The importance of never ignoring an unexplained metabolic acidosis

An 80-year-lady was admitted with coffee ground vomiting and productive cough. She was recently treated for community-acquired pneumonia with Augmentin. Clinical and biochemical deterioration continued despite antibiotics and within 48 h was requiring non-invasive ventilation with a climbing C-reactive protein (CRP), but normal white cell count. Chest X-ray showed right-sided consolidatory changes. Respiratory exam was compatible with aspiration pneumonia, arterial blood gas pre-BIPAP: pH 7.44, pCO2 3.8, pO2 …