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. 1985 Nov;202(5):587–594. doi: 10.1097/00000658-198511000-00009

Assessment of calcium homeostasis in the critically ill surgical patient. The diagnostic pitfalls of the McLean-Hastings nomogram.

G P Zaloga, B Chernow, D Cook, R Snyder, M Clapper, J T O'Brian
PMCID: PMC1250972  PMID: 4051606

Abstract

Hypocalcemia is a common problem in critically ill surgical patients. We prospectively evaluated whether measurement of the total serum calcium (Ca) concentration or calculation of the serum ionized Ca level (by the McLean-Hastings nomogram) accurately reflects the measured serum ionized Ca level. Although 71% and 58% of 156 predominantly surgical intensive care unit (ICU) patients were hypocalcemic by the total serum Ca or calculated ionized Ca level, respectively, only 12% were hypocalcemic by directly measured serum ionized Ca measurement. The total serum Ca and calculated ionized Ca concentrations were sensitive (95% and 89%, respectively) but lacked specificity (32% and 46%, respectively) in predicting ionized hypocalcemia. Analyses of Ca binding to albumin in the serum of surgical ICU patients and normal subjects suggested that there is a circulating factor in critically ill patients that increases the binding of Ca to albumin. These observations may explain why the McLean-Hastings nomogram underestimates the protein-induced changes in serum Ca in critically ill surgical subjects. We conclude that: total serum Ca and calculated ionized Ca concentrations are poor indicators of the true serum ionized Ca status in critically ill surgical patients, and we recommend direct measurement of serum ionized Ca levels in these patients; and variability in the affinity of Ca for binding proteins in critical illness may explain the poor correlation between serum total and ionized Ca measurements.

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Selected References

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  1. BUNKER J. P., BENDIXEN H. H., MURPHY A. J. Hemodynamic effects of intravenously administered sodium citrate. N Engl J Med. 1962 Feb 22;266:372–377. doi: 10.1056/NEJM196202222660802. [DOI] [PubMed] [Google Scholar]
  2. Bristow M. R., Ginsburg R., Minobe W., Cubicciotti R. S., Sageman W. S., Lurie K., Billingham M. E., Harrison D. C., Stinson E. B. Decreased catecholamine sensitivity and beta-adrenergic-receptor density in failing human hearts. N Engl J Med. 1982 Jul 22;307(4):205–211. doi: 10.1056/NEJM198207223070401. [DOI] [PubMed] [Google Scholar]
  3. Chernow B., Smith J., Rainey T. G., Finton C. Hypomagnesemia: implications for the critical care specialist. Crit Care Med. 1982 Mar;10(3):193–196. [PubMed] [Google Scholar]
  4. Chernow B., Zaloga G., McFadden E., Clapper M., Kotler M., Barton M., Rainey T. G. Hypocalcemia in critically ill patients. Crit Care Med. 1982 Dec;10(12):848–851. doi: 10.1097/00003246-198212000-00008. [DOI] [PubMed] [Google Scholar]
  5. Chopra I. J., Solomon D. H., Teco G. N., Eisenberg J. B. An inhibitor of the binding of thyroid hormones to serum proteins is present in extrathyroidal tissues. Science. 1982 Jan 22;215(4531):407–409. doi: 10.1126/science.7058324. [DOI] [PubMed] [Google Scholar]
  6. Das J. B., Eraklis A. J., Filler R. M., Adams J. G. Serum ionic calcium: changes with large volume blood transfusions in the infant. J Pediatr Surg. 1971 Jun;6(3):333–338. doi: 10.1016/0022-3468(71)90475-1. [DOI] [PubMed] [Google Scholar]
  7. Denlinger J. K., Nahrwold M. L., Gibbs P. S., Lecky J. H. Hypocalcaemia during rapid blood transfusion in anaesthetized man. Br J Anaesth. 1976 Oct;48(10):995–1000. doi: 10.1093/bja/48.10.995. [DOI] [PubMed] [Google Scholar]
  8. Fenton J. J., Jones M., Hartford C. E. Calcium fractions in serum of patients with thermal burns. J Trauma. 1983 Oct;23(10):863–866. doi: 10.1097/00005373-198310000-00002. [DOI] [PubMed] [Google Scholar]
  9. Finton C. K., Bjorkland S., Zaloga G. P., Uddin D. E., Chernow B. Gentamicin-induced hypomagnesemia. Am Surg. 1983 Nov;49(11):576–578. [PubMed] [Google Scholar]
  10. Ginsburg R., Esserman L. J., Bristow M. R. Myocardial performance and extracellular ionized calcium in a severely failing human heart. Ann Intern Med. 1983 May;98(5 Pt 1):603–606. doi: 10.7326/0003-4819-98-5-603. [DOI] [PubMed] [Google Scholar]
  11. Griner P. F., Mayewski R. J., Mushlin A. I., Greenland P. Selection and interpretation of diagnostic tests and procedures. Principles and applications. Ann Intern Med. 1981 Apr;94(4 Pt 2):557–592. [PubMed] [Google Scholar]
  12. Henrich W. L., Hunt J. M., Nixon J. V. Increased ionized calcium and left ventricular contractility during hemodialysis. N Engl J Med. 1984 Jan 5;310(1):19–23. doi: 10.1056/NEJM198401053100105. [DOI] [PubMed] [Google Scholar]
  13. Hinkle J. E., Cooperman L. H. Serum ionized calcium changes following citrated blood transfusion in anaesthetized man. Br J Anaesth. 1971 Dec;43(12):1108–1112. doi: 10.1093/bja/43.12.1108. [DOI] [PubMed] [Google Scholar]
  14. Howland W. S., Schweizer O., Jascott D., Ragasa J. Factors influencing the ionization of calcium during major surgical procedures. Surg Gynecol Obstet. 1976 Dec;143(6):895–900. [PubMed] [Google Scholar]
  15. Killen D. A., Grogan E. L., 2nd, Gower R. E., Collins H. A. Response of canine plasma-ionized calcium and magnesium to the rapid infusion of acid-citrate-dextrose (ACD) solution. Surgery. 1971 Nov;70(5):736–743. [PubMed] [Google Scholar]
  16. Killen D. A., Grogan E. L., Gower R. E., Collins I. S., Collins H. A. Effect of ACD blood prime on plasma calcium and magnesium. Ann Thorac Surg. 1972 Apr;13(4):371–380. doi: 10.1016/s0003-4975(10)64869-2. [DOI] [PubMed] [Google Scholar]
  17. Kukreja S. C., Hargis G. K., Bowser E. N., Henderson W. J., Fisherman E. W., Williams G. A. Role of adrenergic stimuli in parathyroid hormone secretion in man. J Clin Endocrinol Metab. 1975 Mar;40(3):478–481. doi: 10.1210/jcem-40-3-478. [DOI] [PubMed] [Google Scholar]
  18. Ladenson J. H., Bowers G. N., Jr Free calcium in serum. I. Determination with the ion-specific electrode, and factors affecting the results. Clin Chem. 1973 Jun;19(6):565–574. [PubMed] [Google Scholar]
  19. Ladenson J. H., Bowers G. N., Jr Free calcium in serum. II. Rigor of homeostatic control, correlations with total serum calcium, and review of data on patients with disturbed calcium metabolism. Clin Chem. 1973 Jun;19(6):575–582. [PubMed] [Google Scholar]
  20. Ladenson J. H., Lewis J. W., Boyd J. C. Failure of total calcium corrected for protein, albumin, and pH to correctly assess free calcium status. J Clin Endocrinol Metab. 1978 Jun;46(6):986–993. doi: 10.1210/jcem-46-6-986. [DOI] [PubMed] [Google Scholar]
  21. Ladenson J. H., Lewis J. W., Boyd J. C. Failure of total calcium corrected for protein, albumin, and pH to correctly assess free calcium status. J Clin Endocrinol Metab. 1978 Jun;46(6):986–993. doi: 10.1210/jcem-46-6-986. [DOI] [PubMed] [Google Scholar]
  22. Moore E. W. Ionized calcium in normal serum, ultrafiltrates, and whole blood determined by ion-exchange electrodes. J Clin Invest. 1970 Feb;49(2):318–334. doi: 10.1172/JCI106241. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Pedersen K. O. Protein-bound calcium in human serum. Quantitative examination of binding and its variables by a molecular binding model and clinical chemical implications for measurement of ionized calcium. Scand J Clin Lab Invest. 1972 Nov;30(3):321–329. doi: 10.3109/00365517209084297. [DOI] [PubMed] [Google Scholar]
  24. Pittinger C., Chang P. M., Faulkner W. Serum ionized calcium: some factors influencing its level. South Med J. 1971 Oct;64(10):1211–1215. doi: 10.1097/00007611-197110000-00011. [DOI] [PubMed] [Google Scholar]
  25. Porter D. L., Ledgerwood A. M., Lucas C. E., Harrigan C. M. Effect of calcium infusion on heart function. Am Surg. 1983 Jul;49(7):369–372. [PubMed] [Google Scholar]
  26. Robertson W. G. Measurement of ionised calcium in body fluids-a review. Ann Clin Biochem. 1976 Nov;13(6):540–548. doi: 10.1177/000456327601300156. [DOI] [PubMed] [Google Scholar]
  27. Rude R. K., Oldham S. B., Sharp C. F., Jr, Singer F. R. Parathyroid hormone secretion in magnesium deficiency. J Clin Endocrinol Metab. 1978 Oct;47(4):800–806. doi: 10.1210/jcem-47-4-800. [DOI] [PubMed] [Google Scholar]
  28. Rude R. K., Oldham S. B., Singer F. R. Functional hypoparathyroidism and parathyroid hormone end-organ resistance in human magnesium deficiency. Clin Endocrinol (Oxf) 1976 May;5(3):209–224. doi: 10.1111/j.1365-2265.1976.tb01947.x. [DOI] [PubMed] [Google Scholar]
  29. Seamonds B., Towfighi J., Arvan D. A. Determination of ionized calcium in serum by use of an lon-selective electrode. I. Determination of normal values under physiologic conditions, with comments on the effects of food ingestion and hyperventilation. Clin Chem. 1972 Feb;18(2):155–160. [PubMed] [Google Scholar]
  30. Sherwood J. K., Ackroyd F. W., Garcia M. Effect of cimetidine on circulating parathyroid hormone in primary hyperparathyroidism. Lancet. 1980 Mar 22;1(8169):616–620. doi: 10.1016/s0140-6736(80)91117-4. [DOI] [PubMed] [Google Scholar]
  31. Sorell M., Rosen J. F. Ionized calcium: serum levels during symptomatic hypocalcemia. J Pediatr. 1975 Jul;87(1):67–70. doi: 10.1016/s0022-3476(75)80070-9. [DOI] [PubMed] [Google Scholar]
  32. Sorell M., Rosen J. F. Ionized calcium: serum levels during symptomatic hypocalcemia. J Pediatr. 1975 Jul;87(1):67–70. doi: 10.1016/s0022-3476(75)80070-9. [DOI] [PubMed] [Google Scholar]
  33. Stulz P. M., Scheidegger D., Drop L. J., Lowenstein E., Laver M. B. Ventricular pump performance during hypocalcemia: clinical and experimental studies. J Thorac Cardiovasc Surg. 1979 Aug;78(2):185–194. [PubMed] [Google Scholar]
  34. Szyfelbein S. K., Drop L. J., Martyn J. A. Persistent ionized hypocalcemia in patients during resuscitation and recovery phases of body burns. Crit Care Med. 1981 Jun;9(6):454–458. doi: 10.1097/00003246-198106000-00004. [DOI] [PubMed] [Google Scholar]
  35. Taylor B., Sibbald W. J., Edmonds M. W., Holliday R. L., Williams C. Ionized hypocalcemia in critically ill patients with sepsis. Can J Surg. 1978 Sep;21(5):429–433. [PubMed] [Google Scholar]
  36. Zaloga G. P., Chernow B., Pock A., Wood B., Zaritsky A., Zucker A. Hypomagnesemia is a common complication of aminoglycoside therapy. Surg Gynecol Obstet. 1984 Jun;158(6):561–565. [PubMed] [Google Scholar]

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