[Assessment of peripheral blood perfusion during open heart surgery with sublingual PCO2 measured by ISFET-PCO2...

Sublingual tissue PCO2 (PSLCO2) was continuously monitored with an ISFET-based PCO2 sensor during and after the open-heart surgery under cardiopulmonary bypass (CPB) in order to study the effect of CPB on the peripheral blood perfusion. In addition, PSLCO2 monitoring was carried out in several cases of off-pump CABG. In the cases of open-heart surgery with CPB, PSLCO2 increased from 35.0 +/- 5.6 mmHg at the induction of anesthesia to the maximum value of 55.7 +/- 6.0 mmHg during CPB. After declamping of the aorta, PSLCO2 decreased gradually to 49.0 +/- 4.0 mm Hg 6 hr after the admission to ICU. The value of arterial lactate as another index of peripheral blood perfusion also increased gradually after the start of CPB, reaching to the maximum value of 8.8 +/- 1.1 mmol.l-1 just after being admitted into ICU. In the case of off-pump CABG, PSLCO2 and arterial lactate showed a slight increase during the later part of the surgery, but the change was not so significant as in the case of open-heart surgery under CPB. Through this study, typical changing pattern of PSLCO2 during the open-heart surgery was recognized. The change of PSLCO2 always preceded that of arterial lactate. We also experienced one case in which early stage of hypoperfusion was detected through the monitoring of PSLCO2. These results suggest clinical advantages of PSLCO2 monitoring.