Portable Oxygen Concentrators Choosing a cannula.

In: Oxygen Therapy|Portable Oxygen Concentrator FAQs

8 Apr 2010

Not that the decision to purchase a particular portable oxygen concentrator was easy, you also have to determine the best oxygen delivery device (aka cannula) for both you and your system.  Each manufacturer has some requirements for the cannula length and the overall length allowed for the entire delivery device, that is tubing plus cannula.  Some portable oxygen concentrators cannot operate with a cannula that is any distance beyond 7 feet; while, other portable oxygen concentrators can operate with a standard 50 foot tubing plus the 7 foot cannula.

So what gives?  If you have a portable concentrator that is capable of generating a continuous flow  of oxygen like the Sequal Eclipse or the Invacare Solo, your going to have a greater ability to move the concentrator away from the end user because these units operate as would any home oxygen concentrator.  That is, the Sequal Eclipse and the Invacare Solo are both capable of generating 3.0 liters per minute of oxygen at a pressure of 5.5 psi.  So our oxygen tester hooked up to the end of a 50 foot tubing will read 96% oxygen purity @ 5.5 psi, and more importantly, you the end user will  be receiving your prescribed dose of oxygen.

If on the other hand your portable oxygen concentrator is not capable of continuous flow greater than one liter per minute, the unit operates in a conserving mode only.     Your maximum cannula for this type of oxygen conserving device is either 7 feet or 4 feet.  The reason for the short leash with conserving only portable oxygen concentrators is the requirement of the machine itself to detect a patient breath.  When a cannula is fitted properly in the patient’s nose, AND the patient is breathing properly THROUGH their nose (and not mouth breathing) the portable oxygen concentrators are designed to sense a drop in back-pressure in the cannula, and upon receiving such data, release the prescribed does of oxygen to the end user. Continuous flow portable concentrators like the Sequal Eclipse or the Invacare Solo that are functioning in a conserving mode are also limited to 7 feet or less, and function in the same fashion.

Some patients prefer a micro cannula, which have smaller prongs, usually for their smaller noses.  Unfortunately the smaller diameter of the micro cannula prongs causes most oxygen conserving devices to malfunction.  That is not to say that they will not work one hundred percent of the time.    When choosing a cannula, the best advice seems to be acquire a number of different cannula models from a few different vendors.  Each vendor makes multiple cannulas, soft, super soft, micro.  Try them all, find the cannula that feels the most comfortable for you, and test your saturation with a pulse oximeter to make sure you are getting the FI02 that your physician is prescribing.

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