Continuous pH and pCO2 Monitoring Using the Paratrend Inserted Through a Pulmonary Artery or Central Venous Catheter

The Paratrend continuous blood gas monitoring system was placed through a pulmonary artery or central venous catheter as a means of continuously monitoring pH, pCO2, and mixed venous oxygen saturation in three neonates at risk for cardiorespiratory dysfunction, two following surgery for congenital heart disease and one with septic shock. After calibration with an arterial/mixed venous blood gas value, the Paratrend monitor provided a clinically useful continuous measurement of pH and pCO2. The difference between the Paratrend and the arterial values for pH and pCO2 were 0.02 ± 0.009 and 2.4 ± 0.8 mmHg, respectively. There was a significant discrepancy between the oxygen saturation reading from the Paratrend and the actual measured mixed venous value (9 ± 5%). The possible applications of the Paratrend placed through a pulmonary artery or central venous catheter are discussed.