Fluid Therapy

Chapter 7 Fluid Therapy



Elizabeth Cox, MD , Keith Baker, MD, PhD




1 How is water distributed throughout the body?


Total body water comprises 60% of body weight in males and 50% of body weight in females. The distribution of this water is 40% in intracellular space (30% in females because of larger amounts of subcutaneous tissue and smaller muscle mass) and 20% in extracellular space. The extracellular fluid is broken down into 15% interstitial and 5% plasma. Total body water decreases with age; 75% to 80% of a newborn infant’s weight is water.



2 What are sensible and insensible fluid losses? How are maintenance fluid requirements calculated?




image Insensible losses (nonmeasurable)


image Skin: 600 mL

image Lungs: 200 mL

image Sensible losses (measurable)


image Fecal: 200 mL

image Urine: 800-1500 mL

image Sweat: Variable

These losses account for 2000 to 2500 mL/day, giving a 24-hour fluid requirement of 30 to 35 mL/kg to maintain normal fluid balance.



3 What are fluid maintenance requirements for children?


Twenty-four–hour fluid requirements for children have been formulated on the basis of weight:



image 4:2:1 rule: 4 mL/kg per hour for the first 10 kg


image Then add additional 2 mL/kg per hour for the next 10 kg to 20 kg


image Then add 1 mL/kg per hour for every kilogram after that


EXAMPLE: 30-kg child


40 + 20 + 10 = 70 mL/hr maintenance



4 Describe the clinical features of volume deficit and volume excess




image Deficits (low volume)


image Central nervous system: decreased mentation in severe cases

image Cardiovascular: tachycardia, hypotension (in later stages)

image Skin: decreased turgor in subacute volume loss
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Jul 6, 2016 | Posted by in CRITICAL CARE | Comments Off on Fluid Therapy

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