Effects of pH, Temperature, Concentration, and Time on Particle Counts in Lipid‐Containing Total Parenteral Nutrition Admixtures

Abstract

It has been standard practice in the United States to separate lipid emulsion from the other components of total parenteral nutrition (TPN) due to the reported instability of admixed intravenous lipid emulsions. Some clinicians, however, have combined all TPN components into one container and administered these admixtures to patients without apparent difficulties. Infusion of all nutrients from one container has many advantages. In this study standard and concentrated admixtures were aseptically prepared using generally accepted guidelines of the nutritional requirements for a 70-kg patient. Treatments of standard and concentrated admixtures consisted of: storing at 4 degrees C without adjusting the pH; increasing the pH to 6.6 and storing at 4 degrees C; increasing the pH to 6.6 and storing at room temperature. Samples were monitored for 3 weeks by means of Coulter Counter analysis, pH determinations, and visual observations. The pH of the admixtures did not change over 3 weeks. Mean counts of particles with sizes between 1.6 and 25.4 mu increased over time for each treatment group. Within treatments, concentrated admixtures had significantly greater particle counts than the corresponding standard admixtures. Within the standard and within the concentrated admixtures, the particle counts were significantly greater for group one than for group three. Particle counts in group two tended to lie between the values of group one and three. Visual signs of emulsion deterioration were greatest in those admixtures in which the pH was not adjusted and occurred earlier in concentrated admixtures.

Effects of temperature and handling conditions on lipid emulsion stability in veterinary parenteral nutrition admixtures during simulated intravenous administration

“…Results of the present study were in contrast to those of other studies 6,31,32 of lipid particle size. In 1 study, 31 the percentage of large particles (1.6 to 25.4 µm in diameter) significantly increased between 0 and 72 hours both in samples kept at refrigeration temperatures and those kept at room temperature. That study did not include direct assessment of particle size, but relied on Coulter counter analysis of numbers of particles at various time points.…”

Effect of the Intravenous Lipid Emulsions on the Availability of Calcium when using Organic Phosphate in TPN Admixtures

“…Low pH, high temperature, time and high concentrations of cations, such as calcium, magnesium, sodium or potassium are factors leading to destabilization of the TPN emulsion (26). Furthermore, PN admixtures intended for very young patients (i.e.…”

“…For that, three consecutives concentrations of the glucose-1-phosphate (G1P) solutions (26,32 or 40 mmol/l of phosphate) were added to the samples. The tubes were shaken and calcium (Ca) at concentrations of 15.5, 24.5 and 30 mmol/l as calcium gluconate (CaGlu), were added respectively to each concentration of G1P, as presented in Table III.…”

Estudo 'In vitro' da compatibilidade entre cálcio e fósforo em nutrições parenterais, utilizando-se gluconato de cálcio e glicerofosfato de sódio

“…O aumento no tamanho das gotículas de gordura é favorecido pela redução do pH (DRISCOLL et al, 1986), aumento da temperatura (BETTNER & STENNET, 1986) e presença de cátions divalentes e trivalentes (DRISCOLL et al, 1995). Em pH menor que 5 o efeito do agente emulsificante é neutralizado e ocorre a quebra da emulsão (DRISCOLL et al, 1986;BETTNER & STENNET, 1986). A 4ºC a emulsão lipídica apresenta maior estabilidade que a temperatura ambiente (DRISCOLL et al, 1995).…”

“…Para evitar a precipitação utiliza-se o fosfato monobásico que possibilita a obtenção de uma nutrição parenteral cujo pH final situa-se entre 4,1 e 6,5. A redução do pH favorece a solubilidade do fosfato de cálcio, no entanto pode ser prejudicial à estabilidade da emulsão lipídica presente (DRISCOLL et al, 1986;BETTNER & STENNET, 1986) e ao paciente em virtude da possibilidade da ocorrência de acidose metabólica em prematuros devido à capacidade renal limitada de eliminar ácidos (GUYTON & HALL, 1996).…”