Fluids & Electrolytes

IV fluids

crystalloids and colloids

crystalloids

ex: sodium chloride, dextrose, lactated ringers

• Uses: dehydration, fluid maintenance, electrolyte imbalances

• Described based on: Isotonic, Hypotonic, Hypertonic

• distributes faster than colloids

Isotonic Fluid Names

• 0.9% NaCl

• Lactated RIngers

• Dextrose 5% and water D5W

0.9% NaCl “normal saline”

sodium chloride

• uses: maintenance fluids, flush IV, give with blood, hypotension and shock

• contraindications: only fluid you give blood with

Lactated Ringers LR

sodium chloride, potassium, calcium, lactate

• uses: maintenance fluids, hypotension and shock

Dextrose 5% and water D5W

free water, dextrose, 1L= 17- cal

• uses: maintenance fluids and provides some carbs

• contraindication: increased blood glucose and no bolus

Hypotonic Fluid

• 0.4% NaCl “half normal saline”

  • uses: maintenance fluid and for hypernatremia

  • contraindications: monitoring neur

• 0.225% NaCl “ quarter normal saline”

• uses: severe symptomatic hypernatremia

• contraindications: monitoring neuro

Hypertonic Fluids

• 3% NaCl

  • uses: severe symptomatic hyponatreamia

  • contraindications: risk of demyelination syndrome and monitoring BP and lung

• dextrose 5% and 0.9% NaCl

  • uses: maintenance fluid with hyponatremia

  • contraindication: monitoring Bp and lungs

water balance basics

• more fat present in body= less total water content

• women have more body fat

• & of body water

  • preterrn and neonates: >70%

  • adults: 50-60%

  • older adults: 45-50%

Colloids

large molecules— stay in vascular space

• increase osmotic pressure

• ex: plasma, blood, albumin

  • dextran= synthetic form

• use: treat conditions that require plasma volume expansion (shock and burns)

• less livekly to cause edema and have a longer duration of action

movement of moleules and fluids

• diffusion:

  • molecules, high to low , no energy uses

• facilitated diffusion

  • requires carrier to move molecules

• osmosis

  • fluid, across permeable membrane, low to high concentration until equal

• active transport

  • molecules against gradient, low to high concentration, requires ATP energy

Osmolality

“concentration”

• normal plasma: 280-295 m0sm/kg

• low plasma osmolality= water excess ( less concentrated) diluted’

• high plasma osmolality= water deficit (more concentrated) not diluted/dark urine

hydrostatic pressure

pushes fluid out of vessel

oncotic pressure

pulls fluid into vessel

Fluid shifts

1. st space: fluid where expected, no edema

2. nd space: fluid shifts from capillary to interstitial space, edema

3. rd space: nonfunctional space between cells (ex: ascites)

Antidiuretic Hormone

posterior pituitary hormone

• tells kidneys to hold onto fluid

Regulation of Fluid Balance: Hypothalamic Pituitary

osmoreceptors in hypothalamus detect FVD and FVE through increased or decreased plasma osmolality

• FVD: hypothalamus stimulates pituitary to secrete ADH

  • kidneys respond by increasing water reabsorption

  • increasing osmolality

• FVE: hypothalamus tells pituitary to suppress ADH release

  • kidneys respond by increasing diruesis

  • decreasing osmolality

Regulation of Fluid Balance: Adrenal Cortex

releases hormones to regulate water and electrolytes

• glucocorticoids: cortisol

  • antiinflammatory effects

  • inceases blood glucose

• mineralocorticoids: aldosterone (when increases it tells kidneys to hold on to urine)

  • sodium and water reabsorption in kidneys

Renin- Angiotensin- Aldosteron System (RAAS)

activated with hypotension & low perfusion

• Goal: conserve water and raise BP

1. Renin released by. kidneys……

2. Angiotensin 1 to be converted to Angiotensin 2

3. Angiotensin 2 is a potent vasoconstrictor which causes secretion of aldosterone

4. aldosterone from adrenal glands —→ sodium and water reabsorbed into circulation by nephrons'

5. result: fluid retention to raise  BP

Regulation of Fluid Balance: Cardiac

(stretching of atria, opposite of endocrine response)

• natriuretic peptides:

  • atrial natriuretic peptide (ANP)

  • B type Natriutretic peptide (BNP)

• sense increased atrial pressure in fluid volume overload

• antagonists to RAAS (suppress aldosterone renin & ADH)

  • leads to decreased blood volume and BO

Regulation of Fluid Balance: Gastrointestinal

• oral intake= most water, including water in foods such as veggies

• diarrhea and vomiting can lead to significant fluid and electrolyte loss

Regulation of Fluid Balance: Older Adult Considerations

• kidneys: decreased ability to conserve water

• endocrine: decrease in renin and aldosterone and increase in ADH and ANP

• skin: loss of subq tissue —> to increased moisture lose

Normal Lab Values

• BUN

• Creatinine

• Hematocrit

• Urine Specific Gravity

• Osmolality

• BUN: 7-20 mm/dL

• Creatinine: 0.84-1.21 mg/dL

• Hematocrit:

  • M: 41-50%

  • F: 36-44%

• Urine Specific gravity: 1.002-1.030

• Osmolality: 280-295 m0sm/kg

Lab values: Fluid defecit

• BUN

• Creatinine

• Hematocrit

• Urine Specific Gravity

• Osmolality

all lab values increase excepts creatinine remain normal

Lab Values: Fluid Excess

all lab values decrease except creatinine remains normal

Fluid Volume Imbalance

Hypovolemia & Hypervolemia

Hypovolemia

ECF loss > intake

• cases: blood loss, GI loses (V/D), insensible loses, sweating, fever

• manifestations: dry mouth, skin turgor, decreased urine output

• signs/symptoms:4 C’s

  • Cap refill delayed

  • confused

  • cramping

  • cool and clammy

Hypervolemia

Fluid Retention > Output

• causes: fluid in lungs, heart failure, dialysis (renal failure), excessive IV administrration

• Manifestations: edema, lung crackles, vein buldge

• signs/symp: 3 C’s

  • crackles

  • cant catch breath (dyspnea)

  • cough

Sodium Main Roles

• ECF volume and concentration

• generation and transmission of nerve impulses

• muscle contractility

• acid base balance

thirst from thalamus= primary protection against imbalances

sodium imbalances

hyponatremia v hypernatremia

Hyponatrremia

<135 mEq/L

• causes: excessive free water intake, diuretic drug (losing), SIADH (increases ADH) syndrome of innappropriate ADH, addisons disease

• Manifestations: asymptomatic, N/V/D, mailase, headache, lethargy and disorentiation, seizure and coma

• managemet: restrict fluid intake and increase sodium intake

Hypernatremia

>135mEq/L

• causes: sweating (decrease fluid), diabetes, hypertonic fluids

• manifestations: severe coma and seizures

  • FRIED

  • Fever (low), flushed skin

  • Restless (irritable)

  • Increased Fluid retention and increased BP

  • Edema (peripheral and pitting)

  • Decreased urine output , dry mouth

• Management: increase fluid

Potassium Main Roles

transmission and conduction of nerve and muscle impulses

• cellular growth

• maintenance of cardiac rhythms

• acid base balance

think kidneys— excrete 90% potassium: renal damage leads to increase potassium retention

Potassium Imbalance

Hypokalemia v Hyperkalemia

Hypokalemia

• causes: GI loss (NG tubve), decreased intake, non potassium sparing diuretic

• Manifestation: (A SIC WALT (decrease)- alkalosis, shallow resp, irritability, confused/ drowsiness, weakness/ fatigure, arythmias (irregular rate and tachycardia), lethargy, thready pulse, decreased intestinal motility, N/V, ileus

• flattened t waves and prominent U waves

• Management: IV potassium and heart monitor

Hyperkalemia

• causes: renal dysfunction, addisson’s disease, trauma, excessive administration

• Manifestations: muscle twitches— cramps— paresthesia, irritability/anxiety, decreased BP, EKG changes (tented T waves), dysrhythmias= irregular rhythms, abdominal cramping, diarrhea

• Management: low potassium diet and heart monitor

Hyperkalemia medications

• calcium gluconate

• sodium polystyrene

• sodium zirconium cyclosilicate

• insulin (w/ dextrose)

• sodium bicarbonate

Calcium Gluconate

hyperkalemia medication

• MOA: stabilizes myocardium

• effect: decrease risk of arrythmias

• nursing considerations: does NOT decrease potassium

Sodium Polystyrene

hyperkalemia medication

• MOA: cation exchange resin

• effect: decrease potassium

• nursing considerations: dont use with ileus 

Sodium Zirconium Cyclosilicate

hyperkalemia medication

• MOA: potassium binder

• effect: decrease potassium

• nursing considerations: dont use w ileus and must jave functioning GI tract

INsulin (w/ dextrose)

hyperkalemia medication

• MOA: shift potassium into cell

• effect: decrease potassium

• nursing consideration: monitor blood glucose

Sodium Bicarbonate

hyperkalemia medication

• MOA: shift potassium into the cell

• Effect: decrease potassium

• nursing consideration: monitor blood glucose

IV potassium Administration

• always diluted

• infused slowly with infusion pump: 11mEq/hr PIV max and 20 mEq/hr CVL max

• monitor urine output: renal impairment —decreased potassium excretion

• monitor for signs of phlebitis: potassium can burn veins

• avoid digoxin toxicity associated with hypokalemia

Calcium Main Roles

• formation of teeth and bone

• blood clotting

• transmission of nerve impulses

• myocardial and muscle contractions

Calcium: Type, Source, Regulation

• obtained by ingested foods (need VD to absorb)

• present in 3 forms (ionized calcium is biologically active)

• changes in pH and serum albumin affect levels

• Balance Controlled by hormones:

  • parathyroid hormone (PH): stimulated by LOW calcium

  • Calcitonin: stimulated by HIGH calcium

Calcium Imbalance

Hypocalcemia v Hypercalcemia

Hypocalcemia

• causes:

  • hypothyroidism

  • malabsorption

  • renal impairment

  • pancreatis

• Manifestations:

  • Chvosteks

  • Trousseau’s

  • Hyperreflexia

  • seizures

  • arrythmias

  • laryngeal spasm / stridor (airway closure)

  • prolonged QT interval

• Management:

  • PO/IV replacement

  • Heart monitor

Hypercalcemia

• causes:

  • 1/3 cause cancer

  • hyperparathyroidism

• Manifestations:

  • weakness

  • fatigue

  • Hypotension

  • Arrythmias

  • Calcium/ kidney stones

  • shorter QT

  • constipation

• Management:

  • heart monitor

  • remove overactive gland

  • increase hydration

Magnesium Functions

• Coenzyme in metabolism of Carbohydrates

• Required for DNA and protein synthesis

• Blood glucose control

• Necessary for ATP production

• Muscles

Magneisum Imbalance

Hypomagnesium vs hypermagnesium

Hypomagnesium

• causes:

  • #1 alcohol use disorder

  • malnutrition

• Sign/Symptom:

  • similar to hypocalcemia (Chvosteks, Trousseau’s, Hyperreflexia, seizures, arrythmias, laryngeal spasm / stridor (airway closure), prolonged QT interval) HYPERTENSION!!

  • Torsade de pointes ( v fib)

• Management: replacement

Hypermagnesium

• causes:

  • #1 renal failure

• Sign/Symptoms:

  • similar to hypercalcemia (weakness, fatigue, Arrythmias’s, Hypotension, Calcium stones, shorter QT)

  • NO KIDNEY STONES

  • bradycardia 

  Management

  • avoid magnesium foods

  • Dialysis
    

Phosphate Function

• most is in the bones and teeth in for of calcium phossphate

• essential to function of muscle, RBCs, and nervous syste,

• involved in acid. base buffering system, ATP production, cellular uptake of glucose, and metabolism of carbs, proteins, fats

• Reciprocal relationship with calcium

Phosphate Imbalance

Hypophosphate vs hyperphosphate

hypophosphate

• causes:

  • decreased intake

  • malabsorption

  • hyperparathyroidism

  • malignancy

• Signs/Symptoms:

  • similar to hypercalcemia (weakness, fatigue, Hypotension, Arrythmias, Calcium Stones, shorter QT)

  • No KIDNEY STONES
    Constipation

• Acute/mild: may be asymp

• Severe: may be fatal, CNS depression, resp/cardiac failure

• chronic: osteomalacia

• Management:

  • Phosphate supplementation

  • osteoporosis

Hyperphosphate

• causes: 

  • renal failures

  • excessive phosphate intake

  • hypoparathroidism

  • tumor lysis sysdrom

• Signs/Symptoms:

  • similar to hypercalemia (Chvosteks, Trousseau’s, Hyperreflexia, seizures, arrythmias, laryngeal spasm / stridor (airway closure), prolonged QT interval

  • neuromuscular irritability

  • may be asymp

  • calcium deposists in soft tissues and kidneys

• Management:

  • phosphate binders

  • avoid phosphate rich foods

  • diuretics