Portable Oxygen Concentrators and Systems

Portable oxygen concentrators are differentiated from a standard home concentrator by their portability, power sources and pulse dose delivery.

Overview of Portable Oxygen Concentrators:

Portable oxygen units were originally introduced to provide patients with increased mobility and flexibility over the traditional oxygen tank solution. Portability is what distinguishes a portable concentrator from a home unit. These units will operate not only on AC power, but also on DC power (plug it into a car cigarette lighter) and batteries. These units are also considerably lighter with the lightest home units, many weighing less than 5 pounds, with the larger ones weighing roughly 18 pounds. In order to create a lighter unit that will run for longer lengths of time on batteries, manufactures designed units that would operate on "pulse dose" technology. This pulse dose means a bolus (puff) of oxygen is delivered when a patient inhales. Portable units are either "pulse dose" only or a combination of "pulse dose" and the traditional "continuous flow" delivery.

Technical Explanation:

Portable oxygen concentrators technically operate in the same manner as a home oxygen concentrator. A concentrator has two cylinders filled with zeolitek, which selectively adsorbs the nitrogen in the air. In each cycle, air flows through one cylinder at a pressure at which the nitrogen molecules are captured by the zeolite, while the other cylinder is vented off to ambient atmospheric pressure, allowing the captured nitrogen to dissipate. Typical units have cycles of around 20 seconds and allow for a continuous supply of oxygen at a flow rate of up to approximately 10 liters per minute (LPM) at concentrations anywhere from 25 to 95 percent. This process is called the pressure swing adsorption(PSA) cycle.

Specifications:

Key specifications for an oxygen concentrator are as follows:

• Electrical / Power Requirements: A "portable oxygen concentrator" by definition will run on AC power, DC power and batteries. Additionally, most portable concentrators will automatically switch between 110 V and 220 V for ease in international travel.
• Weight: The weight of portable concentrators will vary based upon the functionality. The lightest concentrators are "pulse dose" machines and weigh from less than 5 pounds to about 10 pounds. Portable concentrators that can operate in either "pulse dose" mode or "continuous flow" are slightly heavier and weigh between 16 - 18 pounds.
• Dimensions: Dimensions will vary with both manufacturers style and the functionality. The smallest "pulse dose" machine looks like a canteen and is only 9" tall by 7 inches wide by 4 inches thick. The units that are both pulse and continuous flow are a little bigger and are roughly 20 inches tall by 9 inches wide by 7 inches thick.
• Noise Level: Noise level on units is measured in decibels. Portable units are typically between 40 to 50 decibels and will vary slightly with the setting. As a comparison, a "library whisper" is considered to be approximately 30 decibels and "normal conversation" is considered to be in the 60 to 70 decibel range.
• Temperature Operating Range: Home oxygen concentrators are specified to operate in a normal home environment typically between 45 degrees F and 100 degrees F. Outside of these ranges, the unit may not function properly and patients should be careful not to leave units in extremely cold or hot environments.
• Altitude Operating Range: Altitude specifications for portable concentrators vary slightly. Units are specified to operate between 8000 to 13,000 feet. If you are living or traveling in high altitudes you will want to select a unit specified to operate at the higher end of the range. This specification limitation is because the oxygen percentage in the air at higher altitudes decreases.
• Oxygen Concentration: Any oxygen concentrator should deliver "medical grade" oxygen. Medical grade is typically defined as 88 percent pure oxygen and above. Most new concentrators are specified to have between 92 to 95 percent pure oxygen (+/- 3%)
• Warranty: Warranties vary with manufacturer. Most manufacturers have a 2 or 3 year warranty. Patients should clarify both the length of any warranty and the start date of the warranty, as some manufacturers start the warranty when the unit is shipped to the retailer.