Fluid and Electrolytes: Balance and Disturbances

Jimmy Durbin, MSN, RN

Body Fluids

• Factors that influence body fluid• 60% of our body is fluid (water and electrolytes.• Perform numerous functions (what electrolytes

do)– Promote neuromuscular irritability – Maintain body fluid osmolality– Regulates acid/base balance– Regulate distribution of body fluids among body fluid

compartments

Nursing Implications with Electrolytes

• Must assess fluid and electrolyte balance by doing daily I&O

• Assess LOC• Evaluate sensory and motor function and

neuromuscular irritability• Monitor VS and electrolytes• Look at EKG to detect changes• Assess the nutritional status (b/c electrolytes are

obtained thru food intake)• Evaluate the health history for medical conditions

that might alter these fluid and electrolytes • Evaluate medication history for prescriptions or

OTC meds that can affect lytes

Body Fluid Shit

• Younger ppl have a higher percentage of body fluid than old ppl

• Men more body fluid than women

• Obese people have less fluid than those who are thin (b/c fat cells contain very little water)

• Bone has a lower water content

• The highest amt of water is found in muscle, skin, and blood

ICF vs. ECF

• Intracellular space (fluid in the cells) and Extracellular space (fluid outside a cell)

• 2/3rd located in ICF and is usually in skeletal mass.

• 1/3rd located in ECF.

ICF vs. ECF

• ECF further divided – Intravascular-contains plasma

• Plasma is 3 L of the 6 L of blood in your body. Plasma is half of the blood in your body

– Interstitial-fluid that surrounds the cell• Lymph and lymph system. About 11-12 L of this in the body

– Transcellular• 1 L in the body. This consists of cerebrospinal fluid,

pericardial fluid, synovial fluid (in your joints), interoccular fluid, and pleural fluids.

• Shifting of fluid– Normal (keeps normal balance)

• Third spacing– Anything inside the cells is referred to as this. When

it’s in the cell it’s not useable.

Third Spacing

• Manifestations – ↓Urine output (even tho they’re drinking

adequately, b/c the fluid is unuseable)

Other s/s– ↑Heart rate– ↓BP, ↓CVP (central venous pressure), edema– ↑Body weight

• Imbalances in I/O

Electrolytes

• Active chemicals in body fluids

– Cations (+ charge)

• Na+, K+, Ca++, Mg+, H+

• Sodium, potassium, calcium, magnesium, and hydrogen

• Sodium concentration effects the overall concentration of the extracellular fluid. It’s the most important in regulating the volume of body fluid

– Anions (- charge)

• Cl-, HCO3, Phos.

• Chloride, bicarbonate, and phosphorus

Regulation of Fluid • Osmosis and Osmolality

– Osmosis: the movement of a pure solvent, such as water, thru a permeable membrane from a solution with lower solute (or concentration) to a higher solute (or concentration) It’s trying to even out

• Diffusion– Particles in a fluid move from an area of higher concentration to

an area of lower concentration resulting in even distribution. The body always wants to be in homeostasis

• Filtration– Separate out an unwanted material

• Sodium-Potassium Pump– Protein that transports sodium and potassium ions across

membranes against their concentration gradient. In other words, it doesn’t naturally move that way, but the protein assists in moving it against the grain.

Routes of Gains & Losses

• Kidneys– Lose in the form of urine

• Skin– Sweat, visible loss.

• Lungs– Moisture you breathe out in a vapor. Usually lose

400 mL of water Fever can greatly increase this.

• Gastrointestinal Tract– Poop and whatnot

Sodium• Major electrolyte in ECF

• Normal: 135-145 mEq/L

• ECF levels effect ICF levels:

serum Na+ = dilute ECF

• H2O drawn into cells

serum Na+ = concentrated ECF

• H2O pulled out of cells

• Na+ into cell K+ moves out of cell

• Low sodium is hyponatremia

• High sodium is hypernatremia

Function of Sodium

• Controls H2O distribution• Determine ECF concentration• Determine ECF volume (remember, where

Na goes, water follows)• Electrochemical state for proper muscle &

nerve function– Sodium is responsible for establishing the

electro chemical state necessary for muscle contraction and the transmission of nerve impulses

Serum sodium level decreases(water excess)

Serum osmolality falls to less than 280 mOsm/kg

Thirst diminishes, leading to decreased water intake

Antidiuretic hormone (ADH) release is suppressed

Renal water excretion increases

Serum sodium level increases(water deficit)

Serum osmolality rises to more than 300 mOsm/kg

Thirst increases , leading toIncreased water intake

ADH release increases

Renal water excretion diminishes

Serum osmolality normalizes

Hyponatremia

• Sodium < 135 mEq/L

• Causes– Excessive Na loss – Excessive H2O gain (dilutes the Na we

already have, which lowers levels)– Both water and Na levels increase in

ECF, but water is more impressive (cause it can dilute the Na levels). This can happen from HF, liver failure, or admin of hypotonic IV fluids

Sodium Loss

• Loss of GI fluids or secretions• Excessive sweating• Medications• Addison’s Disease

adrenocorticoid & aldosterone secretion– Addison’s is a life threatening condition caused

by partial or complete failure of the adrenal corticoid function resulting from autoimmune processes and also result from infection (either tubercular or fungal), a neoplasm, or hemorrhage

Water Gain

• Excess IVF (hypotonic)

• SIADH (Syndrome of Inappropriate Anti-diuretic

Hormone)

– There’s excessive or inappropriate production of the ADH

(anti diuretic hormone) which results in a dilutional

hyponatremia due to abnormal retention of water. You’re

holding on to water which dilutes the Na you already have,

which lowers the Na levels

• Continuous bladder irrigation

• Fresh H2O near drowning

• Psychogenic polydipsia – excessive water drinking

S/S Hyponatremia

• S/S depend on the cause, magnitude and speed at which the deficit occurs. (if slowly, probably not a lot of initial S/S, but rapid you get these quickly)– Poor skin turgor– Dry mucosa– Headache – Decreased saliva production– Orthostatic fall in BP (you move them and their BP falls)– Nausea– Abdominal cramping

S/S Hyponatremia

• Neurological changes– Altered mental status– Status epilepticus– Obtundation – deadening to pain or a reduced

irritation and it blocks the sensibility at some level of the central nervous system. They are just there, they don’t feel pain. You pinch them and they don’t move.

The more rapid the loss, the more severe and dangerous the signs.

S/S Hyponatremia

• Usually due to sodium loss– Anorexia– Muscle Cramps– Lethargy

• Severity of the symptoms also depend on the degree and speed in which it develops.

• Normally you won’t see S/S until the Na is below 120. At levels of 115, signs of increasing intracranial pressure are lethargy, confusion, muscle twitching, weakness, and they may even go into a coma.

Hyponatremia: Lab Data

• Serum Na+ < 135 mEq/L

• Serum osmolality < 280 mOsm/kg– Normal serum osmolality is greater than 280

• Urinary Na+ < 20 mEq/L

• Urine specific gravity < 1.010

Medical Treatment for Hyponatremia

• Na replacement by mouth, IV, or NG Tube• Replacement depends on the rate lost

– Can use LR, NS – When replacing Na, watch for signs of fluid

overload or pulmonary edema! • Fluid overload S/S are: Tachypnea, tachycardia,

SOB, may hear crackles or rhonchi with ascultation, and an increase in BP

• Rule of thumb: serum Na must not be increased > 12 mEq/L in a 24 hour period. – If you overcorrect this too quickly you can cause

neurological damage.

Medical Treatment for Hyponatremia

Water gain:• Restrict H20 safer than giving Na

(800ml/24hr)• Hypertonic solution 3%-5% NaCl• Edema only-restrict Na• Edema and Na- restrict both• Loop Diuretics (lasix)• With severe hyponatremia, goal is to

elevate Na level until the neurological signs are gone

Nursing Interventions

• Identify pt. at risk– Monitor labs, I&O, daily weight

• Review medications• GI manifestations• Monitor for S/S of hyponatremia• Monitor for neurological changes (big sign

with hyponatremia)• Oral hygiene (esp when they’re on fluid

restrictions or NG tubes)

SIADH

• Syndrome of Inappropriate Anti-Diuretic Hormone

• Body secretes too much antidiuretic hormone (ADH)

• Disturbs fluid and electrolyte balance– Because you’re retaining fluid and dilutes your

levels of stuff

• Major cause of low sodium levels

SIADH

What happens:• ADH increases the permeability of the renal tubules• Increased permeability of renal tubules increases water

retention and extracellular fluid volume

• Leads to: – Reduced plasma osmolality (less stuff in your plasma)– Dilutional hyponatremia– Dimished aldosterone secretion– Elevated GFR (glomerular filtration rate)

• Increased sodium excretion and shifting of fluids into cells

SIADH

Can result from:• Sustained secretion of ADH from

Hypothalamus• Production of ADH-like substance from a

tumor (remember, benign tumors like to pop out stuff like hormones)– Oat cell lung tumor

• Head injury, pulmonary disorders, physical or psychological stress, or certain meds

S/S of SIADH

• Same as Hyponatremia

• Fingerprinting– When the finger is pressed over a bony

prominence it leaves an indention. Leave an indention similar to pitting edema, but just not as dramatic

Lab Values of SIADH

• Low BUN and Creatinine

• Due to over hydration – elevated urine sodium > 20 mEq/L – elevated urine specific gravity > 1.012

Treatment of SIADH

• Treat the underlying cause• Replace sodium

– Hypertonic solution (NS)• NS cannot be used alone to treat hyponatrimia caused

by SIADH because excessive Na would be excreted rapidly and your urine would be highly concentrated with Na.

– Diuretic –Lasix

• If water restriction is difficult– Use lithium or demeclocycline

Nursing Management of SIADH

• Monitor I/O• Daily weight• Monitor for Neurological symptoms• Monitor for lithium toxicity (if they’re on

lithium, of course)• Ensure adequate sodium intake• Avoid excess water supplements• Monitor urine specific gravity • Monitor serum sodium

Hypernatremia• Na+ > 145 mEq/L• Causes:

H2O intake– Hypertonic tube feeding with H2O

supplement(Na+ gain)– IVF with Na+

– H2O loss (thru GI, burns, heat)– CAPD (Continuous Alternating Peritoneal

Dialasis. Tube in their abd and they run a bag of fluid in. Works like a filtration or something b/c their kidneys don’t work).

– Diabetes Insipidus– Partial salt water drowning

S/S Hypernatremia

• Primarily neurological• Moderate hypernatremia

– Restlessness, weakness, fatigue• Severe hypernatremia

– Disoriented, delusional, hallucinations, may see some seizure activity

• Dehydration• Thirsty (all the time)• One of the most important signs of hypernatrimia is

neurological b/c of the effect that fluid shifts have on brain cells. Make sure you don’t give an IV that’s going to push fluid into the cells of the brain and make them expand.

• If hyper is sever enough you can have brain damage. • A healthy person that can drink usually won’t get into trouble

with this. But if their crazy or wandering the desert w/o water this can happen.

S/S of Hypernatremia• Dry, swollen tongue, sticky mucous

membranes

• Flushed skin

• Mild increase in temperature

• Peripheral and pulmonary edema

• Postural hypotension

• Increased deep tendon reflexes and nuchal rigidity (your neck gets stiff)

Memory Jogger

• SALT. Remember, hypernatrimia is caused by too much salt. S/S are as follows:

• S = Skin Flushed• A = Agitation• L = Low grade fever• T = Thirst (complain of intense thirst from

stimulation of hypothalumus b/c of the increased serum osmolality)

Hypernatremia Lab Data

• Serum Na+ > 145 mEq/L

• Serum osmolality > 300 mOsm/L

• Urine specific gravity > 1.015

Hypernatremia Medical Treatment

serum Na+ level gradually– We already talked about how it can cause brain

damage if you do it too fast approx. 0.5-1mEq/L/hr over 48 hrs• Monitor for neuro changes & cerebral edema• Hypotonic solution D5W or 0.45% NS• Desmopressin (DDAVP)• As Na levels rise in the blood, fluid shifts out of

the cells to dilute the blood and equalize the concentration. If too much water is introduced too quickly the water will move into the brain cells causing cerebral edema

Hypernatremia Nsg Interventions

• Identify pt at risk• Monitor fluid loss / gain• Neuro precautions and behavior changes• Monitor labs• Monitor oral Na intake • Offer fluids• Note medication with Na+ content• Pt’s that are at risk for hyper are infants,

confused ppl that won’t take in any liquids, immoble people, elderly, unconscious people, and people post surgery procedures