The Acidosis of Low-Glucose Pleural Effusions3 DANIEL E. POTTS, MARY A. WILLCOX, JAMES T. GOOD, JR., DAVID A. TARYLE, and STEVEN A. SAHN .

SUMMARY. To clarify the relationship between pleural fluid p H and pleural fluid glucose concentration, and to investigate the mechanisms responsible for these phenomena, we studied a heterogeneous population of 21 consecutive patients with pleural effusions. Simultaneous measurements of pleural fluid and blood p H , Pco 2 , glucose, lactate, pyruvate, total protein, total leukocyte count, differential count, and lactic dehydrogenase were determined. Six patients had pleural fluid acidosis (pH < 7.30) and pleural fluid glucose concentrations < 60 mg per 100 ml. None of these 6 had acidemia, and their mean ± SE pleural fluid ratio of lactate to pyruvate was 110.4 ± 36.2 compared with a blood ratio of 11.5 ± 0.8 (P < 0.05). A significant correlation between pleural fluid p H and relative glucose concentration (pleural fluid/blood glucose) was found (r = 0.88; P < 0.01). A significant inverse correlation was observed between pleural fluid p H and pleural fluid lactate (r = -0.91; P ::0

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