The results appear in the second issue for December 2006 of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.
T. Douglas Bradley, M.D., of the Toronto General Hospital, and eight associates measured leg fluid volume, neck circumference and airflow resistance in the throats (pharynx) of 11 healthy, non-obese subjects while they lay on their backs. Next, the researchers applied a lower body positive pressure device (anti-shock trousers) for five minutes to displace fluid from the legs to the neck area.
In obstructive sleep apnea, a blockage in the throat or upper airway causes victims to repeatedly stop breathing long enough to decrease the amount of oxygen in the blood and increase the carbon dioxide. The National Heart, Lung, and Blood Institute estimates that 18 million Americans suffer from sleep apnea.
"Obesity and neck circumference are important risk factors in obstructive sleep apnea, but together only account for approximately one-third of the variability in the apnea-hyponea index," said Dr. Bradley. "A factor not ordinarily considered is fluid accumulation at the nape of the neck and around pharyngeal soft tissue. Obstructive sleep apnea is very common in fluid-retaining states such as heart failure, renal failure and peripheral edema of unknown cause."
"Our data show that displacement of a small amount of fluid such as 340 ml, about 12 ounces, from the legs is sufficient to cause a 102 percent increase in airflow resistance of the pharynx in healthy, non-obese subjects," continued Dr. Bradley
According to the authors, when the pharynx narrows in obstructive sleep apnea and in healthy subjects, airflow resistance increases as the person transits from wakefulness to sleep. Consequently, an even greater degree of fluid shift into the neck during sleep would cause further pharyngeal airflow obstruction.
The seven men and four women who participated in the study had an average age of 36. None had obstructive sleep apnea.
The authors noted that further studies would be required to determine whether fluid displacement increases pharyngeal obstruction as a person moves from upright to a recumbent position, especially when the person does not have a predisposing condition.
Suzy Martin | EurekAlert!
Satellites, airport visibility readings shed light on troops' exposure to air pollution
09.12.2016 | Veterans Affairs Research Communications
Oxygen can wake up dormant bacteria for antibiotic attacks
08.12.2016 | Penn State
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine