The post stem cell transplant complications of neutropenic fever and mucositis, related to the chemotherapy and/or radiation on hematopoietic tissue administered prior to peripheral blood stem cell transplant, are reversible upon neutrophil count recovery. The investigators will investigate the use of hyperbaric oxygen as an intervention to shorten neutropenia post-high-dose chemotherapy and autologous peripheral blood stem cell transplant. The idea of using hyperbaric oxygen therapy in autologous stem cell transplantation is based on the investigators pre-clinical work that supported the use of hyperbaric oxygen to improve umbilical cord blood (cluster of differentiation 34) CD34+ stem cell transplantation.
