A Comparison of the Physiological Effects of Positive Pressure and Negative Pressure Techniques on High-risk Patients With Extubation Failure: a Single-center Randomized Controlled Study

In the intensive care unit (ICU), weaning from mechanical ventilation and extubation are critical clinical goals. Successful extubation not only significantly shortens mechanical ventilation duration but also reduces the incidence of complications such as ventilator-associated pneumonia. However, extubation failure rates remain high, especially in high-risk patient populations. Even after passing the Spontaneous Breathing Trial (SBT), 10%-25% of high-risk patients experience respiratory deterioration post-extubation, necessitating reintubation. Therefore, optimizing extubation strategies for high-risk patients is essential.

Currently, extubation techniques in clinical practice are primarily classified into negative pressure extubation and positive pressure extubation. Traditional negative pressure extubation involves continuous tracheal suction to clear secretions; however, this negative pressure can lead to alveolar collapse, regional ventilation mismatch, and an increased risk of aspiration. In contrast, positive pressure extubation maintains airway pressure (such as pressure support or positive end expiratory pressure), which theoretically facilitates the movement of subglottic secretions toward the oropharynx, while also promoting alveolar recruitment and improving ventilation/perfusion matching. Although randomized controlled trials have explored the safety of these two techniques, the conclusions remain controversial. Some studies suggest that positive pressure extubation reduces post-extubation hypoxemia and reintubation rates, while a meta-analysis indicates no statistically significant difference in overall complication rates between the two methods. This discrepancy may arise from heterogeneity in study populations, inadequate standardization of operational parameters, and the limited sensitivity of traditional monitoring methods in detecting regional pulmonary dynamic changes.

In recent years, Electrical Impedance Tomography (EIT) and Lung Ultrasound (LUS) have emerged as non-invasive bedside monitoring technologies, offering new insights into the physiological effects of extubation. EIT enables real-time dynamic imaging to quantitatively map both whole-lung and regional ventilation distributions, allowing for the sensitive detection of alveolar collapse or over-expansion. LUS, utilizing its B-line scoring system, provides an objective assessment of lung ventilation loss with high sensitivity and specificity. The combined use of these two techniques not only reveals the effects of extubation on overall oxygenation but also facilitates a detailed analysis of regional ventilation heterogeneity and compensatory mechanisms, thereby offering multimodal data to optimize extubation strategies.

This study proposes the design of a single-center, prospective, randomized controlled trial to systematically assess the physiological differences between positive pressure and negative pressure extubation techniques in high-risk patients prone to extubation failure. The goal is to provide evidence-based support for developing individualized extubation strategies tailored to high-risk patients.