Supplementation of calcium and phosphorus in parenteral nutrition for extremely low-birth-weight infants

Abstract

Objective To investigate the usefulness of calcium and phosphorus supplementation in parenteral nutrition for extremely low-birth-weight (ELBW) infants.Methods According to the inclusion criteria,66 ELBW infants hospitalized after birth in neonatal ward of Tongji Hospital from June 2009 to December 2012 were divided into three groups with random number table:28 infants in the first group were treated with parenteral nutrition without calcium and phosphorus supplementation,21 infants in the second group were treated with parenteral nutrition with calcium supplementation only,and 17 infants in the third group was treated with parenteral nutrition with calcium and phosphorus supplementation.The blood levels of ionic calcium,blood phosphorus,and urine calcium and creatinine were determined once a week (total of 4 times).The speed of sound (SOS) was detected for shin bones by quantitative ultrasound at the date of admitting and the end of 4weeks.Results After administrations of supplementation,the blood levels of ionic calcium in the second group were significantly higher than those in the first group [on the 14th day,(1.82 ± 0.35) mmol/L vs.(1.14 ±0.47) mmol/L,t=5.800,P=0.005;onthe21stday,(1.77±0.45) mmol/Lvs.(1.07±0.43) mmol/L,t=5.492,P=0.004; on the 28th day,(1.61±0.58) mmol/Lvs.(0.92±0.44) mmol/L,t=4.556,P=0.025].The blood levels of ionic calcium in the third group were also significantly higher than those in the first group [on the 14th day,(1.55 ± 0.30) mmol/L vs.(1.14 ± 0.47) mmol/L,t =3.570,P =0.001 ; on the 21st day,(1.58 ±0.38) mmol/L vs.(1.07 ±0.43) mmol/L,t =4.151,P=0.000; on the 28th day,(1.55 ±0.35) mmol/L vs.(0.92 ±0.44) mmol/L,t =5.302,P =0.003].The blood levels of phosphorus were significantly elevated in the third group compared with those in the first group [on the 14th day,(1.86 ±0.10) mmol/L vs.(1.65 ±0.17) mmol/L,t=5.217,P=0.012; on the21st day,(1.88 ±0.14) mmol/Lvs.(1.61 ±0.13) mmol/L,t =6.442,P=0.003; on the 28th day,(1.89 ±0.15) mmol/L vs.(1.58 ±0.14) mmol/L,t =6.891,P =0.000] and the second group [on the 14th day,(1.86 ± 0.10) mmol/L vs.(1.53 ±0.15) mmol/L,t =8.100,P=0.000; on 21st day,(1.88 ±0.14) mmo/Lvs.(1.57 ±0.14) mmol/L,t =6.787,P =0.000; on the 28th day,(1.89 ± 0.15) mmol/L vs.(1.62 ± 0.18) mmol/L,t =5.043,P =0.000].The calcium-to-phosphorus ratios markedly increased in the second group compared with those in the first group (on the 14th day,0.69 ±0.18 vs.0.33 ±0.14,t =7.601,P =0.000; on the 21st day,0.66±0.16 vs.0.37 ±0.14,t =6.62,P=0.001 ; on the 28th day,0.62 ±0.15 vs.0.39 ±0.12,t =5.776,P =0.005) while declined in the third group (on the 14th day,0.14 ± 0.10 vs.0.33 ± 0.14,t =5.294,P =0.010; on the 21st day,0.13 ± 0.12 vs.0.37 ± 0.14,t =6.102,P =0.002; on the 28th day,0.12 ± 0.11 vs.0.39 ± 0.12,t =7.711,P =0.000).The third group showed significantly increased SOS values than those in the first and second groups [(381 ± 87) m/s vs.(135 ± 87) m/s,t =9.815,P =0.000;(381 ±87) m/s vs.(146 ±68) m/s,t =9.774,P=0.000].Conclusions Proper supplementation of calcium and phosphorus via parenteral nutrition can achieve increased bone mineral contents and stable blood ionic calcium and phosphorus levels,and avoid hypercalciuria in ELBW infants.PN therapy with calcium and phosphorus supplementation in ELBW infants needs further studies. Key words: Extremely low-birth-weight infants; Mineral intake; Parenteral nutrition; Bone mineral content; Metabolic bone disease