A 20-year-old male, recovering from post-traumatic ARDS, subsequently developed pneumonia with extreme hypercapnia (PaCO2 max 19.4 kPa) and hypoxemia (PaO2 min 5.1 kPa), in spite of maximal mechanical ventilation. Hypothermia was induced by surface cooling, reducing the body temperature from 40 degrees C to a mean of 33.3 degrees C. Buffer infusion (1375 mmol) during the first 2 days increased base excess from 3 to 22 mmol/l and pH from 7.16 to a median value of 7.30. Active cooling was discontinued on day 11. Weaning from the ventilator was possible 9 days later and the patient subsequently recovered fully. Combined use of hypothermia and buffering might offer an alternative to extracorporeal lung assist (ECLA) and facilitate a reduction of barotrauma and oxygen toxicity during mechanical ventilation.