A randomized comparison of total extracorporeal CO2 removal with conventional mechanical ventilation in experimental hyaline membrane disease

Abstract

Apnoeic oxygenation (AO) combined with extracorporeal CO₂ removal (ECCO₂R), using venovenous perfusion across a membrane area of 0.1m² has been shown to be feasible in six healthy anaesthetized rabbits. In a further twelve rabbits, ECCO₂R has been randomly compared with conventional mechanical ventilation (CMV) following saline lavage to induce respiratory failure. Blood gases were maintained for up to 6h within the same range (PaO₂=8–20 kPa, PaCO₂=4–6 kPa) in two groups of six by varying airway pressures and the oxygen fraction delivered either to the membrane lung (ECCO₂R group) or to the ventilator (CMV group). The influence of single hourly sustained inflations (SI) on oxygenation was studied. ECCO₂R subjects remained stable and survived. CMV subjects deteriorated and had 80% mortality. Hyaline membranes were absent from ECCO₂R subjects and present in all CMV subjects. The response to SI suggests that a lung volume recruitment is maintained during AO for up to 1 h but is ineffective during CMV.