Clinical Research Directory

Association of Inspiratory Effort With Dyspnea During Assisted Mechanical Ventilation in Critically Ill Patients

During assisted mechanical ventilation, breathing results from the interaction between the patient and the ventilator. Optimal titration of pressure support is essential to maintain a balance between over-assistance and under-assistance. Excessive respiratory may lead to dyspnea and cause respiratory muscle fatigue, whereas excessive assistance promotes muscle atrophy and delays weaning. Although normal inspiratory effort values in healthy subjects are well defined, acceptable limits in critically ill patients remain unclear. Inspiratory effort is traditionally quantified by the pressure-time product (PTP), but its measurement is technically demanding. Simpler indices such as swings of esophageal pressure (δPes) and airway occlusion pressure at 100 ms (P0.1) are used more often, both with important limitations. Dyspnea, a frequent and distressing symptom among mechanically ventilated critically ill patients, may serve as a physiological marker of unacceptably high effort. This single-center prospective observational study conducted in the intensive care unit (ICU) of the University Hospital of Heraklion aims to (1) determine whether the ratio mean to maximal inspiratory pressure (Pmean/Pmax) correlates more strongly with dyspnea intensity than PTP, δPmus, P0.1 and (2) identify a Pmean/Pmax threshold predictive of clinically significant dyspnea. These findings are expected to define objective upper limits of acceptable inspiratory effort and guide ventilator titration to improve patient comfort and safety.

Assessment of Respiratory Drive and Inspiratory Effort Across Pressure Support Levels in Patients After Major Abdominal Surgery

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.

Use of Nasal Pressure to Assess Inspiratory Effort Under Different Oxygen Treatments

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.