Fluid and Electrolytes



Fluid and Electrolytes

Water Balance = Homeostasis

• Water in the body is used to or for:

• Transporting nutrients & oxygen to cells

• Removing waste from cells

• Provides medium in which electrolyte chemical reactions can occur

• Regulation of body temperature

• Lubricates joints and membranes

• Provides medium for food digestion

• 1 L of H2O weighs 2.2 lbs

• The most accurate measurement of fluid status is daily weights**

Water Distribution

• ICF: Intracellular fluid- found in the lymph fluid

• ECF: Extracellular fluid- interstitial fluid and plasma

• TCF: Transcellular fluid- CSF, fluid found in joints and GI tract and peritoneal fluid

• Third spacing: condition where fluid accumalates in a pocket

• Intervascular fluid- plasma

Osmolarity / Osmolality

■ Osmole: (measuring concentration)

■ the amount of substance that dissociates in solution to form one mole of osmotically active particles (Dorland, Newman W.. Dorland's Illustrated Medical Dictionary, 31st Edition.)

■ Concentration of solution measured in osmoles

■ Osmolality is measured in milliOsmols/Kg (mOsm/Kg)

■ Osmolarity is measured in milliOsmols/L (mOsm/L)

■ Evaluates serum and urine in clinical practice

■ Normal: serum osmolality 275 – 295 mOsm/K**

Concentrations of Solutions

• Isotonic: Same osmolarity as blood plasma…no osmotic “pull”

• Hypotonic: Less concentration than blood plasma…lower osmotic pressure

• Hypertonic: More concentration than blood plasma….higher osmotic pressure

Movement of Water

• Intracellular & extracellular approximately same osmolality

• Solvent (water) and solutes (electrolytes) move across selectively permeable membranes (compartments) in the body

Review of Terms

• Osmosis

• Diffusion

• Active transport

• Passive transport

• Filtration

• Hydrostatic pressure

Osmosis Review

• Movement of water only

• Speed of movement affected by:

– temperature of fluid

– concentration of fluid

– electrical charge of particles in solution

Other Mechanisms of Movement

• Diffusion: Solute (or gas) moves from area of higher concentration to area of lower concentration

• Facilitated diffusion: Solute moves against concentration gradient (passive transport)

• Active transport: Solute moved against concentration gradient using ENERGY

Active Transport

• Na+/K+ pump: Maintains the higher concentrations of extracellular Na+ and intracellular K+

• Filtration: solutes & solvent move together in response to _fluid pressure__; moves from area of _high_ pressure (hydrostatic pressure) to area of _low__ pressure

• Hydrostatic pressure: The force within a fluid compartment (as in the vascular system)

• Colloidal osmotic that pulls fluid back into the capillaries

Regulation of Body Fluids

• Intake: osmoreceptors sense osmolality of serum, signals the hypothalamus, stimulates thirst

• Output: kidneys, lungs, GI tract, skin

• Sensible: measurable….urine output, excessive perspiration, diarrhea, vomiting

• Insensible: immeasurable…normal perspiration, normal breathing

• The output for adults should be 1mL/kg/hr (25-30cc)**

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Role of the Kidneys

• Filter approx 180 Liters of blood per day; GFR (glomerular filtration rate)

• Produces urine between 1-2 Liters/day

• If loss of 1% to 2% of body water, will conserve water by reabsorbing more water from filtrate; urine will be more_concentrated_?

• If gain of excess body water, will excrete more water from filtrate; urine will be more __diluted__?

Hormonal Control

• Antidiuretic hormone (ADH): Prevents diuresis; “water saving”

• Question: Osmoreceptors sensing a/an __increase______ in osmolality will cause the release of ADH?

• RAA (Renin-angiotensin-aldosterone): cascade initiated by decrease in renal perfusion or low Na+

• If extracellular volume is decreased ( renal perfusion decreases ( renin secreted by kidneys ( renin acts to produce angiotensin I which then converts to ( angiotensin II ( results in massive vasoconstriction ( increases renal arterial perfusion and causes increased thirst

• Aldosterone:

• Angiotensin II causes the adrenal gland to release aldosterone

• Aldosterone causes the kidneys to retain Na+ and water

• Volume regulator….released if Na+ is low and K+ is high; increases reabsorption of Na+ (where salt goes, water follows) and the excretion of K+

ANP

• Atrial Natriuretic Peptide: (ANP): secreted from atrial cells of heart

– acts as diuretic

– inhibits thirst mechanism

– suppresses the RAA cascade

Thirst Mechanism

• Regulated by the hypothalamus

• Stimulates thirst:

– increased osmolality of ECF

– decreased ECF

– dry mucous membranes

• Causes: eating salty foods, inadequate intake, excessive water loss

Pressure Sensors

← Baroreceptors: Nerve receptors that sense pressure in blood vessels

← Low pressure: sensors in the cardiac atria; stimulate SNS & inhibits PSNS

← High pressure: sensors in the aortic arch, carotid sinus, and the juxtaglomerular apparatus in the kidney; stimulates PSNS and inhibits the SNS

← Osmorecptors: Sense Na+ concentration

← Positioned on surface of hypothalamus

← Increase in Na+ concentration: stimulates release of ADH

← Decrease in Na+ concentration: inhibits release of ADH

Electrolytes

• Minerals and salts: electrolytes

• Cations: Positively charged; sodium, potassium, calcium, magnesium

– Major cation in ECF is sodium

• Anions: Negatively charged; chloride, bicarbonate, sulfate

– Major cation in ICF is potassium

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Memorize sodium, potassium and calcium for test**

Hyponatremia

• Causes

– Salt wasting fr. Kidney

– Adrenal insufficiency

– GI losses

– Profuse sweating

– Diuretics

– SIADH

– Inadequate intake

• Physical Exam

– Apprehension

– Personality change

– Postural hypotension

– Tachycardia

– Convulsions/coma

– NV&D

– Anorexia

• Labs

– Serum Na+ below 135 mEq/L

– Serum Osmolality below 280 mOsm/kg

– Urine specific gravity below 1.010

• Treatment

– Restrict water

– Sodium replacement

Hypernatremia

• Causes

– ( ingestion of salt

– Iatrogenic

– ( aldosterone

– Water deprivation

• Signs & Sxms

– Thirst, sticky tongue

– Dry, flushed skin

– Fever

– Convulsions, irritability

• Labs

– Serum Na+ above 145 mEq/L

– Serum Osmolality above 295 mOsm/kg

– Urine specific gravity above 1.030

• Treatment

– Hypotonic IV solution or D5W

Urine Na+ Studies

• Urine Na+

– Assesses volume status

– Aids in diagnosing hyponatremia & acute renal failure

• Random normal range = 50 -130 mEq/L

• 24 hour = 75-200 mEq/L

Hypokalemia

• Causes

– Diuretics that “waste” potassium

– D, V, & gastric suction

– ( aldosterone

– Polyuria, sweating

– Iatrogenic – K+ poor solutions

• Signs & Sxms

– Weakness, fatigue

– ( muscle tone

– Hypoactive bowel sounds and distention

– Weak, irregular pulse

– Paresthesias

– Effects the heart**

• Labs

– K+ below 3.5 mEq/L

– ECG abnormalities

• Treatment

– Oral K+ or IV solution w/K+

– Increased dietary K+

Hyperkalemia

• Causes

– Renal failure

– Fluid vol. deficit

– Massive cellular injury (trauma/burns)

– Iatrogenic

– Potassium “sparing” diuretics

– Addison’s disease

• Signs & Sxms

– Anxiety

– Dysrrhythmias

– Paresthesia (numbness, pins & needles feeling)

– Weakness

– Diarrhea

• Labs

– Serum K+ above 5.0 mEq/L.

– ECG abnormalities – can lead to arrest

• Treatment

– Kayexalate

– IV Na+ bicarb

– IV Ca+ gluconate

– Regular insulin and hypertonic dextrose IV

– Limit via diet

– Possible dialysis

Hypocalcemia

• Causes

– Rapid admin of blood w citrate

– Hypoalbuminemia

– Hypoparathyroidism

– Vit. D deficiency

– Pancreatitis

• Signs & Sxms

– Numbness, tingling of fingers & mouth

– Hyperactive reflexes

– Tetany

– Muscle cramps

– Pathological fractures

• Labs

– Serum Ca++ below 4.5 mEq/L

– ECG abnormalities

• Treatment

– Increase dietary intake

– IV calcium gluconate

– Ca+ & vit D supplements

Hypercalcemia

• Causes

– Hyperparathyroidism

– Osteometastasis

– Paget’s disease

– Osteoporosis

– Prolonged immobilization

• Signs & Sxms

– Anorexia, N & V

– Weakness, lethargy

– Low back pain (stones)

– Decreased LOC

– Personality changes

– Cardiac arrest

• Labs

– Serum Ca++ above 5.5 mEq/L

– X-rays showing osteoporosis

– Stones & ( BUN / creatinine fr. FVD or renal damage

• Treatment

– Lasix (diuretic)

– Increased fluids

Hypomagnesemia

• Causes

– Inadequate intake

• Alcohol, Malnutrition

– Inadequate absorption

• V&D, Gastric aspirate

• Fistulas, Sm. Bowel

– Loss fr. Diuretics

– Polyuria

• Signs & Sxms

– Tremors

– Hyperactive deep tendon reflexes

– Confusion

– Dysrhythmias

• Labs

– Serum Mg++ below 1.5 mEq/L

• Treatment

– Mag sulfate IV

– Oral replacement

– Increase dietary intake

Hypermagnesemia

• Causes

– Renal failure

– Excess intake of magnesium

• Signs & Sxms

– Most frequently seen in acute

– Hypoactive deep tendon reflexes & drowsiness

– Decreased depth and rate of resp.

– Hypotension

– flushing

• Labs

– Serum Mg++ levels above 2.5 mEq/L

• Treatment

– IV calcium gluconate

– Loop diuretics

– NS or LR IV solutions

– Dialysis

Additional Lab Data

• Hematocrit

– Measures the volume % of RBC’s in whole blood

• Normal: M = 40-50%; F = 37-47%

– Increases with dehydration (hemoconcentration)

– Decreases with overhydration (hemodilution)

• Blood urea nitrogen (BUN)

– Measures kidney function

– Normal range: 7-20mg/dL

– Varies with protein intake, fever, dehydration, GI bleeding, liver failure, etc.

• Creatinine

– End product of muscle metabolism

– Better indicator of renal function than BUN

• Doesn’t vary w protein intake or metabolic state

– Normal range: 0.7-1.5mg/dL in 24 hr urine collection

– Serum:

• adult female: 0.5 to 1.1mg/dL

• adult male: 0.6 to 1.2mg/dL

• Urine Specific Gravity

– Measures ability of kidney to excrete or conserve water

• Normal range = 1.010 - 1.025

– Increased S.G.= concentrated urine

– Decreased S.G.= dilute urine

• Serum Osmolarity

– Most accurate for kidney function

• Remember norm?

– 280-295 mOsm/L

– Measured directly through blood

– Indirectly using Serum Osmolarity Formula

Fluid Imbalances****

• Isotonic

– Deficit – water, electrolytes and solutes lost in equal proportions to body solutions

– Excess – water, electrolytes and solutes gained in equal proportions to body solution

– FVD - fluid volume deficit-HYPOVOLEMIA**

– FVE - fluid volume excess-HYPERVOLEMIA**

Fluid Disturbances

• Osmolar Imbalances

– Hyperosmolar – Dehydration

– Hypoosmolar – Water excess

– Loss or excesses of water only

– Leads to alteration in concentration of serum

Fluid Volume Deficit (FVD)

• Water AND solutes lost in ____________ proportion.

– Diarrhea, vomiting, fistulas, drains

– Bleeding, burns

– Fever, excessive perspiration

– Inadequate fluid intake

– Diuretics

– GI suctioning

Signs & Symptoms of FVD

• Mild

– Dry mouth, furrowed tongue

– Orthostatic or postural hypotension

– Restlessness & anxiety

– Tachycardia

– Less than 5% weight loss

• Moderate

– Confusion, irritability, thirst, cool & clammy

– Urine output 30cc/hr or less

– Rapid weight loss

– Slowed vein filling

• Severe

– Pale

– Flattened neck veins, delayed capillary refill

– Urine output less than 10cc/hr

– Marked hypotension, tachycardia, weak or absent pulses (shock)

– Can lead to unconsciousness

Labs for FVD

• Lab findings vary depending on the cause

– Decreased H/H with hemorrhage

– Increased Hct

– Elevated BUN

– Urine specific gravity greater than 1.030

Nursing Diagnosis Statement

• Example:

– Fluid volume deficit r/t active fluid volume loss as evidenced by decreased blood pressure (90/50 mmHg), thirst, fever (102°), rapid heart rate (110 bpm), urine output less than or equal to 25 mL/hr, & urine specific gravity of 1.040.

Goal Statement

• Client will achieve fluid balance AEB

– urine output equal to or greater than 30 mL/hr

– Elastic skin turgor and moist mucous membranes

Medical Interventions

• Treat cause

• Replacing fluids intravenously

– isotonic if hypotensive (expand plasma volume)

– hypotonic if normotensive (provides electrolytes and water)

• Encourage fluids

• Ensure adequate O2 and perfusion

• Increase blood counts, BP, & albumin levels

• Teaching

Nursing Interventions

• Ensure patent airway, adjust O2 levels as ordered

• Lower HOB if tolerated or not contraindicated

• Direct pressure to bleeding, if present

• Administer meds, blood, albumin, & IV fluids

• Weigh patients daily

• Provide skin care

• Maintain strict I&O

• Monitor vital signs

• Monitor lab work

Teaching

• Nature of condition & causes

• Warning S/S

• Treatments & importance of compliance

• Change positions slowly

• Monitor BP & pulse rate

• Give prescribed medications

Fluid Volume Excess (FVE)

• Water AND solutes _gained_ in excess of normal body levels

• Causes:

– Isotonic fluid overload

– Excess sodium intake

– CHF, renal failure, cirrhosis

– Increase in steroids or serum aldosterone

Signs & Symptoms

• Generalized

– Acute weight gain

• Mild-mod 5-10%

• Severe > 10%

– Edema

• dependent, sacral, pulmonary

• Cardiovascular

– Tachycardia, bounding pulse, distended neck veins, increased BP

• Respiratory

– Dyspnea, tachypnea, crackles, frothy cough

Lab Values

• Decreased hematocrit

• Decreased BUN

• Low O2 levels

Nursing Diagnosis Statement

• Fluid volume excess r/t excess fluid intake aeb Hct of 23, 10# weight gain in two days, dyspnea (Pt states, “I can’t get enough air.”), and crackles on inspiration and expiration in all lobes.

Related Nursing Diagnosis

• Ineffective breathing pattern r/t increased fluids

• Impaired skin integrity r/t excess fluids

• Confusion

Client Goals & Outcomes

← Aimed at cause

– Decrease circulating fluid volume

– Lower BP and pulse

– Improve breathing status

– Maintain skin integrity

– Teaching

Goal Statement

• Client will achieve fluid balance manifest in following outcomes

– Clear breath sounds

– Denies dyspnea and affirms the ability to breathe adequately

Nursing Interventions

• Restrict Na+ & fluid intake

• Watch for edema - dependent & respiratory

• Provide measures to facilitate breathing

• Provide skin care for weeping & edema

• Monitor response to medications

• Accurate I/O, Consistent daily weight, VS, monitor labs

• Advise HCP if poor response to therapy

• Hemodialysis may be needed

Teaching

• Nature of condition and causes

• Signs and symptoms

• Treatments and importance of compliance

• Need to monitor BP, P, O2 Sat, & weight

• Rationale for Na+ and fluid restrictions

• Medications

Hyperosmolar: Dehydration

• Loss of water =

– increased serum osmolality

– increased serum Na+

• Compensatory Mechanism: water shifts out of cells (ICF) into the ECF…..if not corrected, water continues to move out of cells (ICF) and into ECF causing the cells to shrink….shrunken cells don’t function properly!!

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Causes of Dehydration

• Causes:

– Diabetes insipidus, prolonged fever, watery diarrhea, hyperglycemia, failed thirst drive

– Iatrogenic: hypertonic solutions (IV & tube feeding)

– Diuresis of water alone

Dehydration: Signs & Symptoms

• Irritability, confusion, weakness, dizziness

• Decreased urine output, darkened urine

• Dry, sticky mucous membranes, sunken eyeballs, poor turgor, extreme thirst !!!

• Fever (insensible – continuous)

• Coma

• Tachycardia, weak, thready pulse, hypotension

Dehydration: Labs

• Elevated hematocrit

• Elevated serum osmolarity > 295 mOsm/kg

• Elevated serum sodium > 145 mEq/L

• Urine specific gravity > 1.030

Dehydration: Nursing Diagnoses

• Fluid volume deficit r/t fluid loss

• Deficient fluid volume r/t excessive fluid loss from GI tract

• Risk for impaired skin integrity r/t altered metabolic state

Dehydration: Potential Nursing Diagnoses

• Deficient knowledge: unfamiliarity of disease process

• Disturbed thought processes r/t neurologic changes / decreased cardiac output

• Decreased cardiac output r/t excessive fluid loss

Dehydration: Client Goals & Outcomes

• Aimed at correcting cause

• Replace fluids – hypotonic, slowly re-hydrate over 48 hrs

• Maintain skin integrity

• Teaching

Dehydration: Nursing Interventions

• Replace fluids by PO route first

• SLOW admin. of salt-free IV solutions

• Monitor S/S cerebral & pulmonary edema

• Monitor accurate I/O, VS, daily weights

• Monitor labs

• Provide skin and mouth care

Dehydration: Teaching

• Disease process of dehydration

• Treatments

• Warning signs and symptoms

• Medications / IV (Vasopressin – D5W)

• Importance of compliance with therapy

– Fluid intake not based on thirst alone

Hypoosmolar

• Water excess

• Causes

– SIADH or excess water intake

• Signs & Sxms

– Decreased LOC, convulsions, coma

• Labs

– Serum Na+ below 135 mEq/L and Serum osmolality below 280 mOsm/kg

Nsg Dx – Goals - Interventions

• Similar to FVE

• Make relevant to underlying cause

• Is very acute illness

Physical Assessment

History

• Medical – Acute Illness, surgery, burns

• Environment – exercise, hot/cold/dry areas

• Diet – proteins, lytes, fluids

• Lifestyle – smoking/alcohol

• Medication history

Areas of Concern in PA

• Mental status

• BP and pulse

• Skin

• I & O’s & WEIGHT

• Lungs

Geriatric Focus

• Body-water content (mass related)

• Kidney function

• Cardiac & respiratory function

• Hormonal regulatory function

• Thirst sensation

• Medication Use

• Skin & subcutaneous fat

Assessment of Geriatric Clients

• Skin turgor

– Assessment is performed where?

• Cognition

• Physical being

• Continence

Laboratory Data

• BMP / CMP

• Serum osmolarity

• Urine specific gravity

• Urine sodium

• Hematocrit

• Blood urea nitrogen (BUN)

• Creatinine

Clients at Risk for F&E Imbalances

• Age

– Very young

– Very old

• Chronic Diseases

– Cancer

– Cardiovascular disease, such as congestive heart failure

– Endocrine disease, such as Cushing's disease and diabetes

– Malnutrition

– Chronic obstructive pulmonary disease

– Renal disease, such as progressive renal failure

– Changes in level of consciousness

• Trauma

– Crush injuries

– Head injuries

– Burns

– Major surgery

• Therapies

– Diuretics

– Steroids

– Intravenous (IV) therapy

– Total parenteral nutrition (TPN)

• Gastrointestinal losses

– Gastroenteritis

– Nasogastric suctioning

– Fistulas

Fluid & Electrolytes Nursing DXs

• Risk for imbalanced Body temperature

• Ineffective Breathing pattern

• Decreased Cardiac output

• Deficient Fluid volume

• Risk for deficient Fluid volume

• Excess Fluid volume

• Impaired Gas exchange

• Knowledge deficient regarding disease management

• Impaired Mobility

• Impaired Oral mucous membrane

• Impaired Skin integrity

• Risk for impaired Skin integrity

• Ineffective Therapeutic regimen management

• Impaired Tissue integrity

• Ineffective Tissue perfusion

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Intravenous Fluid Therapy in Fluid Balance Disorders

ISOtonic solutions

• Same osmolarity as body fluids

– 280 - 300 mOsm/kg

• Expands the IVC without pulling fluids from other compartments

• Examples

– Normal saline (NS)

– Lactated Ringers (LR)

IVs: Normal Saline (NS)

• Isotonic

• 0.9% Sodium Chloride

• Different amounts

• Sample order

– NS @ 75cc/hr

IVs: Lactated Ringer’s (LR)

• Isotonic Solution

• Contents

– Na+, Cl-, K+, Ca++, Lactate in sterile water

• One strength, two common amounts

• Sample orders

– LR @ 100cc/hr

– RL @ 75cc/hr

HypOtonic solutions

• Osmolarity less than serum

• Pulls fluid from the IVC into the ICC causing cells to expand

– Over hydration -- RISK

– Rehydration

• Example

– ½ NS

– D5W - after absorbed into body

IVs: Dextrose Solutions

• Concentrations

– 5% in water (hypotonic after enters body)

– 10% in water (hypertonic)

– 50% in water (rescue solution – small volume)

– As additive to NS or LR

• D5NS or D5LR

HypERtonic solutions

• Osmolarity of solution is higher than serum osmolarity

– >300 mOsm/kg

• Pulls fluid from ICC into IVC causing cells to shrink

– dehydrate

• Examples

– D51/2 NS - D5NS - D5LR

– 3% NS (CRITICAL Strength)

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IVs: Common Additives

• Potassium (never add to a bag!)

• Multivitamins

• Additives makes the solution hypertonic to some extent – depends on amount

IV Additives: Potassium

• Available as KCl (potassium chloride)

• NEVER add K+ to a bag of fluid

– Added by pharmacy or premixed

• Different strengths

• Sample orders

– NS c 20 mEq KCl @ 75 cc/hr

– LR c 40 mEq KCl @ 75 cc/hr

Medications Used in Fluid & Electrolyte Imbalance Disorders

Meds: Antidiarrheals

• Assess I /O & electrolytes

• Provide oral care

• Monitor for constipation

• Teaching

– Take as directed

– Avoid overdose

• Examples: Lomotil & Immodium

Meds: Antiemetics

• Assess VS & emesis status before and after

• Monitor for extrapyriamidal side effects

– involuntary movement of eyes, face or limbs, flat affect, shuffled gait, drooling

• Provide fluid replacements

– Oral electrolyte solutions

– Water

• Sample Meds: Zofran, Phenergan & Vistaril

Meds: Diuretics

• Assess

– Weight, edema, skin turgor, & mucus membranes, lung sounds

• Monitor

– weight, I /O, electrolytes

• Teaching

– diet, weigh daily, & dosing times

• Examples:

– Thiazides (HCTZ) – HTN

– Potassium sparing (spironolactone)

– Osmotic (mannitol) – decrease ICP

– Loop (lasix) – pull fluids

Meds: Potassium

• Forms: tablets (SR), effervescent, EC, IV

• Administration considerations

– PO: Give on a full stomach at mealtime am/pm

– IV: NEVER give as bolus, follow protocol, dilute for IV administration, can burn & lead to infiltration

• Monitor: K+ levels – monitor EKG if elevated

Meds: Kayexelate

• Removes K+ from system

• Available as enema or by PO route

– Retain enema for ½ to 1 hr

– Follow resin w 100 mL water

– After expulsion, rinse colon w 1 liter of water and drain out immediately

Other Meds r/t F/E status

• Glucocorticosteroids

• Digoxin

• Electrolyte supplements

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