開心術に対する経皮炭酸ガス電極の応用

抄録

Transcutaneous carbon dioxide tension (tcPCO2) were continuously measured during open heart surgery for fifteen patients aging from 5 to 58.
The Hagihara transcutaneous CO2 electrode was used. This modified Severinghaus blood gas electrode consists of a PH-sensitive glass electrode and a silver-silver chloride reference electrode covered by a hydrophobic CO2 permeable membrane from which they are separated by a sodium bicarbonate electrolyte solution. The heating unit is also contained in this sensor-unit to dilate skin capillaries. Sensor temperature was maintained at 44°C throughout the study.
This sensor was attached at the thigh of the patient. During open heart surgeries, 117 arterial blood samples were taken for the determination of PaCO2. The regression curve between tcPCO2 and PaCO2 was
tcPCO2=1.11×PaCO2+9.5.
Using this formula, corrected tcPCO2 was calculated. During operation, at every thirty minutes the tcPCO2 and PaCO2 was determined and during E. C. C., at every fifteen minutes, the determination was made.
The mean value of corrected tcPCO2 showed no statistical difference from that of PaCO2 throughout the study. Before E. C. C., the corrected tcPCO2 ranged between 26.8 and 34.5 and the PaCO2 between 27.5 and 34.2 During E. C. C., the corrected tcPCO2 ranged between 18.6 and 22.9, PaCO2 between 17.6 and 21.5. After E. C. C., the corrected tcPCO2 ranged between 22.2 and 37.4, PaCO2 between 24.8 and 33.8mmHg respectively.
This value of tcPCO2 with this machine proved to have a good coefficient with that of PaCO2 (r=0.93).
In conclusion, this transcutaneous CO2 electrode is very useful for the monitoring of PaCO2 during open heart surgery.