Serum Ionized Magnesium in Premature and Term Infants

Marcus, Joseph C.; Valencia, Gloria; Altura, Bella T.; Cracco, Roger Q.; Jean-Baptiste, Dominique; Sinha, Kavita; Altura, Burton M.

doi:10.1016/s0887-8994(97)00203-8

Cited by 17 publications

(17 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Because of the small fraction in the extracellular fluid, iMg is a much better estimation of whole body magnesium. The findings in our study are in contrast to human studies that found that neonatal and infant iMg or total magnesium values are initially higher than adults and decline with time. This is postulated to be due to increased nutritional demands .…”

Section: Discussioncontrasting

confidence: 99%

Reference intervals and age‐related changes for venous biochemical, hematological, electrolytic, and blood gas variables using a point of care analyzer in 68 puppies

O'Brien

McMichael

Boedec

et al. 2014

J Vet Emergen Crit Care

View full text Add to dashboard Cite

show abstract

Section: Discussioncontrasting

confidence: 99%

Reference intervals and age‐related changes for venous biochemical, hematological, electrolytic, and blood gas variables using a point of care analyzer in 68 puppies

O'Brien

McMichael

Boedec

et al. 2014

J Vet Emergen Crit Care

View full text Add to dashboard Cite

show abstract

“…In another study aiming to determine normative data in healthy term newborns (22), IMg levels were investigated in umbilical venous blood of 30 newborns at birth and in peripheral venous blood of 32 newborns at 24 h of life, and normal ranges of IMg in both groups reportedly were between 0.4 and 0.56 mM. A reference interval for IMg of 0.41-0.69 mM was reported for 63 term newborns in a study presenting the reference values of normal serum IMg in healthy and premature newborns during the first 72 h of life (23). In the present study including 165 term, appropriate-for-gestational age, and healthy-except for hyperbilirubinemia-newborns, mean plasma IMg levels measured during the first 10 d of life were 0.54 Ϯ 0.12 mM and 0.49 Ϯ 0.1 mM in the total study group and in the cases with moderate hyperbilirubinemia, respectively.…”

Section: Discussionmentioning

confidence: 94%

“…Although these levels are similar and close to those in the previously published studies on newborns, the relatively wider ranges in our study may have resulted from the mean postnatal age (156.1 Ϯ 46.5 h) of the cases, considering physiologic changes in Mg levels during the first week of life. Previously published neonatal IMg studies (22)(23)(24) have been conducted in exclusively healthy newborns during the first 24 -72 h of life. The high serum bilirubin levels also may have contributed to greater variability of IMg; high IMg levels (0.6 Ϯ 0.12 mM) in the group of severe hyperbilirubinemia in our study further supports this hypothesis.…”

Section: Discussionmentioning

confidence: 99%

“…Comparisons between these two groups were performed with independent sample t test. Comparisons and assessment of the relationship between the plasma IMg levels above the critical level of 0.69 mM, which has reportedly been the upper limit of normal in healthy term newborns (22)(23)(24), and the critical serum bilirubin levels of significant (Ն205 M) (21) and severe (Ն290 M) (25, 26) hyperbilirubinemia were made using 2 test. Parameters with nominal values such as sex and mode of delivery were compared with 2 test.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Evaluation of Plasma Ionized Magnesium Levels in Neonatal Hyperbilirubinemia

et al. 2004

View full text Add to dashboard Cite

Plasma levels of ionized magnesium (IMg) measured by ion-selective electrode were investigated in neonatal hyperbilirubinemia by comparing the newborns with (Ն205 M) and without (Ͻ205 M) significant hyperbilirubinemia (groups of severe and moderate hyperbilirubinemia, respectively). Serum bilirubin, plasma IMg, and ionized calcium (ICa) levels were determined in 165 healthy term newborns with nonhemolytic indirect hyperbilirubinemia during the first 10 d of life. Mean serum bilirubin, plasma IMg, and ICa levels were 200.1 Ϯ 126.5 M, 0.54 Ϯ 0.12 mM, and 1.15 Ϯ 0.12 mM, respectively, in 165 newborns whose mean postnatal age was 156.1 Ϯ 46.5 h, and there was a significant positive correlation between the mean serum bilirubin and plasma IMg levels (r ϭ 0.535, p Ͻ 0.001). Serum bilirubin levels (304.4 Ϯ 83.8 M versus 94.1 Ϯ 54.7 M) and plasma IMg levels (0.6 Ϯ 0.12 mM versus 0.49 Ϯ 0.1 mM) were significantly higher and plasma ICa levels (1.13 Ϯ 0.12 mM versus 1.18 Ϯ 0.12 mM) were significantly lower in the group of severe hyperbilirubinemia (n ϭ 83) when compared with the group with moderate hyperbilirubinemia (n ϭ 82). Seventeen of the 83 cases of severe hyperbilirubinemia had IMg levels above the normal range (Ն0.69 mM), whereas none of the 82 cases of moderate hyperbilirubinemia had elevated IMg levels. Fifteen of the 17 with high IMg levels had bilirubin levels Ͼ290 M. Results of the present study suggest that increase in plasma IMg may be due to extracellular movement of Mg, a principally intracellular ion, resulting from generalized cellular injury including neurons and erythrocytes. Considering neuroprotective functions and beneficial effects of Mg ion in improving neurologic outcome, we also may speculate the possibility of a neuroprotective role or a compensatory mechanism in IMg increase against emerging toxicity risk of increasing serum bilirubin levels. Deposition of unbound bilirubin or its acid form in the neuron membrane causes permanent neuronal injury with a distinctive regional topography throughout the CNS. Considering the affinity of bilirubin molecule to phospholipids of the plasma membrane (1-4), the sequence of membrane events initiated by bilirubin molecules damages all adjacent membrane-bound enzymes and receptors. However, distant plasma membrane structures such as N-methyl-D-aspartate (NMDA) receptor/ion channel complex located within neuronal membranes on the synaptic surface of neurons are disrupted as well. Increased and prolonged activation of NMDA receptor as in perinatal asphyxia and hypoxic ischemic encephalopathy (HIE) results in brain cell injury despite its physiologic roles in brain plasticity; neuronal growth; synaptogenesis; and development of learning, memory, and vision. However, it has been shown in newborn piglets that bilirubin also increases activation of the NMDA receptor by modifying its binding characteristics, increases the receptor's affinity for NMDA receptor antagonists, and thus results in neuronal injury (5). Bilirubin-induced neurotoxicity may share common featu...

show abstract

“…Clinical signs of hypomagnesemia lag considerably behind falling total serum levels. Therefore, early treatment of serum Mg changes may be important in preventing or reducing clinical dysfunction [71]. Table 5 suggests that once TMg drops near the lower limit of its reference range (~0.75 mmol·l Ϫ1 ), the frequency of atrial and supraventricular arrhythmias increases dramatically.…”

Section: Monitoring Tmg As An Approach To Guiding Mg Therapymentioning

confidence: 99%

Monitoring magnesium to guide magnesium therapy for heart surgery

Shirey¹

2004

Journal of Anesthesia

View full text Add to dashboard Cite

ionized Mg (iMg). Measurement of TMg requires the isolation of plasma (centrifugation of blood sample) or serum (clotting and centrifugation of blood sample). Measurement is made by atomic absorption spectrophotometry or colorimetry. Reference values for plasma and serum TMg typically range from 0.66 to 1.07 mmol·l Ϫ1 . There is virtually no correlation between plasma/serum TMg and intracellular TMg.Ionized magnesium (iMg ϭ Mg 2ϩ ) represents the activity of unbound Mg in whole blood plasma, plasma, and/or serum. It is the physiologically active Mg fraction, i.e., the fraction to which tissues respond. Reference values typically range from 0.45 to 0.62 mmol·l Ϫ1 . The fact that it can be measured in a whole blood sample by electrode produces a rapid result (Ͻ150 s) on a small sample (Ͻ200 µl). A rapid result can be very helpful for patients (1) with arrhythmia, (2) with changes in cardiac output, (3) receiving cardiovascular drugs, (4) sustaining hypoxic damage, and (5) receiving Mg therapy. Blood plasma iMg correlates with intracellular iMg and therefore represents a better indicator of Mg status than TMg. It is typically 70% of the TMg value, but varies with the protein and small ligand concentrations in the blood. The iMg value may be substantially less than 70% of the TMg value in critically ill patients where binding ligand concentrations (heparin, citrate, lactate, phosphate, bicarbonate, etc.) have increased.Comparisons of iMg to TMg were illustrated in nine clinical settings (hypertension, acute myocardial infarction, head trauma, noninsulin-dependent diabetes, stroke, pregnancy, ischemic heart disease, cyclosporin recipients, and asthma) [3]. Ionized magnesium was found to be a better indicator of disease than TMg. In summary, iMg (1) represents the physiologically important Mg measurement, (2) is a better indicator of disease than TMg, and (3) is a more rapid measurement.The literature should be interpreted with caution. Frequently, if not generally, the Mg values reported in

show abstract

Serum Ionized Magnesium in Premature and Term Infants

Cited by 17 publications

References 27 publications

Reference intervals and age‐related changes for venous biochemical, hematological, electrolytic, and blood gas variables using a point of care analyzer in 68 puppies

Reference intervals and age‐related changes for venous biochemical, hematological, electrolytic, and blood gas variables using a point of care analyzer in 68 puppies

Evaluation of Plasma Ionized Magnesium Levels in Neonatal Hyperbilirubinemia

Monitoring magnesium to guide magnesium therapy for heart surgery

Contact Info

Product

Resources

About