September 1, 2006 Doctors can now keep patients who are in respiratory care safer with a new kind of ventilator. Ventilator oxygen is completely dry and needs to be humidified for the patient's comfort, but water can then condensate along the line, and allow the growth of microbes. The new system, based on capillary force, helps prevent condensation by hydrating oxygen closer to the patient's mouth.
ORLANDO, Fla. -- Most healthy people take for granted the simple act of breathing, but anyone with respiratory problems knows how precious each breath is to their existence. Patients often rely on traditional ventilators, but they sometimes cause more problems than solutions. Now, a new technology may make breathing ... a breeze.
For many, a ventilator can mean the difference between life and death, but doctors say the machine has its drawbacks.
In some, the gas that comes out of the ventilator is completely dry. Oxygen passes over heated water and then travels through this long tube to the patient. Because it's so far away from the patient's mouth, the water often condenses, which can sometimes contaminate the water.
Using the same technology used in spray air fresheners and perfumes, engineers have developed a new way to create water vapor that hydrates the oxygen closer to the patient's mouth.
Dean Hess, assistant director of respiratory care at Massachusetts General Hospital in Boston, says it makes the patient's breathing more comfortable.
"The whole idea of the hydrate is to keep that whole line dry, so there is not water sitting around," says Norman Tiffin of PARI Respiratory Equipment in Monterey, Calif.
The vaporizer uses "capillary force," which mimics the way a tree draws water from its roots. The molecules are squeezed together, and that force is stronger than gravity, so the water goes up.
The PARI hydrate vaporizer will be available to doctors in March 2007.
BACKGROUND: Capillary Force Vaporizer technology is used in many products: air fresheners, perfumes, and insect repellant, to name a few. About the size of a watch battery, CFV is a compact, heat-powered device that generates a powerful jet of pressurized vapor from an unpressurized liquid with no moving parts. Now, engineers are coming up with new ways to make vapor that could open the door to more applications in medicine.
HOW IT WORKS: Traditional methods of producing vapor use a process called atomization: they create tiny droplets, which evaporate into a vapor or gas. The CFV combines two basic natural principles into a single component that vaporizes a liquid and forcefully ejects it as a gas, without resorting to the complicated mechanisms normally needed to do so. Capillary forces arise when liquids and solids interact. A liquid is attracted to itself but also to the surface it contacts. If the surface is covered with tiny holes, the liquid "sticks" better. If the holes are larger, the liquid won't stick as well. A phase transition is the critical temperature/pressure point where one state of matter changes into another: in this case, liquid into gas.
The CFV has three ceramic discs bound together by a glaze. The top disc has a tiny hole in the center. The middle disc has many tiny pores, and the bottom layer has larger pores. The bottom layer is in constant contact with the liquid to be vaporized. Capillary action pulls the liquid up through the pores in the bottom layer, where it becomes trapped by the center disc. Heat is then applied to the top disc, and as the trapped liquid heats up, it evaporates into a gas. The gas naturally takes up more space than the liquid, and since it's contained in a small space, the pressure inside the small space gets higher. The higher pressure forces the gas out through the hole in the center of the top disc in a steady jet.
ADVANTAGES: Controlled vaporization of liquids is a critical component to many different products and processes, such as air fresheners, microchip manufacturing, and jet engines. Eliminating the need for moving parts makes the CFV very compact and efficient. When used in consumer products like fragrances or insect repellant, a CFV can disperse active ingredients directly, with no need for propellants, fillers, or disposable aerosol cans. And when used with liquid fuels, such as in a camping stove, the vapor produced by a CFV burns more like natural gas, reducing emissions. Researchers believe that many pharmaceutical and over-the-counter medications intended to be inhaled could be delivered more cost effectively using CFV technology -- such as asthma inhalers or nicotine vaporizer devices to help people quit smoking.
Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.