Cysteine usage increases the need for acetate in neonates who receive total parenteral nutrition

Abstract

The addition of cysteine (as cysteine HCl) to a total parenteral nutrition (TPN) solution enhances calcium and phosphate solubility because cysteine lowers the pH of the solution. To determine whether adding cysteine to TPN solutions affected the acid-base homeostasis of infants and increased their need for acetate to obviate acidosis, we studied two groups of neonates--those receiving TPN before (group C) and after (group NC) the addition of cysteine. Measurements were made before and during the first 2 wk of TPN administration. We measured the pH of our standard TPN solution with and without the addition of cysteine. Serum carbon dioxide was significantly lower in group C despite a significantly greater intake of acetate in group NC. In the in vitro study the addition of cysteine to the TPN solution lowered the pH from 5.5 to 5.1. Newborns who received TPN solutions to which cysteine was added had lower serum carbon dioxide values and a greater need to receive acetate than did newborns who received TPN solutions without cysteine.

Assessment of cysteine synthesis in very low–birth weight neonates using a [13C6]glucose tracer

“…However, cysteine is not currently present in commercial parenteral nutrition formulas available in the United States. A concern exists regarding the infusion of acidic solutions required to solubilize cysteine and the consequent metabolic acidosis that may evolve [14,15].…”

Effect of High‐Dose Cysteine Supplementation on Erythrocyte Glutathione

“…Decreased PN administration of calcium and phosphorus concentrations are associated with rickets and neonatal fractures in infants dependent on prolonged PN. However, the decreased pH due to cysteine can result in an increased risk for metabolic acidosis 19 , 22 . Despite providing additional sodium acetate to the CYS group in this study, the CYS group did have a larger anion gap in comparison with the ISO group (Table 1).…”

“…The investigational pharmacy allocated the assigned supplement masked to the medical team and investigators. All subjects received PN composed of dextrose, amino acids (10% Premasol, Baxter, Deerfield, IL; containing minimal cysteine‐HCl of 0.016 g/100 mL), and lipids (20% Intralipid; Fresenius Kabi, Uppsala, Sweden) along with 121 mg/kg/d of supplement (approximately 40 mg/g amino acids/d) as either cysteine‐HCl (Sicor Pharmaceuticals, Inc, Irvine, CA) and sodium acetate (2 mEq/kg/d to offset the additional acid load) or additional Premasol amino acids 22 . The supplement was continued until PN discontinuation or 60 days of PN, whichever came first.…”

Selective reversal of muscle relaxation in general anesthesia: focus on sugammadex

“…Use of these solutions, however, has been associated with the development of acidosis in infants. 50 In view of the multiple putative mechanisms by which l-cysteine could be neuroexcitatory and neurotoxic, there are still many unanswered questions regarding the safety of giving humans exogenous cysteine in doses required for adequate antagonism of the new chlorofumarate muscle relaxants gantacurium and/or AV002. These questions would be particularly applicable in clinical scenarios such as trauma, neurosurgery, obstetrics, to name a few, as well as specific patient populations such as patients at extremes of age, those with diabetes, treated hypertensive patients, or those with pre-existing neurodegenerative disease.…”