What depth is the threshold for a patient to breathe 100% oxygen?

The threshold depth for a patient to breathe 100% oxygen is typically 45 feet of seawater (fsw). This depth is significant because beyond this point, the risks associated with breathing air increase due to the effects of increased ambient pressure on nitrogen and other gases in the body, as well as oxygen toxicity.

At depths around 45 fsw, hyperbaric oxygen therapy becomes increasingly useful for treating conditions such as decompression sickness and carbon monoxide poisoning, where the administration of pure oxygen can expedite the elimination of carbon dioxide from the body and provide a beneficial environment for healing.

Breathing 100% oxygen at this depth helps prevent oxygen toxicity while still being effective for treatment. As one descends deeper below this threshold, the effects of increased pressure necessitate a cautious approach to the concentration of oxygen being delivered, as it can become toxic at higher pressures. Thus, the depth of 45 fsw serves as a critical threshold where the benefits of 100% oxygen become paramount for patient care.