Hyperbaric Oxygen Therapy and Allogeneic Peripheral Blood Stem Cell (PBSC) Transplant

This study is testing whether adding hyperbaric oxygen therapy (breathing pure oxygen in a pressurized chamber) before and after a stem cell transplant improves outcomes for people with blood cancers like leukemia and myelodysplastic syndrome (MDS). Hyperbaric oxygen may help stem cells engraft and reduce transplant-related complications. **You may be eligible if...** - You are between 18 and 75 years old - You have been diagnosed with acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), or certain other blood cancers (CMML, atypical CML, MDS/MPN) - You are scheduled to receive a stem cell transplant from a donor (allogeneic transplant) - You are in adequate health to undergo transplant **You may NOT be eligible if...** - You have a condition that makes hyperbaric oxygen therapy unsafe (e.g., untreated pneumothorax, severe lung disease, active ear infection) - Your cancer has not responded enough to prior treatment to qualify for transplant - You have severe organ dysfunction - You are pregnant Talk to your doctor to see if this trial is right for you.