Indications:
The review for the determination of main extracellular cation (sodium, Na), himself a good indicator of body hydration.
For example, in cases of diarrhea and chronic vomiting, especially in a fragile patient as a person, the dosage of serum sodium becomes important.
Principle:
The stability of serum sodium is essential for a good cellular and extracellular internal balance.
It is that of blood electrolytes. Sampling 5 mL of venous blood on heparin tube:
– Quickly send to the laboratory;
– Reduce to a minimum the time of the withers;
– Do not make a fist;
– Absolutely avoid hemolysis.
Results:
Standard value:
of 138-145 mEq / L, which represents 95% of osmolality (see ‘chemistry panel “).
Pathological changes:
– Hyponatremia rate below 136 mEq / L: sodées observed in case of urinary or digestive losses, regular use of diuretics, vomiting and / or repeated diarrhea, nephrotic syndrome, heart failure, cirrhosis:
– Up to 130 mEq / L: no neurological consequences
– Less than 130 mEq / L: onset of digestive and neurological disorders (headache, disorientation, convulsions, coma)
– Less than 110 mEq / L: coma may be irreversible;
– Hypernatremia, rate higher than 144 mEq / L: water loss is greater than the loss of salt, much rarer than hyponatremia; this is the case, for example, of a person who lost the notion of thirst and with dehydration.
Cost:
B15.
Practical advice:
Of pseudohyponatrémies may be due to hyperprotidémies, hyperlipemia, hyperglycemia, even to excess Dextran, gelatin.
We must look all medications used to assess the dosage to its fair value.
If in doubt, a urinary electrolytes can be helpful.