Meliones J N, Moler F W, Custer J R, Snyder S J, Dekeon M K, Donn S M, Chapman R A, Bartlett R H
Department of Pediatrics, C.S. Mott Children's Hospital, University of Michigan Medical Center, Ann Arbor 48109-0204.
Crit Care Med. 1991 Oct;19(10):1247-51. doi: 10.1097/00003246-199110000-00006.
To prospectively document the occurrence of ionized hypocalcemia in infants and children treated with extracorporeal membrane oxygenation (ECMO), to determine if the type of calcium salt (calcium chloride or gluconate) used in priming the ECMO circuit affected ionized calcium, to determine if ionized calcium concentrations correlate with total calcium, protein, albumin, or total magnesium values, and to determine if the hypotension usually observed after ECMO initiation correlates with low circulating ionized calcium concentrations.
Prospective study.
Pediatric ICU and neonatal ICU.
Sixteen neonatal and three pediatric patients who were started on ECMO for cardiopulmonary support.
The ECMO circuit was primed in a standardized manner, 100 mg of calcium gluconate was added in group 1 patients and 100 mg of calcium chloride was added in group 2 patients.
Ionized calcium was measured from the circuit before initiation of ECMO and from the patient before, and then 5, 10, 15, 30, 60, 120, and 240 mins after initiation of ECMO. Total calcium and ionized calcium concentrations were measured simultaneously every 6 hrs. Serum total protein, albumin, magnesium, and ionized calcium values were measured from blood samples collected simultaneously twice daily.
A significant decrease in the mean serum ionized calcium value occurred 5 mins after the initiation of ECMO in both groups, p less than .001. The ionized calcium value remained significantly decreased until 30 mins after the initiation of ECMO. There were no differences between the ionized calcium concentrations obtained during priming with calcium gluconate vs. those concentrations obtained with calcium chloride priming (p = .79). Throughout the course of ECMO, the serum ionized calcium concentrations ranged from 0.60 to 1.86 mmol/L. Poor correlations existed between circulating ionized calcium values and total calcium (r2 = .30), total protein (r2 = .20), albumin (r2 = .20), and magnesium concentrations (r2 = .10). There was a good correlation between the patients' BP and ionized calcium concentrations after bypass was initiated (r2 = .87).
Our data demonstrate that ionized hypocalcemia is a frequent occurrence after the initiation of ECMO. Since there is a poor correlation between ionized calcium and total calcium, ionized calcium concentrations should be measured directly in these patients.
前瞻性记录接受体外膜肺氧合（ECMO）治疗的婴幼儿发生离子化低钙血症的情况，确定在ECMO回路预充中使用的钙盐类型（氯化钙或葡萄糖酸钙）是否会影响离子化钙，确定离子化钙浓度是否与总钙、蛋白质、白蛋白或总镁值相关，以及确定ECMO启动后通常观察到的低血压是否与循环离子化钙浓度低相关。
前瞻性研究。
儿科重症监护病房和新生儿重症监护病房。
16例新生儿和3例儿科患者开始接受ECMO进行心肺支持。
以标准化方式对ECMO回路进行预充，第1组患者添加100mg葡萄糖酸钙，第2组患者添加100mg氯化钙。
在ECMO启动前从回路以及患者开始前测量离子化钙，然后在ECMO启动后5、10、15、30、60、120和240分钟测量。每6小时同时测量总钙和离子化钙浓度。每天两次同时采集血样测量血清总蛋白、白蛋白、镁和离子化钙值。
两组在ECMO启动后5分钟时平均血清离子化钙值均显著下降，p小于0.001。离子化钙值在ECMO启动后30分钟内一直显著下降。用葡萄糖酸钙预充期间获得的离子化钙浓度与用氯化钙预充获得的浓度之间无差异（p = 0.79）。在整个ECMO过程中，血清离子化钙浓度范围为0.60至1.86mmol/L。循环离子化钙值与总钙（r2 = 0.30）、总蛋白（r2 = 0.20）、白蛋白（r2 = 0.20）和镁浓度（r2 = 0.10）之间相关性较差。旁路启动后患者血压与离子化钙浓度之间存在良好相关性（r2 = 0.87）。
我们的数据表明，离子化低钙血症在ECMO启动后经常发生。由于离子化钙与总钙之间相关性较差，这些患者应直接测量离子化钙浓度。
