Basic Concepts of Fluid and Electrolyte Therapy

5. Prescription and Administration
Appropriate fluid and electrolyte prescriptions may be administered
orally, enterally, subcutaneously, or intravenously, depending on the
clinical situation. Before any prescription is written it is important to
ask a number of questions:
(1) Does the patient need any prescription at all today?
(2) If so, does the patient need this for
a. resuscitation,
b. replacement of losses, or
c. merely for maintenance?
(3) What is the patient’s current fluid and electrolyte status and
what is the best estimate of any current abnormality?
(4) Which is the simplest, safest, and most effective route of
administration?
(5) What is the most appropriate fluid to use and how is that
fluid distributed in the body?
(1) If the patient is eating and drinking, the answer is usually no. In
the case of a post-operative patient, for example, any intravenous
fluids should be discontinued as soon as possible. Intravenous fluids
are often continued unnecessarily, leading to fluid overload as
well as increased risk of cannula-site sepsis. Nasogastric tubes are
only indicated for drainage in the presence of true ileus or gastric
dysfunction (e.g. delayed gastric emptying after pancreatic surgery).
In the majority of cases, morbity from nasogastric tubes
exceeds any benefit. Gastrointestinal function returns more rapidly
post-operatively than previously assumed. The absence of
bowel sounds per se does not mean that food and drink will not be
tolerated. In the past, a combination of naso-gastric tubes and
excess intravenous fluids has frequently caused unnecessary delay
in reestablishing oral intake, thereby prolonging the length of stay.
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