Neonatal Intensive Care Drug Manual

Measured Ca (mmol/L) + (40 – albumin (g/L) x 0.025)

Recommended mineral intake:

One mmol of calcium (Ca) equates to 40 mg calcium and 1 mmol of phosphorus equates to 31 mg phosphorus (P).[2] A 1:1 Ca:P molar ratio is equal to 1.3: 1 weight (mg) ratio. Transplacental Ca and P delivery to the fetus occurs actively against a concentration gradient and is greatest after the 24th gestational week. It is estimated that 80% of mineral accretion occurs in the 3rd trimester of pregnancy.[3] The average accretion rates during the last 3 months of pregnancy are 3 mmol/kg/day of Ca and 1.9 mmol/kg/day of P.[4]
For prevention and treatment of metabolic bone disease in premature infants, the goal is not only to maintain normal serum levels but also mimic in utero bone accretion rates for calcium and phosphorus.[5] The recommended calcium intake is 150 to 220 mg/kg per day [3.7 to 5.5 mmol/kg/day] and phosphorus 75 to 140 mg/kg per day [2.4 to 4.5 mmol/kg/day] to provide a calcium-to-phosphorous ratio less than 2:1. Although no optimal calcium-to-phosphorous ratio is identified, a 1.5 to 1.7:1 ratio may be optimal for preterm infants.[6] There is a concern that an intake of calcium 5 mmol/kg/day may be associated with nephrocalcinosis.[7]
Infants on full feeds with multicomponent fortified human milk (or preterm formula) reach an optimal level of mineral intake with approximately 180- 220 mg/kg/day calcium and 100-130 mg/kg/day phosphorus.[5]
Oral mineral supplementation: A single RCT in 40 premature human milk fed infants compared oral calcium gluconate 10% 5ml/kg/day (45mg/kg/day of elemental divided 8 hourly), potassium phosphate 17% 1 ml/kg/day (24 mg/kg/day divided 12-hourly) and vitamin D 400 U daily versus a control group that received only vitamin D 400 U daily. Although serum alkaline phosphatase concentration was reduced in the group receiving supplementation at six weeks postnatal age, the difference is unlikely to be of clinical significance.[8, 9] A second control study compared calcium intake varied from 2.5 versus 3.75 versus 5 mmol/kg/day combined with phosphate 2.5 mmol/kg/day. Low calcium intake was associated with raised alkaline phosphatase. High calcium intake was associated with nephrocalcinosis.[7] Conclusion: A calcium intake of 3.75 mmol/kg/day in combination with phosphate 2.5 mmol/kg/day is sufficient for adequate bone mineralization with a low level of side effects.[7] Further trials of mineral supplementation are not recommended as supplementation with multicomponent human milk fortifiers is now usual.[8]

Optimising mineral supplementation: In infants with mineral deficiency serum calcium is protected by increased parathyroid hormone so is not useful for optimising intake. Reaching target mineral intakes through optimised use of multicomponent human milk fortifiers for enterally fed infants lowers the probability of development of metabolic bone disease in preterm infants.[10] For infants with hypophosphatemia, phosphorus supplementation can be adjusted to reach a target serum phosphorus of >5.5 mg/dl [1.8 mmol/L).[5] An alternative method to optimise mineral intake is to supplement calcium and phosphate with the goal of achieving a slight surplus of supply (SSS).[11] In infants not on diuretics or methylxanthines, this is achieved by regular adjustments to mineral intake with a goal of achieving a slight excess of urinary mineral excretion: Urinary calcium ≥ 1.2mmol/L and phosphate ≥0.4 mmol/L.[11-13]

Hypocalcaemia may be defined as a serum total calcium concentration <1.875 mmol/L (7.5 mg/dL) or ionized calcium < 1.2 mmol/L.[1] Calcium concentrations decrease transiently after birth.[14-16] Early neonatal hypocalcaemia occurs within the first 3 days of life and is common in premature infants with 26% to 50% having levels < 1.75 mmol/L (7 mg/dL).[14-16] Most infants will be asymptomatic, with hypocalcaemia detected only on routine chemistries. They may present with symptoms of neuromuscular irritability including tremulousness, tetany, exaggerated startle response, seizures and laryngospasm, and nonspecific symptoms such as apnea.[1, 15]

Treatment of hypocalcaemia: In normocalcaemic infants, a randomised trial of calcium chloride 10% (2.5 mg/kg) vs calcium gluconate 10% (7.5 mg/kg) reported an equal effect on calcium concentrations.[17] However, in 49 critically ill, hypocalcaemic infants (age 1 day to 17 years), calcium chloride 0.136 mEq/kg per dose resulted in a greater increase in ionised calcium and blood pressure than calcium gluconate 0.136 mEq/kg per dose. The group receiving calcium chloride had an increase in MAP of nearly 6 mm Hg (p <0.05). No change in blood pressure was seen in the group receiving calcium gluconate.[18] In 104 newborns with late symptomatic hypocalcaemia after artificial feeding with a full-cream evaporated milk were randomly allocated to calcium gluconate 10% 10 ml orally vs phenobarbitone 75 mg 6-hourly orally for 48 hours vs magnesium sulphate 50% 0.2 mL/kg intramuscularly on two occasions 12 hourly. The plasma calcium levels rose in all groups, but infants treated with magnesium sulphate had higher plasma-calcium concentrations after 48 hours’ treatment and fewer convulsions during and after the treatment period.[19] Recommendation: Treatment of newborns with acute or symptomatic hypocalcaemia is accomplished best by the intravenous infusion of calcium salts - 10% calcium gluconate (9.3 mg/mL of elemental calcium) is used most commonly. In asymptomatic newborns, treatment is indicated when the total serum calcium concentration < 1.5 mmol/L (6 mg/dL) in the preterm infant and less than <1.75 mmol/L (7 mg/dL) in the term infant. Calcium supplementation can be given either by the intravenous or oral route, depending on the clinical status of the infant. [1] [Expert opinion].
Safety:

Excessive mineral intake (calcium 5 mmol/kg/day) may contribute to nephrocalcinosis.[7]

Calcium gluconate solution in glass containers contains almost 200 times more aluminium than calcium gluconate in plastic containers, due to the solution leaching aluminium from the glass. The Paediatric Medicines Expert Advisory Group recommended that these products should no longer be used for repeated or prolonged treatment of children or those with impaired renal function. [20]

Calcium can slow the heart rate and precipitate arrhythmias. Do not give calcium solutions and sodium bicarbonate simultaneously by the same route to avoid precipitation.[21]

Do not give Calcium and Phosphate supplements with feeds

1. 
   Hyman SJ, Novoa Y, Holzman I. Perinatal Endocrinology: Common Endocrine Disorders in the Sick and Premature Newborn. Endocrinology and Metabolism Clinics of North America. 2009;38:509-24.
   
2. 
   Nutrient Reference values for Australia and New Zealand. https://www.nrv.gov.au/nutrients/calcium. Accessed on 29 August 2017.
   
3. 
   Sparks JW. Human intrauterine growth and nutrient accretion. Semin Perinatol. 1984;8:74-93.
   
4. 
   Widdowson EM, Mc CR, Spray CM. The chemical composition of the human body. Clin Sci. 1951;10:113-25.
   
5. 
   Rustico SE, Calabria AC, Garber SJ. Metabolic bone disease of prematurity. J Clin Transl Endocrinol. 2014;1:85-91.
   
6. 
   Abrams SA, Committee on N. Calcium and vitamin d requirements of enterally fed preterm infants. Pediatrics. 2013;131:e1676-83.
   
7. 
   Kreuder J, Otten A, Reiter H, Klingmüller V, Wolf H. Efficacy and side effects of differential calcium and phosphate administration in prevention of osteopenia in premature infants. Monatsschrift Kinderheilkunde [serial on the Internet]. 1990; 138(11): Available from: http://onlinelibrary.wiley.com/o/cochrane/clcentral/articles/567/CN-00337567/frame.html.
   
8. 
   Harding JE, Wilson J, Brown J. Calcium and phosphorus supplementation of human milk for preterm infants. Cochrane Database Syst Rev. 2017;2:CD003310.
   
9. 
   Torabi Z, Moemeni N, Ahmadiafshar A, Mazloomzadeh S. The effect of calcium and phosphorus supplemtation on metabolic bone disorders in premature infants. Journal of the Pakistan Medical Association. 2014;64:635-9.
   
10. 
    Brown JV, Embleton ND, Harding JE, McGuire W. Multi-nutrient fortification of human milk for preterm infants. Cochrane Database of Systematic Reviews [serial on the Internet]. 2016; (5): Available from: http://cochranelibrary-wiley.com/doi/10.1002/14651858.CD000343.pub3/abstract.
    
11. 
    Pohlandt F, Mihatsch WA. Reference values for urinary calcium and phosphorus to prevent osteopenia of prematurity. Pediatr Nephrol. 2004;19:1192-3.
    
12. 
    Demarini S. Calcium and phosphorus nutrition in preterm infants. Acta Paediatr Suppl. 2005;94:87-92.
    
13. 
    Pohlandt F. Prevention of postnatal bone demineralization in very low-birth-weight infants by individually monitored supplementation with calcium and phosphorus. Pediatr Res. 1994;35:125-9.
    
14. 
    Altirkawi K, Rozycki HJ. Hypocalcemia is common in the first 48 h of life in ELBW infants. Journal of Perinatal Medicine. 2008;36:348-53.
    
15. 
    Rosli A, Fanconi A. Neonatal hypocalcaemia. 'Early type' in low birth weight newborns. Helvetica Paediatrica Acta. 1973;28:443-57.
    
16. 
    Tsang RC, Oh W. Neonatal hypocalcemia in low birth weight infants. Pediatrics. 1970;45:773-81.
    
17. 
    Cote CJ, Drop LJ, Daniels AL, Hoaglin DC. Calcium chloride versus calcium gluconate: comparison of ionization and cardiovascular effects in children and dogs. Anesthesiology. 1987;66:465-70.
    
18. 
    Broner CW, Stidham GL, Westenkirchner DF, Watson DC. A prospective study, randomized, double-blind comparison of calcium chloride and calcium gluconate therapies for hypocalcemia in critically ill children. Journal of Pediatrics. 1990;117:986-9.
    
19. 
    Turner TL, Cockburn F, Forfar JO. Magnesium therapy in neonatal tetany. Lancet. 1977;1:283-4.
    
20. 
    Medicines and Healthcare products Regulatory Agency (MHRA) report. Calcium gluconate 10% in 10 mL glass containers: risk of aluminium exposure. http://www.mhra.gov.uk/safety-public-assessment-reports/CON105682. 2010.
    
21. 
    Soar J, Nolan JP, Bottiger BW, Perkins GD, Lott C, Carli P, Pellis T, Sandroni C, Skrifvars MB, Smith GB, Sunde K, Deakin CD, Adult advanced life support section C. European Resuscitation Council Guidelines for Resuscitation 2015: Section 3. Adult advanced life support. Resuscitation. 2015;95:100-47.
    
22. 
    Calcium chloride – Micromedex. Accessed online 24/3/2016.
    
23. 
    Calcium gluconate – Micromedex. Accessed online 24/3/2016.
    
24. 
    Australian Injectable Drugs Handbook, 6th Edition, Society of Hospital Pharmacists of Australia 2014. Accessed on 24/3/2016.
    
25. 
    Calcium equivalents. http://www-users.med.cornell.edu/~spon/picu/calc/cacalc.htm. Accessed on 7 06 2016
    
26. 
    MIMS online. Accessed on 14 January 2020.