Pharm exam 3 - fluid and electrolyte imbalances

Intracellular fluid

Fluid contained inside all body cells

Extracellular fluid

All fluid outside of the body cells

What are the three subcomponents of extracellular fluid?

• Intravascular fluid (blood vessels)

• Interstital fluid (tissue spaces)

• Transcellular fluid (CSF, Pleural spaces, joint spaces)

  • Does not contribute significantly to fluid balance

Osmolality

describes fluids inside the body, the solute concentration in fluid by weight

What is the normal range for osmolality?

275-295 mOsm/kg

What is a Volume contraction?

decreased body water/ FVD (fluid volume deficit)

What is isotonic contraction?

Loss of equal amounts of sodium and water, causing fluid volume deficit (FVD) without changing osmolality.

• volume contraction

What are the common causes of isotonic contraction?

Hemorrhage, vomiting, diarrhea, NG suction, too many diuretics

What is the treatment for isotonic contraction?

Infuse isotonic fluids

• .9% Sodium Chloride AKA Normal Saline

Desired Outcomes CJMM contractions

Serum Sodium & Osmolality Normal; Moist Mucous Membranes; Stable BP & HR; Improved Mentation & Comfort

What assessment findings suggest isotonic contraction (FVD)?

• Dry mucous membranes

• Poor skin turgor

• Hypotension

• Tachycardia

• Decreased urine output

What labs are expected with isotonic contraction?

• Normal sodium

• Normal osmolality (275–295 mOsm/kg)

• Slightly high urine specific gravity

What is the biggest complication of untreated isotonic contraction?

Hypovolemic shock due to decreased tissue perfusion.

What are the priority nursing interventions for isotonic contraction?

• 0.9% Normal Saline or Lactated Ringer's

• Monitor BP, HR, urine output

• Stop the source of fluid loss (bleeding, vomiting, diarrhea)

What is normal salines (.9%) action?

Increases circulating plasma volume replaces fluid losses without altering fluid concentrations

(most commonly ordered)

Used for: Volume depletion

Special considerations normal saline

• watch for fluid volume overload

• first line choice for volume depletion it is inexpensive and LR has not shown to be superior

What is lactated ringers action?

Replaces fluid and buffers pH

Used for: volume depletion

Special considerations lactated ringers

Contains potassium so do not use in patients with renal failure or in patients with liver disease (can’t metabolize lactate)

What is a hypertonic contraction?

Loss of water exceeds loss of sodium (cell shrivels)

• volume contraction

What are the causes of a hypertonic contraction?

Excessive sweating, severe burns, osmotic diuresis (Mannitol)

What is the treatment for hypertonic contraction?

• Drink water

• Infuse Hypotonic fluids (.45% sodium chloride AKA ½ NS, or D5W)

What is the osmolality for a hypertonic contraction?

Increased = >295 mOsm/kg

What assessment findings suggest hypertonic contraction (FVD)?

• Fever, excessive sweating, heat exposure

• Dry mucous membranes, thirst

• Hypotension, tachycardia

• Weakness, confusion

What labs are expected with hypertonic contraction?

• Hypernatremia (↑ sodium)

• High plasma osmolality

• High urine specific gravity

Memory: Water loss > sodium loss = sodium becomes concentrated.

What is the biggest complication of untreated hypertonic contraction?

• Hypovolemic shock

• Altered mental status/seizures

• Renal impairment

What are the priority nursing interventions for hypertonic contraction?

• Give hypotonic IV fluids slowly (½ NS or D5W)

• Monitor sodium, osmolality, neuro status

• Encourage oral hydration

Remember: Correct slowly to avoid cerebral edema.

What do hypotonic solutions ½ NS and D5W do?

Raise total fluid volume

Example uses of ½ NS and D5W

• Water replacement in dehydration (pt has hypernatremia)

• Excessive sweating

• Hypernatremia

• Hyperglycemia

• Severe burns

• Osmotic diuresis

Special considerations for ½ NS and D5W

• Watch for increased ICP

• Hypovolemia

• Hypotension

• Sodium level

What is a hypotonic contraction?

Loss of sodium exceeds loss of water (cell swells)

• volume contraction

What are the causes of a hypotonic contraction?

Excessive diuretics, chronic renal insufficiency, increased ICP, lack of aldosterone

What is the treatment for a hypotonic contraction?

• depends on sodium levels and renal function

• Mild and severe

What is the treatment for mild hyponatremia?

Infuse isotonic solutions (.9% AKA NS)

What is the treatment for severe hyponatremia?

Infuse hypertonic solutions (3% sodium chloride)

What should we watch for hypotonic treatment?

Fluid volume overload!!

What is the osmolality for hypotonic contraction?

Decreased = <275 mOsm/kg

What assessment findings suggest hypotonic contraction (FVD)?

• Excessive diuretic use

• Fatigue, muscle weakness

• Hypotension, tachycardia

• Confusion or seizures

What labs are expected with hypotonic contraction?

• Hyponatremia (↓ sodium)

• Low plasma osmolality

Memory: More sodium lost than water = diluted blood.

What is the biggest complication of untreated hypotonic contraction?

• Cerebral edema

• Seizures

• Hypovolemic collapse

What are the priority nursing interventions for hypotonic contraction?

• 3% Hypertonic Saline (severe hyponatremia)

• 0.9% Normal Saline (mild/moderate cases)

• Monitor sodium, osmolality, neuro status

• Adjust diuretics if indicated

What does 3% NS or %5 NS do?

Causes a free water shift from the intracellular space to the extracellular space, expanding the extracellular fluid volume

What are the special considerations for hypertonic 3% NS or %5 NS?

• infuse slowly to avoid fluid overload

• watch for fluid overload

• causes phlebitis in small veins infuse via central line

What is volume expansion fluid imbalance?

Increase in total body fluid / FVE (fluid volume excess)

What causes volume expansion?

• Too much IVF

• Heart failure

• Kidney disorders

• Liver disease

What is the treatment for volume expansion?

Diuretics

What does potassium do?

Conducts nerve impulses and maintains the electrical excitability of muscle (heart)
Regulates acid-base balance
Levels regulated by the kidneys

How are potassium levels affected by pH?

◦ Alkalosis enhances K uptake by cells = Blood K⁺ decreases (hypokalemia)
◦ Acidosis enhances K kick-out by cells = Blood K⁺ increases (hyperkalemia)

What does insulin do to potassium?

stimulates K uptake by cells = Blood K⁺ decreases (hypokalemia)

S/S Hypokalemia

The patient may report muscle weakness, muscle cramping, irregular heartbeat & thirst.
The nurse may observe tachycardia, dysrhythmias, & confusion.

What are the treatment options for hypokalemia?

Oral KCL

IV KCL

Oral KCL

• Several preparations available

• Differ by speed of release

• Adverse GI effects, take with plenty of water

• Raises potassium

IV KCL

• Must give diluted and slow

• Can be very irritating to veins

• check K levels periodically to avoid hyperkalemia

• Raises potassium

S/S Hyperkalemia

The patient may report shortness of breath, muscle weakness, fatigue, nausea & tingling of the hands & feet.
The nurse may observe confusion, bradycardia, EKG changes (tented t waves), cardiac arrest.

What do we do first if we suspect hyperkalemia?

withhold K-rich foods or supplements (TOES)

What do we do second if we suspect hyperkalemia?

infusion of insulin and glucose

What do we do if we suspect acidotic hyperkalemia?

sodium bicarbonate will correct pH and encourage K uptake by cells

What do we do finally if we suspect hyperkalemia?

can directly remove K
◦ Kayexalate absorbs K into stool (causes diarrhea)
◦ Dialysis

Normal pH

7.35-7.45

Below 7.35 = acidic

Above 7.45 = alkalosis

Normal CO2 levels

35-45

CO2 is an acid so high levels above 45= acid and low levels below 35 = less acid

How do CO2 levels and pH move

in OPPOSITE directions

Low pH, high CO2 = respiratory acidosis

High pH, low CO2 = respiratory alkalosis

What problem does CO2 indicate?

Respiratory

What is the normal range for HCO3?

22-26

HCO3 is a base so more HCO3 more basic it is

What direction does HCO3 move in with pH?

the SAME direction

low pH, low HCO3 = metabolic acidosis

high pH, high HCO3 = metabolic alkalosis

What problem does HCO3 indicate?

Metabolic problem

Respiratory Acidosis causes:

Asthma attack, airway obstruction (COPD), ARDS, respiratory depression, pneumonia, PE

Respiratory Acidosis produced by:

HYPOventilation
•Decreases pH (Acidosis)
•Decreased breathes retain CO2 (Respiratory)

Respiratory Acidosis treatment:

•Correct respiratory impairment (bronchodilator, oxygen, bipap)
•Sodium bicarb if severe
•Kidneys may try to compensate by retaining more bicarb (to raise pH)

What is the ABG for respiratory acidosis?

Low pH, High CO2

Respiratory Alkalosis cause:

fear/anxiety, panic attack, hypoxia, shock, trauma, CNS injury

Respiratory Alkalosis produced by:

HYPERventilation
•Deep, rapid breathing that blows off CO2 (Respiratory)
•Increases pH (Alkalosis)

Respiratory Alkalosis treatment:

•Bag over nose & mouth (breathe in exhaled CO2)
•Sedative (Benzo)

Respiratory Alkalosis ABG:

High pH, low CO2

Metabolic Acidosis produced by:

•Low bicarb levels in the body (Metabolic)
•Decreased pH (Acidosis)

Metabolic Acidosis caused by:

•Chronic renal failure (reduces bicarb levels)
•Severe diarrhea (loss of bicarb causes acidosis)
•Overproduction of lactic or keto acids (liver disease, DKA)

Metabolic Acidosis treatment:

•Correct cause (hypokalemia? → potassium)
•Give sodium bicarb - po if mild, IV if severe (to raise bicarb levels)
•Pt may have deep, labored breathing (Kussmaul) to blow off CO2 and increase
the pH

Metabolic Acidosis ABG:

Low pH, low HCO3

Metabolic Alkalosis produced by:

•Increased bicarb in plasma (Metabolic)
•Increased pH (Alkalosis)

Metabolic Alkalosis caused by:

•Excessive loss of gastric acid (vomiting or NG tube suction)
•Antacid OD

Metabolic Alkalosis treatment:

•IVF 0.9% NS + KCL (makes kidneys excrete bicarb, lowering pH)
•Infusion of hydrochloric acid via central line (to lower pH)
•Body will compensate by hypoventilation (to retain CO2)

Metabolic alkalosis ABG:

High pH, high HCO3