Impact of an Intravenous Magnesium Shortage on Potassium Doses in Adult Surgical Patients Receiving Parenteral Nutrition

Background: Shortages of parenteral nutrition (PN) components have been common in recent years. Effects on patient management and outcomes have not been well documented. This study aimed to determine the effect of a parenteral magnesium shortage, and an institutional decision to omit magnesium from adult PN, on magnesium and potassium doses and serum concentrations. Materials and Methods: This was a retrospective cohort study of adult surgical patients during two 6‐month periods: prior to the magnesium shortage (2011) and during the shortage (2012). The relation between study period and electrolyte doses was evaluated by unadjusted and adjusted mixed models, while the relation between study period and hypokalemia and hypomagnesemia exposure was evaluated by Student's t tests and multiple linear regression. Results: During the shortage, patients received more supplemental magnesium (0.11–0.12 mEq/kg/d, P < .0001) but received less total daily magnesium (0.08–0.09 mEq/kg/d, P < .0001) and had greater exposure to hypomagnesemia (9.6–14.2 h·mcg/dL/h, P < .05 for all comparisons except multivariate analysis in a matched subpopulation). Patients received similar amounts of potassium in PN (0.06–0.08 mEq/kg/d less, P < .05 for full cohort but P > .05 for matched cohort), in supplemental doses (0.01–0.05 mEq/kg/d less, P > .05), and in total (0.07–0.14 mEq/kg/d less, P > .05), and they had similar exposure to hypokalemia. Conclusion: Daily magnesium doses were lower and hypomagnesemia exposure was greater during the shortage, but the differences were numerically small and their clinical significance was questionable. Potassium doses and hypokalemia exposure were not higher during the shortage. This supports the strategy of omitting magnesium from PN of select patients and supplementing as clinically necessary.     

A Reproducible and Individualized Method to Predict Osmolality of Compounded Pediatric Parenteral Nutrition Solutions

Background: Osmolality is a well‐known factor in complications associated with parenteral nutrition (PN). The osmolality of compounded pediatric PN solutions is often inappropriately approximated by theoretical osmolarity, which carries a major risk of underestimation, especially in highly concentrated solutions. Only a few studies have proposed equations to overcome this problem, and to date their accuracy in settings other than those of their development has not been assessed. We propose a reproducible method to develop a predictive model of osmolality adapted to local practice, and we compare its predictive performance to osmolarity calculation and other equations. Methods: From measures performed on dilutions of basic components of PN solutions, a predictive model establishing the relationship between the quantitative and qualitative composition of a PN solution and its osmolality was developed. This model was validated in routine practice on daily compounded pediatric PN solutions, and its predictive performance was compared with osmolarity calculation, 2 previously published predictive equations, and multilinear regression. Results: We measured the osmolality of 321 routinely produced PN solutions. The model predicted osmolality with a mean relative error of ?0.28% (±2.75%). All the other ways to approximate osmolality were less precise and sometimes provided critically underestimated values (from ?16.67% to ?33.24%). Conclusions: Our model predicted osmolality accurately and may be used in routine practice in any setting once adapted to the local production practice. Approximations by osmolarity severely underestimate actual osmolality. Keeping osmolarity <800 mOsm/L seems sufficient to ensure that actual osmolality does not exceed 1000 mOsm/kg.     

Risk Factors for the Development of Catheter‐Related Bloodstream Infections in Patients Receiving Home Parenteral Nutrition

Background: Risk factors for development of catheter‐related bloodstream infections (CRBSI) were studied in 125 adults and 18 children who received home parenteral nutrition (HPN). Methods: Medical records from a national home care pharmacy were reviewed for all patients that had HPN infused at least twice weekly for a minimum of two years from January 1, 2006‐December 31, 2011. Infection and risk factor data were collected during this time period on all patients although those patients who received HPN for a longer period had data collected since initiation of HPN. Results: In adults, 331 central venous catheters (CVCs) were placed. Total catheter years were 1157. Median CVC dwell time was 730 days. In children, there were 53 CVCs placed. Total catheter years were 113.1. Median CVC dwell time was 515 days. There were 147 CRBSIs (0.13/catheter year;0.35/1000 catheter days). In children there were 33 CRBSIs (0.29/catheter year;0.80/1000 days; P < .001 versus adults). In adults, univariate analysis showed use of subcutaneous infusion ports instead of tunneled catheters (P = .001), multiple lumen catheters (P = .001), increased frequency of lipid emulsion infusion (P = .001), obtaining blood from the CVC (P < 0.001), and infusion of non‐PN medications via the CVC (P < .001) were significant risk factors for CRBSI. Increased PN frequency was associated with increased risk of CRBSI (P = .001) in children, but not in adults. Catheter disinfection with povidone‐iodine was more effective than isopropyl alcohol alone. There were insufficient patients to evaluate chlorhexidine‐containing regimens. Conclusion: Numerous risk factors for CRBSI were identified for which simple and current countermeasures already exist.     

Parenteral Nutrition

This article explores parenteral nutrition (PN) not only as a therapy but also as a system of care, highlighting the potential “evidence gaps” in guidelines for PN use. The importance of interdisciplinary nutrition care, error reporting, and data‐driven practice changes on improving PN therapy is emphasized. Finally, the American Society for Parenteral and Enteral Nutrition's current and future role in advancing the science, practice, and safety of PN is reviewed.     

Parenteral Nutrition Drug Shortages: A Single‐Center Experience With Rapid Process Change

Disruptions in the medication supply chain and consequent drug product shortages, including shortages of parenteral products used for parenteral nutrition (PN) compounding, have become an increasingly common occurrence. The amino acid solution shortage that resulted from the devastating impact of Hurricanes Maria and Irma on manufacturing facilities in Puerto Rico in 2017 necessitated a rapid, coordinated shift from use of compounded PN to commercial multichamber‐bag PN (MCB‐PN) at our hospitals. We describe our experience operationalizing this intervention via a framework that may be adapted for addressing other drug product shortages to promote rapid yet safe use of therapeutic alternatives.     

A.S.P.E.N. Parenteral Nutrition Safety Consensus Recommendations

Parenteral nutrition (PN) serves as an important therapeutic modality that is used in adults, children, and infants for a variety of indications. The appropriate use of this complex therapy aims to maximize clinical benefit while minimizing the potential risks for adverse events. Complications can occur as a result of the therapy and as the result of the PN process. These consensus recommendations are based on practices that are generally accepted to minimize errors with PN therapy, categorized in the areas of PN prescribing, order review and verification, compounding, and administration. These recommendations should be used in conjunction with other A.S.P.E.N. publications, and researchers should consider studying the questions brought forth in this document.     

Outcome Indicators for Home Parenteral Nutrition Care

Background and Aims: Patients receiving home parenteral nutrition (HPN) deserve a high‐quality and patient‐centered care. Patient‐centered care can be delivered only if the patient's priorities and concerns are known. Therefore, the aim is to identify the top 3 most important outcome indicators according to patients' perspectives and the differences between several centers, HPN regimen, and HPN experience. Methods: A questionnaire, based on previously developed outcome indicators, was translated into the mother tongue using forward‐backward translation and distributed to adult HPN patients with benign disease in March 2013. To identify differences, a Kruskal‐Wallis or Mann‐Whitney test was performed with GraphPad Prism (significance level <.05) when applicable. Results: Nine centers over 8 countries (300 patients) participated. The top 3 outcome indicators for patients were (1) incidence of catheter‐related infection (CRI), (2) survival, and (3) quality of life (QoL). Between the participating centers, significant differences on rating were found for 5 outcome indicators (catheter obstruction, .015; weight, .002; energy, .010; fear, <.001; and independence, .010). The independence outcome indicator (.050) was considered less important for experienced (>2 years HPN) vs less experienced patients. For this outcome indicator, patients' view also differed significantly based on number of HPN days per week (.0103). Conclusion: A cohort of HPN patients identified incidence of CRI, survival, and QoL as the most important outcome indicators for their care; however, there were significant differences between the participating centers. For one outcome indicator (independence), there were significant differences based on experience and regimen.     

Ceramide in Lipid Emulsions Used in Parenteral Nutrition

Parenteral nutrition-associated liver disease is a prevalent and severe complication of long term parenteral nutrition. We present here for the first time data on the presence of ceramide, a bioactive compound involved in a variety of metabolic processes, in different lipid emulsions used in parenteral nutrition. Further research is needed to determine whether this potential harmful bioactive compound is involved in parenteral nutrition-associated liver disease.     

Transitioning Preterm Infants From Parenteral Nutrition: A Comparison of 2 Protocols

Background: Growth in preterm infants is compromised during the transition phase of nutrition, when parenteral nutrition (PN) volumes are weaned with advancing enteral nutrition (EN) feeds, likely due to suboptimal nutrient intakes during this time. We implemented new PN guidelines designed to maintain optimal nutrient intakes during the transition phase and compared growth outcomes of this cohort with a control group. Materials and Methods: A chart review was conducted on infants born <32 weeks’ gestation, before (control group) and after (study group) a new transition PN protocol was implemented in the neonatal intensive care unit. Weight parameters and nutrient intakes were calculated for the transition phase and compared between the 2 groups. Results: Demographic and clinical characteristics of the 2 groups were comparable except for higher rates of sepsis in control group. Weight‐for‐age z scores at birth, at 1 week of life, and at the start of the transition phase were similar. At the end of the transition phase, infants in the study group had significantly higher z scores compared with the control group, even when corrected for sepsis, a difference that persisted at 35 weeks’ gestation. During the transition phase, study infants gained 16.1 ± 4.6 g/kg/d compared with 13.2 ± 5.4 g/kg/d in control group (P < .001). Similar results were observed in the subset of expressed breastmilk–only fed infants (15.9 ± 4.6 g/kg/d in the study group compared with 13.2 ± 5.4 g/kg/d in the control group, P < .004). Conclusion: Optimizing nutrition by the use of concentrated PN during the transition phase to maintain appropriate nutrient intakes improves growth rates in preterm infants.     

Physical Compatibility of Calcium Chloride and Sodium Glycerophosphate in Pediatric Parenteral Nutrition Solutions

Background: Calcium and phosphate precipitation is an ongoing concern when compounding pediatric parenteral nutrition (PN) solutions. Considerable effort has been expended in producing graphs, tables, and equations to guide the practitioner in prescribing PN that will remain stable. Calcium gluconate is preferred over calcium chloride when compounding PN because of its superior compatibility with inorganic phosphates. PN solutions containing calcium gluconate carry a higher aluminum load than equivalent solutions compounded with calcium chloride, leading to increased potential for aluminum toxicity. This study tested the solubility of calcium chloride in PN solutions compounded with an organic phosphate component, sodium glycerophosphate (NaGP), in place of sodium phosphate. Methods: Five PN solutions were compounded by adding calcium chloride at 10, 20, 30, 40, and 50 mEq/L and corresponding concentrations of NaGP at 10, 20, 30, 40, and 50 mmol/L. Each of the 5 solutions was compounded using 1.5% and 4% amino acids, cysteine, and lipids. The physical stability was evaluated by visual inspection (precipitation, haze, and color change). Solutions were evaluated microscopically for any microcrystals using U.S. Pharmacopeia <788> standards. Results: Compatibility testing showed no changes in the PN solution in any of the concentrations tested. Calcium chloride was found to be physically compatible with NaGP in PN at the tested concentrations. Conclusion: Utilization of NaGP in PN solutions would eliminate the need for precipitation curves and allow for the use of calcium chloride. Compounding with NaGP and calcium chloride allows the practitioner a mechanism for reducing the aluminum load in PN.     

Central Venous Catheter Salvage in Home Parenteral Nutrition Catheter‐Related Bloodstream Infections

Background: Catheter‐related bloodstream infections (CRBSIs) are a serious complication in the provision of home parenteral nutrition (HPN). Antibiotic salvage of central venous catheters (CVCs) in CRBSI is recommended; however, this is based on limited reports. We assessed the efficacy of antibiotic salvage of CRBSIs in HPN patients. Materials and Methods: All confirmed CRBSIs occurring in patients receiving HPN in a national intestinal failure unit (IFU), between 1993 and 2011, were analyzed. A standardized protocol involving antibiotic and urokinase CVC locks and systemic antibiotics was used. Results: In total, 588 patients were identified with a total of 2134 HPN years, and 297 CRBSIs occurred in 137 patients (65 single and 72 multiple CRBSIs). The overall rate of CRBSI in all patients was 0.38 per 1000 catheter days. Most (87.9%) infections were attributable to a single microorganism. In total, 72.5% (180/248) of CRBSIs were salvaged when attempted (coagulase‐negative staphylococcus, 79.8% [103/129], Staphylococcus aureus, 56.7% [17/30]; polymicrobial infections, 67.7% [21/30]; and miscellaneous, 66.1% [39/59]). CVC salvage was not attempted in 49 episodes because of life‐threatening sepsis (n = 18), fungal infection (n = 7), catheter problems (n = 20), and CVC tunnel infection (n = 4). Overall, the CVC was removed in 33.7% (100/297) of cases. There were 5 deaths in patients admitted to the IFU for management of the CRBSI (2 severe sepsis at presentation, 3 metastatic infection). Conclusions: This is the largest reported series of catheter salvage in CRBSIs and demonstrates successful catheter salvage in most cases when using a standardized protocol.     

Parenteral Nutrition Electrolyte Abnormalities and Associated Factors Before and After Nutrition Support Team Initiation

Background: Studied since the 1940s, refeeding syndrome still has no universal definition, thus making comparison of studies difficult. Negative outcomes (eg, metabolic abnormalities) may occur with the use of specialized nutrition, such as parenteral nutrition (PN). Less than half of medical institutions have a nutrition support team (NST) managing PN. Interdisciplinary team management of PN may reduce negative outcomes of PN. The objective of this study was to show the value of the NST by measuring differences in PN variables, especially electrolyte abnormalities (EAs), before and after NST initiation at a large medical center and to identify factors associated with EAs among adult subjects receiving PN. Materials and Methods: During this retrospective study, computerized medical charts (N = 735) from 2007–2010 were reviewed for electrolyte changes (particularly potassium, magnesium, and phosphorus) the first 3 days following PN initiation in hospitalized adults. Changes in EAs with other variables were compared before and after NST implementation. Equivalent samples sizes were collected to better evaluate the impact of the team. Results: Following the implementation of the NST, fewer EAs were seen in PN patients (53%; χ² = 10.906, P = .004); significantly less potassium, phosphorus, and magnesium intravenous piggyback supplementation (88.8% vs 94%; χ² = 5.05, P = .026) was used; and mortality within 30 days of PN cessation was significantly less (12.7% vs 10.6%, P = .012). Conclusion: Our study complements existing research, finding that an NST was associated with a decreased occurrence of EAs and mortality in the hospitalized adult receiving PN.     

Management of Parenteral Nutrition in Hospitalized Adult Patients

Despite the high prevalence of malnutrition in adult hospitalized patients, surveys continue to report that many clinicians are undertrained in clinical nutrition, making targeted nutrition education for clinicians essential for best patient care. Clinical practice models also continue to evolve, with more disciplines prescribing parenteral nutrition (PN) or managing the cases of patients who are receiving it, further adding to the need for proficiency in general PN skills. This tutorial focuses on the daily management of adult hospitalized patients already receiving PN and reviews the following topics: (1) PN basics, including the determination of energy and volume requirements; (2) PN macronutrient content (protein, dextrose, and intravenous fat emulsion); (3) PN micronutrient content (electrolytes, minerals, vitamins, and trace elements); (4) alteration of PN for special situations, such as obesity, hyperglycemia, hypertriglyceridemia, refeeding, and hepatic/renal disease; (5) daily monitoring and adjustment of PN formula; and (6) PN‐related complications (PN‐associated liver disease and catheter‐related complications).