Mercy Medical Center's Wound Healing & Hyperbaric Center in Cedar Rapids, Iowa describes hyperbaric oxygen therapy (HBOT) as a painless treatment in which patients breathe 100% oxygen at higher-than-normal atmospheric pressure during 90-minute to two-hour sessions. The website explains that HBOT has been used since the mid-1960s for diabetic ulcers, pressure ulcers, infections, compromised skin grafts and flaps, and wounds that haven't healed within 30 days. Patients lie inside one-ton acrylic chambers and can watch movies during treatment. The average course is 20-40 daily weekday sessions. Medicare and most private insurers cover HBOT for chronic, non-healing wounds, and a physician at the center evaluates each candidate.