From the Guidelines
Excessive oxygen administration can indeed cause hallucinations, a condition known as central nervous system (CNS) oxygen toxicity, which occurs when breathing pure oxygen at high pressures or receiving supplemental oxygen at high concentrations for extended periods. This phenomenon is particularly relevant in hyperbaric oxygen therapy, deep sea diving with enriched oxygen mixtures, and in critical care settings where patients receive high-flow oxygen 1. The mechanism involves the formation of excessive reactive oxygen species in brain tissue, which damages cellular structures and disrupts normal neurotransmitter function.
Some of the key risks associated with excessive oxygen administration include:
- Worsening of hypercapnic respiratory failure
- Delay in recognition of clinical deterioration
- Potentially worse outcomes in mild-to-moderate stroke
- Specific risk in patients with previous bleomycin lung damage or with paraquat poisoning or acid aspiration 1
- Unknown risk–benefit balance in acute coronary artery disease with normal oxygen saturation
Healthcare providers carefully monitor oxygen saturation and adjust delivery to maintain appropriate levels, typically aiming for 94-98% saturation in most patients, to prevent these complications while still providing adequate oxygenation 1. Symptoms of CNS oxygen toxicity, including hallucinations, seizures, dizziness, vision changes, and anxiety, typically resolve when oxygen levels are reduced to normal.
It is essential to note that the benefits and harms of oxygen therapy are unknown in certain cases, such as acute coronary artery syndromes, and unnecessary use of high concentration oxygen may increase infarct size 1. Therefore, oxygen therapy should be used judiciously and with careful consideration of the potential risks and benefits.
From the Research
Excessive Oxygen Administration and Hallucinations
- The relationship between excessive oxygen administration and hallucinations is not directly addressed in the provided studies, but some studies mention the effects of oxygen toxicity and hypoxia on the central nervous system.
- According to 2, short exposures to high partial pressures of oxygen at greater than atmospheric pressure can lead to central nervous system toxicity, which may result in symptoms such as seizures, but hallucinations are not specifically mentioned.
- 3 also discusses the toxicity of oxygen and its effects on the central nervous system, including seizures, but does not mention hallucinations as a possible symptom.
- However, 4 mentions that hypoxia, rather than excessive oxygen, can cause central nervous system functional disturbances, including hallucinations, especially when not accompanied by rapid carbon dioxide retention.
- There is no direct evidence in the provided studies to suggest that excessive oxygen administration can cause hallucinations, but it is possible that oxygen toxicity may contribute to central nervous system disturbances that could lead to hallucinations in some cases.
- More research is needed to fully understand the relationship between excessive oxygen administration and hallucinations, as the current evidence is limited and indirect.
- It is worth noting that 5 reports cases of hallucinations in patients with obstructive sleep apnea-hypopnea syndrome, which is related to hypoxia rather than excessive oxygen administration, and suggests that treatment with continuous positive airway pressure therapy may help control hallucinations in these patients.