This 65 year old gentleman presented to ED with fever and productive cough. For several days he has been too short of breath to eat or drink, and appeared severely dehydrated at triage. The chest Xray revealed an extensive right lower lobe pneumonia. BP on presentation was 78/40, and MAP remained below 60 in spite of large volumes of crystalloid. The ICU team were contacted after the seventh litre of fluid had not only failed to produce a sustained hemodynamic effect, but also catalysed an episode of acute pulmonary oedema. This ABG was taken while the patient was still conscious, being pre-oxygenated for intubation with a Laerdel bag-mask device.