Effects of Different Anesthesia Machine Modalities on Bariatric Surgery Patients: a Prospective Randomized Controlled Study

The goal of this clinical trial is to explore the clinical significance and value of the PRVC ventilation mode in Bariatric Surgery Patients. The main questions it aims to answer are： * Do different ventilation patterns affect intracranial pressure and partial pressure of carbon dioxide in bariatric surgery patients? * Does PRVC mode reduce intracranial pressure and partial pressure of carbon dioxide in bariatric surgery patients? * Whether intracranial pressure can be quickly measured by monitoring a patient\'s optic nerve sheath diameter (ONSD)？ Researchers randomized bariatric surgery patients into PC, VC, and PRVC groups for comparison, looking at breathing mechanics, PaCO2, and ICP. Participants will: * take PC mode ventilation, VC mode ventilation, and PRVC mode ventilation * monitor Respiratory mechanics, PaCO2, and ONSD