Effects of Thoracentesis in Patients Under Invasive Mechanical Ventilation: A Retrospective Analysis of Clinical and Paraclinical Parameters.

Background: Thoracentesis is pivotal in managing pleural effusion (PE), particularly in invasive mechanical ventilation (IMV), with documented improvements in respiratory mechanics, oxygenation, and hemodynamic parameters. However, its efficacy may vary based on effusion type and drained volume. Methods: A retrospective longitudinal study was conducted at a high-complexity care center in Cali, Colombia (2019-2024), including 93 (IMV) patients who underwent therapeutic thoracentesis (TT). Respiratory and hemodynamic parameters were assessed before and up to 24 h post-procedure. Stratified analysis was performed by drained volume, fluid type, and left ventricular ejection fraction (LVEF). Results: TT yielded significant improvements in fraction of inspired oxygen (FiO2) (-4%), positive end expiratory pressure (PEEP) (-0.5 cmH2O), and Oxygen arterial Pressure Index/Inspired Oxygen Fraction (PaO2/FiO2-ratio) (+27.1), with greater impact for volumes ≥500 mL and transudative PE. Patients with LVEF ≤ 40% showed increased mean arterial pressure (MAP) and PaO2. Complication rates were low (<4%). Conclusions: TT is safe and effective in critically ill IMV patients, particularly for transudative PE and drained volumes ≥500 mL, as well as in subjects with LVEF ≤ 40%. Its positive impact on oxygenation and ventilation supports its therapeutic utility in critical care.