Hyperbaric oxygen therapy (HBOT) is the use of 100% oxygen at pressures more than atmospheric. Several approved applications and indications exist for HBOT in the literature. Non-healing wounds, such as diabetic and vascular insufficiency ulcers, have been a major area of application, and the use of HBOT as an adjunct has been approved by several studies and trials. HBOT is also indicated for acute soft tissue infection, as also for traumatic wounds, crush injury, compartment syndrome, and compromised skin grafts and flaps. Another major area of application of HBOT is radiation-induced wounds. With increasing availability of chambers and studies proving the benefits of use, HBOT should be considered as an essential part of the overall management strategy for plastic surgeons.
HBOT has been used successfully for over 80 years to treat many conditions, including:
- Diabetic wounds, such as non healing foot ulcers
- Dry gangrene caused by poor circulation
- Radiation injuries from cancer or radiotherapy treatment
- Compromised skin grafts and flaps from surgery
- Soft tissue injury from car accidents, falls or industrial accidents
- Infection resulting from trauma or surgery
- Osteomyelitis (bone infection)
- Tooth abscesses and oral infections
HBOT is also used to speed recovery time after surgery, particularly orthopedic procedures.
How does hyperbaric oxygen therapy work?
HBOT increases the amount of oxygen that is delivered to damaged soft tissue by increasing the patient’s blood oxygen levels. This in turn speeds up healing and reduces the risk of complications such as necrosis and scarring. HBOT also encourages new blood vessel formation, which promotes better blood circulation. This helps prevent infection and accelerates healing by increasing nutrients to the affected area.
The era of modern-generation hyperbaric chambers begins in 1955, when Churchill-Davidson et al. began to use oxygen therapy in a hyperbaric chamber to treat radiotherapy-induced damage in cancer patients. After encouraging reports, there was an upsurge in the number of chambers and applications; however, reports of use of HBOT without sound rationale (e.g. as anti-aging treatment) led to calls for better regulation during the 1960s.
The Undersea and Hyperbaric Medical Society (UHMS) was established in 1967 with the rationale of giving HBOT a full professional status in terms of regulation, staffing, training, and certification. UHMS acts as the primary scientific body for HBOT in the USA and provides with a list of emergent and non-emergent applications proved by reasonable scientific evidence or clinical experience. These indications had also been subsequently supported by the British Hyperbaric Association. Most recently, the 2016 European consensus conference recommended HBOT for some additional conditions based on sufficient evidence in the form of expert consensus opinion.
HBOT mechanisms of action
In normobaric conditions, we live at 1 ATA of pressure measured at the sea level, meaning that downward pressure exerted on a body equals the weight of the atmosphere above a body. Commonly, the atmospheric pressure is measured in millimetres of mercury, where 1 ATA is equal to 760 mm Hg, 1.101 bar, 14.7 psi, 760 torr, or 10 m of seawater.
The physics behind HBOT lies within the ideal gas laws, Boyle and Henry laws. Boyle law states that the absolute pressure exerted by a given mass of gas is inversely proportional to the volume it occupies (if the temperature and amount of gas remain un- changed):
PV=k
and Henry law states that the amount of dissolved gas is proportional to its partial pressure in the gas phase:
C=kPgas
The application of Boyle law is seen in many aspects of HBOT. This can be useful with embolic phenomena such as decompression sickness or arterial gas embolism, as the volume of a bubble decreases directly in proportion to increasing pressure. On the other hand, Henry law accounts for the increase in oxygen dissolved in the plasma by increasing the atmospheric pressure in the chamber. Thus, the dissolved plasma oxygen concentration of 0.3 ml/dL at 1 ATA increases to 1.5 ml/dL upon administration of 100% oxygen, while hyperbaric oxygen delivered at 3 ATA yields a dissolved oxygen content of 6 ml/dL. The raise in the partial pressure of oxygen in the blood, and subsequently in tissues, has been shown to have many downstream biological effects:
Article in Giornale di Chirurgia – Journal of Surgery · July 2019
- Neovascularization;
- Reduction of inflammation;
- Control of infection;
- Promotion of wound healing;
There is evidence that HBOT facilitates this process. Fibroblasts proliferation increases in a dose-dependent manner between 1.0 and 2.5 ATA. This occurs for both normal and diabetic skin fibroblasts.
Fibroblasts participate in wound repair by synthesis of collagen. Procollagen is formed in a hypoxic environment. However, maturation of collagen requires oxygen: HBOT promotes polymerization and cross linking of collagen in a dose-dependent manner.
Extracellular matrix formation is closely linked to neovascularization and it is another oxygen dependent process.
Hyperbaric Oxygen Therapy (HBOT) in Plastic Surgery and Ahestetics
Hyperbaric oxygen therapy before and after Plastic Surgery practice are tightly connected: a large number of conditions treated by this surgical specialty are eligible to benefit from HBO as adjunct treatment. In 2015, the Italian Undersea and Hyperbaric Medicine Society updated its current indications for HBOT. Applications related to plastic surgery and ahestetics are several and discussed below.
Several randomized, controlled trials have been performed to study HBOT in a variety of clinical settings. These studies have shown that HBOT can help patients recover more quickly from surgery, experience less pain and take fewer pain medication, and have a lower risk of infection. Taken together, these studies show that HBOT is an effective means of treating patients after surgery (particularly patients with problems like chronic wounds, edema, or inflammation).
The idea of having surgery is scary for most people. But even before surgery, there’s the problem of having to recover from it — and that can take a long time.
The aim of preoperative and postoperative hyperbaric oxygen therapy (HBOT) protocols is to prepare the body and tissue for such intervention, reduce the time of recovery and make your recovery less painful.
- Hyperbaric therapy treatments before surgery have been shown to reduce general surgery complications and improve recovery following non-surgical cosmetic treatments like chemical peels.
- Hyperbaric therapy has been reported to aid in the treatment of Complex Regional Pain Syndrome, which is a common side effect of plastic surgery.
- After invasive procedures, hyperbaric therapy has been demonstrated to help avoid necrosis.
- Hyperbaric oxygen therapy has been discovered that it helps to minimize scarring.
- HBOT has been shown to improve and accelerate wound healing following surgery.
The “Hyperbaric oxygen therapy in Plastic Surgery practice: case series and literature overview” confirmed the usefulness of HBOT as auxiliary treatment for many plastic surgical conditions and the low incidence of complications.
However, the timing and start of the treatment seems to impact on the final outcome. A previously published case series from our group (108) showed that amongst 33 patients affected by complex injuries of the upper arm and who were treated with a mean of 12.3 HBOT treatment sessions per patient, the only two secondary amputations were performed in patients who underwent the first HBOT session more than 48 hours after the injury. Moreover, a late start of HBOT therapy with a significantly higher infection rate (15.4% vs 57.1% in patients receiving the first session within and after the first 48 hours from the injury, respectively).
Article in Giornale di Chirurgia – Journal of Surgery · July 2019
Dangers, side effects and contraindications
HBOT is generally considered safe and with few side effects. The most common problem is barotrauma of the middle ear. Patients are taught autoinflation techniques and sometimes decongestants are used. If necessary, grommets can be inserted. However this is not the case for mild hyperbaric oxygen therapy (mHBOT) where usually working pressures don’t exceeds 1.6 ATA.
The only absolute contra-indications are an untreated pneumothorax and certain anticancer drugs, i.e. doxorubicin, bleomycin and cis-platinum, as HBOT significantly increases their cytotoxicity.
Conclusions
HBOT was started as a treatment modality for management of decompression sickness and, with the passage of time, its scope has gradually increased to include numerous indications. While there has been substantial advancement of the field in recent years, more work is required to establish the place of HBOT in 21st century medicine. Investigation of fundamental mechanisms is still needed, and better patient selection criteria would improve cost-efficacy.
Hyperbaric oxygen therapy in Plastic Surgery practice: case series and literature overview
