Mark J B, FitzGerald D, Fenton T, Fosberg A M, Camann W, Maffeo N, Winkelman J
Brigham and Women's Hospital, Boston, Mass. 02115.
J Thorac Cardiovasc Surg. 1991 Sep;102(3):431-9.
A new monitoring technique, based on optical fluorescence chemistry, allows continuous monitoring of all blood gas variables during cardiopulmonary bypass. To evaluate the clinical performance of this monitor, we drew 220 arterial and 216 venous blood samples from 15 patients, and simultaneous blood gas values displayed by the monitor were compared with standard laboratory measurements. The continuous monitor predicted laboratory values with varying degrees of accuracy. (R2 values by linear regression: arterial oxygen tension 0.86, venous oxygen tension 0.36, arterial carbon dioxide tension 0.58, venous carbon dioxide tension 0.72, arterial pH 0.53, venous pH 0.58; pH 0.53, venous pH 0.58; p less than 0.0001). Monitor values of arterial oxygen tension overestimated laboratory values (bias = + 43.5 mm Hg), but the laboratory reference method likely underestimated true arterial oxygen tension in the high range achieved on bypass. Monitoring of venous oxygen tension was imprecise (precision = +/- 6.51 mmHg), regardless of whether stable conditions existed during the sampling period. Monitoring of carbon dioxide tension and pH showed small bias (carbon dioxide tension within 2 mm Hg, pH within 0.03) and good precision (carbon dioxide tension within 3 mm Hg, pH within 0.03). With the development of unstable conditions on bypass, monitor arterial oxygen tension values showed a changing relationship to corresponding laboratory values. In conclusion, arterial and venous carbon dioxide tension and pH monitoring provide acceptably accurate alternatives to laboratory measurement of these variables during cardiopulmonary bypass. Arterial oxygen tension monitoring accurately indicates changes in oxygen tension in the arterial oxygen tension range typically produced during extracorporeal circulation. Oxygen tension monitoring in the venous oxygen tension range is too imprecise for clinical decision-making purposes.
一种基于光学荧光化学的新型监测技术能够在体外循环期间持续监测所有血气变量。为评估该监测仪的临床性能，我们从15名患者身上采集了220份动脉血样本和216份静脉血样本，并将监测仪显示的同步血气值与标准实验室测量值进行比较。该连续监测仪对实验室值的预测具有不同程度的准确性。（线性回归的R2值：动脉血氧分压0.86，静脉血氧分压0.36，动脉血二氧化碳分压0.58，静脉血二氧化碳分压0.72，动脉血pH值0.53，静脉血pH值0.58；P<0.0001）。动脉血氧分压的监测值高估了实验室值（偏差=+43.5 mmHg），但实验室参考方法可能低估了体外循环时所达到的高范围内的真实动脉血氧分压。无论采样期间是否存在稳定状况，静脉血氧分压的监测都不准确（精密度=±6.51 mmHg）。二氧化碳分压和pH值的监测显示偏差较小（二氧化碳分压在2 mmHg以内，pH值在0.03以内）且精密度良好（二氧化碳分压在3 mmHg以内，pH值在0.03以内）。随着体外循环不稳定状况的发展，监测仪的动脉血氧分压值与相应实验室值之间的关系发生了变化。总之，在体外循环期间，动脉和静脉二氧化碳分压及pH值监测为这些变量的实验室测量提供了可接受的准确替代方法。动脉血氧分压监测能准确指示体外循环期间通常产生的动脉血氧分压范围内的氧分压变化。静脉血氧分压范围内的氧分压监测对于临床决策而言不够精确。
