Basic Concepts of Fluid and Electrolyte Therapy

(3) The answer to this question is summarised in Chapter 3. Decision
making should be informed by all the information available,
including history, examination, vital signs, measurements and
tests including urine output and concentration and serum biochemistry,
fluid balance charts, weight changes, and an understanding
of the likely patho-physiological changes. It should not
be based just on casual bedside assessment of unreliable and nonspecific
signs such as dry mouth or diminished skin turgor.
Remember, serial weighing is the most accurate measure of external
water balance.
(4) The most appropriate method of administration should be the
simplest and safest that is effective (Chapter 6). The oral route
should be used whenever possible. In acute situations and in the
presence of gastrointestinal dysfunction or large deficits, the
intravenous route is the most appropriate. This, however, should
be discontinued at the earliest opportunity. Enteral tube administration
may be appropriate where swallowing is the major problem.
Subcutaneous infusions should be considered, particularly in
the elderly, for the management of chronic or recurrent problems.
(5) The most appropriate fluid to use is that which most closely
matches any previous or ongoing losses (Chapter 4). Recent published
data favours the use of balanced electrolyte solutions
rather than 0.9% saline to replace salt and water deficits, except
in the case of losses of gastric juice with its high chloride content.
Following intravascular fluid losses, current thinking favours a
combination of artificial colloid and balanced electrolyte solutions,
supported by packed cells after significant blood loss.
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