There are several sizes of portable HBOT chambers used for home treatment. These are usually referred to as “mild hyperbaric chambers,” because of the lower pressures used as compared to hard chambers. In the U.S. mild hyperbaric chambers are categorized by the FDA as CLASS II medical devices and they require a prescription in order to rent/purchase one or take treatments. These personal chambers are only FDA-approved to reach 1.3 ATA. Hard chambers available in the US go up to 4.4 pounds per square inch (psi) above atmospheric pressure, which equals 1.4 atmospheres absolute (ATA).
Hyperbaric chamber distributors and manufacturers cannot supply a chamber in the U.S. with any form of elevated oxygen delivery system. The most common solution (but one not approved by the FDA) is to acquire an oxygen concentrator, which typically delivers 85-95% oxygen as the breathing gas. Due to the high circulation of air through the chamber, the total concentration of oxygen in the chamber never exceeds 25% (as this can increase the fire hazard).
Oxygen is never fed directly into soft chambers; it is connected by a line and mask directly to the patient. FDA approved oxygen concentrators for human consumption in confined areas used for HBOT are regularly monitored for purity (+ or – 1%) and flow (10 to 15 liters per minute outflow pressure). Personal hyperbaric chambers use 120 volt or 220 outlets. They range in size from 21 inches up to 40 inches in diameter, 84 inches (7 feet) to 120 inches (10 feet) in length. The soft chambers are approved by the FDA for altitude sickness, but are commonly used for other “off-label” purposes.
Mild chambers are most easily identified as the type of hyperbaric chambers athletes and celebrities tend to keep in their homes. They are much more portable than any other kind of hyperbaric chamber due to the fact that they are soft-sided and inflatable. They are single occupancy and, when deflated, can fit into a backpack.
The mild chamber was designed after the Gasmow bag, an airtight bag that is zipped shut with the person inside. The bag is then inflated with atmospheric air by a small electric pump. All FDA-approved mild chambers are equipped with relief valves calibrated to release the built up air pressure once it reaches a certain point (usually anything over 4 psi).
Commonly, mild chambers are on hand for emergency situations, home use, and high altitude treks. Originally mild chambers were developed to treat altitude sickness that occurred in climbing treks.
The drawbacks to mild chambers are the very limited pressures that they can achieve. The highest common pressure a mild chamber can achieve is 4 psi, which is about the pressure one would experience by being 11 feet under water.35
While many athletes and celebrities can attest to the health and healing properties of having a mild chamber at their home for weekly use, mild chambers are far from being a staple in every home. The manufacturer’s price for these inflatable chambers ranges from $15,000 to $17,000.36 However, there has been quite a bit of controversy when it comes to professional athletes who use mild chambers at home, as HBOT has not been approved by the FDA for healing sports injuries.37