The Settings on Portable Oxygen Concentrators (pocs)

& Oxygen Conserving Devices (ocd)

Need Regulated By the FDA So Setting Numbers
 Are Equivalent To LPM Numbers

All poc & ocd settings need to be equivalent to LPM settings @ 16 BPM and a 3.5 to 1 conserving ratio. (see the two bottom charts)

Download as a Brochure


As the Tables Below Show, It Doesn’t Take Rocket Science To

Make the Conversions, Just Horse Sense & Simple Math

The first column shows the name of the Company and the units they manufacture.  The second column shows the maximum milliliters of oxygen produced in one minute by the unit.  The third column shows the number of settings the unit has.  Overall there is no correlation between maximum mlpm and the number of settings.  Logically there should be.  The fourth column shows the conserving ratio and is the most important.  It determines the amount of oxygen delivered each minute.  A 3 to 1 conserving ratio will deliver 1/3 liter or 333 milliliters per minute.  A 4 to 1 conserving ratio will deliver ¼ liter or 250 milliliters per minute.  Simple division.  3 to 1 ratio = 1 liter ÷ 3 = 333

From the research I have done as an individual with severe COPD(emphysema) I believe the conserving ratio used to find a settings equivalent LPM is 3.5 to 1.  My body quickly lets me know if the setting number is delivering less oxygen than the equivalent LPM number. A logical argument may also be made for the 3.5 to 1 conserving ratio.

The fifth column shows the unit's maximum LPM setting.  Use this column to see if the unit will fill your prescription and meet your needs.

The formula – max mlpm ÷ 288 = the units maximum LPM (1000 ml ÷ 3.5 = 285.7. for ease of use I rounded 285.7 up to 288).  Using the Caire Focus as an example – 330 ÷ 288 = 1.1.   Rounding down ensures the consumer will get the oxygen stated.

I am not a medical professional or caregive, just an individual with a prescription for oxygen whose well-being depends on knowing which portable oxygen concentrator (poc) or oxygen conserving device (ocd) will meet my needs.  I watch my blood oxygen levels on a daily basis and recomend all with a prescription for oxygen do the same.

Poc Chart


All units need to indicate whether they are Fixed Mililiter or Fixed Bolus.


Many pocs are fixed milliliter per minute.  Notice how the bolus size decreases as the breaths per minute increase and the conserving ratio remains steady.

fixed mililiter

Some pocs and most conservators are fixed bolus size.  Notice how the milliliters per minute increase as the breaths per minute increase.  The conserving ratio decreases as the breaths per minute increase. 

fixed bolus

Because the numbers on the tables change, all comparisons need to be done at 16 breaths per minute and a 3.5 to 1 conserving ratio.  The same is true when checking to see if setting numbers and LPM numbers deliver an equivalent amount of oxygen.

 If you have any comments on these tables, please e-mail them to oxygen@hors-sens.com.


Copyright © 2016-2018 Gerald Miller. All Rights Reserved.


Copyright © 2016-2017 Gerald Miller. All Rights Reserved.