per day for 3+ years) or heavy (1-2 packs for 10+
Subjects must be willing to make the time commitment necessary for the study.
Any study subject who does not fulfill the criteria for eligibility.
Individuals with a history of allergy or adverse reactions to atropine or any local
Individuals testing positive for the human immunodeficiency virus or hepatitis virus;
Individuals on chronic medications or currently receiving medications;
Pregnant or lactating individuals, since the effects of hyperoxia on the fetus are
Joel Moss, M.D.
National Heart, Lung, and Blood Institute (NHLBI)