If you’ve been prescribed oxygen, the type of delivery matters as much as the number on the dial. Here’s how pulse dose and continuous flow differ, using manufacturers’ manuals.
The basics
| Continuous flow | Pulse dose | |
|---|---|---|
| How it delivers | Steady stream all the time | A bolus at the start of each inhalation |
| Measured in | Liters per minute (LPM) | mL per breath; total mL per minute |
| Typical devices | Home stationary concentrators; some larger portables | Small portables (Rove 6, FreeStyle Comfort, OxyGo NEXT) |
| Needs your breath to trigger | No | Yes |
| Battery and size | More power, larger | CAIRE: “conserves oxygen and extends battery life” |
| Use with CPAP bleed-in | CPAP oxygen limits are given in L/min (e.g. ResMed AirSense 11: 15 L/min) | Rove 6 manual: don’t use with CPAP; NEXT: not to be connected with other equipment |
Sources: CAIRE FreeStyle Comfort manual, Inogen Rove 6 manual, OxyGo NEXT manual.
How much oxygen a pulse setting delivers
Inogen’s Rove 6 delivers a fixed total per minute at each setting, split across your breaths:
| Setting | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|
| mL per minute | 210 | 420 | 630 | 840 | 1,050 | 1,260 |
| mL per breath at 15 breaths/min | 14 | 28 | 42 | 56 | 70 | 84 |
| mL per breath at 30 breaths/min | 7 | 14 | 21 | 28 | 35 | 42 |
Source: Rove 6 manual, ±15%. The OxyGo NEXT lists the same 210–1,260 mL/min totals, and the FreeStyle Comfort lists 210–1,050 mL/min over 5 settings.
So on a minute-volume unit, breathing faster means smaller puffs. CAIRE’s FreeStyle Comfort offers an alternative, autoSAT, on by default, which keeps the dose per breath the same as your breathing rate rises (up to 40 breaths a minute), so more oxygen per minute is delivered during activity (FreeStyle Comfort manual).
Pulse settings are not liters
Inogen’s manual cautions: “The settings of this device may not correspond with the setting for devices that provide continuous flow oxygen”, and settings of other brands may not correspond either (Rove 6 manual). CAIRE says pulse settings “must be determined for each user individually for their needs at rest, during exercise, and when traveling” (FreeStyle Comfort manual). Don’t convert a “2 LPM” prescription to “setting 2” yourself.
Triggering and no-breath alerts
Pulse units must sense your breath:
- Inogen says the Rove 6 is contraindicated if your normal resting breathing can’t trigger it.
- CAIRE notes that “some respiratory efforts of the patient might not trigger the conserving function”.
- If no breath is detected, the Rove 6 and OxyGo NEXT start automatic pulses after 60 seconds, and the FreeStyle Comfort after 15 seconds, at 20 pulses a minute, until a breath is detected again.
Those backups are safety features, not a substitute for proper triggering. This matters most during sleep.
Which fits you
| Situation | Likely fit (your clinician decides) |
|---|---|
| Active during the day, low to moderate prescription, tested on pulse | Pulse portable |
| Need oxygen with CPAP or BiPAP | Continuous source (CPAP with oxygen) |
| Breathing too shallow to trigger reliably | Ask about continuous flow |
| Higher flow needs at home | Stationary continuous, e.g. 5 or 10 LPM (5 vs 10 LPM) |
| Flying | Either type, if FAA-labeled (FAA rules) |
Medicare
Medicare covers home oxygen equipment, including portable equipment, when its testing criteria are met. See Medicare home oxygen coverage. The FDA says you shouldn’t use an oxygen concentrator at home unless a health care provider has prescribed it (FDA).
Verdict
Pulse dose makes small, light portables possible and stretches battery life. It only works if your breathing triggers it, and its settings aren’t liters per minute. Continuous flow is the safer default with CPAP, for shallow breathers, and for higher prescriptions. Ask your clinician to test you on the exact device and setting you’ll use.
Related: battery life by model, Rove 6 vs FreeStyle Comfort, oxygen concentrator buyer’s guide.
Continuous-flow portable example: Oxlife Independence review.