A patient who weighs 70 kg has 2100 mL of water (70 kg ×30 mL/kg). In other
words, a patient who weighs 150 lbs weighs 68 kg (150 lbs/2.2 lbs/kg) and has
2240 mL of water.
Each day the patient losses:- 400 mL to 500 mL of water through evaporation from the skin.
- 400 mL to 500 mL of water through breathing.
- 100 mL to 200 mL of water in feces.
- 1000 mL to 1200 mL of water in urine.
This means that each day the patient must take in between 1900 mL and
2400 mL of fluid in order to maintain fluid-electrolyte balance. However, dis-
ease and the treatment of disease can increase the patient’s output of water
requiring that the patient increase the intake of water.
For example, a patient who has a fever loses as much as 15% more water
than the normal daily water loss. That is, the patient loses between 2185 mL and
2760 mL of water each day when he or she has a fever.FLUID REPLACEMENT AND THE NURSING PROCESS
When a patient is experiencing the loss of fluid, the nurse should:- Establish baseline vital signs and weight.
- Review lab results and report elevations in the hematocrit and BUN. If
both values are elevated this could indicate the patient is dehydrated. If the
BUN is >60 mg/dL, renal impairment may be the cause. - Measure urine output. Report if output is <30 mL/h or 600 mL/day.
Normal urine output should be >35 mL/h or 1000 to 1200 mL/day. - Review the lab results for urine specific gravity (SG). Normal range is 1.005
to 1.030. If the SG is greater than 1.030, dehydration may be the cause. - Verify that the proper osmolality of the IV fluids are ordered. If there is
continuous use of one type of IV fluid such as 5% dextrose in water
(D 5 W), hypo-osmolality of body fluid could occur.
Potential nursing diagnoses for a patient that is receiving fluid volume
replacement therapy are:- Risk for fluid volume excess.This can occur when the patient is given too
much replacement fluid, fluid is infused too rapidly, or the volume is
too much for the patient’s physical size or condition.
(^162) CHAPTER 10 Fluid and Electrolyte Therapy