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!
TSRI researchers develop new method to 'fingerprint' HIV
29.03.2017 | Scripps Research Institute
Periodic ventilation keeps more pollen out than tilted-open windows
29.03.2017 | Technische Universität München
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
29.03.2017 | Materials Sciences
29.03.2017 | Physics and Astronomy
29.03.2017 | Earth Sciences