Fluid and Electrolytes

Describe the composition of the major body fluid compartments.

Interstitial space 

• 70% 

Extracellular space 

• 30% 

• Transcellular 

• Interstitial 

• Intravascular 

diffusion

Diffusion - moves from high to low concentration, no energy required

Osmosis

movement of water from low to high  concentration 

Hydrostatic pressure

Push force, higher in the arterial end due to being closer to the pumping heart 

Oncotic pressure

Pull force, higher in the venous end, pulled by the proteins (albumins) 

Osmotic pressure

• The pressure needed to stop osmosis, preventing further movement of water.

2nd spacing 

• Edema , when the Push > than the Pull in the venous end so the fluid is forced into the interstitial space 

• The fluid is still accessible to the body 

• Interventions: compression stocking, colloid

  3rd spacing 

• Ascites, burns, peritonitis

• fluid in the transcellular space 

• The fluid is no longer accessible to the body 

• Interventions : Thoracentesis, pleuracentesis

Identify the impact of normal aging on fluid and electrolyte balance.

-    Decreased thirst mechanism

-    Loss of subcutaneous tissue and thin epidermis – increased loss of moisture

-    Decrease in renin, aldosterone

-    Increases in ADH and ANP

-    Decreased renal blood flow

-    Decreased GFR

-    Loss of ability to conserve water and concentrate urine

-    Decreased creatinine clearance

Recognize indications for and examples of common intravenous fluid solutions (iso-/ hypo-/ hypertonic solutions)

Isotonic - NaCl, LR, D5W 

Hypertonic - D10W, 0.9% NaCL, D5 

Hypotonic - 0.45% NaCl, 

List and summarize the ways in which the body regulates water balance.

Hypothalamus

• thirst receptor

• ADH - increases permeability of reabsorption of water in the distal tubule

• Aldosterone - increases reabsorption of water and sodium in the distal tubule and excrete potassium

CVS

• ANP detects increase in Blood pressure and fluid, vasoconstriction → increased excretion of urine and sodium

  GI

• small amounts of water loss with feces

• large amounts of fluid and electrolyte lost with diarrhea and vomiting

  insensible loss

• water lost that cannot be measured

Hyperkalemia

High amount of potassium in serum

causes

• renal failure

• excess ingestion of potassium

• infection and burn → catabolic state

• acidosis state

S+S

• muscle weakness

• nerve system is altered

• ventricular fibrillation

• cardiac dysrhythmia

• fatigue

treatment

• CBIGKD

Hypokalemia

Alkalotic state

caused by

• abnormal loss - vomiting

• NG suction

• diuretic

• magnesium deficiency

• ASCITES

S+S

• cardiac and skeletal muscle weakness

Tx: oral or IV, do not push IV

Hypercalcemia

Cause

• Hyperthyroidism

• bone malignancy

S+S

• cardiac dysrhythmia

• neuro alteration

TX

• diuretic

• promote excretion of calcium

• diet - consume less calcium

• weight bearing exercise

Hypocalcemia

Cause:

Hypothyroidism, Vit D deficiency

S+S

Trosseau - lack of circulation, wrist is hyper-flexed

Chvostek - touch ear → facial spasm

Tx

• diet and promote intake

Hypomagnesia

Cause

• starvation, diabetes, Nausea + vomiting

S+S

• dysrhythmia, muscle cramp, confusion, seizure

Tx

• oral supplment, IV

Hypermagnesia

Cause

• increased intake, renal failure

S+S

• impair nerve + muscle

• lethargy

• urinary retention

• deep tendon reflex

Tx: dialysis, decrease diet

Hypernatremia

cause: Cushings, hyperaldosternin

S+S: muscle weakness, lethargy, confusion

treatment: decrease sodium and increase fluid intake

Hyponatremia

Fluid loss and Fluid retention

S+S: muscle weakness, cramp, lethargy confusion

treatment: decrease fluid and increase sodium intake

Hypovolemia

• fluid loss

• high fall risk, dizziness, decreased BP and decreased skin turgor

• treatment: increase water intake

Hypervolemia

• fluid retention

• Increase in HR/ BP/ edema, fluid in lungs crackles in the base

• treatment: diuretic, dialysis, restriction, daily I&O