Increased Renal Net Acid Excretion in Prematures below 1,600 g Body Weight Compared with Prematures and Small-for-Date Newborns above 2,100 g on Alimentation with a Commercial Preterm Formula

Kalhoff, Hermann; Wiese, Björn; Kunz, Clemens; Diekmann, L; Stock, G. J.; Manz, Friedrich

doi:10.1159/000244084

Cited by 15 publications

(11 citation statements)

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“…However, feeding of a certain batch of a preterm formula to infants with an actual body weight below 1.6 kg resulted in a higher renal NAE (1.86 mmol/kg per day) than feeding the same batch to infants with an actual body weight above 2.1 kg (1.28 mmol/kg per day) [49]. Urinary ionogram data of the two subgroups showed that the increased renal NAE of the smaller premature infants was the result of a lower urinary excretion rate of Na + K -Cl, due to a higher daily weight gain and probably a higher retention of these minerals.…”

Section: Figmentioning

confidence: 96%

Renal acid excretion in early infancy

Manz

Kalhoff

Remer

1997

Pediatric Nephrology

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In early infancy, complex disorders of acid base metabolism are more frequent than in any other age group, with a predisposition to metabolic acidosis due to an age-related low renal capacity for acid excretion and an unphysiologically high actual renal acid load in nutrition with common formulas. Recently in preterm and small-for-gestational-age infants, persistent maximum renal net acid excretion (NAE) with subnormal or normal blood acid base status, impaired weight gain, and adaptive hormonal reactions have been observed. Incipient late metabolic acidosis is one example of a mixed disorder of acid base metabolism with maximum renal NAE in early infancy. Alkali therapy is highly effective and can be realized both on an individual basis, using urine pH screening as a diagnostic criterium for maximum renal acid stimulation, or on a general preventive level using modified standard formula with a reduced actual renal NAE similar to that seen on alimentation with human milk. From an integrated point of view, the low glomerular filtration rate and renal capacity for acid excretion beyond the developmental age of more than 44 weeks, may well be interpreted as the result of a specific adaptation to breast feeding sparing energy, and thus an evolutionary advantage for the survival of mother and child.

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Section: Figmentioning

confidence: 96%

Renal acid excretion in early infancy

Manz

Kalhoff

Remer

1997

Pediatric Nephrology

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“…Fig. 1 shows urinary ionograms of preterm infants on nutrition with either human milk or with a standard preterm formula [16,23]. The urinary excretion of electrolytes is mainly the result of intake, intestinal absorption and retention [4,24].…”

Section: Renal Excretion Of Acidmentioning

confidence: 99%

“…Fig. 1 Urinary ionograms (mmol/kg/day) in premature infants on nutrition with either human milk (left, [23]) or standard formulas for prematures (right, [16]). Renal net acid excretion is defined as the sum of titratable acidity and ammonium minus bicarbonate.…”

Section: Renal Nae In Infants Fed Human Milk or Formulasmentioning

confidence: 99%

“…However, nutrition with standard formulas already results in an actual renal net acid excretion in the range of renal acid excretion capacity in small premature infants [16,[57][58][59]. Thus, very low birth-weight and premature infants may be assumed to transiently be at a high risk of spontaneously developing acid retention [59,60].…”

Section: Renal Nae Capacitymentioning

confidence: 99%

“…Furthermore, nutrition with standard formulas already results in a high renal net acid excretion [15,16]. Thus, in early infancy, complex disorders of acid-base metabolism are frequent, with a predisposition for metabolic acidosis [5,6,14].…”

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Nutrition, acid-base status and growth in early childhood

Kalhoff¹,

Manz

2001

European Journal of Nutrition

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Optimal growth is only possible in a well-balanced "inner milieu". Premature infants are especially vulnerable for disturbances of acid-base metabolism with a predisposition to metabolic acidosis due to a transient disproportion between age-related low renal capacity for net acid excretion (NAE) and an unphysiologically high actual renal NAE on nutrition with standard formulas. During a 50 month period, 452 low birth-weight infants were screened for spontaneous development of incipient late metabolic acidosis (ILMA), an early stage during the development of retention acidosis, characterized by maximum renal acid stimulation (MRAS, urine-pH < 5.4) on two consecutive days but still compensated systemic acid-base status. Compared with controls, patients with ILMA showed higher serum creatinine values, an increased urinary excretion of sodium, aldosterone and nitrogen, but only slightly lower blood pH (7.38 vs 7.41) and base excess (-2.8 vs. 0.2 mmol/l) with respiratory compensation (PCO2 35 vs 37 mm Hg). Patients with altogether 149 episodes of ILMA were subsequently randomly allocated to either treatment with NaHCO3 2 mmol/kg/d for 7 days or no special therapy in protocol I, or NaHCO3 vs NaCl each 2 mmol/kg/d for 7 days in protocol II. Patients of protocol I with persistent MRAS for 7 days showed lowest weight gain and a tendency for a further increase in urinary aldosterone and nitrogen excretion. NaCl supplementation (protocol II) seemed to promote weight gain without affecting either impaired mineralization or suboptimal nitrogen retention. Patients with alkali therapy under both protocols showed normal weight gain and normalization of hormonal stimulation, mineralization (protocol II) and nitrogen assimilation. Modification of the mineral content of a standard preterm formula decreased renal NAE to the low level seen on alimentation with human milk and reduced the incidence of ILMA in preterm and small-for-gestational-age infants to 1%. The data show that ILMA is associated with impaired growth. Activation of secondary homeostatic mechanisms (extracellular volume contraction, depletion of disposable net base pools) might be important for impaired growth. Production of new formulas for reduced renal NAE could be an effective general preventive measure to reduce the clinical importance of one component of mixed acid-base disorders in early childhood.

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Modified Cow's Milk Formula with Reduced Renal Acid Load Preventing Incipient Late Metabolic Acidosis in Premature Infants

Kalhoff,

Diekmann,

Hettrich

et al. 1997

J. pediatr. gastroenterol. nutr.

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Background:Premature infants receiving alimentation with cow's milk formulas are at a considerably high risk of developing incipient late metabolic acidosis, an early stage in the development of manifest late metabolic acidosis. Is it possible to reduce this risk by modification of the composition of a standard formula?Methods:The mineral composition of a cow's milk preterm formula A was modified (formula B) with the aim of reducing the alimentary load to that of human milk. 160 premature infants were fed either mother's milk (n = 50) or the modified formula B (enriched with sodium and potassium) (n = 110), and their urine pH was tested twice a week. Randomly collected subgroups of infants were studied in detail for nutrient balances. The results were compared with earlier observations of 282 premature infants fed either mother's milk (n = 28) or the standard formula A (n = 254).Results:Incipient late metabolic acidosis was observed in nine of 78 premature infants receiving mother's milk, 53 of 254 premature infants receiving the standard formula A, and only one of 110 premature infants fed the modified formula B. Net acid excretion was 0.58 mmol/kg/day in 11 premature infants receiving alimentation with the modified formula B compared with 1.73 mmol/kg/day in 23 premature infants fed formula A. This reduction was mainly due to an increased alkali excess (sodium + potassium‐chloride) in intake and urine.Conclusions:Reduction of renal acid load with the modified formula B had a preventive effect on the rate of development of incipient late metabolic acidosis in premature infants.

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Increased Renal Net Acid Excretion in Prematures below 1,600 g Body Weight Compared with Prematures and Small-for-Date Newborns above 2,100 g on Alimentation with a Commercial Preterm Formula

Cited by 15 publications

References 5 publications

Renal acid excretion in early infancy

Renal acid excretion in early infancy

Nutrition, acid-base status and growth in early childhood

Modified Cow's Milk Formula with Reduced Renal Acid Load Preventing Incipient Late Metabolic Acidosis in Premature Infants

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