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

Inclusion Criteria:

• Voluntary written informed consent

• Men or women, age ≥ 18 years of age, with upper limit of 75 years old.

• Subjects with acute myeloid leukemia (AML) or Myelodysplastic Syndrome (MDS) forcohort 1.

• Subjects with chronic myelomonocytic leukemia (CMML), atypical chronic myeloidleukemia (aCML), CML, chronic neutrophilic leukemia (CNL), myelofibrosis, andmyelodysplastic/myeloproliferative (MDS/MPN) overlap syndrome for cohort 2.

• Karnofsky performance status (KPS) of ≥ 70%

• Patients should have New York Heart Association (NYHA) Functional Classification,Class I (ordinary physical activity does not cause undue fatigue, palpitation,dyspnea, or anginal pain) or Class II (ordinary physical activity results infatigue, palpitation, dyspnea, or anginal pain).

• Adequate hepatic, renal, cardiac and pulmonary function to be eligible fortransplant. Minimum criteria include: Hepatic: ALT, AST < 4x IULN and serum totalbilirubin ≤ 2.0 mg/dL; Renal: serum creatinine: ≤ 2.0 mg/dL; Left ventricularejection fraction ≥ 45% measured by 2D-ECHO or MUGA scan; EKG with no clinicallysignificant arrhythmia; FEV1, FVC and DLCO ≥ 50% of predicted value (corrected toserum hemoglobin)

• Women of child-bearing potential and men with partners of child-bearing potentialmust agree to use adequate contraception (hormonal or barrier method of birthcontrol; abstinence) prior to study entry, for the duration of study participation,and for 30 days following completion of therapy. Should a woman or partner becomepregnant or suspect she is pregnant while participating in this study, she shouldinform her treating physician and the investigator immediately.

• A woman of child-bearing potential is any female (regardless of sexual orientation,having undergone a tubal ligation, or remaining celibate by choice) who meets thefollowing criteria: Has not undergone a hysterectomy or bilateral oophorectomy; orHas not been naturally postmenopausal for at least 12 consecutive months (i.e., hashad menses at any time in the preceding 12 consecutive months)

• Women of child-bearing potential should have a negative urine or serum pregnancytest within 4 weeks of starting preparative regimen

Exclusion Criteria:

• Pregnant or breastfeeding

• Severe chronic obstructive pulmonary disease requiring oxygen supplementation

• History of spontaneous pneumothorax, prior chest surgery requiring thoracotomy ordirect chest irradiation to the lungs

• Evidence of pneumothorax or significant pulmonary fibrosis on chest imaging within 60 days of transplant.

• Active malignancy excluding AML, MDS, CMML, aCML CML, CNL, MF and MDS/MPN overlapsyndrome.

• Active ear/sinus infection. Patients with chronic sinusitis or sinus headaches areexcluded unless cleared by ear, nose, and throat specialist.

• Recent sinus surgery (within the last 5 years).

• Ear surgery excluding myringotomy or ear tubes

• Subjects must agree to refrain from active tobacco or e-cigarette use 72 hours priorto transplant until complete transplant recovery. Nicotine replacement therapy isallowed.

• Claustrophobia

• History of recurrent seizures within 5 years of study enrollment.

• Uncontrolled asthma

• Uncontrolled viral or bacterial infection at the time of study enrollment

• Active or recent (prior 6 months) invasive fungal infection withoutinterdisciplinary (ID) consult and approval

• Patients who had intrathecal chemotherapy within 2 weeks of starting preparativeregimen or cranial irradiation within 4 weeks of starting preparative regimen