摘要目的研究低温和血液稀释对挥发麻醉药的综合影响。方法　12名男性健康志愿者，每人抽取230 ml静脉血，并将其红细胞压积调整至40％。然后用生理盐水依次稀释到红细胞压积36％、32％、28％、24％和20％。用顶空二次平衡法测定地氟醚、七氟醚、异氟醚、安氟醚和氟烷在37℃、33℃、29℃、25℃、21℃和17℃条件下的血/气分配系数。结果　随温度下降，血/气分配系数的自然对数增大，称负直线相关（P<0.05）。随红细胞压积下降，血/气分配系数的自然对数减小，称直线相关（P<0.05）。低温和血液稀释对血/气分配系数的综合影响可用下列多元直线回归方程表示：　地氟醚: logeλB/G=-0.0302×T+0.0094×HCT＋0.119 R2=0.973 　七氟醚: logeλB/G=-0.0295×T+0.0092×HCT＋0.306 R2=0.961 　异氟醚: logeλB/G=-0.0382×T+0.0154×HCT＋1.120 R2=0.997 　安氟醚: logeλB/G=-0.0408×T+0.0198×HCT＋1.408 R2=0.982 　氟烷: logeλB/G=-0.0417×T+0.0218×HCT＋1.649 R2=0.994 方程中：(B/G 为血/气分配系数；T为温度（℃）；HCT为红细胞压积（%）。结论　低温使挥发麻醉药的血液溶解度增大，而晶体液稀释使其减小。应用上述多元回归方程，可预测温度自37℃到17℃，红细胞压积自40％到20％任一交叉点的麻醉药血液溶解度。

abstractsObjective To determine the combined effect of hypothermia and crystalloid hemodilution on blood solubility of volatile anesthetics.Methods Two hundred and thirty ml blood samples obtained from each of twelve healthy male volunteers were adjusted to a hematocrit of 40% and then diluted with normal saline to hematocrits of 36%, 32%, 28%, 24%, and 20%. Blood/gas partition coefficients of desflurane, sevoflurane, isoflurane, enflurane and halothane were measured at 37℃, 33℃, 29℃, 25℃, 21℃ and 17℃ using a two-stage headspace double equilibration method.Results As the temperature decreased, the logarithm of the blood/gas partition coefficient increased linearly (P<0.05). As the hematocrit decreased, the logarithm of the blood/gas partition coefficient decreased linearly (P<0.05). The combined effect of hypothermia and crystalloid hemodilution on blood solubility of anesthetics was expressed by multiple linear regression equations as follows:Desflurane: logeλB/G=-0.0302×T+0.0094×HCT+0.119 R2=0.973Sevoflurane: logeλB/G=-0.0295×T+0.0092×HCT+0.306 R2=0.961Isoflurane: logeλB/G=-0.0382×T+0.0154×HCT+1.120 R2=0.997Enflurane: logeλB/G=-0.0408×T+0.0198×HCT+1.408 R2=0.982Halothane: logeλB/G=-0.0417×T+0.0218×HCT+1.649 R2=0.994Where λB/G is the blood/gas partition coefficient, T is temperature (℃) and HCT is hematocrit (%).Conclusions Hypothermia increases, while crystalloid hemodilution decreases the blood solubility of volatile anesthetics. The combined effect of hypothermia and hemodilution on blood solubility at any cross point of temperature from 37℃ to 17℃ and hematocrit from 40% to 20% could be predicted by the multiple linear regression equations developed in this study.