Serum electrolyte determination

Individualize dosage. Guide dosage and rate of infusion by EGG and serum electrolyte determinations. The following may be used as a guide ... 

Determine and monitor the patient s serum electrolyte concentrations to determine the presence or absence of hypokalemia, hyperkalemia, hypomagnesemia, or hypermagnesemia. 

Blood gases (Table 74-1), serum electrolytes, medical history, and clinical condition are the primary tools for determining the cause of acid-base disorders and for designing therapy. 

Electrolyte imbalance Electrolyte imbalance may occur, especially in patients receiving high doses with restricted salt intake. Perform periodic determinations of serum electrolytes. 

Frequently monitor both ethylene glycol levels and acid-base balance, as determined by serum electrolyte (anion gap) or arterial blood gas analysis... 

During each blood pressure measurement session, five measurements are recorded for each animal. The blood pressure is taken as the mean of the last 3 recordings. Urinary protein is determined by the Pyrogallol Red-molybdate method (RA-1000 Tech-nicon). Urinary sodium, creatinine and urea and serum electrolytes, creatinine, albumin, cholesterol and triacylglycerols are measured by a standard autoanalyser technique. Kidney samples are fixed in formalin and embedded in paraffin. Sections are stained with the periodic acid/Schiff technique. Focal glomerular sclerosis is scored semiquantitatively by light microscopy. 

E693 Woody, R.C., Turley, C.P. and Brewster, M.A. (1990). The use of serum electrolyte concentrations determined by automated analyzers to indirectly quantitate serum bromide concentration. Ther. Drug Monit. 12, 490-492. 

Table 2 shows that on the 2071 patients, 31,439 tests were performed. Of these 77% (24,203) would not normally have been requested. For individual determinations there was a wide variation in the percentage of patients that would not normally have had a particular determination. Thus 96% of patients would not normally have been tested for serum uric acid, while 35% would not normally have had urea and electrolyte determinations. 

Arterial blood gases and serum electrolytes should be measured regularly in patients with CKD. These patients should also have a complete medical history and review of medications to determine if there are other potential causes of acid-base disturbances (e.g., diabetic ketoacidosis, ingestion of toxins, or GI disorders). The anion gap, indicating the differences in unmeasured anions and cations, should also be calculated (see Chap. 51). An elevated anion gap (>17 mEq/L) is often present in those with CKD due to the accumulation of organic anions, phosphates, and sulfates. 

Regular monitoring of arterial blood gases and serum electrolytes are necessary to determine the effectiveness of therapy. A gradual correction is appropriate to avoid overcorrection and subsequent complications such as alkalosis and other electrolyte abnormalities (see Chap. 51). Laboratory measurement of serum bicarbonate is associated with several technical problems. Blood collection techniques, transportation, and assay methodology can affect the measured concentrations. Blood samples should not have contact with air process delays should be avoided and consistent analytical methods should be used with serial measurements to improve accuracy. ... 

Arterial blood gases, along with serum electrolytes, physical findings, medical and medication history, and the clinical condition of the patient, are the primary tools to determine the cause of an acid-base disorder and to design and monitor a course of therapy. 

The major serum electrolytes—sodium, potassium, calcium, magnesium, chloride, and bicarbonate (CO2)—are fairly easy to determine. The metals are most readily determined by the use of fiame-spectrophotometiic or atomic absorption methods, although colorimetric methods exist for calcium and magnesium. Calcium and, less frequently, magnesium are also titrated with EDTA. Ion-selective electrodes are used for the routine analysis of sodium, potassium, and calcium. Bicarbonate is analyzed also by titration against standard acid (see Experiment 8) in addition to a manometric method. Chloride is widely determined by automatic coulometric titration with electrogenerated silver ion. 

In the case of calcium such comparison was not possible as the certificate contains the total calcium content and not the ionized calcium. The effects of drugs on the potentiometric determination of serum electrolytes is shown on Figs 1 to 4. All measurements were carried... 

The maintainance of water and electrolyte balance is one of the most important therapeutic activities in the clinic. Normal diet and adequate fluid intake cover one s requirements. Imbalance (see above) has to be verified by electrolyte determination in blood serum as well as in urine and possibly by other diagnostic parameters. Water equilibrium must be attained and compensation of electrolyte deficiency should be performed by oral or parenteral application of medicaments containing the required amount of electrolytes. A very large number of solutions and tablets is available to solve these clinical problems. For further details, see Refs. 27 and 41-44. 

Along with an effective electrolyte and screening program for genetic disease, the laboratory of Neonatology needs to have the capability of analyzing for other components in blood serum, which aid in the diagnosis of disease. These include such determinations as alkaline phosphatase, and various other enzymes, creatinine, uric acid and a host of other components which are normally assayed by the main clinical laboratory. 

The most important application of the valinomycin macroelectrode is for the determination of potassium in serum [9, 126,141,174] and in whole blood [45, 71, 224]. This electrode with a polymeric membrane is a component of most automatic instruments for analysis of electrolytes in the serum. It has also been used for monitoring the K level during heart surgery [168]. The valinomycin ISE is also useful for determination of Rb [33]. 

There are numerous substances that are administered intravenously and have a direct effect on biochemical analysis. Obviously, glucose or electrolyte concentrations will be spuriously elevated if the specimen is taken from the same vein into which these substances are being administered. The presence of sulfobromophthalein dye (BSP) in serum or plasma will interfere with protein determined by the biuret method. The... 

Fluid/Electrolyte balance Perform initial and periodic determinations of serum... 

Instruments are offered in the market for clinical determination of electrolytes in blood, plasma or serum. One of them, for example, carries out simultaneous determinations of Na, K, Ca, Mg, hematocrit and pH. The cations are of the free type (see Section m.A) and are measured with specific ion-selective electrodes. In complex matrices such as blood or its derived fractions the concentration of free Ca and Mg is affected by the pH of the solution, for example, a slight change of pH will produce or neutralize anionic sites in the proteins, binding or releasing these cations furthermore, the response of the Mg-selective electrode is also affected by the concentration of free Ca(II). The correction... 

The method was designed for the determination of ionized (free) magnesium (iMg2"1") together with other major electrolytes (Na+, K+, Cl and Ca2+) and pH in blood serum, plasma or whole blood in the environment of the commercially available Microlyte 6 analyzer supplied by Thermo Fisher Scientific, Finland (previously KONE Instruments, Finland) [1-3]. 

Polystyrene latexes have been prepared using persulfate initiator for many years, but only recently have methods been developed to determine the number and loci of the sulfate surface groups. To determine these surface groups, the latex is cleaned to remove the adsorbed emulsifier and solute electrolyte, then the surface sulfate groups in the H+ form are titrated conductometrically with base. The latexes can be cleaned effectively by ion exchange (2-5) or serum replacement (6) dialysis is not effective in removing the adsorbed emulsifier and solute electrolyte (3,5,6). +... 

For serum replacement (6), the latex is confined in a cell with a uniform-pore-size Nuclepore filtration membrane. Distilled, deionized water is pumped through the latex until the conductance of the effluent stream is about the same as that of the distilled, deionized water. This serum replacement removes the adsorbed emulsifier and solute electrolyte quantitatively and allows recovery of the serum in a form suitable for further analysis however, it does not+replace the Na+ and K counterions of the surface groups with Vl ions. To do this, dilute hydrochloric acid (ca. 10 N) is pumped through the latex, followed by distilled, deionized water to remove the excess acid. The latex is then titrated conductometrically to determine the surface charge. 

The latexes were cleaned by ion exchange and serum replacement, and the number and type of surface groups were determined by conductometric titration. The molecular weight distributions of the polymers were determined by gel permeation chromatography. The stability of the latexes to added electrolyte was determined by spectrophotometry. The compositional distribution was determined by dynamic mechanical spectroscopy (Rheovibron) and differential scanning calorimetry, and the sequence distribution by C13 nuclear magnetic resonance. 

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