Intravascular Membrane Oxygenation and Carbon Dioxide Removal with Permissive Hypercapnia — New Concepts in the Management of Respiratory Failure

Abstract

Despite advances in ventilatory support, antibiotic therapy and critical care, mortality from adult respiratory distress syndrome (ARDS) remains between 50 and 77% [1–3]. Treatment of ARDS is mainly supportive, with mechanical ventilation being the mainstay of therapy. However, current techniques of ventilator management are associated with high inspiratory airway pressures (barotrauma), overdistension of normal lung regions (volutrauma), and toxic levels of inspired oxygen (oxygen toxicity), leading to exacerbated lung injury as manifested by progressive deterioration in total lung compliance, functional residual capacity, and arterial blood gas [4–6]. High positive airway pressure also contributes to cardiovascular instability [7]. Disappointing results with conventional management of ARDS patients have resulted in an increased urgency for developing alternative strategies that provide sufficient oxygenation, carbon dioxide removal, and “lung rest”. Over the past 5 years, many have recognized that the primary goal of respiratory support should focus on CO₂ removal and O₂ exchange with avoidance of high tidal volumes and airway pressures. We and others have shown that a modified form of cardiopulmonary bypass, known as venovenous extracorporeal membrane oxygenation (VV ECMO), has been successful in supporting total gas exchange during severe respiratory failure [8–10], but application of this technology involves blood-surface interactions that may exacerbate lung injury [8, 11, 12]. In addition, ECMO is labor-intensive and requires expensive equipment and a highly sophisticated team.