Contraindications for Hyperbaric Oxygen Therapy (HBOT)
The only absolute contraindication to HBOT is untreated pneumothorax, while relative contraindications include uncontrolled seizure disorders, severe heart failure, active upper respiratory infections, and certain lung pathologies—though most can be managed with appropriate precautions and optimization.
Absolute Contraindication
- Untreated pneumothorax: This is universally recognized as the sole absolute contraindication to HBOT 1. The pressure changes during treatment can convert a simple pneumothorax into a life-threatening tension pneumothorax.
Relative Contraindications
Seizure Disorders
Seizure history is considered a relative contraindication due to oxygen toxicity risk. However, recent evidence shows HBOT can be administered safely with proper protocols:
- In a 2025 study of 22 patients with seizure history undergoing 634 HBOT sessions, only one seizure occurred (0.16% incidence) 2
- Management approach: Use 5-minute air breaks during treatment, ensure patients are on optimized antiseizure medications, and treat at standard pressures (1.8-2.4 ATA) 2
- The single seizure case had no permanent sequelae after HBOT discontinuation 2
Heart Failure
Heart failure has traditionally been considered a relative contraindication due to HBOT's hemodynamic effects (increased afterload from vasoconstriction, decreased cardiac output):
- A 2024 study of 23 HF patients (including 7 with reduced ejection fraction as low as 24%) completing an average of 39 sessions showed only 2 patients (8.7%) developed complications 3
- Management approach:
- Optimize HF therapy before starting HBOT
- Ensure strict fluid restriction and diuretic compliance
- Monitor closely during initial sessions
- One patient with LVEF 24% successfully completed 33 sessions after holding diuretics was identified as the cause of initial pulmonary edema 3
Thoracic Trauma
Recent 2025 data from earthquake victims with thoracic injuries showed HBOT can be administered safely:
- Among 25 patients with blunt thoracic trauma, only 20% developed respiratory/cardiac symptoms during treatment 4
- One patient developed pneumomediastinum (managed conservatively) and one had CNS oxygen toxicity seizure (no permanent sequelae) 4
- Management approach: Individualized risk assessment, multidisciplinary monitoring, and careful patient selection are essential 4
Clinical Situations Requiring Deferred Decision-Making
Severe Burns with CO Poisoning
When patients present with both significant body burns and CO poisoning, defer the HBOT decision to an experienced burn surgeon 5. Mortality risk from burns may supersede CO poisoning concerns, and these patients should be managed in specialized burn units 5.
Severe Metabolic Acidosis
If arterial pH < 7.20 or lactate ≥ 10 mmol/L in fire victims, suspect concomitant cyanide poisoning rather than focusing solely on HBOT for CO poisoning 5. These patients have 30-50% short-term mortality regardless of COHb levels 5.
Common Pitfalls to Avoid
Don't withhold HBOT from CO-poisoned patients who appear clinically stable: The goal is preventing long-term neurocognitive dysfunction, not just survival, as only 3% of CO-poisoned patients die 5
Don't assume all relative contraindications are absolute: Most can be managed with optimization and monitoring protocols 2, 3
Screen for coingestions in intentional CO poisoning: 44% have coingestions (66% involving ethanol), which may explain disproportionate mental status changes 5
Ensure pneumothorax is definitively ruled out before any HBOT session in trauma patients 1