Abstract
Class III obesity is increasingly prevalent and presents unique perioperative challenges, particularly in the context of general anaesthesia and mechanical ventilation. The altered cardiopulmonary physiology in these patients increases susceptibility to alveolar collapse with impaired respiratory mechanics and gas exchange, significantly contributing to an increased risk of postoperative pulmonary complications. Positive end-expiratory pressure (PEEP) plays a pivotal role in lung-protective ventilation strategies but must be carefully titrated to balance its respiratory benefits against potential cardiovascular compromise. This narrative review explores the dual impact of PEEP on respiratory and cardiovascular outcomes during general anaesthesia in patients with obesity. We examine the obesity-related cardiopulmonary pathophysiology that influences the response to PEEP, including reduced lung compliance, increased pleural pressures, and altered venous return. Evidence from perioperative and critical care literature is synthesised to highlight the importance of PEEP in preventing atelectasis and improving oxygenation, while also considering its potential to impair cardiopulmonary function, particularly at higher levels. This review proposes a physiology-based framework and core recommendations to inform personalised PEEP management during general anaesthesia in patients with obesity, with the objective to optimise lung mechanics while preserving cardiovascular stability. We conclude that a nuanced, physiology-driven strategy to personalise PEEP, integrating respiratory mechanics, gas exchange, and cardiovascular parameters, can help optimise respiratory function and maintain cardiovascular stability in patients with obesity undergoing surgery. However, the clinical impact of such strategies needs to be confirmed in larger studies before they can guide evidence-based perioperative management in this high-risk population.