"Please wear the mask. We will supply oxygen. If you feel uncomfortable, please raise your hand."
On the 15th, a medical staff announcement played in the hyperbaric oxygen therapy room at Hallym University Sacred Heart Hospital in Yeongdeungpo District, Seoul. The therapy room had chairs for 13 people. Wearing masks hanging from the ceiling, we breathed oxygen for about 30 minutes. Atmospheric pressure at sea level is 1 atmosphere, but the therapy room was at 1.5 atmospheres. That is similar to being at a depth of 5 meters underwater.
My ears felt clogged and prickly, but it got better when I pinched my nose and mouth closed. When pressure rises, pressure in the outer ear, which includes the auricle and the ear canal, increases, but the middle ear, blocked by the eardrum, does not change. The difference in pressure between the two caused these symptoms.
Hyperbaric oxygen therapy involves breathing 100% pure oxygen in a therapy room where high pressure is maintained. It treats patients with oxygen deprivation, such as those with gas poisoning or decompression sickness. Decompression sickness, also called caisson disease, occurs when a diver ascends to the surface and the sudden drop in pressure prevents nitrogen from leaving through the lungs, forming bubbles that block blood vessels. The session that day was conducted at 1.5 atmospheres, but actual patients have oxygen pushed into their lungs at 2 to 4 atmospheres, equivalent to a depth of 10 to 40 meters. Medical staff monitored patients' conditions on screens outside the hyperbaric oxygen therapy room.
Oxygen travels attached to red blood cells in the blood vessels. When someone is poisoned by carbon monoxide, oxygen has difficulty moving. Ultimately, a lack of oxygen can lead to loss of consciousness or, in severe cases, death. Heo Jun, director of Hallym University Sacred Heart Hospital, said, "As pressure increases, oxygen can dissolve in plasma even without attaching to red blood cells and reach the peripheral blood vessels," adding, "It boosts the body's overall ability to recover and helps wounds heal faster."
Hyperbaric oxygen also treats burn wounds and ulcers that form on the feet of people with diabetes. During the coronavirus disease (COVID-19) pandemic, it was also used for fatigue recovery. Overseas soccer player Cristiano Ronaldo was also known to have received hyperbaric oxygen therapy in the past. However, in Korea, hyperbaric oxygen therapy for cosmetic purposes or fatigue recovery is not covered by health insurance.
Hallym University Sacred Heart Hospital has recorded 10,000 hyperbaric oxygen therapy sessions. Ninety-nine percent are burn patients, and treatment lasts about two hours. Patients must refrain from smoking for about one hour before and after treatment. Air travel is prohibited for 48 hours after treatment. Because 100% pure oxygen is used, electronic devices such as cellphones and smartwatches, as well as lighters, matches, and batteries, are not allowed inside to prevent fires. The use of volatile products such as cosmetics and perfumes is also restricted. A nurse at Hallym University Sacred Heart Hospital said, "After hyperbaric oxygen therapy, mild myopia symptoms can rarely occur," adding, "Most recover within a few weeks."