A 16-yr-old female suffering acute, rapidly progressive combined respiratory and cardiac failure that was unresponsive to conventional volume-cycled ventilation, was stabilized with the simultaneous short-term use of veno-venous membrane oxygenation and high-frequency jet ventilation. Percutaneousl) introduced cannulas afforded rapid vascular access for membrane oxygenation, minimal wound problems during the perfusion, and easy decannulation. This is the first reported combined use of high-frequency jet ventilation and extracorporeal membrane oxygenation, and the first reported percutaneous initiation of veno-venous bypass. The patient remained alive and well 4 months after therapy.