Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 5 uppsatser.

Cell membrane potential and inorganic ion distributions are currently viewed from a kinetic electric paradigm, which ignores thermodynamics. The resting membrane potential is viewed as a diffusion potential. The 9 major inorganic ions found in blood plasma (Ca2+, Na+, Mg2+, K+, H+, Cl-, HCO3-, H2PO4-, and HPO42-) are distributed unequally across the plasma membrane. This unequal distribution requires the energy of ATP hydrolysis through the action of the Na+-K+ ATPase. The cell resting membrane potential in each of 3 different tissues with widely different resting membrane potentials has been shown to be equal to the Nernst equilibrium potential of the most permeant inorganic ion. The energy of the measured distribution of the 9 major inorganic ions between extra- and intracellular phases was essentially equal to the independently measured energy of ATP hydrolysis, showing that the distribution of these 9 major ions was in near-equilibrium with the ΔG' of ATP. Therefore, thermodynamics does appear to play an essential role in the determination of the cell resting membrane potential and the inorganic ion distribution across the plasma membrane.-Veech, R. L., King, M. T., Pawlosky, R., Bradshaw, P. C., Curtis, W. Relationship between inorganic ion distribution, resting membrane potential, and the ΔG' of ATP hydrolysis: a new paradigm.

Thesis (MNutr)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Objectives: The objectives of this study were to determine the nutritional content/ contribution of intravenous (IV) fluid and electrolyte administration on the total feeding prescription of intensive care unit (ICU) patients. Methods: Retrospective review of ICU charts of consecutive patients (>18 years) with APACHE II scores ≥10 and on ≥72 hours nutrition therapy (NT) admitted to a medical/surgical ICU. Total fluid, electrolyte, energy and macronutrient intake from nutritional and non-nutritional sources were reviewed from ICU admission until discharge, discontinuation of NT or death for ≤7 days. Energy and protein delivery were compared to calculated targets of 25.4 – 28.6kCal/kg and 1.3 – 1.5g/kg respectively. Summary statistics, correlation coefficients and appropriate analysis of variance were used to describe and analyse the data. Results: A total of 71 patients (49% male), average age 49.2 ± 17.1, average APACHE II score 21.0 ± 6.1, 68% medical and 32% surgical, were included. Fluid and nutrient intake were reviewed over a mean of 5.7 ± 1.1 days. Mean daily fluid delivery was 3.2 ± 0.6L. IV fluid therapy (IVFT) contributed 32.0 ± 12.0% to total fluid delivery (TFD), whereas IV drug administration, including fluids used for reconstitution and dilution purposes, contributed 20.7 ± 8.1% to TFD. Balanced electrolyte solutions (BES) were the crystalloid of choice, prescribed in 91.5% of patients with a mean daily volume (MDV) of 0.5 ± 0.4L. Hypertonic low molecular weight (LMW) 130/0.4kD hydroxyethyl starch (HES) was the colloid of choice, prescribed in 78.9% of patients with a MDV of 0.2 ± 0.1L. Potassium salts were the most frequently prescribed IV electrolyte supplement (IVES), prescribed in 91% of patients (±20 – 60mmol per administration). NT was initiated within 14.5 ± 14.1 hours. The majority (80%) received enteral nutrition (EN). The mean daily energy delivered was 1613 ± 380kCal (25.1kCal/kg), meeting 93.6 ± 17.7% of mean target range (MTR). Mean daily protein delivery (PD) was 72 ± 22g (1.1g/kg), meeting 82.8 ± 19.9% of MTR. Non-nutritional energy sources (NNES), mostly derived from carbohydrate-containing IV fluids, contributed 10.1 ± 7.5% to total energy delivered (156kCal/d). Mean cumulative energy and protein balance was -674.0 ± 1866.1kCal and -86.0 ± 106.9g respectively. The majority (73%) received >90% of the minimum energy target but only 49% >90% of minimum protein target; 59% of those with energy intake 90-110% of target had adequate protein intake. A significant negative correlation was found between cumulative energy/protein balance and the time to initiation of NT (energy: r=-0.28, p=0.02; protein: r=-0.32, p=0.01). Conclusion: In this ICU BES are the crystalloid of choice and hypertonic LMW 130/0.4kD HES the colloid of choice for IVFT. Potassium salts are the most frequently prescribed IVES. NNES added significantly to energy delivery and should be included in the calculation of feeding prescriptions to avoid the harmful effects of overfeeding. Early initiation of EN with conventional products which are energy rich is insufficient to achieve adequate PD. EN formulae with a more favorable nitrogen to non-protein energy ratio could help to optimise PD during the first week of ICU care. / AFRIKAANSE OPSOMMING: Doelwitte: Die doelwit van hierdie studie was om die voedingswaarde/ bydrae van intraveneuse (IV) vog en elektroliet toediening tot die totale voedings voorskrif van pasiënte in ‘n intensiewe sorg eenheid (ISE) te bepaal. Metodes: Retrospektiewe bestudering van die ISE kaarte van agtereenvolgende pasiënte (>18 jaar) opgeneem in ‘n mediese/chirurgie ISE en met APACHE II tellings ≥10 en ≥72 ure voedingsterapie (VT). Totale vog, elektroliet, energie en makronutriënt inname vanaf voedingsverwante en nie-voedingsverwante bronne is vanaf ISE opname tot en met ontslag, staking van VT of sterfte, vir ≤7 dae hersien. Energie en proteiën inname is vergelyk met berekende doelwitte van 25.4 – 28.6kKal/kg en 1.3 – 1.5g/kg onderskeidelik. Beskrywende statisitiek, korrelasie koeffisiënte en toepaslike analises van variansie is gebruik vir data analise. Resultate: 71 pasiënte (49% mans), gemiddelde ouderdom 49.2 ± 17.1, gemiddelde APACHE II telling 21.0 ± 6.1, 68% medies en 32% chirurgie, is ingesluit. Vog en voedingstof inname is hersien oor ‘n gemiddelde tydperk van 5.7 ± 1.1 dae. Gemiddelde vog inname was 3.2 ± 0.6L/dag. IV vog terapie (IVVT) het 32.0 ± 12.0% bygedra tot totale vog inname (TVI). IV medikasie toediening, insluitende die herkonstruksie en verwatering van medikasie, het 20.7 ± 8.1% bygedra tot TVI. Die mees voorgeskrewe kristalloiëd en kolloiëd vir IVVT was gebalanseerde elektroliet oplossings (GEO), voorgeskryf in 91.5% van pasiënte (gemiddeld 0.5 ± 0.4L/dag), en hipertoniese lae molekulêre gewig (LMG) 130/0.4kD hidroksie-etiel stysel (HES), voorgeskryf in 78.9% van pasiënte (gemiddeld 0.2 ± 0.1L/dag), onderskeidelik. Die mees voorgeskrewe IV elektroliet supplement was kalium soute, voorgeskryf in 91% van pasiënte (±20 – 60 mmol per toediening). VT is binne 14.5 ± 14.1 ure geinisieër. Die meerderheid (80%) het enterale voeding (EV) ontvang. Die gemiddelde daaglikse energie inname van 1613 ± 380kCal (25.1kKal/kg) het 93.6 ± 17.7% van die gemiddelde doelwit rykwydte (GDR) bereik. Die gemiddelde daaglikse proteiën inname van 72 ± 22g (1.1g/kg) het 82.8 ± 19.9% van die GDR bereik. Nie voedings-verwante energie bronne (NVEB), meestal vanaf koolhidraat-bevattende IV vloeistowwe, het 10.1 ± 7.5% tot totale energie inname (TEI) bygedra (156kKal/d). Die gemiddelde kumulatiewe energie en proteiën balans was -674.0 ± 1866.1kKal en -86.0 ± 106.9g onderskeidelik. Die meerderheid (73%) het >90% van die minimum energie doelwit (ED) bereik. Slegs 49% het >90% van die minimum proteiën doelwit (PD) bereik. Opsomming: Die kristalloiëd en kolloiëd van keuse vir IVT is GEO en hipertoniese LMG 130/0.4kD HES onderskeidelik. Kalium soute word mees algemeen voorgeskryf. NVEB dra beduidend by tot TEI en moet inaggeneem word tydens die berekening van voedingsvoorskrifte ten einde oorvoeding te voorkom. Vroeë inisiëring van EV met konvensionele energie-ryke EV produkte is onvoldoende om genoegsame proteiën inname te verseker. EV produkte met ‘n gunstiger stikstof tot nie-proteiën energie verhouding sal help om proteiën inname gedurende die eerste week van intensiewe sorg te optimaliseer.Slegs 59% van pasiënte met genoegsame energie inname (90-110% van ED) het hul minimum PD bereik. Daar was ‘n beduidende negatiewe korrelasie tussen kumulatiewe energie/proteiën balans en die tyd tot inisiëring van VT (energie: r=-0.28, p=0.02; proteiën: r=-0.32, p= 0.01).