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  All Conserving Devices Are Not Created Equal!

Since all oxygen conservers are not the same, is your head spinning trying to figure them all out?  These days it can be difficult to distinguish among the dozens of oxygen conserving devices on the market.  All boast a different set of claims regarding their clinical efficacy, economic benefits, and ease of use.  So,  how do you decide which is the right conserver for your patient and your budget?  Here's some information to help you with your decision.
  What is a conserving device?
 

An oxygen conserver is a device that delivers oxygen to the patient only on inhalation rather than continuous flow, as through conventional oxygen delivery.  This provides advantages to the patient in allowing them to carry smaller tanks that last longer.  It also eliminates the need for an E cylinder and cart for all but the most oxygen-dependent patients, while at the same time reducing the provider's cost in oxygen refilling and home delivery.
  Liquid Oxygen (LOX) vs. Cylinders with Conservers
 

Until CHAD Therapeutics introduced the first oxygen conserving device in 1986, LOX was considered the standard for ambulatory oxygen.  Cooled to a liquid state for storage then rewarmed to gas upon use, liquid oxygen takes up less space than its equivalent in compressed gas, making it a favorable choice for a portable oxygen system.  However, LOX has its significant drawbacks as well.  Its constant evaporation, even when not in use, makes it impractical and costly for long-term storage and travel.  Portables must be refilled frequently from a stationary reservoir.  If this procedure is not done correctly, it can result in oxygen waste, spills, or worse, yet, burns to the patients.

At the same time, compressed gas cylinders have evolved from a 20 lb. steel tank on a wheel cart to ultra-lightweight aluminum cylinders that can be as small as 9" high and weigh as little as 1.5 lbs.  Combined with a highly efficient conserver, today's compressed gas cylinders can be part of a small, lightweight ambulatory system with none of LOX's drawbacks. They can be stored with no oxygen loss, and extra cylinders can be taken along for weekend or long-term travel, making them a favorable alternative to liquid oxygen.  

  What are the types of conservers available?
  Electronic vs. Pneumatic
 

Both electronic and pneumatic conservers deliver oxygen on inhalation only; however, their methods in doing so are quite different.  Electronic conservers operate on a battery and use electronic circuitry to measure a dose of oxygen that is "pulsed" to the patient at the beginning of inhalation.  Pneumatic devices do not require batteries and are strictly mechanical.  Most deliver oxygen through the entire inhalation cycle.  CHAD's electronic conservers provide a 5:1 savings ratio, while most pneumatics average about 2:1.  What does a 5:1 savings vs. a 2:1 savings mean?  It means that your cylinders will last five times longer than continuous flow when utilizing a CHAD electronic conserver, as compared to only twice as long as with a pneumatic conserver.
  Pulse vs. Demand
 

You may hear conserving devices described as "pulse" or "demand."  All electronic conservers fall into the pulse category; that is, they deliver a measured pulse of oxygen at the beginning of inspiration.  Most pneumatic conservers are not true demand systems but hybrids, providing a pulse at the beginning of inspiration followed by a declining continuous flow through the rest of the inspiratory cycle.  The continuous flow delivery of the hybrid conservers is simply a design characteristic of some pneumatic devices and does not contribute significantly to blood oxygen levels.  By contrast, the CYPRESS OXYPneumatic conserver closely mimics the operation of an electronic conserver by delivering fixed pulse volumes without a continuous flow.
  Stand-Alone vs. All-in-One
 

Some electronic conservers are stand-alone type units (signifying they do not have built-in regulators) and require the use of supply tubing to connect to the regulator on top of the cylinder.  All-in-one units possess integrated regulators, thereby attaching like a regulator to the top of a post valve cylinder.  Stand-alone conservers offer the versatility of using different regulators and cylinder styles.  However, all-in-one conservers are easy to use and allow oxygen to be delivered with the simple turn of a dial or press of a button.
  Minute Volume vs. Uniform Pulse
  New to the market are pneumatic conservers that control minute volume delivery rather than uniform pulse delivery.  Essentially, a "minute volume" conserver restricts the amount of oxygen delivered per minute and holds it within a chamber from which oxygen pulses are delivered.  This delivery is said to mimic continuous flow, which has a static volume per minute as well.  However, the drawback to this kind of conserver when compared to a standard "pulse" delivery is that as a patient's breath rate increases (indicating increased oxygen need) the volume of each pulse decreases.  Therefore, at 40bpm a standard "pulse" conserver delivers twice as much per minute as at 20bpm, whereas a "minute volume" conserver delivers the same amount of oxygen per minute, but half as much per pulse.