Early non invasive detection of hypercarbia in two cardiac surgical patients.

The availability of transcutaneous monitors has provided a means of non invasive assessment of CO(2) tension and a trend of the ventilation status commonly in infants and neonates. The authors describe two cases of hypercapnia diagnosed early in adults by the non invasive transcutaneous measurement of carbon dioxide (tcpCO(2)) using TINA TCM4 in postoperative cardiac surgical patients who were mechanically ventilated. Curiously, this increase in tcpCO(2) levels was associated with a false increase in the tcpO(2) values though no changes in the ventilatory parameters to increase oxygenation were made. The probable mechanism of the increase in tcpO(2) levels with hypercarbia is discussed.