Overview of Topical Oxygen
Oxygen is crucial to help our bodies heal. It plays a significant role in various internal processes, including the creation and transportation of cells. A boost of oxygen increases the body’s natural ability to fight off infections and is particularly important for the process known as respiratory burst, which our immune system uses to clear out harmful debris and bacteria.
The amount of oxygen in our bodies also influences how quickly and how well new blood vessels can grow in an area that’s healing. This is because the creation of new blood vessels, a process known as angiogenesis, is a key part of repairing and growing healthy tissue in a wound.
Oxygen also plays a role in the formation of collagen, a protein that forms fibers in our bodies to give structure to skin and other tissues. More oxygen leads to better collagen formation, which can result in stronger wound healing and less scarring. By increasing our oxygen levels, we can sped up cell growth, skin rebuilding, and collagen formation, all of which can speed up wound healing.
Additionally, oxygen helps kick start various growth signals in our bodies. This includes bringing white blood cells to an injury site (which is a crucial part of recovering from something like a diabetic foot ulcer), assisting with the creation of new blood vessels (angiogenesis), and forming an extracellular matrix—a kind of net that supports all our cells and tissues. All these processes are affected by the level of oxygen in our bodies.
Anatomy and Physiology of Topical Oxygen
The process of oxygen reaching a clean, moist wound, like oxygen reaching the lungs, is through diffusion. In simpler terms, diffusion means that molecules like gases or liquids go from an area with a lot of them (high pressure) to an area where there are fewer of them (low pressure). For example, if you have a mix of gases in a box, each gas will spread out until it fills the entire box evenly.
This similar concept happens when a wound is exposed to air. The oxygen in the air will spread to, or diffuse into, the wound until the amount of oxygen in the wound is approximately the same as in the surrounding air. This is based on Henry’s law, which states that at a fixed temperature, the amount of a gas that can dissolve in a liquid is directly related to the pressure of the surrounding gas.
Normally, the oxygen levels in human tissue are about 50 mmHg, a unit of pressure, at a depth of about 3 to 4 mm below the wound surface. When topical oxygen, which is pure oxygen applied directly to the wound surface, is used, the amount of oxygen in the wound increases three-fold. In fact, studies have shown that using topical oxygen can significantly and rapidly increase the oxygen levels in a wound, which is beneficial for the healing process.
Scientists use a tool called a probe, which they insert 2mm into the middle of the wound, to measure this increase. During these experiments, they found that when only the surrounding air was present, the wound’s oxygen level was less than 10 mmHg. However, with the application of topical oxygen, this level rose to 40 mmHg in just four minutes.
Why do People Need Topical Oxygen
Topical oxygen therapy is a treatment method that can help heal chronic wounds – long-lasting injuries that don’t seem to get better with usual treatment methods. This therapy can be used in treatment of a variety of wound types, such as:
- Skin ulcers caused by diabetes or poor blood circulation
- Wound infections after surgery
- Pressure injuries, usually caused by staying in one position for long
- Residual wounds from amputations and infected stumps
- Wounds from skin grafts
- Injuries associated with tissue-based products
- To prevent wounds reopening after surgery (dehiscence)
- Wounds in tissues with poor blood supply (ischemic tissues)
- Burns
- Frostbite
A key part of wound care is checking for arterial insufficiency, a condition where blood flow through the arteries is reduced. It can be the cause of wound formation or an obstacle to healing. To check for this, a detailed patient history and physical exam is done. It is also recommended to perform an ankle-brachial index test for chronic wounds on the lower limbs. This test compares the blood pressure in your ankle to the blood pressure in your arm to see if there’s any reduced blood flow.
If arterial insufficiency is found, the patient might need to see a vascular surgeon or specialist. Wounds associated with this condition could require revascularization, a procedure that improves blood flow, before starting with oxygen therapy. If the wounds still don’t improve after basic wound care and revascularization, topical oxygen therapy might still be needed.
When a Person Should Avoid Topical Oxygen
Oxygen therapy applied directly on skin lesions is still being studied, and we don’t fully know the limitations; for example, we’re yet to find out if there’s a certain level of poor blood flow (ischemia) in a wound that could prevent this therapy. However, we think there may not be a minimum level because the oxygen goes straight into the tissue.
This treatment doesn’t have many restrictions or safety concerns. However, the same safety measures needed for moist wound therapy are required here as well. It’s important to ensure the wound doesn’t have any dead tissue (necrotic tissue). By removing dead skin and pus (eschar and slough), oxygen is able to reach the wound directly, which has been found to improve outcomes. Anything that could block oxygen from making its way to the wound, such as petroleum-based ointments, should be avoided.
Equipment used for Topical Oxygen
Oxygen is used in medical treatments in a couple of different ways. It can be breathed in or applied directly to the skin, and it can be used for a set amount of time each day, or continuously. For instance, in hyperbaric oxygen (HBO) therapy, which uses the method of inhalation and is intermittent, oxygen is inhaled in a room with higher-than-normal pressure (greater than 1.4 times the pressure of the atmosphere) for roughly 90 minutes per day, usually for 3 to 5 days per week. Oxygen that is applied to the skin, or “topically applied,” can also follow this same schedule, or be applied around the clock.
The way oxygen that is applied topically intermittently works is by directing a high concentration (around 93%) of oxygen right around a patient’s wound. This oxygen is delivered slightly above normal air pressure and comes from a machine that supplies high amounts of oxygen. It’s applied by placing a bag or sealed chamber around the wound. On the other hand, continuous topical oxygen therapy applies pure, moist oxygen (over 99% concentration) directly to the wound around the clock. The oxygen is provided by a small, wearable generator that produces oxygen.
All of these techniques are used to help wounds heal and they all depend on oxygen’s ability to heal wounds. The level of oxygen delivered to the wound varies depending on factors such as the pressure used, the concentration and the duration of the therapy, and how the oxygen is delivered. These variations can be seen in a chart and figure showing what a week of oxygen therapy might look like. The chart and figure show the potential concentration of oxygen that could reach the wound for each method over time. The amount of space beneath each line on the graph represents the potential amount of oxygen the wound could receive.
All three methods work by allowing oxygen to permeate, or diffuse, into the affected tissues at the cellular level. HBO primarily uses inhaled oxygen, which goes into and through the small air sacs (or alveoli) in the lungs, is then taken up by the blood and distributed throughout the body. Once the hemoglobin, which is the molecule in red blood cells that carries oxygen, becomes full of oxygen, the extra oxygen is in the liquid part of the blood, the plasma. One limitation of HBO in wound care is that it needs a good blood supply to get the oxygen to the wound. Topically applied oxygen, on the other hand, bypasses the need to rely on the body’s small blood vessels and delivers oxygen directly to the wound tissue. This allows oxygen to quickly get to wounds affected by poor blood flow, or ischemia.
There are different types of topically applied oxygen therapy. These range from large systems with high flow oxygen concentrators and hard-walled chambers to small, wearable oxygen generators with oxygen delivery systems. One advantage is that these systems can all be used in most settings, including at home. They all apply oxygen directly to the wound and can be used along with many other treatments. There are three main types of gaseous topical oxygen delivery, known as TO, TCOT, and CDO. Each type has similarities and differences.
The first type, TO, uses a machine that concentrates oxygen and delivers it via tubing to a reusable chamber or a disposable bag placed around the wound. TO applies oxygen to the wound for 90-minute sessions, 3 to 5 days per week. The patient has to stay still during the treatment, but TO can be used in many locations, including at home. For the best results, the wound dressing is removed during treatment and the wound is kept moist. However, the machines used to concentrate oxygen (at 87 to 93%) are heavy, make a lot of noise and heat, and deliver a high flow of oxygen.
The first type of continuous system, known as TCOT, was introduced in the mid-2000s. These systems use tape-based machines that convert air into pure oxygen and supply it to a wound through tubing that can be placed in a moist dressing on the wound. The entire system is meant to be thrown away after being used for up to 15 days. These systems are small, lightweight, portable, and silent. They can be worn all of the time and carried inconspicuously.
The latest continuous systems, known as CDO, are similar to TCOT but have a few improvements. These systems are also compact, lightweight, wearable, and silent, allowing them to be worn around the clock and carried discreetly. However, they use durable, reusable oxygen generators and systems that evenly distribute oxygen into the wound. These systems can be fully integrated into dressings that distribute oxygen or into rotating oxygen distribution wheels, both key to evenly spreading oxygen across the entire wound. CDO is essentially moist wound therapy plus oxygen. This helps the wound to “breathe” in a way similar to the way we do.
Possible Complications of Topical Oxygen
When it comes to the safety of the treatment and related equipment, using topical oxygen therapy (a treatment involving oxygen directly applied to a wound) is regarded as safe. It doesn’t pose any extra risks to the patient beyond those associated with moist wound therapy (a method of healing where wounds are kept moist to speed up healing). There have been no severe side effects or reactions reported in medical literature linked to the use of oxygen therapy applied directly on the wound.
What Else Should I Know About Topical Oxygen?
Research shows that applying oxygen directly to open, moist wounds is safe and effective. This is especially true with updated devices and methods that have been developed more recently. Unfortunately, older research on this topic can show varying results, often due to poorly designed studies or outdated devices that didn’t properly deliver the oxygen to the wound.
The technology has improved greatly in the past decade, with recent studies showing significant increases in wound healing using top-quality devices and proper application methods. These advancements have resulted in consistent, positive results for a range of different wounds.
One thing researchers have noted is that these improved methods made the wounds heal significantly faster. More than that, some patients also noted rapid pain relief. This allowed patients to follow their treatment plans more closely which in turn, helped to lower the recurrence of wounds, and reduced infection rates, as well as the overall cost of treatment. Even more promising, is that the benefits of oxygen treatment seemed to increase for larger wounds, deeper wounds, and wounds that take longer to heal.
One particular type of wound this method has been very successful with is the diabetic foot ulcer. A recent analysis of several studies showed that the use of oxygen treatment on these wounds significantly increased their healing rate.
Overall, these results show that applying oxygen directly to wounds is a highly beneficial treatment in wound care. With the right devices and application techniques, it can speed up wound healing and bring additional benefits such as pain relief and lower infection risk.
