A52-13 Positive Airway Pressure as a Physiologic Adjunct to Complicated Pleural Effusion Drainage

Case A 90-year-old man with atrial fibrillation, chronic kidney disease stage 3, and hypertension presented with one day of dyspnea and left flank pain after poor oral intake. He was in atrial fibrillation with rapid ventricular response (RVR) and required 2L oxygen for 95% saturation. Exam revealed wheezing, diminished left lower breath sounds, and flank tenderness. CT showed a moderate left pleural effusion with consolidation, and point-of-care ultrasound revealed a complex, loculated effusion. Diagnosis Complex pleural effusion. Clinical Course He received fluids, empiric antibiotics, and amiodarone for rate control. Chest tube placement drained 50 mL of serosanguineous fluid. Intrapleural tPA and dornase alfa were deferred pending anticoagulation hold. After tPA administration on ICU Day 4, drainage remained minimal. The following morning, he developed atrial fibrillation with RVR (HR 167 bpm), hypotension (MAP 54 mmHg), tachypnea (40 breaths/min), and mixed respiratory failure requiring bilevel-positive airway pressure (BiPAP). Venous blood gas showed pH 7.17 and pCO2 60 mmHg; lactate was 3.67 mmol/L. Within 15 minutes of BiPAP initiation, chest tube output surged to 750 mL of serosanguineous fluid with continued high-volume drainage thereafter. His respiratory status rapidly improved, allowing BiPAP discontinuation within four days and eventual discharge home. Discussion This case highlights the potential utility of positive airway pressure as a physiologic adjunct to enhance pleural drainage in complex effusions. After partial improvement with standard therapy, the patient’s decompensation and subsequent initiation of BiPAP temporally correlated with renewed, high-volume chest tube output and rapid clinical recovery. This suggests that increased pleural pressure from positive airway pressure may augment pleural evacuation.Existing evidence supports this mechanism. In a randomized trial, continuous positive airway pressure (CPAP) added to standard therapy reduced chest tube duration, hospital stay, and infectious complications in pleural effusion patients. Postoperative studies have shown similar benefits, with fewer complications and faster recovery among those receiving positive pressure. In mechanically ventilated surgical ICU populations, ultrasound-guided drainage under positive pressure achieved mean first-day outputs > 800 mL and earlier liberation from ventilation. Additionally, case reports describe spontaneous high-volume effusion drainage under CPAP, attributed to sustained supra-atmospheric pleural pressure gradients. Animal models corroborate these findings, demonstrating rapid pleural pressure equalization and improved flow dynamics during mechanical ventilation.This case adds to a growing body of evidence suggesting that positive airway pressure may serve as a valuable mechanical adjunct alongside intrapleural fibrinolytics in facilitating drainage of complex pleural effusions when traditional measures are insufficient.