Continuous pH monitoring using the Paratrend 7 inserted into a peripheral vein in a patient with shock and congenital lactic acidosis.

The authors present a 25-year-old woman who was admitted to the ICU for treatment of shock, respiratory failure, and acidosis related to congenital lactic acidosis from pyruvate dehydrogenase deficiency. To aid in ongoing management of the metabolic acidosis, the Paratrend blood gas monitoring sensor was inserted through a peripheral venous site to provide a continuous measurement of pH and partial pressure of carbon dioxide (Pco2). With the venous insertion of the Paratrend, a clinically useful correlation with arterial blood gas values was noted. Linear regression analysis of the pH values from the venous blood gas analyses and the Paratrend monitor revealed r2 = 0.71 with p = 0.001 and r2 = 0.78 with a p = 0.0003 for the Pco2 values. Our preliminary experience suggests that venous placement of the Paratrend monitor can be used to provide clinically useful, continuous measurement of pH and Pco2.