Prediction of parenteral nutrition osmolarity by digital refractometry

Evaluating the rumen-protected lysine stability in forage-based total mixed rations in vitro and determining the lysine Brix value

Three rumen-protected lysine (RPL) products (AjiPro^® -L, LysiPEARL^TM , and Feedtech Bypass Lysine^TM : A, B, and C, respectively) were tested for stability in two forage-based total mixed rations (TMR1, 41.3% dry matter (DM), and TMR2, 49.5% DM) (experiment 1) and for Brix value (experiment 2). In experiment 1, each RPL product (2 g each) and TMR diet (200 g) were mixed and stored in plastic bags at 20°C for 0, 1, 3, 6, 12, 24, and 48 hr. In experiment 2, each RPL product (2 g) was dispensed into ion-exchanged water (20 ml) and kept at 20°C for 0, 0.5, 1, 3, 6, 12, 24, and 48 hr. At each time point, free lysine (Lys) content and Brix values of extracts were measured, and Lys release (LR, %) was calculated. All RPL products LR% varied with varying diets DM and increased with increasing of time exposed to diets; it was highest in C, followed by B, and then A. Water LR% positively correlated with that from diets and with Brix values of Lys dissociated in water. Our results indicated that Lys dissociation from RPL products is affected by diet DM content. Brix value may be used as a potential marker for RPL protection efficacy.

Technology in Parenteral Nutrition Compounding

Technology is constantly being used in novel ways, and its use in the practice of medicine is no exception. Examples of this include computer physician order entry, barcode-medication scanning, electronic health records (EHRs), and bedside patient charts, to name a few. Compounding parenteral nutrition has been included in this technological revolution, with improvements such as barcode-assisted medication preparation systems and EHR-to-compounder interfaces. Along with some of these electronic advancements come the inevitable improvements and challenges, which are explored in this article.

Applicability of refractometry for fast routine checking of hospital preparations

Quality control of hospital pharmacy formulations is of the utmost importance to ensure constant quality and to avoid potential mistakes before administration to the patient. In this study we investigated the applicability of refractometry as a fast, inexpensive and easy-to-use quality control measurement. Refractive indices (RI) of a multitude of different hospital formulations with varying concentrations of active compound were measured. The samples consisted of a number of binary aqueous solutions (one compound in water), complex aqueous solutions (multiple compounds in water or in a constant matrix), two suspensions and one emulsion. For all these formulations, linear regression analysis was performed, quality control limits determined and accuracy and repeatability were checked. Subsequently, actual hospital pharmacy samples were analyzed to check whether they were within the specified limits. For both binary and complex aqueous formulations, repeatability was good and a linear correlation for all samples could be observed on condition that the concentration of the active compound was sufficiently high. The refractometer was not sensitive enough for solutions of folic acid and levothyroxine, which had too low a concentration of active compound. Due to lack of homogeneity and light scattering, emulsions and suspensions do not seem suitable for quality control by refractometry. A mathematical equation was generated to predict the refractive index of an aqueous solution containing clonidine HCl as active compound. Values calculated from the equation were compared with measured values and deviations of all samples were found to be lower than 1.3%. In order to use refractometry in a hospital pharmacy for quality control of multicomponent samples, additional intermediate measurements would be required, to overcome the fact that refractometry is not compound specific. In conclusion, we found that refractometry could potentially be useful for daily, fast quality measurements of relatively concentrated binary and more complex aqueous solutions in the hospital pharmacy.

Target Fortification of Breast Milk: Predicting the Final Osmolality of the Feeds

For preterm infants, it is common practice to add human milk fortifiers to native breast milk to enhance protein and calorie supply because the growth rates and nutritional requirements of preterm infants are considerably higher than those of term infants. However, macronutrient intake may still be inadequate because the composition of native breast milk has individual inter- and intra-sample variation. Target fortification (TFO) of breast milk is a new nutritional regime aiming to reduce such variations by individually measuring and adding deficient macronutrients. Added TFO components contribute to the final osmolality of milk feeds. It is important to predict the final osmolality of TFO breast milk to ensure current osmolality recommendations are followed to minimize feeding intolerance and necrotizing enterocolitis. This study aims to develop and validate equations to predict the osmolality of TFO milk batches. To establish prediction models, the osmolalities of either native or supplemented breast milk with known amounts of fat, protein, and carbohydrates were analyzed. To validate prediction models, the osmolalities of each macronutrient and combinations of macronutrients were measured in an independent sample set. Additionally, osmolality was measured in TFO milk samples obtained from a previous clinical study and compared with predicted osmolality using the prediction equations. Following the addition of 1 g of carbohydrates (glucose polymer), 1 g of hydrolyzed protein, or 1 g of whey protein per 100 mL breast milk, the average increase in osmolality was 20, 38, and 4 mOsm/kg respectively. Adding fat decreased osmolality only marginally due to dilution effect. Measured and predicted osmolality of combinations of macronutrients as well as single macronutrient (R² = 0.93) were highly correlated. Using clinical data (n = 696), the average difference between the measured and predicted osmolality was 3 ± 11 mOsm/kg and was not statistically significant. In conclusion, the prediction model can be utilized to estimate osmolality values after fortification.

Parenteral nutrition: considerations for practice

Malnutrition in the UK is estimated to affect 3 million people in the UK, costing the economy pound 13 billion a year. The effects can adversely affect an individual's wellbeing by exacerbating illness or reducing the prospect of a speedy recovery. The early identification of this actual or potential risk is recognised by using a validated nutritional screening tool as part of the patient assessment. Where risks are identified a structured plan should be put in place utilising oral and enteral techniques in nutritional support. However, for a number of patients these routes of feeding may not be an option, or may not fully meet the patient's nutritional requirements. It is in these circumstances that parenteral feeding may be considered under the supervision of a nutrition team. The careful selection of the parenteral solution alongside the most appropriate venous device to deliver the nutrition can assist in the effectiveness of this treatment and help in reducing the potential complications associated with this route.