不同年龄国人的吸入麻醉药血/气分配系数及决定因素

目的 测定吸入麻醉药在不同年龄国人中的血／气分配系数，判断年龄是否影响Ｂ／Ｇ及确定影响Ｂ／Ｇ的血液成份。方法：１００例从出生至８４岁的国人按年龄分为１０组，每组１０例，男女各半。应用两次平稳法同时测定地氟醚、七氟醚、异氟醚、安氟醚和氟烷的Ｂ／Ｇ，并测定血浆白蛋白，球蛋白，甘油三酯和胆固醇浓度及血红细胞压积。     

冠心病和风心病患者吸入麻醉药血/气分配系数

测定并比较不同成人心脏病患者的吸入麻醉药血／气分配系数（Ｂ／Ｇ），判断血液成分对Ｂ／Ｇ的影响。方法：健康人、冠心病患者和风湿性心脏病患者各２０例，采静因１０ｍｌ，用两次平衡法测定地氟醚、异氟醚和氟铁Ｂ／Ｇ，并测定红细胞压积、血浆总胆固醇、甘油三酯、白蛋白和球蛋白浓度。结果：冠心病患者地氟醚、异氟醚、和氟烷的Ｂ／Ｇ和血浆甘油三酯浓度均高于健康人和风心病患者；三种吸入麻醉药的Ｂ／Ｇ均与甘油三酯含量有关     

温度对体外循环预充液的吸入麻醉药液/气分配系数的影响

目的 探讨温度对吸入麻醉药体外循环预充液／气分配系数的影响。方法 采用注射器两次平衡法,利用气 谱仪分别测定乳酸林格氏液、琥珀酰明胶、人体血浆和库血在３７℃、℃３３℃、２９℃、２５℃、２１℃和１７℃的六个不同温度点的液／气分配系数。结果 地氟醚、异氟醚和氟烷分别在乳酸林格氏液、琥珀酰明胶、人体血浆和库血中的液／气分配系数均与温度之间呈负直线相关（Ｐ〈０．０５）,同一种液体在同一温度中,地氟醚的液／     

30%脂肪乳剂对异氟醚血/气分配系数以及"洗入"的影响

目的 观察30%脂肪乳剂对异氟醚的血/气分配系数（B/G）的影响以及静脉注射不同剂量的30%脂肪乳剂对异氟醚“洗入”的影响.方法 （1）采集桡动脉血，配成不同浓度的30%脂肪乳剂与血的混合液.用二次平衡法测定异氟醚对上述混和液的B/G.（2）24例行冠状动脉旁路移植术的患者分为四组，每组6例.麻醉诱导后，静脉单次注射0、0.2、0.4及0.8 ml/kg的30%脂肪乳，随后开启异氟醚挥发罐，将挥发罐刻度设定在2%，并同时用微量泵注入相应剂量的30%脂肪乳0、0.2、0.4、0.8 ml·kg^-1·h^-1.持续吸入异氟醚1 h，监测异氟醚呼气末浓度（Fa）和吸入浓度（Fi）.其中0 m1/kg的30%脂肪乳组为对照组.结果 （1）异氟醚B/G随血中混合的30%脂肪乳剂浓度的增加而升高.（2）0.8 ml/kg剂量组的异氟醚Fa/Fi值与对照组比较明显降低（P＜0.05）.结论 注入较大剂量脂肪乳剂后，造成异氟醚“洗入”速度减慢，这可能是由于输注的脂肪乳剂造成异氟醚的B/G增大所致.     

异氟醚、七氟醚和地氟醚预处理对脑缺血再灌注损伤大鼠海马CBS/H2S、iNOS/NO和HO-1/CO的影响

目的 研究异氟醚、七氟醚和地氟醚预处理对脑缺血再灌注损伤大鼠海马CBS／H，S、iNOS／NO和HO-1／CO的影响，探讨吸入麻醉药脑保护作用的机制。方法30只Wistar大鼠随机分为5组（n=6）：对照组（C组）、脑缺血再灌注组（I／R组）、异氟醚组（I组）、七氟醚组（S组）和地氟醚组（D组）。采用四动脉阻断法建立大鼠全脑缺血再灌注模型。Ⅰ组、S组和D组夹闭两侧颈总动脉前分别吸入氧气＋0．65MAC的异氟醚、七氟醚和地氟醚30min，C组和I／R组吸入氧气。缺血20min，再灌注12h后处死大鼠，取海马，测定大鼠海马组织中HS、NO、CO、cAMP和cGMP含量和CBS，iNOS和HO活性以及CBS—mRNA、iNOS，mRNA和HO—1-mRNA的表达水平；电镜下观察海马线粒体的变化。结果与C组相比，I／R组海马组织CO、H2S、NO、cAMP、cGMP含量和HO、CBS、iNOS活性升高，CBS—mRNA、iNOS-mRNA和HO-1-mRNA表达升高，海马神经细胞线粒体变性率升高（P〈0．01）；与I／R组相比，Ⅰ组、D组和S组CO含量和HO活性升高，H2S、NO、cAMP含量和CBS、iNOS活性降低，CBS—mRNA和iNOS-mRNA表达降低而HO-1-mRNA表达升高，线粒体变性率降低（P〈0．05或0．01）。结论 异氟醚、七氟醚和地氟醚预处理可通过抑制CBS／142S、iNOS／NO，激活HO-1／CO，减轻了大鼠脑缺血再灌注损伤。     

紫绀型与非紫绀型先天性心脏病患儿吸人麻醉药血／气分配系数

目的测定并比较紫绀型与非紫绀型先天性心脏病患儿吸入麻醉药血／气分配系数(B／G),判断红细胞压积(Hct)对B／G的影响。方法紫绀型与非紫绀型先天性心脏病患儿各10例,平均年龄5岁,采桡动脉血10ml,用两次平衡法测定地氟醚、异氟醚和氟烷的B／G,并测定血浆总胆固醇、甘油三脂、白蛋白、球蛋白浓度和Hct,t检验比较两组间血液成分和吸入麻醉药B／G有无差别。结果紫绀型与非紫绀型先天性心脏病患儿Hct有显著差异(紫绀型为68．7％±11．1％,非紫绀型37．7％±2．9％,P<0．05);但两组间其他血浆成分和三种吸入麻醉药的B／G无差异(P>0．05)。结论Hct对B／G无影响,紫绀型与非紫绀型先天性心脏病患儿的B／G无显著性差异。     

紫绀型与非紫绀型先天性心脏病患儿吸入麻醉药血／气分配系数

目的：测定并比较紫绀型与非紫绀型先天性心脏病患儿吸入麻醉药／气分配系数（Ｂ／Ｇ）,判断红细胞压积对Ｂ／Ｇ影响。方法：紫绀型与非紫绀型先天性心脏病患儿各１０例,平均年龄５岁,采桡动脉血１０ｍｌ,用两次平衡法测定地氟醚,异氟醺客氟烷的Ｂ／Ｇ,并测定血浆总胆固醇、甘油三脂,白蛋白、球蛋白浓度和Ｈｃｔ,ｔ检验比较两组间血液成分和吸入麻醉药Ｂ／Ｇ有无差别。结果：紫绀型与非紫绀型先天性心脏病患儿Ｈｃｔ有显著差     

30%脂肪乳剂对异氟醚血/气分配系数的影响

目的　测定一定量的 30 %脂肪乳剂与血液混合后的异氟醚血 /气 (B/G)分配系数 ,观察血中含有不同浓度的 30 %脂肪乳剂后异氟醚B/G的变化。方法　 (1)选择 18例接受择期心脏手术的病人 ,静脉诱导后采集桡动脉血 2 0ml,用微量加样器分别配成含 4 %、2 %、1%、0 5 %及 0 2 5 %(Vol/Vol% )的 30 %脂肪乳剂与血的混合液。 (2 )用注射器 注射器二次平衡法测定 37℃、一个大气压下含不同浓度脂肪乳剂血液的异氟醚B/G。结果　异氟醚对含 4 %、2 %、1%、0 5 %及 0 2 5 %(Vol/Vol% )的 30 %脂肪乳剂的B/G分别为 2 5 2± 0 0 8、2 0 6± 0 0 9、1 72± 0 14、1 5 8± 0 11和1 5 2± 0 0 9,同时测定的异氟醚B/G为 1 4 2± 0 0 8。结论　临床应用的 30 %脂肪乳剂使挥发性麻醉药的B/G增大     

体外循环中吸入地氟醚、异氟醚和氟烷血/气分配系数的计算

体外循环（ＣＰＢ）期间,低温和血液稀释均影响吸入麻醉药的血／气分配系数（Ｂ／Ｇ）。本研究实际测定了常用吸入麻醉药在ＣＰＢ期间的Ｂ／Ｇ,并与根据经验公式得出的推测值进行了相关性分析,为正确了解ＣＰＢ中吸入麻醉药的药代动力学特点提供帮助。资料和方法选择２０例风湿性心脏病,拟行心脏瓣膜置换术的患者,于ＣＰＢ转机后１５分钟取血标本,每例５０ｍｌ。应用注射器两次平衡法同时测定地氟醚、异氟醚和氟烷在３７℃、３３℃、２９℃、２５℃、２１℃、和１７℃条件下的Ｂ／Ｇ。记录病人入手术室后至取血标本时的静脉输液和ＣＰ…     

吸入麻醉药对离体鼠肝线粒体内膜流动性的影响

使用ＤＰＨ（１，６－ｄｉｐｈｅｎｙｌ　１，３，５－ｈｅｘａｔｒｉｅｎｅ）作为荧光探剂，应用荧光偏振技术研究不同浓度的氟烷、安氟醚、异氟醚、七氟酸在能化和非能化条件下对离体鼠肝线粒体内膜流动性的影响，以探讨四种吸入麻醉药的肝毒性。材料与方法根据Ｅｓｔａｂｒｏｏｋ［１］方法提取肝线粒体内膜体，用ＤＰＨ标记，将实验组七氟醚（Ｓ）、安氟醚（Ｅ）、异氟醚（Ｉ）、氟烷（Ｈ）分５μｌ、５０μｌ、１００μｌ浓度加入到比色杯基质４ｍｌ中，对照组（能化组）则先加５ｍＭ琥珀酸５μｌ，使用日立８５０荧光分光光度仪加偏振…     

The blood/gas solubilities of sevoflurane, isoflurane, halothane, and serum constituent concentrations in neonates and adults

To determine the effect of prematurity on the solubility of volatile anesthetics in blood, the authors measured the blood/gas partition coefficients of sevoflurane, isoflurane, and halothane and the serum concentrations of albumin, globulin, cholesterol, and triglycerides in umbilical venous blood from ten preterm and eight full-term neonates and in venous blood from eight fasting adult volunteers. The authors found that the blood/gas partition coefficient of sevoflurane did not differ significantly among the three age groups. The partition coefficients of isoflurane and halothane in preterm neonates did not differ significantly from those in full-term neonates. However, the partition coefficients of both anesthetics in neonates were significantly less than those in adults. The blood/gas partition coefficients of the three volatile anesthetics in preterm neonates did not change significantly with gestational age. The blood/gas partition coefficients of sevoflurane, isoflurane and halothane for all three age groups combined correlated only with the serum concentration of cholesterol. The authors conclude that the blood/gas partition coefficients of isoflurane, halothane, and sevoflurane in preterm neonates are similar to those in full term neonates and that gestational age does not significantly affect the blood/gas solubility.     

The effect of temperature on solubility of volatile anesthetics in human tissues.

Hypothermia often occurs during surgery, a factor influencing anesthetic pharmacokinetics through its influence on solubility. Information on the tissue solubility of volatile anesthetics under hypothermia is limited. The present study supplies this information for the solubility of volatile anesthetics in human tissues. Tissue specimens of brain, heart, liver, muscle, and fat were obtained from 10 postmortem males (27 +/- 8 yr). Tissue/gas partition coefficients of desflurane, sevoflurane, enflurane, isoflurane and halothane were measured at 37 degrees C, 33 degrees C, 29 degrees C, 25 degrees C, 21 degrees C, and 17 degrees C. For each given tissue, the order of tissue/gas partition coefficient was halothane >enflurane >isoflurane >sevoflurane >desflurane. Tissue/gas partition coefficients at 37 degrees C differed significantly (P < 0.05) across drugs, except that liver/gas partition coefficients for isoflurane and enflurane did not differ. The logarithm of all tissue/gas partition coefficients increased linearly with decreasing temperature (P < 0.05). In conclusion, hypothermia increases tissue/gas partition coefficients of volatile anesthetics. The increases are proportional to those for blood/gas partition coefficients, and therefore tissue/blood partition coefficients will not change during hypothermic conditions. Implications: Volatile anesthetics are often used during hypothermic conditions, and tissue solubility of volatile anesthetics is an important determinant for the wash-in and washout of the anesthetics in tissue. Tissue/gas partition coefficients during hypothermia have implications for understanding the pharmacokinetics of volatile anesthetics at hypothermic conditions.     

Solubility of desflurane (I-653), sevoflurane, isoflurane, and halothane in human blood

The blood/gas partition coefficients for the new volatile anesthetic agent desflurane (I-653), sevoflurane, isoflurane, and halothane were determined, simultaneously, in 8 human volunteers to compare the solubilities of these agents in blood. The blood/gas partition coefficient for desflurane [0.49 +/- 0.03 (mean +/- SD)] was smallest, followed by sevoflurane (0.62 +/- 0.04), isoflurane (1.27 +/- 0.06), and halothane (2.46 +/- 0.09). Differences among the anesthetic agents were significant (P less than 0.001). The results of this study confirm that among these agents the solubility of desflurane in human blood is the smallest. The results suggest that the washin and washout of desflurane will be more rapid than that of sevoflurane, isoflurane, and halothane, and the washin and washout of sevoflurane will be more rapid than that of isoflurane and halothane.     

Pharmacokinetics of desflurane, sevoflurane, isoflurane, and halothane in pigs

We tested the prediction that the alveolar washin and washout, tissue time constants, and pulmonary recovery (volume of agent recovered during washout relative to the volume taken up during washin) of desflurane, sevoflurane, isoflurane, and halothane would be defined primarily by their respective solubilities in blood, by their solubilities in tissues, and by their metabolism. We concurrently administered approximately one-third the MAC of each of these anesthetics to five young female swine and determined (separately) their solubilities in pig blood and tissues. The blood/gas partition coefficient of desflurane (0.35 +/- 0.02) was significantly smaller (P less than 0.01) than that of sevoflurane (0.45 +/- 0.02), isoflurane (0.94 +/- 0.05), and halothane (2.54 +/- 0.21). Tissue/blood partition coefficients of desflurane and halothane were smaller than those for the other two anesthetics (P less than 0.05) for all tissue groups. As predicted from their blood solubilities, the order of washin and washout was desflurane, sevoflurane, isoflurane, and halothane (most to least rapid). As predicted from tissue solubilities, the tissue time constants for desflurane were smaller than those for sevoflurane, isoflurane, and halothane. Recovery (normalized to that of isoflurane) of the volume of anesthetic taken up was significantly greater (P less than 0.05) for desflurane (93% +/- 7% [mean +/- SD]) than for halothane (77% +/- 6%), was not different from that of isoflurane (100%), but was less than that for sevoflurane (111% +/- 17%). The lower value for halothane is consistent with its known metabolism, but the lower (than sevoflurane) value for desflurane is at variance with other presently available data for their respective biodegradations.     

Solubility of I-653, sevoflurane, isoflurane, and halothane in human tissues

Tissue/blood partition coefficients of anesthetics are important indicators of the rate of tissue wash-in and wash-out, and wash-in and wash-out are determinants of the rates of induction of and recovery from anesthesia. In the present study of human tissues, we found that the tissue/blood partition coefficients (for brain, heart, liver, kidney, muscle, and fat) for the new anesthetic I-653 were smaller than those for isoflurane, sevoflurane, and halothane (anesthetics listed in order of increasing tissue/blood partition coefficients). For example, the respective brain/blood partition coefficients were 1.29 +/- 0.05 (mean +/- SD); 1.57 +/- 0.10; 1.70 +/- 0.09; and 1.94 +/- 0.17. This indicates that induction of and recovery from anesthesia with I-653 should be more rapid than with the other agents. The finding of a lower tissue/blood partition coefficient for I-653 parallels the previous finding of a lower blood/gas partition coefficient.     

Age and the solubility of volatile anesthetics in ovine tissues

To determine the effect of age on the solubility of volatile anesthetics in tissues, we measured the blood/gas and tissue/gas partition coefficients of isoflurane, enflurane, halothane, and methoxyflurane in vitro at 37 degrees C in newborn lambs and postpartum adult sheep. The tissue specimens examined were brain, heart, liver, kidney, muscle, and fat. Hematocrit and serum concentrations of albumin, globulin, cholesterol, and triglycerides were measured. The blood/gas partition coefficients, hematocrit, and the serum concentrations of albumin, globulin, cholesterol, and triglycerides in the newborn lambs did not differ from those in the adult sheep. The tissue/blood partition coefficients [the ratio of (tissue/gas)/(blood/gas)] in newborn lambs were 28% [mean value for the four anesthetics] less than those in the adults. The tissue/blood partition coefficients for enflurane and methoxyflurane in newborn tissues were significantly less (P less than 0.05) than those for halothane and isoflurane. We conclude that the blood/gas partition coefficients in sheep do not change significantly with age, and that the time required for equilibration of volatile anesthetics (particularly enflurane and methoxyflurane) in newborn tissues is probably less than in adult sheep.     

Solubility of volatile anesthetics in plasma substitutes,albumin, intravenous fat emulsions,perfluorochemical emulsion,and aqueous solutions

Using the gas chromatographic headspace sampling technique, we determined the solubility of volatile anesthetics (halothane, enflurane, isoflurane, and sevoflurane) in plasma substitutes, albumin solution, intravenous fat emulsions, perfluorochemical FC-43 emulsion, and aqueous solutions at 37°C. The order of magnitude of λ value (liquid/gas partition coefficients) was halothane >enflurane>isoflurane> sevoflurane in all the parenteral infusion fluids except the perfluorochemical emulsion (FC-43). The FC-43/gas partition coefficients of the volatile anesthetics were almost the same at 5.5. The partition coefficients were affected by the osmolarity of solutions, hydrophobicity, and the structure of solutes. Also, the blood/gas partition coefficients in intravenous fat emulsions and FC-43 were calculated. It is suggested that fluid therapy, especially with intravenous fat emulsions or FC-43, may influence the blood/gas partition coefficients of anesthetics, and affect the induction of anesthesia.     

The partial pressure of isoflurane or halothane does not affect their solubility in rabbit blood or brain or human brain: inhaled anesthetics obey Henry's Law

We tested the possibility that the solubility of halothane or isoflurane in rabbit blood or human or rabbit brain does not obey Henry's Law. We measured the blood/gas and brain/gas partition coefficients for both anesthetics at approximately 1 MAC and at 0.01 MAC at 37 degrees C. The partition coefficients determined at the high vs low partial pressures did not differ. We conclude that the solution of isoflurane and halothane in blood and brain obeys Henry's Law.     

Effect of age on the solubility of volatile anesthetics in human tissues

To determine the effect of age on the solubility of volatile anesthetics in human tissues, the authors measured the solubilities of isoflurane, enflurane, halothane, and methoxyflurane in vitro at 37 degrees C in 35 postmortem human tissue specimens. Specimens were taken from neonates, and young (20-50 yr), middle-aged (50-70 yr), and elderly adults (greater than 70 yr). Brain/gas, heart/gas, and liver/gas partition coefficients for all four anesthetics increased significantly (P less than 0.05) between birth and adulthood, although brain/gas partition coefficients in young adults tended to be higher than those in middle-aged and elderly adults. Heart/gas and liver/gas partition coefficients tended to increase with aging. Muscle/gas partition coefficients for the four anesthetics increased linearly with age. Fat/gas partition coefficients did not change significantly with age. Tissue/blood solubilities for the four anesthetics were of the same order of magnitude for a given tissue and age group. Tissue/blood solubilities for enflurane were 30% lower than those for isoflurane in the same tissue and age group. In summary: the solubility of volatile anesthetics in human tissues increases with age; the lower solubility of anesthetics in neonates partially explains the more rapid increase of alveolar and tissue anesthetic partial pressures in neonates; despite the higher blood solubility of enflurane, its lower tissue solubility may explain a rate of recovery comparable with that of isoflurane.     

Solubility of volatile anesthetics in bovine white matter, cortical gray matter, thalamus, hippocampus, and hypothalamic area

Although known for whole brain, values are lacking for solubilities of modern volatile anesthetics in specific brain regions. Some regions should differ from others (e.g., gray matter versus white matter) because they differ in lipid content and because potent inhaled anesthetics are lipophilic. In the present report, we examined this issue in bovine brain, finding that white matter/gas partition coefficients are 1.6 (desflurane) to 2.4 (halothane) times larger than gray matter/gas partition coefficients, with values for isoflurane and sevoflurane lying between these at 1.9. Values for thalamus/gas, hypothalamic area/gas, and hippocampal/gas partition coefficients lie between those for gray and white matter. These data may be useful in defining the parts of the brain involved with return to consciousness during recovery from anesthesia.