To investigate the evidence for the integration of hyperbaric oxygen therapy (HBOT) as part of interdisciplinary stroke rehabilitation.

Pneumonia complicating stroke is very difficult to manage and has a very poor prognosis, leading to a significantly higher risk of death. Oral opportunistic pathogens have been reported to be associated with the incidence of pneumonia among non-stroke immunocompromised subjects. Preliminary studies found that patients with stroke had higher carriage rates of oral opportunistic pathogens than healthy subjects. Therefore, investigators hypothesize that pneumonia complicating stroke is associated with oral opportunistic pathogens, and hyperbaric oxygen therapy may reduce the incidence of pneumonia complicating stroke by increasing the flow of saliva, which can affect the species and relative abundance of oral opportunistic pathogens. In order to prove this, investigators need to (1) firstly conduct a randomized controlled trial to confirm whether hyperbaric oxygen therapy is able to reduce the levels of plaque, and the incidence of pneumonia complicating stroke at clinical level; (2) secondly employ metagenomics analysis to compare oral rinse samples and respiratory samples, and to identify pneumonia-associated "oral opportunistic pathogens group"; (3) finally elucidate how hyperbaric oxygen therapy influences the species and relative abundance of oral opportunistic pathogens. This proposed study will provide evidence for the integration of hyperbaric oxygen therapy as part of interdisciplinary stroke rehabilitation.

Inclusion Criteria:

• New stroke events within 1-3 months (confirmed by CT and MRI)
• Moderate to severe disability (Barthel Index < 70)
• The patient is conscious, breathing autonomously, not undergoing tracheotomy or tracheal intubation for ventilator-assisted respiration
• No concurrent lower respiratory infections and other lung diseases
• The condition is relatively stable
• Cognitive function is normal to moderately impaired (Mini-Physical State Exchange, MMSE score>18)
• The Gugging Swallowing Screen (GUSS) shows swallowing difficulties
• No systemic and local use of antibiotic-containing mouthwash

Exclusion Criteria:

• A mild disability (Barthel Index > 70)
• The swallowing function is normal
• Indwelling nasogastric feeding tube
• The neurological status of the patient was significantly dynamically altered (significantly improved or worsened) in the short term prior to inclusion in the trial
• The patient had been treated with hyperbaric oxygen for other indications
• Had a chest condition and cannot withstand the pressure changes caused by hyperbaric oxygen therapy
• Have an inner ear disease
• Claustrophobia
• Communication barriers and inability to give informed consent