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Fluid Assessment
Cherelle Fitzclarence
2009
Overview
Revision Cases
We are approximately two-thirds water
PG
JXZ
Fluid shifts / intakes
Intracellular
30 litres
Interstitial9 litres
IV 3 litres
Kidneys Gut Lungs Skin
Extracellular fluid - 12 litresPG
Fluid shifts / intakes
Intracellular
30 litres
Interstitial9 litres
IV 3 litres
Kidneys Gut Lungs Skin
Extracellular fluid - 12 litresPG
REGULATION OF FLUID VOLUME
BODY FLUID COMPARTMENTS
RULE OF THIRDS1. Intracellular: 2/3 (40% TBW)
2. Extracellular: 1/3 (20% TBW)
a. Interstitial + Lymph: 2/3 (15% TBW)
b. Intravascular: 1/3 (5% TBW)
Fluid Pressures (Starling’s Law)
ECF and ICF fluid shifts occur related to changes in pressure within the compartments
Fluid flows only when there is a difference in pressure
3 types of body fluids Isotonic Hypotonic Hypertonic
Fluid shifting
1st space shifting- normal distribution of fluid in both the ECF compartment and ICF compartment.
2nd space shifting- excess accumulation of interstitial fluid (edema)
3rd space shifting- fluid accumulation in areas that are normally have no or little amounts of fluids (ascites)
FLUID VOLUME DEFICIT
Hypovolemia: isotonic extracellular fluid deficit
Deficiency of both water & electrolytes
Caused by decreased intake, vomiting, diarrhea, fluid shift
Dehydration: hypertonic extracellular fluid deficit
Deficiency of water Caused by water loss
related to high blood glucose, inadequate ADH production, high fever, excess sweating
Assessment of Fluid Deficit
Hypotension Weak rapid pulse Temperature decreased if hypovolemic, and
increased in dehydration Weight loss Skin turgor poor in dehydration and possible
edema in hypovolemic Concentrated urine and blood
FLUID VOLUME EXCESS
Extracellular: isotonic fluid excess Excess of both water and
electrolytes Caused by retention of water
and electrolytes related to kidney disease; overload with isotonic IV fluids
Intracellular: water excess Excess of body water
without excess electrolytes Caused by over-hydration
in the presence of renal failure; administration of D5W
FLUID VOLUME EXCESS/Assessment Isotonic
Hypertension Bounding pulse Crackles, dyspnea Weight gain Edema in extremities JVD Irritable, confused
Hypotonic Systolic B/P ^ Decreased pulse Increased respirations Weight gain Cerebral edema Irritable, confused
FLUID VOLUME EXCESS/ Treatment Isotonic
Correct cause Restrict H2O and Na Diuretics Digitalis Possible dialysis
Hypotonic Correct cause Restrict H2O intake IV fluids with E-lytes
Dehydration
Occurs when fluid loss exceeds intakesweating vs time
Fluid lost mostly from ECFdecreased circulating blood volume
inadequate tissue perfusion, inefficient transport of substrates to muscle, and elevated HR