Higuchi H, Yoshii S, Osawa H, Suzuki S, Abraham S J K, Hosaka S, Shindo S, Tada Y
Department of Surgery, University of Yamanashi, University Hospital, Yamanashi, Japan.
Kyobu Geka. 2002 Nov;55(12):1021-5.
During cardiopulmonary bypass, perfusion flow rate is generally calculated only with the patient body surface. Recently, far advanced hemodilution during cardiopulmonary bypass and tepid bypass circulation are common.
We have arrived at an appropriate flow rate formula, in which factors like temperature, hemoglobin concentration, the target mixed venous oxygen saturation (SvO2), and the amount of oxygen consumption are included. Our formula was compared with the conventional one.
Seventy-four points of cardiopulmonary bypass data under total cardiopulmonary bypass in 33 patients were studied. Our formula's validity was re-evaluated. Then, the SvO2 values were predicted by applying the flow rate value as per conventional calculation in to our formula.
The flow rate of our formula and the actual flow rate are well correlated (r = 0.9212). In the prediction of the SvO2 by the conventional method, 36.5% were calculated to have a SvO2 of less than 60%. Furthermore, with a hemoglobin concentration of 7 g/dl, 73.3% were calculated to have a SvO2 of less than 60%. With a body temperature of 34 degrees centigrade, 53.8% were calculated to have a SvO2 of less than 60%. On the other hand, to maintain SvO2 level at 70% by the conventional method, if the patient hemoglobin concentration was 10 g/dl, temperature should be maintained at 36 degrees centigrade, and when hemoglobin concentration is 7 g/dl, the temperature should be maintained at 33 degrees centigrade.
In advanced hemodilution or tepid cardiopulmonary bypass, use of appropriate flow rate formula is recommended, which takes into account the indispensable factors such as hemoglobin levels, temperature, and the target SvO2.
在体外循环期间，灌注流速通常仅根据患者体表面积来计算。近来，体外循环期间深度血液稀释和微温体外循环已很常见。
我们得出了一个合适的流速公式，其中纳入了诸如温度、血红蛋白浓度、目标混合静脉血氧饱和度（SvO2）和氧耗量等因素。将我们的公式与传统公式进行了比较。
研究了33例患者在全体外循环下74个体外循环数据点。重新评估了我们公式的有效性。然后，将按照传统计算得出的流速值应用于我们的公式来预测SvO2值。
我们公式的流速与实际流速高度相关（r = 0.9212）。采用传统方法预测SvO2时，计算得出36.5%的患者SvO2低于60%。此外，血红蛋白浓度为7 g/dl时，计算得出73.3%的患者SvO2低于60%。体温为34摄氏度时，计算得出53.8%的患者SvO2低于60%。另一方面，采用传统方法将SvO2水平维持在70%时，如果患者血红蛋白浓度为10 g/dl，体温应维持在36摄氏度，而当血红蛋白浓度为7 g/dl时，体温应维持在33摄氏度。
在深度血液稀释或微温体外循环中，建议使用考虑了血红蛋白水平、温度和目标SvO2等必要因素的合适流速公式。
