Overview of Hyperbaric Management of Frostbite
While there isn’t much scientific proof that using hyperbaric oxygen – a therapy where you breathe pure oxygen in a special, pressure-controlled room – can effectively treat frostbite, some results from individual case reports and inconclusive animal studies suggest that it could work. The idea behind it makes sense, and it might even offer extra benefits if started right after warming up the frostbitten area.
It’s important to note though, that the animal studies we have so far aren’t perfect matches for human frostbite. They typically use a method that freezes tissues quickly, causing immediate and deep tissue damage. However, in real-life cases of human frostbite, the freezing happens slowly over time and progresses gradually.
Anatomy and Physiology of Hyperbaric Management of Frostbite
Frostbite commonly happens when your body is exposed to intense cold for a long period, causing damage to your outer body parts like hands and feet. Here’s how this happens: When your body starts to feel too cold, it’ll try to keep your vital organs—that is, your “core”— warm, while restricting cooler blood from reaching your core. This process leads to reduced blood flow to your skin, which usually reduces from roughly 200-250 ml/min (millilitres per minute) down to 20-50 ml/min when your skin’s temperature drops to around 59°F (15°C).
When temperatures drop below this, our body tries to keep our tissues functioning by alternating between tightening and loosening blood vessels, a process called the “hunting response”, or the Lewis reaction. This reflex happens every 20-30 minutes and lasts for about 5-10 minutes at a time. Below 50°F (10°C), we start losing feeling in our skin due to damage to the sensory nerves, a condition called neuropraxia.
Further dropping temperatures makes the blood thicker, causing the formation of clumps in your blood cells and leading to inflammation of the blood vessels lining. This sets off a number of complex processes, leading to an inflammatory response and reduced blood flow to your skin. This continues until the blood flow stops completely, leading to leakages in the blood vessels and lack of oxygen supply to your tissues.
All this damage can be reversed up to this point. But once temperatures drop below freezing (32°F or 0°C), the damage becomes permanent. Without any circulation, your skin’s temperature drops very quickly. This causes your skin to freeze, starting from the smallest blood vessels to the larger ones, and from the veins to the arteries. Prolonged freezing leads to the formation of ice crystals in the fluid outside your cells first, then inside. This causes fluid to shift from the inside of your cells to the outside, eventually leading to cell death. Cell death happens due to a combination of lack of oxygen, dehydration from the fluid shift, and possibly from physical damage due to the ice crystals in the tissues.
Why do People Need Hyperbaric Management of Frostbite
Hyperbaric oxygen therapy might be considered for treating frostbite. This method, which involves breathing in pure oxygen in a pressure-controlled room, could be used either on its own or combined with other treatments. Some of these treatments include drugs that help widen blood vessels, prevent blood clotting, or improve blood flow, such as pentoxifylline. However, it’s important to note that the evidence supporting this approach mainly comes from individual case studies, and more research is needed.
When a Person Should Avoid Hyperbaric Management of Frostbite
Hyperbaric oxygen therapy (or HBO2 for short) is a treatment that is generally safe. However, the most common side effect people experience is pain or discomfort in their ears or sinuses due to pressure changes, a condition known as barotrauma. This therapy is not suitable for everyone. For example, if an individual has a condition called pneumothorax (an untreated pocket of air in the chest), they should not have HBO2.
We also need to be careful with people with respiratory infections, like the flu or a cold, as well as those who are experiencing symptoms of seasonal allergies, or sinus infections. Those who have recently had surgeries or who have conditions like emphysema or chronic obstructive pulmonary disease (which means they have long-term lung damage), especially if they have open gas pockets or blebs (small trapped pockets of air), also need special considerations.
It’s important to note that HBO2 should not be combined with certain medications. These include doxorubicin, Sulfamylon, or disulfiram. Also, after stopping the use of either bleomycin or cisplatinum, patients should wait for a while before receiving HBO2.
For patients with asthma, their condition needs to be assessed for any air trapped in the lungs. However, these patients can also take part in HBO2 if given the proper education and training about the procedure.
For those who feel anxious in small closed spaces, they might need some medication to help them relax. And finally, for patients with implanted devices (like a pacemaker or insulin pump), we need to check with the device’s manufacturer to make sure the treatment won’t harm it. This ensures the effective and safe delivery of HBO2 therapy.
Equipment used for Hyperbaric Management of Frostbite
Medical facilities should use specially designed equipment, such as multiple or single-level chambers, and ensure that the staff using these tools are properly trained. The Undersea and Hyperbaric Medical Society (UHMS), a professional organization, gives its stamp of approval to these facilities and their team. This accreditation is a way to show patients that the facility meets their high safety standards and uses the best treatment methods.
Who is needed to perform Hyperbaric Management of Frostbite?
Treatments with HBO2, which is a kind of oxygen-rich therapy, have to be watched over closely by a particular type of doctor who specializes in hyperbaric medicine. These doctors have had at least 40 hours of special training in this area. They’re usually mentored by another doctor who has even more training, demonstrated by being Board Certified in Undersea and Hyperbaric Medicine (UHM) or having a Certificate of Additional Qualification (CAQ) in UHM.
Other healthcare workers help these doctors. These can be nurses who also have special certification in hyperbaric medicine (CHRN) and technicians who have specific hyperbaric training (CHTs).
If treatment takes place in a chamber that can accommodate several patients, there are specific roles assigned. One licensed person will be inside the chamber with the patient to assist them, another will be overseeing the operation of the chamber, and a third person will be outside the chamber observing. If treatment takes place in a smaller, single-patient chamber, a certified technician can monitor two of these chambers at the same time.
Preparing for Hyperbaric Management of Frostbite
Patients who are about to undergo certain medical procedures are advised to wear clothing that don’t easily build up static electricity. It’s generally safe to wear clothes made of cotton and polyester, as long as the blend is no more than 60% polyester.
It’s also important to remember that certain items can increase the risk of fire. For this reason, patients need to ensure they don’t have any oil or petroleum-based products, like some types of makeup, nail polish, or deodorants, on their hair or skin. They’re also asked to not bring any electronic devices, including phones, watches, and hearing aids, with them into the procedure room.
Further, no heating devices that use chemical or gas, are allowed in the procedure area. Patches that deliver medication through the skin, known as transdermal patches, should be avoided if possible, or at the very least, inspected and appropriately covered.
For people with diabetes, checking their blood sugar levels before and after the procedure is particularly important. Medical staff will follow approved guidelines to determine the best course of treatment, taking into account the patient’s blood glucose levels.
How is Hyperbaric Management of Frostbite performed
There isn’t a set method for treatment, but past cases have shown that some practices could be beneficial. One approach used in these cases is to administer high-pressure oxygen therapy at approximately 2.0 to 2.5 atmospheres absolute (ATA) for a period of 90 to 110 minutes. This can be done with or without a break for air. This intensive therapy is typically carried out twice a day at the start, for about eight to twelve sessions. Afterward, the therapy is done daily until it’s clear that the maximum health benefit has been reached. Usually, this point is reached after around 12 to 20 sessions. An atmosphere absolute (ATA) is a unit of pressure and is used here to explain the intensity of the oxygen therapy.
Possible Complications of Hyperbaric Management of Frostbite
The most common issue that can come up after a person receives Hyperbaric Oxygen Therapy (HBO2), a type of treatment that involves breathing in pure oxygen in a pressurized room or tube, is what’s called “barotrauma.” This often involves discomfort or pain in the ears, and less frequently, the sinuses. Barotrauma is pressure-related damage that can happen in areas of the body that contain air, like the ears.
Another concern is oxygen toxicity, but that is reported to happen very rarely. Oxygen toxicity can occur when one breathes pure oxygen at pressure for extended periods. No cases have been reported where this problem occurred again or caused other issues. Although rare, it’s also possible for barotrauma to occur in the lung tissue, leading to a condition known as pneumothorax, where air leaks into the space between your lung and chest wall. This can cause the lung to collapse.
Out of 782 patients who underwent 11,376 HBO2 treatments in one study, 17% reported some ear pain or discomfort. However, only 3.8% of all patients had confirmed barotrauma-induced injury. No issues with teeth or sinuses were found. Four of these patients had seizures due to too much oxygen, but none of them went through the same problem again or had other related issues.
Other minor complications that can potentially occur include a temporary worsening of existing cataracts and a small, usually temporary, change in vision. Typically, this would manifest as a temporary increase in nearsightedness (difficulty seeing far away), resolving itself a few weeks after treatment.
Finally, individuals who have anxiety related to being in small spaces (claustrophobia) might need calming medication for their anxiety before and during the treatment.
What Else Should I Know About Hyperbaric Management of Frostbite?
Frostbite, which is when skin and the tissues under it freeze, often happens slowly and leads to damage in blood vessels and loss of tissues. The last stage of frostbite involves ice crystals forming inside cells which essentially kills off the tissue and prevents any chance for it to heal. However, if someone with frostbite is warmed up before the tissue dies, there is a chance for recovery. Treatment revolves around warming up the area, increasing blood flow, and reducing inflammation. This process can be split into three phases.
The first phase involves initial care to prepare for thawing out the tissues. The second phase is where rewarming, usually done in a hospital, happens. The third phase can span from a few weeks to several months while the tissues heal.
However, because frostbite is often not detected early, treatment usually doesn’t start until it’s clearly visible that the tissues have been damaged. This usually happens more than a day or two after rewarming. This delayed diagnosis can lead to further tissue loss. Hence, early detection and treatment is critical to save tissues from irreversible damage.
Currently, the existing treatments for frostbite struggle due to insufficient evidence from well-structured clinical trials. However, the common therapeutic strategies aim at reducing inflammation in blood vessels and restoring blood flow quickly. Medicines like nitroglycerine or papaverine that open up blood vessels have been useful, particularly when combined with medicines like tissue plasminogen activator (rTPA) or streptokinase that help in breaking down blood clots.
Use of Hyperbaric oxygen therapy, which involves breathing in pure oxygen in a pressurized room, is noted as it can provide the necessary oxygen for injured tissue, immediately reverse low oxygen levels and reduce inflammation. However, lack of clinical trials to assess this treatment means it’s not widely accepted, despite positive results from various case studies. The studies suggested faster and better recovery when this treatment was started earlier. Some studies have reported success using a combination of hyperbaric treatment and medications that widen blood vessels and improve blood flow, such as pentoxifylline.