Types of nebulizers
The most commonly used nebulizers are Jet nebulizers, which are also called "atomizers". Jet nebulizers are connected by tubing to a compressor, that causes compressed air or oxygen to flow at high velocity through a liquid medicine to turn it into an aerosol, which is then inhaled by the patient. Currently there seems to be a tendency among physicians to prefer prescription of a pressurized Metered Dose Inhaler (pMDI) for their patients, instead of a Jet nebulizer that generates a lot more noise (often 60dB during use) and is less portable due to a heavier weight. However Jet nebulizers are commonly used for patients in hospitals who have difficulty using inhalers, such as in serious cases of respiratory disease, or severe asthma attacks. The main advantage of the Jet nebulizer is related to its low operational cost. If the patient needs to inhale medicine on a daily basis the use of a pMDI can be rather expensive. Today several manufacturers have also managed to lower the weight of the Jet nebulizer down to 635 grams (22.4 oz), and thereby started to label it as a portable device. Compared to all the competing inhalers and nebulizers, the noise and heavy weight is however still the biggest draw back of the Jet nebulizer.
Ultrasonic wave nebulizers were invented in 1964 as a new more portable nebulizer. The technology inside an ultrasonic wave nebulizer is to have an electronic oscillator generate a high frequency ultrasonic wave, which causes the mechanical vibration of a piezoelectric element. This vibrating element is in contact with a liquid reservoir and its high frequency vibration is sufficient to produce a vapor mist. As they create aerosols from ultrasonic vibration instead of using a heavy air compressor, they only have a weight around 170 grams (6.0 oz). Another advantage is that the ultrasonic vibration is almost silent. Examples of these more modern type of nebulizers are: Omron NE-U17 and Beurer Nebulizer IH30.
A new significant innovation was made in the nebulizer market around 2005, with creation of the ultrasonic Vibrating Mesh Technology (VMT). With this technology a mesh/membrane with 1000-7000 laser drilled holes vibrates at the top of the liquid reservoir, and thereby pressures out a mist of very fine droplets through the holes. This technology is more efficient than having a vibrating piezoelectric element at the bottom of the liquid reservoir, and thereby shorter treatment times are also achieved. The old problems found with the ultrasonic wave nebulizer, having too much liquid waste and undesired heating of the medical liquid, have also been solved by the new Vibrating Mesh nebulizers. A partial list of available VMT nebulizers includes: Pari eFlow, Respironics i-Neb, Omron MicroAir, Beurer Nebulizer IH50, and Aerogen Aeroneb. As the price of the ultrasonic VMT nebulizers carry a higher price compared to the previous models, most of the manufacturers continue also to sell the more "old fashioned" Jet nebulizer. The most recent innovation in nebulizer technology is the human-powered nebulizer being developed by Dr. Lars E. Olson of Marquette University.
The medical company Boehringer Ingelheim also invented a new device named Respimat Soft Mist Inhaler in 1997. This new technology provides a metered dose to the user, as the liquid bottom of the inhaler is rotated clockwise 180 degrees by hand, adding a build up tension into a spring around the flexible liquid container. When the user activates the bottom of the inhaler, the energy from the spring is released and imposes pressure on the flexible liquid container, causing liquid to spray out of 2 nozzles, thus forming a soft mist to be inhaled. The device features no gas propellant and no need for battery/power to operate. The average droplet size in the mist was measured to a somewhat disappointing 5.8 micrometers, which could indicate some potential efficiency problems for the inhaled medicine to reach the lungs. Subsequent trials have proven this was not the case. Due to the very low velocity of the mist, the Soft Mist Inhaler in fact has a higher efficiency compared to a conventional pMDI. In 2000, arguments were launched towards the European Respiratory Society (ERS) to clarify/expand their definition of a nebulizer, as the new Soft Mist Inhaler in technical terms both could be classified as a "hand driven nebulizer" and a "hand driven pMDI".
Ultrasonic wave nebulizers were invented in 1964 as a new more portable nebulizer. The technology inside an ultrasonic wave nebulizer is to have an electronic oscillator generate a high frequency ultrasonic wave, which causes the mechanical vibration of a piezoelectric element. This vibrating element is in contact with a liquid reservoir and its high frequency vibration is sufficient to produce a vapor mist. As they create aerosols from ultrasonic vibration instead of using a heavy air compressor, they only have a weight around 170 grams (6.0 oz). Another advantage is that the ultrasonic vibration is almost silent. Examples of these more modern type of nebulizers are: Omron NE-U17 and Beurer Nebulizer IH30.
A new significant innovation was made in the nebulizer market around 2005, with creation of the ultrasonic Vibrating Mesh Technology (VMT). With this technology a mesh/membrane with 1000-7000 laser drilled holes vibrates at the top of the liquid reservoir, and thereby pressures out a mist of very fine droplets through the holes. This technology is more efficient than having a vibrating piezoelectric element at the bottom of the liquid reservoir, and thereby shorter treatment times are also achieved. The old problems found with the ultrasonic wave nebulizer, having too much liquid waste and undesired heating of the medical liquid, have also been solved by the new Vibrating Mesh nebulizers. A partial list of available VMT nebulizers includes: Pari eFlow, Respironics i-Neb, Omron MicroAir, Beurer Nebulizer IH50, and Aerogen Aeroneb. As the price of the ultrasonic VMT nebulizers carry a higher price compared to the previous models, most of the manufacturers continue also to sell the more "old fashioned" Jet nebulizer. The most recent innovation in nebulizer technology is the human-powered nebulizer being developed by Dr. Lars E. Olson of Marquette University.
The medical company Boehringer Ingelheim also invented a new device named Respimat Soft Mist Inhaler in 1997. This new technology provides a metered dose to the user, as the liquid bottom of the inhaler is rotated clockwise 180 degrees by hand, adding a build up tension into a spring around the flexible liquid container. When the user activates the bottom of the inhaler, the energy from the spring is released and imposes pressure on the flexible liquid container, causing liquid to spray out of 2 nozzles, thus forming a soft mist to be inhaled. The device features no gas propellant and no need for battery/power to operate. The average droplet size in the mist was measured to a somewhat disappointing 5.8 micrometers, which could indicate some potential efficiency problems for the inhaled medicine to reach the lungs. Subsequent trials have proven this was not the case. Due to the very low velocity of the mist, the Soft Mist Inhaler in fact has a higher efficiency compared to a conventional pMDI. In 2000, arguments were launched towards the European Respiratory Society (ERS) to clarify/expand their definition of a nebulizer, as the new Soft Mist Inhaler in technical terms both could be classified as a "hand driven nebulizer" and a "hand driven pMDI".
