Background and objectives: Pumpless arteriovenous extracorporeal lung assist is increasingly used as a rescue therapy in acute respiratory distress syndrome. Arteriovenous extracorporeal lung assist is highly efficient in eliminating carbon dioxide and allows the application of ventilator techniques that prioritize lung protection and aim to reduce ventilator-induced lung injury and remote organ dysfunction.
Methods: Retrospective data analysis performed in a 12-bed university hospital ICU. In all, 22 patients with acute respiratory distress syndrome refractory to standard care were included. Arteriovenous extracorporeal lung assist as central part of a multimodal treatment concept was combined with tidal volume (VT) reduction below 4 mL kg-1 predicted body weight, a positive end-expiratory pressure titrated to optimize oxygenation and continuous axial rotation.
Results: Hypercapnia was reversed within 24 h in survivors (39 mmHg (35-42) (median and interquartile range) vs. 65 mmHg (54-72), P < 0.05) and non-survivors (5.2 kPa (5.5-6.0) vs. 10 kPa (6.9-13.9), P < 0.05). Oxygenation was significantly improved in survivors after 24 h (PaO2/FiO2 ratio 20.7 kPa (17.4-22.7) vs. 11.7 kPa (7.3-20.8), P < 0.05). All patients required norepinephrine infusion and volume resuscitation. The overall complication rate was 23%, predominantly due to reversible lower limb ischaemia. One patient (5%) was permanently disabled due to amputation of a seriously injured lower leg 9 days after initiation of arteriovenous extracorporeal lung assist therapy; however, the patient survived without neurological deficits despite an initial oxygenation index of 4.4 kPa. The overall mortality rate was 27%.
Conclusions: A multimodal treatment concept with arteriovenous extracorporeal lung assist as its central part provides reversal of hypercapnia and stabilization of oxygenation. In an attempt to maximize lung protection and potentially reduce ventilator-induced lung injury, a further VT reduction below 4 mL kg(-1) predicted body weight combined with a high mean airway pressure and continuous axial rotation is safely possible.