Early Prone Positioning After Acute Type A Aortic Dissection Surgery for Moderate-to-Severe Acute Respiratory Distress Syndrome Is Safe and Shortens Duration of Mechanical Ventilation

IMPORTANCE: Evidence for prone positioning in post-cardiac surgery acute respiratory distress syndrome (ARDS), especially after acute type A aortic dissection (ATAAD) repair, is extremely limited. Clinicians remain uncertain about its safety, feasibility, and the optimal timing of initiation in this hemodynamically vulnerable population. OBJECTIVES: To evaluate the effectiveness and safety of prone positioning for moderate-to-severe ARDS (MS-ARDS) after ATAAD repair, and to determine whether early initiation (≤ 48 hr) provides additional clinical benefit. DESIGN, SETTING, AND PARTICIPANTS: A retrospective, single-center cohort study conducted in a tertiary cardiovascular center. Seventy-eight adults with MS-ARDS after ATAAD surgery were included: 58 received prone positioning and 20 remained supine. MAIN OUTCOMES AND MEASURES: Primary outcomes were duration of mechanical ventilation (MV) and postoperative ICU length of stay (LOS). Secondary outcomes included hospital LOS, hospitalization cost, and 28- and 90-day mortality. Adverse events were systematically captured using prespecified hemodynamic and respiratory categories. RESULTS: Preoperative and perioperative characteristics were comparable between groups. In the prone cohort, the Pao2/Fio2 improved from 92.67 ± 21.04 to 152.45 ± 64.28 mm Hg at 4 hours (p < 0.001), demonstrating rapid oxygenation gain. Patients were further stratified by timing of intervention: early prone positioning (EPP: ≤ 48 hr from ARDS onset) and delayed prone positioning (DPP). EPP was associated with a significantly shorter duration of MV 5.03 ± 1.87 days compared with DPP 8.32 ± 4.73 days and the supine group 7.51 ± 4.08 days (p = 0.002). No increase in adverse events was observed, and no episodes of malignant arrhythmia or cardiac arrest occurred. CONCLUSIONS AND RELEVANCE: Prone positioning for MS-ARDS after ATAAD repair was feasible, safe, and rapidly improved oxygenation. Initiation within 48 hours was associated with a clinically meaningful reduction in ventilation duration. These findings support early, protocolized prone positioning in selected postoperative ATAAD patients and justify further evaluation in prospective trials.