Inspiratory Effort

This physiological observational study will assess respiratory drive and inspiratory effort across varying levels of pressure support ventilation (PSV) in adult surgical ICU (SICU) patients after major abdominal surgery. By using non-invasive bedside indices (airway occlusion pressure at 100 ms after the onset of inspiration \[P0.1\], maximum negative occlusion pressure \[Pocc\], and pressure muscle index \[PMI\]), we aim to quantify how patients adapt to changes in ventilatory support and determine patterns of under- and over-assistance. Findings may inform optimal titration of PSV to reduce complications and improve clinical outcomes.

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.