Stem cell transplantation is an important treatment for hematological diseases, immune system disorders, and some malignant tumors. However, patients are in an extremely fragile state after surgery, prone to complications such as infection, tissue damage, and slow recovery of hematopoietic function. As a physical adjuvant therapy, hyperbaric oxygen therapy supplies high-concentration oxygen in a hyperbaric environment, which can specifically solve multiple clinical problems after surgery and lay a solid foundation for patients' rehabilitation. Its necessity is mainly reflected in the following core dimensions.
I. Accelerate Hematopoietic Function Reconstruction and Shorten Recovery Cycle
After stem cell transplantation, the patient's bone marrow hematopoietic microenvironment is damaged, and the colonization, proliferation, and differentiation abilities of hematopoietic stem cells are reduced, which easily leads to myelosuppressive symptoms such as agranulocytosis and thrombocytopenia. This not only increases the risk of infection and bleeding but also prolongs the length of hospital stay. Hyperbaric oxygen can significantly increase the dissolved oxygen content in the blood, providing sufficient oxygen supply for stromal cells and hematopoietic stem cells in the bone marrow hematopoietic microenvironment. Stromal cells have enhanced activity in a hyperoxic environment and can secrete more hematopoietic growth factors (such as granulocyte colony-stimulating factor and erythropoietin), promoting the colonization and proliferation of hematopoietic stem cells. At the same time, hyperoxia can improve local blood circulation in the bone marrow, alleviate hypoxic damage to hematopoietic tissue, accelerate the recovery of bone marrow hematopoietic function, help patients get out of the agranulocytosis and thrombocytopenia phases faster, and reduce the incidence of transfusion dependence and related complications.
II. Inhibit Infection Spread and Reduce Postoperative Infection Risk
Due to severe immunosuppression after surgery (the killing of immune cells by conditioning regimens and insufficient production of immune cells caused by myelosuppression), patients are at high risk of infection, and infections can easily progress to severe pneumonia, sepsis, etc., endangering life. Hyperbaric oxygen therapy exerts anti-infective effects in two aspects: on the one hand, high-concentration oxygen can directly inhibit the growth and reproduction of anaerobic bacteria and some aerobic bacteria, especially having a significant inhibitory effect on anaerobic infections that may occur after surgery (such as perianal abscess and wound infection); on the other hand, sufficient oxygen supply can enhance the phagocytic activity and bactericidal ability of immune cells such as neutrophils and macrophages. In a hyperoxic environment, immune cells can clear pathogens more efficiently, promote the excretion of metabolic wastes at the inflammatory site, reduce inflammatory responses, and prevent infection spread. Clinical studies have shown that adjuvant hyperbaric oxygen therapy can reduce the incidence of postoperative pulmonary infection and perianal infection in stem cell transplantation patients and shorten the infection treatment cycle.
III. Repair Tissue Damage and Reduce Complications
Preoperative conditioning regimens (chemotherapy, radiotherapy) and surgical operations for stem cell transplantation can cause damage to tissues and organs such as the gastrointestinal mucosa, skin mucosa, and liver, easily leading to complications such as oral ulcers, gastrointestinal ulcers, and liver damage, which affect patients' eating, nutrient absorption, and overall rehabilitation. Hyperbaric oxygen can penetrate the vascular barrier, reach the damaged tissue directly, increase local tissue oxygen partial pressure, and promote the regeneration and repair of damaged mucosal cells and hepatocytes. For oral ulcers and gastrointestinal mucosal damage, hyperoxia can accelerate the proliferation of mucosal epithelial cells, promote wound healing, relieve symptoms such as pain and bleeding, and help patients resume normal eating as soon as possible to ensure nutrient intake. For liver damage, sufficient oxygen supply can reduce hepatocyte edema and necrosis, promote hepatocyte repair, and reduce the risk of liver failure. In addition, hyperbaric oxygen can improve the healing environment of skin wounds (such as central venous catheter puncture sites and surgical incisions), reducing the probability of wound infection and delayed healing.
IV. Improve Microcirculatory Disorders and Alleviate Ischemic-Hypoxic Damage
Chemotherapeutic drugs and radiotherapy in conditioning regimens can damage vascular endothelial cells, leading to vasospasm and insufficient microcirculatory perfusion, which in turn causes ischemic-hypoxic damage to tissues, commonly occurring in the kidneys, heart, nervous system, and other parts, manifested as abnormal renal function, myocardial damage, cognitive dysfunction, etc. Hyperbaric oxygen can dilate microvessels, reduce blood viscosity, improve systemic microcirculatory perfusion, increase oxygen supply to ischemic tissues, reduce vascular endothelial cell damage, inhibit free radical generation, and reduce ischemia-reperfusion injury. For the kidneys, it can alleviate renal parenchymal ischemia and hypoxia and protect renal function; for the nervous system, it can improve cerebral tissue oxygen supply, reduce neurotoxicity caused by conditioning, and reduce the incidence of postoperative cognitive dysfunction and peripheral neuropathy; for the heart, it can improve myocardial ischemia, protect cardiomyocytes, and reduce the risk of cardiovascular complications such as arrhythmia and heart failure.
V. Adjunctive Treatment of Graft-Versus-Host Disease and Reduction of Immune Damage
Graft-versus-host disease (GVHD) is one of the serious complications after stem cell transplantation. It is caused by donor immune cells attacking the recipient's tissues and organs, which can involve multiple parts such as the skin, gastrointestinal tract, and liver, seriously affecting the patient's survival rate. Although hyperbaric oxygen cannot directly block the immune response of GVHD, it can assist in controlling GVHD symptoms by repairing damaged tissues and reducing inflammatory responses. For cutaneous GVHD, hyperoxia can promote the regeneration of damaged skin epithelial cells and relieve symptoms such as rash, ulcer, and itching; for gastrointestinal GVHD, it can accelerate the repair of gastrointestinal mucosa, alleviate manifestations such as diarrhea, abdominal pain, and gastrointestinal bleeding. At the same time, it provides a better physical foundation for patients to tolerate therapeutic drugs such as immunosuppressants and improve the therapeutic effect of GVHD.
VI. Improve Overall Rehabilitation Quality and Reduce the Risk of Long-Term Sequelae
After stem cell transplantation, patients not only face the threat of short-term complications but also may suffer from long-term sequelae such as chronic fatigue, cognitive decline, and organ dysfunction due to long-term ischemia and hypoxia and tissue damage, affecting the quality of life. Through continuously improving systemic oxygen supply, repairing damaged tissues, and regulating body metabolism, hyperbaric oxygen therapy can help patients recover physical strength faster and relieve postoperative chronic fatigue symptoms. At the same time, its protective effect on the nervous system, cardiovascular system, etc., can reduce the occurrence of long-term sequelae and help patients return to normal life and work better.