Fluid & Electrolyte Balance

NCM 103Lecture

Prepared by: Marjo S. Malabanan

Body Fluids Water= most important nutrient for life. Water= primary body fluid.

Adult weight is 55-60% water. Loss of 10% body fluid = 8% weight loss SERIOUS Loss of 20% body fluid = 15% weight loss FATAL Fluid gained each day should = fluid lost each day

(2 -3L/day average) What is the minimum output per hour necessary to

maintain renal function? 30ml/hr

Functions of Body Fluid

Medium for transport Needed for cellular metabolism Solvent for electrolytes and other

constituents Helps maintain body temperature Helps digestion and elimination Acts as a lubricant

Mechanisms of Fluid Gain and Loss

Gain Fluid intake 1500ml Food intake 1000ml Oxidation of

nutrients 300ml(10ml of H20 per 100 Kcal)

Loss “Sensible”

Can be seen.Urine 1500mlSweat 100ml

“Insensible”Not visible.Skin (evaporation) 500mlLungs 400mlFeces 200ml

Regulation of Fluids

Hypothalmus –thirst receptors (osmoreceptors) continuosly monitor serum osmolarity (concentration). If it rises, thirst mechanism is triggered.+Vasopressin (AKA ADH )– increasing H20 reabsorption

Pituitary regulation- posterior pituitary releases ADH (antidiuretic hormone) in response to increasing serum osmolarity. Causes renal tubules to retain H20.

Thirst is a late sign of water deficit

Regulation of Fluids (continued )

Renal regulation- Nephron receptors sense decreased pressure (low osmolarity) and kidney secretes RENIN. Renin – Angiotensin I – Angiotensin II

Angiotensin II causes Na and H20 retention by kidneys AND…..

Stimulates Adrenal Cortex to secrete Aldosterone which causes kidneys to excrete K and retain Na and H20.

Consider This….

The Geriatric Client-normal physiological aging results in decreased thirst mechanism decreased # of sweat glands decreased renal function-there also may be decreased mobility and/or cognitive function which impacts their ability to get adequate fluid intake.

Variations in Body Fluids

Elderly: Have lower % of total body fluid than younger adults

Women: Have lower % total body fluid than men

WHY DO YOU THINK THIS IS ?????

Muscle tissue has more H20 content THAN adipose tissue

Fluid Compartments

Intracellular fluid (ICF)

Fluid inside the cell

Most (2/3) of the body’s H20 is in the ICF.

Extracellular Fluid (ECF)

Fluid outside the cell. 1/3 of body’s H20 More prone to loss 3 types:Interstitial- fluid

around/between cellsIntravascular-

(plasma) fluid in blood vessels

Transcellular –CSF, Synovial fluid etc

Consider this….

Age variations exist in regards to H20 content of fluid compartments

Infants =60% of H20 is found in ECF40% of H20 is found in ICF

What might this mean in regards to fluid loss for an infant? Reverse of adults!

Infant MORE PRONE to fluid LOSS!

Fluid Balance Dynamic process Balance between body fluids

and electrolytes Attraction between ions

(electrolytes) and water (fluids) causes fluids to move across membranes and leave their compartments.

Solvent (H20) Movement

Cell membranes are semipermeable allowing water to pass through

Osmosis- major way fluids transported Water shifts from low solute concentration to high solute concentration to reach homeostasis (balance).

Osmolarity

Concentration of particles in solution The greater the concentration (Osmolarity) of a

solution, the greater the pulling force (Osmotic pressure)

Normal serum (blood) osmolarity = 280-295 mOSM/kg

A solution that has HIGH osmolarity is one that is > serum osmolarity = HYPERTONIC solution

A solution that has LOW osmolarity is one that is < serum osmolarity = HYPOTONIC solution

A solution that has equal osmolarity as serum = ISOTONIC solution

Hypertonic Fluids Hypertonic fluids have a higher

concentration of particles (high osmolality) than ICF

This higher osmotic pressure shifts fluid from the cells into the ECF

Therefore Cells placed in a hypertonic solution will shrink

Hypertonic Fluids

Used to temporarily treat hypovolemia Used to expand vascular volume Fosters normal BP and good urinary output

(often used post operatively) Monitor for hypervolemia !

Not used for renal or cardiac disease.

Hypotonic Fluids

Hypotonic fluids have less concentration of particles (low osmolality) than ICF

This low osmotic pressure shifts fluid from ECF into cells

Cells placed in a hypotonic solution will swell

Hypotonic Fluids Used to “dilute” plasma

particularly in hypernatremia Treats cellular dehydration Do not use for pts with increased

ICP risk or third spacing risk

Isotonic Fluid Isotonic fluids have the same

concentration of particles (osmolality) as ICF (275-295 mOsm/L)

Osmotic pressure is therefore the same inside & outside the cells

Cells neither shrink nor swell in an isotonic solution, they stay the same

Isotonic Fluid Expands both intracellular and

extracellular volume Used commonly for: excessive

vomiting,diarrhea 0.9% Normal saline D5W Ringer’s Lactate

Other Osmotic Factors ALBUMIN ( a serum protein ) Albumin in the serum has osmotic properties

called colloid pressure Albumin pulls H20 from the interstitial

compartments into the intravascular compartments (serum). Helps to maintain BP.

Persons with low serum albumin levels tend to retain fluid in their interstitial layers.

What abnormal assessments might you find in the client with low serum albumin levels?

Edema, hypotension

Hmmm…….

What type of IV fluid(hypotonic – isotonic – hypertonic)might be of benefit to this client with low albumin levels?

Consider this….

When tissue injury occurs, proteins pathologically leak from the intravascular space into the intersititial space.Termed: Third spacing

This explains __________ as a sign of the inflammatory process.

EDEMA

Solute Movement - Diffusion

Movement of solutes from high concentration to low concentration

It is a PASSIVE movement DOWN the concentration gradiant. (requires no energy)

Many body processes use diffusion. Example: O2 and CO2 exchange

Rate is affected by: concentration gradiant, permeability-surface area-thickness of membranes, and size of particles. (Fick’s Law)

Solute Movement –other mechanisms

Active transport- requires energy (ATP) to move from low concentration to high concentration (uphill)Example: Na / K pump

May be enhanced by carrier molecules with binding sites on cell membraneExample: Glucose (Insulin promotes the insertion of binding sites for Glucose on cell membranes).

Filtration Solvent AND solute movement Passage from an area of High Pressure to an

area of Low Pressure Termed: Hydrostatic Pressure

Example:Arterioles have higher pressure than ICFFluid, oxygen and nutrients move into cellsVenules have lower pressure than ICFFluid, carbon dioxide and wastes move out of cells

Definitions

An arteriole is a small diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries.

A venule is a very small blood vessel in the microcirculation that allows blood to return from the capillary beds to the larger blood vessels called veins.

Fluid volume deficit FVD (Hypovolemia)

Loss of both H20 and electrolytes from ECF.

Causes include:Increased output, Hemorrhage, vomiting, diarrhea, burns, OR

Fluid shift out of vascular space ( “third spacing” ) into interstitial spaces

Dehydration

Isotonic dehydration = H20 & electrolyte loss in equal amounts; diarrhea and vomiting

Hypertonic dehydration = H20 loss greater than electrolyte loss; excessive perspiration, diabetes insipidus

AssessmentFVD - Hypovolemia

Cardiovascular: Diminished peripheral pulses; quality 1+

(thready) Decreased BP & orthostatic hypotension Increased HR Flat neck & hand veins in dependent position Elevated Hematocrit (Hct)

Gastrointestinal: Thirst Decreased motility; diminished bowel sounds,

possible constipation

Assessment FVD – Hypovolemia (continued)

Neuromuscular: Decreased CNS activity

(lethargy to coma) Possible fever Skeletal muscle weakness Hyperactive DTR

Renal: Decreased output Increased spec grav of

urine Weight loss Hypernatremia

Integumentary: Dry mouth & skin Poor turgor (tenting) Pitting edema Sunken eyeballs

Respiratory: Increased rate and depth

Nursing Diagnosis - FVD

Deficient Fluid Volume

R/T loss of GI Fluids via vomitingAEB elevated Hct, dry mucous membranes, decreased output, thirst

Planning - FVD

Client will demonstrate fluid balance aeb moist mucous membranes, balanced I & O measurements, Hct WNL, by ….

Interventions for FVD - Hypovolemia

Prevent further fluid loss Oral rehydration therapy IV therapy Medications; antiemetics, antidiarrheals Monitor CV, Resp, Renal, GI status Monitor electrolytes – possible supplement

rx MONITOR WEIGHT and I & O

Fluid Volume ExcessFVE - Hypervolemia

Fluid overload is an excess of body fluid - overhydration

Excess fluid volume in the intravascular area-hypervolemia

Excess fluid volume in interstitial spaces edema

Fluid Volume Excess Causes: Increased Na/H2O retention Excessive intake of Na (PO or IV) Excessive intake of H2O ( PO or IV)

(Water intoxication) Syndrome of inappropriate

antidiuretic hormone (SIADH) Renal failure, congestive heart failure

AssessmentFVE - Hypervolemia

CV: Elevated pulse; bounding, elevated BP, distended neck & hand veins, ventricular gallop (S3)Hyponatremia

Resp: Dyspnea, Moist Crackles,Tachypnea

Integumentary: Periorbital edemaPitting or Non-pitting edema

GI: Increased motilityStomach crampsNausea & Vomiting

Renal: Weight gainDecreased spec grav of urine

Neuromuscular: Altered LOC, headache, skeletal muscle twitching

Nursing Diagnosis - FVE

Fluid volume excess

R/T excessive H20 intake

confusion, headache, muscle twitching, abdominal cramps, elevated BP and HR, hyponatremia.

Planning - FVE

Client will demonstrate fluid balance by balanced I & O measurements, Serum Na WNL, etc. by ….

Interventions FVE - Hypervolemia

Restore normal fluid balance, prevent further overload

Drug therapy; diuretics Diet therapy; decrease Na &

fluids Monitor intake and output (I & O) Monitor weights Monitor electrolytes Monitor CV, Resp, Renal systems

Electrolytes Work with fluids to keep the body healthy

and in balance They are solutes that are found in

various concentrations and measured in terms of milliequivalent (mEq) units

Can be negatively charged (anions) or positively charged (cations)

For homeostasis body needs: Total body ANIONS = Total body CATIONS

Electrolytes

CationsPositively charged

Sodium Na+

Potassium K+

Calcium Ca++

Magnesium Mg++

AnionsNegatively

charged

Chloride Cl- Phosphate PO4- Bicarbonate

HCO3-

Electrolyte Functions

Regulate water distribution Muscle contraction Nerve impulse transmission Blood clotting Regulate enzyme reactions (ATP) Regulate acid-base balance

Sodium Na+ 135-145mEq/L Major Cation Chief electrolyte of the ECF Regulates volume of body fluids Needed for nerve impulse & muscle

fiber transmission (Na/K pump) Regulated by kidneys/ hormones

Hmmm…

Hyper and Hypo Natremia are the most common electrolyte disturbances. Why do you think that is?

It is most abundant in the EXTRACELLULAR FLUID and therefore more prone to fluctuation.

Hyponatremia Serum Na+ <135mEq/L Results from excess of water or

loss of Na+ Water shifts from ECF into cells S/S: abd cramps, confusion, N/V,

H/A, pitting edema over sternum Tx: Diet/IV therapy/fluid

restrictions

Lets think about …Hyponatremia

What are some medical conditions that may cause a dilutional hyponatremia?CHFRenal FailureSIADH ( Cancer, pituitary trauma )Addisons Disease ( hypoaldosteronism & Na loss )

What are some conditions that might cause actual loss of sodium from the body?GI losses – nasogastric suctioning, vomiting, diarrheaCertain diuretic therapies

Permanent neurological damage can occur when serum Na levels fall below 110 mEq/L. Why?Hypotonic environment swells cells, increasing ICP – brain damage

Hypernatremia Serum Na+> 145mEq/L Results from Na+ gained in excess of

H2O OR Water is lost in excess of Na+

Water shifts from cells to ECF S/S: thirst, dry mucous membranes

& lips, oliguria, increased temp & pulse,flushed skin,confusion

Tx: IV therapy/diet

Let’s think about….Hypernatremia

What are some medical conditions that may cause elevated serum Na?Renal failureDiabetes InsipidusDiabetes Mellitus ( hyperglycemic dehydration)Cushings syndrome (hyperaldosteronism)

What are some other patient populations at risk for hypernatremia?Elderly ( decreased thirst mechanism )Patient’s receiving:-tube feedings-corticosteroid drugs-certain diuretic therapies

Seizures, coma, death my result if hypernatremia is left untreated. Why?Cells loose fluid into the ECF causing irreversible cell damage.

Potassium K+ 3.5-5.0 mEq/L Chief electrolyte of ICF Major mineral in all cellular fluids Aids in muscle contraction, nerve &

electrical impulse conduction, regulates enzyme activity, regulates IC H20 content, assists in acid-base balance

Regulated by kidneys/ hormones Inversely proportional to Na

Hypokalemia Serum level < 3.5mEq/L Results from decreased intake, loss via

GI/Renal & potassium depleting diuretics Life threatening-all body systems

affected S/S muscle weakness & leg cramps,

decreased GI motility, cardiac arrhythmias

Tx: diet/supplements/IV therapy

Lets think about …Hypokalemia

What are some medical conditions that may cause a hypokalemia?Renal Disease / CHF (dilutional)Metabolic AlkalosisCushings Disease ( Na retention leads to K loss )

What are some conditions that might cause actual loss of potassium from the body?GI losses – nasogastric suctioning, vomiting, diarrheaCertain diuretic therapies Inadequate intake – ( body cannot conserve K, need PO intake)

Cardiac arrest may occur when serum K levels fall below 2.5 mEq/L. Why?Increased cardiac muscle irritability leads to PACs and PVCs, then AF

Hyperkalemia Serum level >5 mEq/L Results from excessive intake,

trauma, crush injuries, burns, renal failure

S/S muscle weakness, cardiac changes, N/V, parathesias of face/fingers/tongue

Tx:diet/meds/IV therapy/ possible dialysis

Lets think about …Hyperkalemia

What are some medical conditions that may cause hyperkalemia?Renal Disease=most common causeBurns and other major tissue traumaMetabolic Acidosis Addison’s Disease ( Na loss leads to K retention )

What are some conditions that might cause potassium levels to rise in the body?Certain diuretic therapies Excessive intake – ( inappropriate supplements)

Cardiac arrest may occur when serum K levels rise above mEq/L. Why?Decreased electrical impulse conduction leads to bradycardia and eventual asystole.

Calcium Ca++

4.5-5.5mEq/L Most abundant in body but:

99% in teeth and bones Needed for nerve transmission,

vitamin B12 absorption, muscle contraction & blood clotting

Inverse relationship with Phosphorus Vitamin D needed for Ca absorption

Hypocalcemia Serum Ca < 4.3mEq/L Results from low intake, loop

diuretics, parathyroid disorders, renal failure

S/S osteomalacia, EKG changes, numbness/tingling in fingers, muscle cramps / tetany, seizures, Chovstek Sign & Trousseau Sign

Tx: diet/IV therapy

Chovstek Trousseau

Lets think about …Hypocalcemia

What are some medical conditions that may cause hypocalcemia?Hypoparathyroidism (low PTH levels = decreased release of Ca from bones)S/P thryoid surgery ( low Calcitonin = decreased release of Ca from bones) Acute pancreatitisCrohns DiseaseHyperphosphatemia ( ESRF)

What are some other conditions that might cause low Ca? GI losses – nasogastric suctioning, vomiting, diarrheaLong term immobilization Lactose intolerance

If hypocalcemia is prolonged, the body will utilize stored Ca from bones.What complication might arise?Fractures ( late sign )

Hypercalcemia

Serum Ca > 5.3mEq/L Results from hyperparathyroidism,

some cancers, prolonged immobilization

S/S muscle weakness, renal calculi, fatigue, altered LOC, decreased GI motility, cardiac changes

Tx: medication/ IV therapy

Lets think about …Hypercalcemia

What are some medical conditions that may cause hypercalcemia?Hyperparathyroidism (high PTH levels = increased release of Ca from bones)Paget’s DiseaseSome Cancers – Multiple MyleomaChronic Alcoholism ( with low serum phosphorus )

What are some other conditions that might cause low Ca? Excessive intake of Ca OR Vitamin DExcessive intake of OTC antacids

If hypercalcemia is uncorrected, AV block and cardiac arrest may occur.

Magnesium Mg2+

1.5-2.5mEq/L Most located within ICF Needed for activating enzymes,

electrical activity, metabolism of carbs/proteins, DNA synthesis

Regulated by intestinal absorption and kidney

Hypomagnesemia Serum < 1.5mEq/L Results from decreased intake, prolonged

NPO status, chronic alcoholism & nasogastric suctioning

S/S: muscle weakness, cardiac changes, mental changes, hyperactive reflexes & other hypocalcemia S/S.

Tx: replacement IV therapy restore normal Ca levels ( Mg mimics Ca) seizure precautions

Hypomagnesemia

Common in critically ill patients Associated with high mortality rates Increases cardiac irritability and

ventricular dysrhythmias - especially in patients with recent MI

Maintenance of adequate serum Mg has been shown to reduce mortality rates post MI

Hypermagnesemia Serum>2.5mEq/L Results from renal failure,

increased intake S/S: flushing, lethargy, cardiac

changes (decreased HR),decreased resp, loss of deep tendon reflexes

Tx: restrict intake diuretic rx

Chloride Cl-

95-105mEq/L Most abundant anion in ECF Combines with Na to form salts Maintains water balance, acid-base

balance, aids in digestion (hydrochoric acid) & osmotic pressure (with Na and H20)

Regulated by kidneys Follows Sodium (Na)

Hypochloremia

Serum level 96mEq/L Results from prolonged vomiting &

suctioning S/S metabolic alkalosis, nerve

excitability, muscle cramps, twitching, hypoventilation, decreased BP if severe

Tx: diet/IV therapy

Hyperchloremia Serum level > 106mEq/L Results from excessive intake or

retention by kidneys – metabolic acidosis

S/S Arrhythmias, decreased cardiac output, muscle weakness, LOC changes, Kussmauls’s respirations

Tx: restore fluid & electrolyte balance

Phosphate PO4- 2.5-4.5mg/dl Needed for acid-base

balance,neurological & muscle function, energy transfer ATP & affects metabolism of carbs/proteins/lipids, B vitamin synthesis

Found in the bones Regulated by intake and kidneys Inversely proportional to Calcium

Therefore some regulation by PTH as well

Hypophosphatemia

Serum level < 1.8mEq/L Results from decreased intestinal

absorption and increased excretion

S/S bone & muscle pain, mental changes, chest pain, resp. failure

Tx: Diet/ IV therapy

Hyperphosphatemia Serum level> 2.6mEq/L Results from renal failure, low intake of

calcium S/S: neuromuscular changes (tetany),

EKG changes, parathesia-fingertips/mouth Tx: Diet; hypocalcemic interventions

Medications: phosphate binding The body can tolerate hyperphosphatemia

fairly well BUT the accompanying hypocalcemia is a larger problem!

Electrolyte homeostasis

This means to maintain balance… to control by balancing the dietary intake of electrolytes with the renal excretion and reabsorption of electrolytes

Interventions for F/E balance

Assess patient carefully- note changes

Monitor I & O (Intake & Output) Monitor weight changes Monitor urine Monitor vs Monitor lab results and dx test Maintain proper IV therapy

Summary Fluid compartments in the body must

balance Body systems regulate F&E balance Assessment of body fluid is important

to determine causes of imbalance Interventions for imbalances are

based on the cause