When PEEP Becomes a Balancing Act: Ventilatory Challenges in a Patient with PFO Undergoing Laparoscopic Surgery in Trendelenburg Position

Background Advances in cardiology and perioperative care have markedly improved survival rates in patients with congenital heart disease, including atrial septum defect (ASD) and persistent foramen ovale (PFO). Consequently, an increasing number of these patients reach present for non-cardiac surgery in adulthood. With advancing age, 97concomitant comorbidities, such as chronic obstructive pulmonary disease (COPD), become more prevalent. Although laparoscopic surgery offers potential benefits over open procedures, pneumoperitoneum and Trendelenburg positioning may adversely affect cardiopulmonary physiology, particularly in patients with intracardiac shunts or obstructive airway disease Case presentation : We present the case of a 53-year-old man with a history of embolic stroke and presumed PFO undergoing robotic-assisted laparoscopic surgery. Intraoperatively, previously undiagnosed obstructive airway disease caused severe dynamic hyperinflation with intrinsic PEEP. Escalation of ventilatory pressures was restricted due to concern for right-to-left shunt exacerbation under pneumoperitoneum and Trendelenburg positioning, and persistent ventilatory compromise required conversion to mini-laparotomy. After relief of pneumoperitoneum and individualized PEEP adjustment, respiratory mechanics improved. Postoperative transthoracic echocardiography unexpectedly demonstrated an ASD with left-to-right shunt instead of the presumed PFO. Conclusion This case highlights the complex interplay between ventilatory mechanics and intracardiac shunt physiology during laparoscopic surgery. It underscores the importance of comprehensive preoperative evaluation, critical reassessment of historical diagnoses, and dynamic intraoperative echocardiographic assessment. Individualized anesthetic and ventilatory strategies are essential to minimize perioperative risk in patients with congenital heart disease and concomitant obstructive lung pathology .