Oxygen toxicity
Background
- The harmful effects of breathing oxygen at higher partial pressures than normal
- Partial pressure of O2 at sea level = 0.21 ATM
- Toxicity based on both time of exposure and partial pressure of oxygen
- Generally, FiO2 of 40% or less (0.40 ATM) can be tolerated indefinitely[1]
- Most common in hyperbaric oxygen therapy, scuba divers and prolonged administration of normobaric supplemental oxygen
- Pulmonary toxicity occurs sooner and at lower partial pressures than CNS toxicity[1], however there is no predictable pattern or sequence of symptoms for CNS toxicity (initial symptom may be seizure/coma)[2]
Clinical Features
Pulmonary
- Tracheobronchial irritation (initial manifestation) → pleuritic chest pain, dyspnea and coughing[3][2]
- Atelectasis
- Diffuse alveolar damage → Pulmonary edema/ARDS
Central nervous system
- Tunnel vision
- [[Tinnitus[[
- Nausea
- Facial twitching
- Irritability (personality changes, anxiety, confusion, etc.)
- Seizure
Ocular
- Retinopathy of prematurity (retrolental fibroplasia) - seen in premature infants
- Hyperoxic myopia - seen in adults exposed to repeated toxic levels of oxygen[4]
- Resolves spontaneously over several weeks
Differential Diagnosis
Scuba Diving Emergencies
- Barotrauma of descent
- Otic barotrauma
- Sinus barotrauma
- Face squeeze
- Barotrauma of ascent
- At depth injuries
- Oxygen toxicity
- Nitrogen narcosis
- Hypothermia
- Contaminated gas mixture (e.g. CO toxicity)
- Caustic cocktail from rebreathing circuit
Evaluation
- Generally clinical
Management
- Lower inhaled partial pressure of oxygen to as low as tolerated while maintaining tissue perfusion[5]
Disposition
- Admit
See Also
External Links
References
- Hedley-Whyte J. Pulmonary Oxygen Toxicity: Investigation and Mentoring. The Ulster Medical Journal. 2008;77(1):39-42.
- Bitterman H. Bench-to-bedside review: Oxygen as a drug. Critical Care. 2009;13(1):205. doi:10.1186/cc7151.
- Thomson L, Paton J. Oxygen toxicity. Paediatr Respir Rev. 2014 Jun;15(2):120-3.
- Anderson B, Farmer JC. Hyperoxic myopia. Transactions of the American Ophthalmological Society. 1978;76:116-124.
- Deutschman, C. S., & Neligan, P. J. (2010). Evidence-based practice of critical care. Philadelphia, PA: Saunders/Elsevier.
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