The concept of oxygen toxicity in certain circumstances is well known among medical professionals. To anesthesia providers, however, the most common errors concerning oxygen toxicity are in the following assumptions: (a) the benefits of oxygenation will outweigh its potential toxic effects; (b) it is irrelevant in the emergency department (ED) or the operating room (OR), where long-term exposure to high concentration oxygen is rare; and (c) damage from high-concentration oxygen is mild to moderate.

Indeed, the importance of oxygenation cannot be exaggerated, and the most well-known toxicities take days to develop clinical signs after exposure to high-concentration oxygen (hyperbaric oxygen is not discussed in this chapter). Certainly, a high inspired concentration of oxygen is warranted in some situations—for instance, if a patient who is being turned prone and placed in pins becomes extubated, the anesthesia providers have several minutes longer to turn him back over and get him reintubated if he is being ventilated with 100% oxygen as opposed to an intentionally lowered FiO2. In the past decades, however, we have come to realize that oxygen toxicity can have very acute and significant effects in multiple clinical scenarios such as cardiopulmonary resuscitation (CPR), cardiopulmonary bypass (CPB), and organ transplantation. It is clearly an inevitable issue confronting every anesthesia provider in the intensive care unit (ICU), the OR, or the ED. Avoiding oxygen toxicity may not only avoid tissue damage, it may also reduce mortality.

We will briefly discuss several clinical scenarios of oxygen toxicities. Among them, pulmonary injuries secondary to prolonged exposure and retinopathy of prematurity might be viewed as “chronic” toxicity of high concentration oxygen, whereas the others represent acute detrimental effects, happening minutes to hours after exposure to high oxygen concentrations.