Published on : 23 May 20194 min reading time

The Portable Oxygen Concentrator (POC) is a portable device used to deliver oxygen therapy to people requiring higher oxygen concentrations than ambient air levels. It is similar to a home oxygen concentrator, but is smaller and more mobile. The portable oxygen concentrator facilitates the movement of patients. They are small enough to fit in a car and many concentrators are now approved by the FAA for use on aircraft.

How it works?

Additional information: pressure swing adsorption and operation of oxygen concentrators

Portable oxygen concentrators operate on the same principle as a domestic home concentrator, pressure swing adsorption. The atmosphere contains about 21% oxygen and 78% nitrogen; the remaining 1% is a mixture of other gases. An internal air compressor forces this air through a system of chemical filters known as molecular sieves. This filter consists of silicate granules called zeolites that attract nitrogen molecules more strongly (through the adsorption of molecular bonds) on their surfaces than those that attract oxygen molecules – which filters the molecule Nitrogen from the air by concentrating the oxygen. Part of the oxygen produced is delivered to the patient; a portion is reintroduced into the sieves (at a greatly reduced pressure) to evacuate the accumulated nitrogen, preparing the granule surfaces for the next cycle. Through this process, the system is able to produce medical grade oxygen up to 90% steadily. The latest models can be powered by the power supply, 12v DC (car / boat / plane) and batteries, which frees the patient from the use of cylinders or other current solutions that limit the time, the weight and size.

Most current portable oxygen concentrator systems provide oxygen on a pulse delivery (on demand). The system provides a high concentration of oxygen and is used with a nasal cannula to deliver oxygen to the patient.

Advantages

COPs enable patients with chronic oxygen therapy to maintain their mobility and independence throughout their daily activities. Here are some benefits of using portable oxygen concentrators:

  • Allows patients to use oxygen 24 hours a day, 7 days a week, which helps to increase survival.
  • Helps improve exercise tolerance, allowing the user to exercise longer.
  • Helps increase endurance throughout daily activities.
  • The freedom to travel lightly and easily. No need to carry oxygen bottles.

In addition to this, portable oxygen has a variety of commercial uses; for example, for use in the glass-blowing industry, health clubs, beauty spas as well as airports.

The difference between demand and continuous flow

On-demand COPs (also called intermittent or pulsed doses) are the smallest, often not larger than a briefcase or picnic cooler and weigh as little as 5 pounds (2.2 kg) . These deliver oxygen only when patients inhale, avoiding wasting oxygen during expiration. Their ability to retain oxygen is the key to keeping units so compact without sacrificing the duration of oxygen delivery. [3] Thin carrying bags maximize the flexibility to carry these units almost anywhere – even at altitudes of 10,000 feet – as long as the battery run time or power supply is sufficient.

The most important consideration for a COP is its ability to provide adequate supplemental oxygen to relieve hypoxia (oxygen deficiency) during normal activities. With continuous flow units, the oxygen supply is measured in LPM (liters per minute). With a demand or pulsed flow rate, the distribution is measured by the size (in milliliters) of the “bolus” of oxygen per breath, referring to a puff of oxygen released at the time of inhalation. Other variables include maximum oxygen purity (oxygen percentage), number and increment of settings to adjust oxygen flow and battery capacity (or the number of extra batteries) and options power cord for charging.

Although portable concentrators are a useful option for active patients, it is advisable to seek the help of a specialist, prescribe the correct flow of oxygen and choose a COP that best suits the needs of the patient.

A great deal of controversy surrounds the use of COP during sleep. On-demand units are generally not recommended for sleep apnea patients, who generally require a Continuous Positive Airway Pressure (CPAP) mask. For other patients, the nocturnal use of COPs, especially with the advent of alarms and technology that detect a patient’s slower breathing during sleep and adjusts the rate or size of the bolus accordingly.