Catinella F P, Cunningham J N, Strauss E D, Adams P X, Laschinger J C, Spencer F C
J Cardiovasc Surg (Torino). 1983 Nov-Dec;24(6):593-602.
Twenty patients undergoing cardiac surgery were studied to examine variations in total and ionized serum calcium and urine calcium during cardiopulmonary bypass. Serial samples of blood and urine were analyzed during bypass using a highly specific calcium electrode to determine the effects of hemodilution, various pharmacologic agents, and transfusions of citrated blood. Calcium chloride was routinely added to the crystalloid pump prime (400 mgs/L) and also administered when additional blood or crystalloid were infused. An average of 4.8 +/- .50 grams of calcium chloride was given per procedure. After induction of general anesthesia with nitrous oxide and Halothane, total serum calcium decreased from 10.0 +/- 0.3 to 8.5 +/- 0.8 mg% (p less than 0.05). Following heparinization, ionized calcium decreased from 4.2 +/- .08 to 3.9 +/- 12 mg% (p less than 0.05). Ionized calcium was not affected by reversal of heparin with Protamine. Following institution of cardiopulmonary bypass the ratio of ionized to total calcium declined about 13.4% (0.49 vs. 0.43). This ratio did not change during bypass but returned to normal immediately post-perfusion. Urinary calcium excretion averaged 1.9 +/- 0.6 mg/min and could not be implicated as a cause of hypocalcemia during bypass. Post-perfusion, ionized serum calcium rose 1.3 +/- .01 mg% for each gram of exogenously administered calcium chloride (p less than 0.05). From these observations, we conclude: (1) ionized and total serum calcium levels decreased significantly following institution of cardiopulmonary bypass alone, presumably as a result of hemodilution from the crystalloid pump prime and addition of citrated blood products; (2) induction of general anesthesia alone with nitrous oxide and Halothane is associated with a significant decrease in total serum calcium; (3) ionized calcium declined following heparinization but is unchanged by Protamine administration; (4) changes in total and ionized serum calcium are unaffected by urinary excretion during bypass; (5) exogenously administered calcium chloride significantly increases serum ionized calcium and these changes are inversely related to the circulating pool of calcium; (6) current protocols for administration of exogenous calcium chloride during bypass may result in insufficient levels of ionized calcium and we have adopted measures to correct these deficiencies, when indicated.
对20例接受心脏手术的患者进行了研究，以检查体外循环期间血清总钙、离子钙和尿钙的变化。在体外循环期间，使用高特异性钙电极对血液和尿液的系列样本进行分析，以确定血液稀释、各种药物制剂以及输注枸橼酸盐血的影响。氯化钙常规添加到晶体泵预充液中（400mg/L），并且在输注额外的血液或晶体液时也予以给药。每次手术平均给予4.8±0.50克氯化钙。在用氧化亚氮和氟烷诱导全身麻醉后，血清总钙从10.0±0.3降至8.5±0.8mg%（p<0.05）。肝素化后，离子钙从4.2±0.08降至3.9±0.12mg%（p<0.05）。离子钙不受鱼精蛋白逆转肝素的影响。开始体外循环后，离子钙与总钙的比值下降约13.4%（0.49对0.43）。该比值在体外循环期间没有变化，但在灌注后立即恢复正常。尿钙排泄平均为1.9±0.6mg/min，在体外循环期间不能认为是低钙血症的原因。灌注后，每给予1克外源性氯化钙，血清离子钙升高1.3±0.01mg%（p<0.05）。从这些观察结果中，我们得出结论：（1）仅开始体外循环后，血清离子钙和总钙水平显著下降，推测是由于晶体泵预充液的血液稀释和添加枸橼酸盐血制品所致；（2）仅用氧化亚氮和氟烷诱导全身麻醉与血清总钙显著降低有关；（3）肝素化后离子钙下降，但鱼精蛋白给药对其无影响；（4）体外循环期间血清总钙和离子钙的变化不受尿排泄的影响；（5）外源性给予氯化钙显著增加血清离子钙，且这些变化与钙的循环池呈负相关；（6）目前体外循环期间给予外源性氯化钙的方案可能导致离子钙水平不足，我们已采取措施在必要时纠正这些不足。
