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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