Clinical trials

After neurosurgery, many patients need to stay in the intensive care unit (ICU) and use a breathing machine (mechanical ventilation) because of issues like decreased consciousness, weak breathing, or poor airway protection. During this period, the natural balance of bacteria in the lungs-known as the lung microbiota-can be disturbed by surgery, antibiotics, and airway procedures. This may reduce healthy bacteria and allow harmful bacteria to grow, increasing the risk of lung infections such as ventilator-associated pneumonia (VAP). This study will follow 220 postoperative neurosurgical ICU patients at three centers: Beijing Tiantan Hospital, Beijing Shijitan Hospital, and Beijing Anzhen Hospital from August 2025 to August 2026. These patients will include those undergoing surgery for brain tumors, brain hemorrhage, or traumatic brain injury. Airway secretion samples (tracheal aspirates) will be collected shortly after surgery and at several subsequent time points to assess how lung bacteria change over time while patients are using a breathing machine. Using advanced laboratory methods, the investigators will measure both the amount and types of bacteria in the lungs. The aim is to determine how these changes are related to patient outcomes, such as the occurrence of lung infections. The results of this study may contribute to earlier detection of lung infections and the development of personalized treatment plans to improve recovery in ICU patients after neurosurgery.

The aim of this study was to investigate the effects of different oxygen therapy modalities (including nasal cannula oxygen, mask oxygen and high-flow nasal cannula oxygen) on the correlation between Nasal Pressure and Esophageal Pressure by means of a prospective physiological study, to assess the dynamic changes of nasal pressure and esophageal pressure and their underlying mechanisms under different conditions of oxygen therapy, to analyse the effects of oxygen therapy parameters on the relationship between the two, and to explore the feasibility of nasal pressure as a non-invasive monitoring indicator, in order to replaceor supplement esophageal manometry in clinical practice, especially in patients with respiratory distress and instability.Meanwhile, this study will also evaluate the effects of different oxygen therapy modalities on patients' respiratory mechanics and comfort, provide a scientific basis for the clinical selection of individualised oxygen therapy regimens, and ultimately provide new physiological evidence for the management of oxygen therapy in patients with acute respiratory failure in the intensive care unit (ICU) and outside the ICU, promote the development of non-invasive monitoring technology, and improve the clinical prognosis and therapeutic experience of patients.

Spontaneous breathing trials (SBT) are essential for assessing extubation tolerance, yet optimal approaches are debated. High-flow nasal oxygen offers benefits like precise oxygen delivery, flow-related positive end-expiratory pressure generation and improved lung function. While high-flow tracheal oxygen can also be used as an SBT method, it has reduced physiological effects due to bypassing the upper airway with a more open circuit. To enhance this limitation, investigators developed a modified high-flow tracheal oxygen tube with a smaller expiratory end diameter to increase expiratory resistance and airway pressure. This is a prospective randomized crossover study that aims to compare the physiological effects of standard and modified high-flow tracheal oxygen versus T-piece during SBT.

High-flow nasal oxygen therapy offers benefits like precise oxygen delivery, flow-related positive end-expiratory pressure generation and improved lung function. High-flow oxygen therapy can be applied via tracheostomy as high-flow tracheal oxygen. While high-flow tracheal oxygen has been used to facilitate weaning, it has diminished physiological effects due to bypassing upper airways. To enhance its effectiveness, researchers developed a modified high-flow tracheal oxygen tube with a smaller expiratory end diameter to increase airway resistance and pressure. This is a prospective randomized crossover study that aims to compare the physiological effects of standard and modified high-flow oxygen therapy in tracheostomized patients.

It is critical to maintain a relatively normal inspiratory effort during pressure support ventilation (PSV), the support level should be adjusted to match the patient's inspiratory effort. The inspiratory muscle pressure index (PMI) can reflect the elastic work of the respiratory system at the end of inspiration and has a significant correlation with inspiratory effort, and it has the outgoing advantages of being non-invasive and easy to obtain. Previous studies on PMI were based on physiological research and experimental conditions (PMIref), which require special pressure monitoring devices and software to collect and measure airway pressure. If PMI is going to be used in clinical practice, it is necessary to find a simple measurement method of PMI to replace PMIref. Most ventilators have airway pressure monitoring and end-inspiratory holding functions, and PMI can be measured by freezing the ventilator screen (PMIvent). The overall aim of this study was to determine PMIvent's clinical feasibility and validity for accessing inspiratory effort during PSV.