An exhaust gas flow control system for an oxygenator of an extracorporeal ventilation system connected to an oxygenation gas supply line and to an exhaust line for removal of exhaust gas comprises a flow control path, a pressure control path, an exhaust flow regulator responsive to the controller, and an exhaust gas pressure regulator responsive to a controller configured to maintain a pre-determined pressure level in the exhaust line. This provides a better degree of control over the pressure across the oxygenator from oxygenation gas inlet to exhaust.