| Quick Answer LPM stands for litres per minute, the volume of oxygen delivered to your patient every minute. It is the number on the oxygen prescription. For prescriptions up to 5 LPM, a 5-litre concentrator is the correct equipment. For prescriptions of 6 LPM or above, a 10-litre concentrator is needed. Never adjust the flow rate yourself above the prescribed level, even if the patient seems to be struggling. A change in oxygen requirement means a change in the patient’s condition and needs a doctor’s assessment first. |
The prescription says oxygen at 2 LPM, 16 hours daily. You know you need a concentrator. But the catalogue shows 5L and 10L models and you are not sure which one matches 2 LPM. Then the concentrator arrives and there is a dial on the front. Does the 2 on the dial mean 2 LPM? What if the doctor increases the rate later?
All of that answered here, in order.
What LPM Means and What the Machine Numbers Mean
LPM is litres per minute: the volume of oxygen flowing through the nasal cannula or mask each minute. The number on your prescription (1 LPM, 2 LPM, 3 LPM etc.) tells you the flow rate the doctor has calculated your patient needs to maintain safe blood oxygen levels.
The number on the concentrator (5L or 10L) is the machine’s maximum flow capacity, meaning the highest LPM it can deliver while still maintaining oxygen purity above 87%. These two numbers are directly related:
| Prescription Flow Rate | Concentrator Needed | Oxygen Purity Delivered |
| 1 LPM | 5L concentrator | 93 to 96% |
| 2 LPM | 5L concentrator | 93 to 95% |
| 3 LPM | 5L concentrator | 92 to 95% |
| 4 LPM | 5L concentrator | 90 to 93% |
| 5 LPM | 5L concentrator (at rated maximum) | 87 to 90% |
| 6 LPM | 10L concentrator | 90 to 93% |
| 8 LPM | 10L concentrator | 90 to 93% |
| 10 LPM | 10L concentrator (at rated maximum) | 87 to 90% |
At maximum rated flow (5 LPM on a 5L unit, 10 LPM on a 10L unit), purity drops to the lower end of the acceptable range. For patients prescribed exactly at the maximum, a 10L concentrator at a moderate setting is preferable to a 5L concentrator running at its limit continuously.
Setting the Flow Rate on the Concentrator
Every oxygen concentrator has a flow control dial on the front panel. On a 5L unit, the dial is marked 1 through 5. On a 10L unit, 1 through 10. The dial clicks into each LPM position.
The Sanjeevia delivery team sets the flow rate correctly at delivery and confirms SpO2 response before leaving. The Philips EverFlo 5L is the most prescribed concentrator for home use in India for flows up to 5 LPM.
Common Prescriptions and What They Typically Indicate
| Flow Rate | Typical Condition | Hours Per Day |
| 1 to 2 LPM | Mild COPD, post-COVID oxygen support, early-stage ILD | 8 to 16 hours |
| 2 to 3 LPM | Moderate COPD, cardiac conditions, post-surgical respiratory support | 15 to 20 hours |
| 3 to 5 LPM | Severe COPD, advanced ILD, post-ICU respiratory compromise | 20 to 24 hours (LTOT) |
| Above 5 LPM | Severe respiratory failure, high-flow nasal oxygen | Often continuous (24 hours) |
What to Do If the Doctor Changes the Prescription
If the prescription flow rate increases to a level the current concentrator cannot safely handle, contact Sanjeevia immediately. We arrange a swap to the appropriate machine. Do not run a 5L concentrator at 6 LPM. The machine will try to deliver the flow but purity will drop significantly below therapeutic levels.
If the flow rate decreases because the patient is improving, simply turn the dial to the new rate. No equipment change is needed.
If the doctor stops the oxygen prescription entirely, return the concentrator. Do not keep running it because the patient feels safer with it on. Oxygen at home above prescribed levels can suppress the respiratory drive in COPD patients.
Frequently Asked Questions
Q: SpO2 is still low after 20 minutes on the concentrator at the prescribed rate. What do I do?
Do not increase the flow rate on your own. Check the nasal cannula is correctly positioned and the tubing has no kinks. Check the concentrator filter is not clogged. If both are fine and SpO2 remains low, call the physician. A drop in SpO2 below the target despite correct equipment use indicates the patient’s condition has changed and needs clinical assessment.
Q: Can my patient use a higher flow rate at night when they sleep?
Only if the prescription specifically says so. Some patients are prescribed different flow rates for rest versus activity. If the prescription states one rate, use that rate at all times. Changes require a doctor’s instruction.
Q: My patient doesn’t like the nasal cannula and removes it during the night. What can we do?
Nasal cannula discomfort is common and usually solvable. Try adjusting the fit so the prongs are not too deep into the nostrils. A cannula with soft cushioned prongs may be more comfortable. A simple face mask (Venturi or simple oxygen mask) is an alternative for patients who consistently remove cannulas. Discuss with the physician before switching delivery method.
Q: Is it safe to use the oxygen concentrator while the patient also uses a BiPAP machine?
Yes. Many COPD patients use both simultaneously. Supplemental oxygen is introduced into the BiPAP circuit through the oxygen inlet port on the BiPAP machine. The specific flow rate into the circuit is prescribed separately. Sanjeevia’s team configures this combination correctly at delivery when both are ordered together.
| Rent an oxygen concentrator for home delivery in Delhi NCR: Browse all oxygen concentrators View the Philips EverFlo 5L (most prescribed for home use, up to 5 LPM). Have your prescription ready. WhatsApp us for same-day delivery. |
| Next Read: Concentrator is running. The next question most families ask is whether it is safe to use overnight. Read: Can You Use an Oxygen Concentrator at Night? Safety and Setup Guide |
For prescription-led oxygen care, the links below explain the next decision and point to the exact equipment pages discussed.
Medical Disclaimer: This article is for general informational purposes only and does not constitute medical advice. All clinical and equipment decisions should be guided by your treating physician.
Published by Sanjeevia Medical | sanjeevia.com | Delhi NCR
