Phosphate supplementation in parenteral nutrition

A scoping review of parenteral requirements (macronutrients, fluid, electrolytes and micronutrients) in adults with chronic intestinal failure receiving home parenteral nutrition

INTRODUCTION

Home parenteral nutrition (HPN) prescriptions should be individualised in adults with chronic intestinal failure (IF). The aims of the review were to explore HPN requirements and available guidelines and to determine whether adults (≥ 18 years) receive recommended parenteral nutrient doses.

METHODS

Online databases searches identified empirical evidence (excluding case-reports), reviews and guidelines (Published 2006-2024 in English language). Additional reference lists were hand-searched. Older studies, cited in national guidelines were highlighted to map evidence source. Two reviewers screened 1660 articles independently, with 98 full articles assessed and 78 articles included (of which 35 were clinical studies). Citation tracking identified 12 older studies.

RESULTS

A lack of evidence was found assessing parenteral macronutrient (amounts and ratios to meet energy needs), fluid and electrolyte requirements. For micronutrients, 20 case series reported serum levels as biomarkers of adequacy (36 individual micronutrient levels reported). Studies reported levels below (27 out of 33) and above (24 out of 26) reference ranges for single micronutrients, with associated factors explored in 11 studies. Guidelines stated recommended parenteral dosages. Twenty-four studies reported variable proportions of participants receiving HPN dosages outside of guideline recommendations. When associated factors were assessed, two studies showed nutrient variation with type of HPN administered (multichamber or individually compounded bags). Five studies considered pathophysiological IF classification, with patients with short bowel more likely to require individualised HPN and more fluid and sodium.

CONCLUSIONS

This review highlights substantial evidence gaps in our understanding of the parenteral nutritional requirements of adult receiving HPN. The conclusions drawn were limited by temporal bias, small samples sizes, and poor reporting of confounders and dose. Optimal HPN nutrient dose still need to be determined to aid clinical decision-making and further research should explore characteristics influencing HPN prescribing to refine dosing recommendations.

Parenteral Nutrition in the Pediatric Oncologic Population: Are There Any Sex Differences?

Gender-based medicine is attracting increasing interest every day, but studies on pediatric populations are still limited. In this setting, sex differences among patients undergoing total parenteral nutrition (TPN) have not been previously reported. This study investigated the presence of sex differences in parenteral nutrition composition and outcomes among a cohort of pediatric patients admitted at the Oncohematology and Bone Marrow Transplant Unit of the Institute for Maternal and Child Health "Burlo Garofolo" of Trieste, Italy. For all 145 recruited patients (87 males, 58 females), the following data were collected: age, sex, volume and duration of TPN, macro- and micronutrient composition of TPN bags, electrolytic or blood gases imbalance, glycolipid alterations, liver damage during TPN, and the incidence of sepsis and thrombosis. The analysis showed that females required higher daily phosphate intake (p = 0.054) and essential amino acid supplementation (p = 0.07), while males had a higher incidence of hypertriglyceridemia (p < 0.05) and cholestasis. A higher incidence of sepsis was found in the non-transplanted male population (p < 0.05). No significant differences were appreciable in other analyzed variables. This study aims to create a basis for future gender-based nutritional recommendations in the pediatric field.

Effects of magnesium, phosphate, or zinc supplementation in intensive care unit patients-A systematic review and meta-analysis

BACKGROUND

Low-serum levels of magnesium, phosphate, and zinc are observed in many intensive care unit (ICU) patients, but clinical equipoise exists regarding supplementation strategies. We aimed to assess the desirable and undesirable effects of supplementation with magnesium, phosphate, or zinc in adult ICU patients.

METHODS

We conducted a systematic review with meta-analysis of randomised clinical trials assessing the effects of supplementation with magnesium, phosphate, or zinc in adult ICU patients. Primary outcomes were mortality and duration of mechanical ventilation. We registered the protocol, followed the Preferred Reporting Items for Systematic Review and Meta-Analysis statement, used the Cochrane risk of bias 2 tool, and the grading of recommendations, assessment, development and evaluation (GRADE) approach for assessing the certainty of the evidence.

RESULTS

We identified no low risk of bias trials. For magnesium supplementation, we included three trials (n = 235); the relative risk (RR) for mortality was 0.54, 95% confidence interval (CI) 0.30-0.96 compared to no supplementation (very low certainty of evidence). For zinc supplementation, two trials were included (n = 168); the RR for mortality was 0.73, 95% CI 0.41-1.28 compared to control. No trials assessed the effects of phosphate supplementation on mortality. For outcomes other than mortality, only zero or one trial was available.

CONCLUSIONS

In adult ICU patients, the certainty of evidence for the effects of supplementation with magnesium, phosphate, or zinc was very low. High-quality trials are needed to assess the value of supplementation strategies in these patients.

Treatment of hypophosphatemia in patients receiving specialized nutrition support using a graduated dosing scheme: results from a prospective clinical trial

OBJECTIVE

To determine the safety and efficacy of a graduated dosing scheme of phosphorus replacement therapy in patients with hypophosphatemia receiving specialized nutrition support.

DESIGN

Prospective clinical trial.

SETTING

A 455-bed tertiary care institution, with Level I trauma designation.

PATIENTS

Seventy-eight adult patients, followed and co-managed by a multidisciplinary Nutrition Support Service, with a serum phosphorus concentration of < 3 mg/dL (< 0.97 mmol/L) and no evidence of renal insufficiency, calcium or parathyroid disorders, or obesity.

INTERVENTIONS

Patients were enrolled into one of three categories based on their serum phosphorus concentration: mild hypophosphatemia (2.3 to 3 mg/dL [0.74 to 0.97 mmol/L]), moderate hypophosphatemia (1.6 to 2.2 mg/dL [0.52 to 0.71 mmol/L]), or severe hypophosphatemia (< 1.5 mg/dL [< 0.48 mmol/L]). Each patient received one intravenous phosphorus bolus dose, based on the assigned category of hypophosphatemia, according to a graduated dosing scheme: 0.16 mM/kg (mild), 0.32 mM/kg (moderate), or 0.64 mM/kg (severe). Serum/blood concentrations of phosphorus, calcium, albumin, magnesium, urea nitrogen, and creatinine were measured for three consecutive days.

MEASUREMENTS AND MAIN RESULTS

Sixty-seven patients completed the protocol. There were 31 patients with mild hypophosphatemia, 22 patients with moderate hypophosphatemia, and 14 patients with severe hypophosphatemia. Serum phosphorus concentrations increased significantly (p < .001) in all groups after the phosphorus bolus: 2.6 +/- 0.6 to 3.3 +/- 0.6 mg/dL (0.84 +/- 0.19 to 1.1 +/- 0.19 mmol/L) for the mild group; 1.9 +/- 0.6 to 2.7 +/- 0.6 mg/dL (0.61 +/- 0.19 to 0.87 +/- 0.19 mmol/L) for the moderate group; 1.3 +/- 0.8 to 2.3 +/- 0.8 mg/dL (0.42 +/- 0.26 to 0.74 +/- 0.26 mmol/L) for the severe group. There were no clinically significant changes in serum/blood calcium, albumin, urea nitrogen, or creatinine concentrations and no adverse reactions to the phosphorus regimens throughout the 3-day study period.

CONCLUSION

The graduated dosing scheme of phosphorus replacement therapy is both safe and efficacious in patients receiving specialized nutrition support.

Observations of hypophosphatemia and its management in nutrition support

Severe hypophosphatemia is associated with significant morbidity in hospitalized patients. Specialized nutrition support is an important factor that contributes to the development of this metabolic disorder. Current treatment regimens for hypophosphatemia are empiric and often fail to normalize serum phosphorus concentrations in these patients. Patients who develop hypophosphatemia during the administration of specialized nutrition support exhibit increased phosphorus demands and require aggressive replacement therapy.

A key to the literature of total parenteral nutrition: update 1987

This comprehensive bibliography is intended to enhance the education of the practitioner, student, and academician in the area of parenteral nutrition. This bibliography is not all-inclusive but serves as an update from the original published in 1983. Of particular note in this work is the addition of topics that reflect a growing interest in medical specialties with regard to patient nutritional status and support.

Post-operative substrate utilisation and gas exchange using two different TPN-systems: Glucose versus fat

Twenty patients were studied over the first 4 post-operative days following abdominal aortic surgery. Ten patients had 93% of their non-protein energy as glucose and insulin was given to keep blood glucose below 10 mmol/l. The other 10 patients had 80% of non-protein energy as fat (Intralipid). Amino acids corresponding to 12 g of nitrogen were given in both groups. Gas exchange, nitrogen balance, phosphate balance, vanillylmandelic acid (VMA) excretion, 1- and 3-methylhistidine in urine, acute phase proteins, immunoglobulins and albumin were followed. Substrate utilisation was calculated from indirect calorimetry data and nitrogen excretion. Metabolism in the early post-operative phase was found to adapt to the nutrition regimen given even though the composition was extreme either in fat or carbohydrate content. The glucose-insulin regimen had a better nitrogen sparing effect and based on the difference in 3-methylhistidine excretion it is suggested that mainly protein muscle benefitted from this. Regardless of the TPN-regimen given, those patients whose RQ deviated the most from the average in their group had the highest nitrogen excretion. The two groups showed no differences in plasma proteins and catecholamine excretion.