What is hyperbaric oxygen therapy (HBOT)?

Hyperbaric Oxygen Therapy (HBOT)

Hyperbaric oxygen therapy (HBOT) is a medical treatment that involves breathing 100% oxygen in a pressurized chamber at a pressure of at least 1.4-3.0 absolute atmospheres (ATA), which increases oxygen delivery to tissues and has specific approved indications including diabetic foot ulcers, necrotizing soft tissue infections, and sudden sensorineural hearing loss. 1, 2, 3

Basic Principles and Mechanism of Action

HBOT works through several key physiological mechanisms:

• Increases dissolved oxygen in plasma based on Henry's Law, allowing oxygen delivery independent of hemoglobin 3
• Enhances tissue oxygenation in hypoxic areas 2
• Reduces inflammation and edema through arteriolar vasoconstriction 3
• Promotes wound healing through increased collagen deposition and angiogenesis 2
• Enhances neutrophil bactericidal capacity 3
• Provides direct toxic effects against certain microorganisms 3
• Reduces ischemia-reperfusion injury 3

Approved Indications

According to current guidelines, HBOT is recommended for:

1. Diabetic Foot Ulcers:

   • Conditionally recommended for neuro-ischemic or ischemic diabetic foot ulcers when standard care has failed 1
   • Moderate desirable effects with benefit in improving absolute wound healing and reduction in ulcer area 4

2. Necrotizing Soft Tissue Infections:

   • Recommended as adjunctive therapy after prompt surgical debridement 1
   • Provides significant mortality reduction (RR = 0.47; 95% CI, 0.30-0.74) 1

3. Sudden Sensorineural Hearing Loss:

   • Recommended within 3 months of diagnosis for idiopathic sudden sensorineural hearing loss 1
   • Better outcomes in younger patients (under 50-60 years), early treatment, and moderate to severe hearing loss 4
   • Number needed to treat: 5 patients to improve 1 person's hearing by 25% 4, 1

4. Carbon Monoxide Poisoning:

   • Considered on a case-by-case basis 1

Contraindications and Precautions

HBOT is contraindicated in:

• Acute decompensated heart failure (NYHA class IV) 1
• Recent cardiac arrest 1
• Severe hemodynamic instability 1
• Severe respiratory compromise 1
• Recently placed vascular closure devices (<7 days) 1
• Within 1 year after heart transplantation 1
• Within 2 weeks after implantable cardioverter-defibrillator or cardiac resynchronization therapy 1

Patients requiring special consideration:

• History of spontaneous pneumothorax or bullous lung disease (risk of barotrauma) 1
• COPD with CO2 retention (risk of respiratory depression) 1
• Seizure disorders (require optimized anti-seizure medications) 1
• NYHA Class III heart failure (need careful evaluation) 1

Treatment Protocol

• HBOT typically involves:
  • Breathing 100% oxygen
  • Pressure of 1.5-3.0 ATA
  • Sessions lasting 60-120 minutes
  • Treatment course depends on the condition being treated 5

Facility and Safety Requirements

• HBOT should only be performed in facilities specifically designed and equipped for this purpose 1
• Staff must have appropriate training to manage potential complications 1
• Comprehensive cardiac history and targeted cardiac investigations are essential for cardiac patients 1

Common Pitfalls and Considerations

1. Accessibility Issues: HBOT is not widely available in all regions, which may limit its use 4

2. Patient Selection: Not all patients are suitable candidates; careful assessment is required, especially for those with cardiac or pulmonary conditions 1

3. Timing Matters: Early intervention is crucial for certain conditions:

   • For sudden sensorineural hearing loss, treatment within 2 weeks to 3 months shows better outcomes 4, 1

4. Cost Considerations: HBOT involves significant costs, though established units treating other conditions may be cost-effective when used for approved indications 4

5. Risk-Benefit Analysis: Always weigh potential benefits against risks, especially for critically ill patients who require transport to specialized facilities 1

HBOT represents a specialized treatment modality that, when used appropriately for evidence-based indications, can provide significant clinical benefits. However, its use should be guided by established protocols and administered by trained professionals in properly equipped facilities.