Shift isotonic

Fluids can be classified further according to their tonicity. Isotonic solutions (i.e., normal saline or 0.9% sodium chloride [NaCl]) have a tonicity equal to that of the ICF (approximately 310 mEq/L or 310 mmol/L) and do not shift the distribution of water between the ECF and the ICF. Because hypertonic solutions (i.e., hypertonic saline or 3% NaCl) have greater tonicity than the ICF (greater than 376 mEq/L or 376 mmol/L), they draw water from the ICF into the ECF. In contrast, hypotonic solutions (i.e., 0.45% NaCl) have less tonicity than the ICF (less than 250 mEq/L or 250 mmol/L) leading to an osmotic pressure gradient that pulls water from the ECF into the ICF. The tonicity, electrolyte content, and glucose content of selected fluids are shown in Table 24—3. 

NaCI is 0.9 g NaCI/100 ml, 1 equivalent to 9 g/L. NaCI has a molecular weight of 58 g/mole, so the concentration of NaCI in isotonic saline is 0.155 M, or 155 mM. If all of the NaCI were dissociated into Na+and Cl ions, the osmolality would be 310 mOsm/kg water. Because NaCI is not completely dissociated and some of the hydration shells surround undissociated NaCI molecules, the osmolality of isotonic saline is approximately 290 mOsm/kg HjO. The osmolality of plasma, interstitial fluids, and ICF is also approximately 290 mOsm/kg water, so that no large shifts of water or swelling occur when isotonic saline is given intravenously. 

As a result of the shift, the concentration of carbonic acid in the blood increases, the HCO3 /H2CO3 ratio deCTeases to less than 20 1, and respiratory acidosis sets in. The treatment of respiratory acidosis involves identifying the underlying causes and possibly the intravenous administration of isotonic sodium bicarbonate solution or hemodialysis. 

Borate buffers show a minimal pH shift when the temperature increases (e.g. during heating or sterilisation) or decreases (fi-eezing) and the concentration that is required to achieve an isotonic solution is relatively low. These two factors contribute to this buffer s suitability for ophthalmic solutions (see Sect. 10.6.1). 

The isotonic-pressure process. The gas is produced at 8.5 MPa, following desulphurization, steam shift, de-carbonization, reinforcing N2, and then enter the converter at 7.5 MPa. 

Fig. 5. Relative isotope shifts in heavy elements. The shifts are normalized and aligned for 6 of the isotones N = 122 and 124 (heavy lines). (Courtesy O. Redi.)...

Fig. 5 also permits relative isotonic shift comparisons. Recently, many more such isotonic comparisons have been made possible (Fig. 8), as well as an isobaric one (Fig. 9). We expect that with adequate precision the differences in the isotonic shifts, particularly between even and odd Z elements, can provide new insights into nuclear interactions.

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