Portable vs stationary: choosing the right concentrator

“Portable” and “stationary” describe two genuinely different devices that happen to share a name. A stationary home concentrator is a 15–25 kg PSA machine that sits beside a bed or chair and runs on mains power. A portable oxygen concentrator (POC) is a 2–5 kg battery-capable device engineered to deliver smaller bolus doses on demand. They solve different clinical problems; the mistake to avoid is picking one thinking it will behave like the other.

Continuous flow vs pulse dose — the core difference

Stationary concentrators deliver continuous flow: a steady, measurable stream of ~93% oxygen at the prescribed LPM. The patient breathes from that stream through a nasal cannula. The oxygen waste during the exhalation phase is accepted as the cost of a clinically simple delivery.

Most portable concentrators deliver pulse dose (also called on-demand or bolus). The device has a small compressor and sieve bed that cannot sustain the volumetric flow a stationary unit produces. Instead, the device senses the start of inspiration (via a pressure drop in the cannula), and fires a timed bolus of oxygen synchronised to the first part of the breath. Oxygen is delivered only when the patient is inhaling — which is when it can reach the alveoli.

Pulse-dose devices are rated not in LPM but in dose settings — “setting 1”, “setting 2”, and so on, typically 1 through 5 or 1 through 6. Each setting corresponds to a bolus volume (for example, 192 mL per breath at setting 2 on one popular model). The effective oxygen delivered depends on respiratory rate: a higher-than-expected breathing rate dilutes the dose over more breaths.

Clinical implication: pulse-dose is not automatically equivalent to a given continuous flow. Manufacturers publish conversion tables (“setting 2 ≈ 2 LPM continuous”), but these assume a specific breathing rate (usually 20 breaths per minute). In practice, overnight use — when breathing is slower and shallower — often produces a lower effective FiO₂ than the daytime equivalent setting suggests. Several studies have shown pulse-dose users desaturating overnight at a setting that was adequate during the day.

Some newer POCs offer a low continuous-flow mode (up to 2 LPM) for a limited subset of prescriptions, at the cost of much shorter battery runtime. If the prescription specifies continuous flow, this capability — not just the pulse-dose rating — is what to look for.

Weight and battery trade-offs

The portable category splits roughly into three tiers:

• Ultra-light (2.0–2.5 kg): bolus-only, 1–3 dose settings, 3–5 hours on the internal battery, 5–8 hours on a supplemental. Example units: pulse-only POCs intended for short outings.
• Mid-size (2.5–3.5 kg): bolus, 1–5 dose settings, 4–6 hours on internal, 8–12 hours on a double battery. The mainstream POC class.
• Large portable (4.5–5.5 kg): bolus and continuous-flow up to 2 LPM, 2–4 hours on a double battery in continuous-flow mode. These are less “portable” than “transportable” and are usually used with a wheeled cart.

The iron trade-off: lighter device → smaller battery → shorter runtime, and smaller compressor → lower maximum dose. There is no unit that is both featherweight and capable of supporting a 4 LPM continuous-flow prescription; the physics of a sieve bed set the floor weight for each flow class.

Flight approval

For air travel from India on an international itinerary, the practical rule is:

• POCs approved by the US FAA are accepted by most international carriers. The FAA maintains a list of approved POC models; any model on that list is broadly accepted across major international airlines, including those serving Indian routes (Air India, Lufthansa, Emirates, Qatar, Singapore Airlines, British Airways). (FAA SFAR 106)
• Each airline has its own booking process. Most require 48–72 hours’ notice, a medical fitness letter from your physician, and enough batteries for 150% of the total in-flight time.
• Domestic Indian flights (Air India, IndiGo, Vistara, Akasa) accept FAA-approved POCs with similar notice requirements. DGCA rules align with the FAA list in practice, though the Indian carrier must clear the specific model.
• Stationary concentrators are not permitted on flights — they are too large, too power-hungry, and not designed to run on battery.

Before flying, confirm with the airline. The model-specific acceptance letter is the document the airline will ask for at the gate; the FAA approval sticker is the document the device has on it.

Who should consider a portable

• Active patients who leave the house daily and whose prescribed flow is within what pulse-dose (or low continuous on the larger portables) can deliver.
• Travellers — air, long train journeys, road trips to locations where a stationary unit cannot follow.
• Patients on intermittent oxygen — for example, those prescribed supplemental oxygen only during exertion but not at rest. A portable used only during walking or errands can be a clean fit.
• Post-acute convalescents with a short-duration, low-flow prescription who want the flexibility to keep walking and moving during recovery.

For any of the above, a portable is either the primary device or a companion to a stationary unit at home. Running only a portable for all-day high-flow therapy is not a setup the hardware supports.

Who should stick to stationary

• Bedridden or low-mobility patients whose therapy is effectively always in one room. The stationary concentrator is cheaper, quieter, more durable, and more generous on delivered flow.
• High prescribed flow — 4 LPM or above continuous. No portable meets this reliably outside of the 5 kg+ transportable class, and even there, battery runtime in continuous-flow mode is measured in single-digit hours.
• Overnight supplemental oxygen — most overnight prescriptions are better served by continuous flow, both for therapeutic consistency and because the patient is not relying on a bolus trigger at a lower respiratory rate.
• Primary-device buyers on a fixed budget. A stationary 5 LPM at ₹40,000 covers a larger clinical space than a portable at the same price point can.

A common hybrid setup

Many long-term-oxygen patients in India end up with both: a stationary unit at home for overnight and resting-daytime use, and a portable for errands, doctor visits, and travel. At that point the portable doesn’t need to cover the full prescription — it only needs to cover the activity window. A 3 kg mid-size POC running at a setting that matches exertional demand for 4–6 hours is adequate for most hybrid users. Total cost for this setup — stationary plus portable — is typically ₹1,10,000–₹1,70,000 in 2026.

This is the setup we recommend most often when we are asked. It is not the cheapest route, but it matches how ambulatory patients actually live.

A short decision flow

1. Is your prescription continuous-flow and ≥ 3 LPM? → stationary is the primary device. Add a portable only if the activity window justifies it.
2. Is your prescription pulse-dose or continuous ≤ 2 LPM, and are you active? → a portable as primary device is viable. Verify overnight delivery with a pulse oximeter in the first week.
3. Do you travel by air regularly? → whichever device you choose, it must be FAA-approved (the portable, at minimum).
4. Are you bedridden or in a one-room therapy pattern? → stationary. Portables solve a problem you do not have.
5. Not sure about mobility in the next 12 months? → start stationary; add a portable when the clinical case is clear. Most buyers regret buying portable first more than the other way around.

Portables are not worse devices than stationaries — they solve a different problem. The decision is not about quality. It is about matching the device to the life you actually lead.

This guide is editorial opinion and general information. It is not medical advice. Consult your physician for therapy decisions, and verify all specifications with the manufacturer before purchase.