What is hyperbaric oxygen therapy (HBOT) induced tissue necrosis?

From the Guidelines

Hyperbaric oxygen therapy (HBOT) induced tissue necrosis refers to the rare but potential complication of tissue death due to excessive exposure to high-pressure oxygen, which can cause oxygen toxicity and cellular damage. This condition can occur as a result of HBOT, which involves breathing pure oxygen in a pressurized chamber, typically used to treat conditions like decompression sickness, serious infections, bubbles of air in blood vessels, and wounds that won't heal due to diabetes or radiation injury. The necrosis occurs because excessive exposure to high-pressure oxygen can cause oxygen toxicity, leading to cellular damage through the formation of reactive oxygen species that overwhelm the body's antioxidant defenses. This can affect various tissues, particularly the central nervous system and lungs. To prevent hyperbaric oxygen necrosis, HBOT sessions are carefully controlled with specific pressure limits (typically 2-3 atmospheres absolute), limited duration (usually 60-120 minutes per session), and "air breaks" where patients breathe normal air during treatment. Some of the key points to consider when evaluating HBOT include:

• The risk of serious side effects with HBOT is small, but some risks do exist, such as damage to ears, sinuses, and lungs from pressure changes, temporary worsening of short-sightedness, claustrophobia, and oxygen poisoning 1.
• The primary complication of HBOT was difficulty equalizing pressure in the middle ear, which occurred in 17% of patients 1.
• Patients undergoing HBOT for SSNHL may have fewer complications as the use of concurrent systemic steroids is common and may decrease the inflammation or edema that may lead to difficulty in pressure equalization or eustachian tube dysfunction 1.
• HBOT is an expensive and time-consuming intervention, with therapy typically involving multiple 1- to 2-hour sessions over days to weeks 1. Patients should be monitored for early signs of oxygen toxicity such as facial twitching, dizziness, vision changes, or seizures. If these symptoms occur, the oxygen pressure should be immediately reduced and the treatment paused. Proper medical screening before HBOT and adherence to established protocols significantly reduces the risk of this serious complication 1. It is essential to weigh the potential benefits of HBOT against the risks and to carefully select patients who are likely to benefit from this treatment, as the evidence for its effectiveness in certain conditions, such as acute ischemic stroke, is inconclusive or shows no improvement in outcomes 1.

From the Research

Hyperbaric Oxygen Therapy (HBOT) Induced Tissue Necrosis

There is no direct evidence of HBOT induced tissue necrosis in the provided studies. However, the studies do discuss the potential side effects and adverse reactions associated with HBOT.

Potential Side Effects of HBOT

• Ear discomfort is the most frequent side effect of HBOT, with 113 reported cases 2
• Other potential side effects include:
  • Barotrauma (middle ear barotrauma occurred in 9.2% of patients) 3
  • Central nervous system- and pulmonary oxygen toxicity 3
  • Claustrophobia, anxiety, and visual disturbances 3
  • Hypoglycemia, dizziness, dyspnea, and chest pain 3
• The incidence of adverse effects is higher when the chamber pressure is above 2.0 ATA or when the treatment course is >10 sessions 2

Safety of HBOT

• HBOT is considered a relatively safe therapy, with an overall per-session incidence of adverse events of 0.72% 3
• Strict operational protocols, including pre-HBO2 therapy evaluations and in-chamber monitoring, are essential to improve patient safety 3
• Patients with heart failure, including those with preserved ejection fraction, may develop heart failure symptoms during HBOT and warrant ongoing surveillance 4