FLUID AND ELECTROLYTESFLUID AND ELECTROLYTES

NPN 205NPN 205

FLUIDSFLUIDS

• 50-60% of the human body is water 50-60% of the human body is water (decreases (decreases with age)with age)

• Body fluids are classified according to their location Body fluids are classified according to their location with most of the body’s fluids found within the cellwith most of the body’s fluids found within the cell– IntracellularIntracellular – ExtracellularExtracellular (mainly responsible for transport of nutrients (mainly responsible for transport of nutrients

and wastes)and wastes)

• Fluid compartments are separated by selectively Fluid compartments are separated by selectively permeable membranes that control movement of permeable membranes that control movement of water and soluteswater and solutes

• The process of homeostasis involves delivery of The process of homeostasis involves delivery of oxygen and nutrients to the cells and removal of oxygen and nutrients to the cells and removal of waste waste

Transport of Water and Transport of Water and FluidsFluids• OsmolalityOsmolality: concentration of a solution determined by the number : concentration of a solution determined by the number

of dissolved particles per kilogram of water. Osmolality controls of dissolved particles per kilogram of water. Osmolality controls water movement and distribution in body fluid compartmentswater movement and distribution in body fluid compartments

• DiffusionDiffusion: the random movement of particles in all directions : the random movement of particles in all directions through a solutionthrough a solution

• Active transportActive transport: movement of solutes across membranes; : movement of solutes across membranes; requires expenditure of energyrequires expenditure of energy

• FiltrationFiltration: transfer of water and solutes through a membrane from : transfer of water and solutes through a membrane from a region of high pressure to a region of low pressurea region of high pressure to a region of low pressure

• OsmosisOsmosis: movement of water across a membrane from a less : movement of water across a membrane from a less concentrated solution to a more concentrated solutionconcentrated solution to a more concentrated solution

Fluid Pressures (Starling’s Fluid Pressures (Starling’s Law)Law)• ECF and ICF fluid shifts occur related to ECF and ICF fluid shifts occur related to

changes in pressure within the changes in pressure within the compartmentscompartments

• Fluid flows Fluid flows only only when there is a difference when there is a difference in pressurein pressure

• 3 types of body fluids3 types of body fluids– IsotonicIsotonic– HypotonicHypotonic– Hypertonic Hypertonic

Hydrostatic Pressure and Hydrostatic Pressure and Colloid Osmotic PressureColloid Osmotic Pressure• Tissue fluids and plasma in the capillaries Tissue fluids and plasma in the capillaries

have hydrostatic and colloid osmotic have hydrostatic and colloid osmotic pressurepressure

• Hydrostatic pressure forces fluid and Hydrostatic pressure forces fluid and solutes through the capillary wallssolutes through the capillary walls

• When the hydrostatic pressure inside the When the hydrostatic pressure inside the capillary is greater than the pressure in capillary is greater than the pressure in the surrounding interstitial space, fluids the surrounding interstitial space, fluids and solutes inside the capillary they are and solutes inside the capillary they are forced out into the interstitial space forced out into the interstitial space

• This also happens in the reverseThis also happens in the reverse

Albumin’s Role in F/E Albumin’s Role in F/E Balance Balance • Reabsorption prevents too much fluid from Reabsorption prevents too much fluid from

leaving the capillariesleaving the capillaries• Albumin is a large molecule and will not pass Albumin is a large molecule and will not pass

through the capillary membranethrough the capillary membrane• When fluid filters through the capillary, the When fluid filters through the capillary, the

protein albumin remains behindprotein albumin remains behind• When the concentration of albumin increases, When the concentration of albumin increases,

fluid begins to move back into the capillary wall fluid begins to move back into the capillary wall by osmosisby osmosis

• The pulling force of albumin in the intravascular The pulling force of albumin in the intravascular space is called plasma colloid oncotic pressurespace is called plasma colloid oncotic pressure

Plasma Colloid Osmotic Plasma Colloid Osmotic PressurePressure

SolutesSolutes

Interstitial SpacerInterstitial Spacer CapillaryCapillary

Regulation of Fluid VolumeRegulation of Fluid Volume

• Kidneys Kidneys – Capillary pressure forces fluid through Capillary pressure forces fluid through

the walls and into the tubulethe walls and into the tubule– At this point H2O or electrolytes are At this point H2O or electrolytes are

then either retained or excretedthen either retained or excreted– The urine becomes more dilute or more The urine becomes more dilute or more

concentrated based on the needs of the concentrated based on the needs of the bodybody

Regulation of Fluid Volume, Regulation of Fluid Volume, cont.cont.

• Antidiuretic hormone (ADH)Antidiuretic hormone (ADH)– Produced by the hypothalamusProduced by the hypothalamus– Stored in the pituitary glandStored in the pituitary gland– Restores blood volume by increasing or Restores blood volume by increasing or

decreasing excretion of water decreasing excretion of water – Increased osmolality or decreased blood Increased osmolality or decreased blood

volume stimulates the release of ADHvolume stimulates the release of ADH– Then the kidneys reabsorb waterThen the kidneys reabsorb water– Also may be released by stress, pain, surgery, Also may be released by stress, pain, surgery,

and some medsand some meds

Regulation of Fluid Volume, Regulation of Fluid Volume, cont.cont.

• Renin-angiotensin-aldosterone systemRenin-angiotensin-aldosterone system– Renin secreted in kidneyRenin secreted in kidney

•Amount of renin produced depends on blood Amount of renin produced depends on blood flow and amount of Na in the bloodflow and amount of Na in the blood

– Produces angiotensin II (vasoconstrictor)Produces angiotensin II (vasoconstrictor)– Angiotensin causes peripheral Angiotensin causes peripheral

vasoconstrictionvasoconstriction– Angiotensin II stimulates the production of Angiotensin II stimulates the production of

aldosteronealdosterone

Regulation of Fluid Volume, Regulation of Fluid Volume, cont.cont.

• AldosteroneAldosterone– Secreted by the adrenal gland response to Secreted by the adrenal gland response to

angiotensin IIangiotensin II– The adrenal gland may also be stimulated by The adrenal gland may also be stimulated by

the amount of Na and K + in the bloodthe amount of Na and K + in the blood– Causes the kidneys to retain Na and H2OCauses the kidneys to retain Na and H2O– Leads to increases in fluid volume and Na Leads to increases in fluid volume and Na

levelslevels– Decreases the reabsorption of K+Decreases the reabsorption of K+– Maintains B/P and fluid balanceMaintains B/P and fluid balance

Regulation of Fluid Volume, Regulation of Fluid Volume, contcont• Atrial natriuretic peptide or factor (ANP) (ANF)Atrial natriuretic peptide or factor (ANP) (ANF)

– Cardiac hormoneCardiac hormone– Released in response to increased pressure in the Released in response to increased pressure in the

atria (increased blood volume)atria (increased blood volume)– Opposes the renin-angiotensin-aldosterone systemOpposes the renin-angiotensin-aldosterone system– Stimulates excretion of Na and H2OStimulates excretion of Na and H2O– Suppresses renin levelSuppresses renin level– Decreases the release of aldosteroneDecreases the release of aldosterone– Decreases ADH releaseDecreases ADH release– Reduces vascular resistance by causing Reduces vascular resistance by causing

vasodilationvasodilation

Fluid shiftingFluid shifting• 1st space shifting- normal 1st space shifting- normal

distribution of fluid in both the ECF distribution of fluid in both the ECF compartment and ICF compartment.compartment and ICF compartment.

• 2nd space shifting- excess 2nd space shifting- excess accumulation of interstitial fluid accumulation of interstitial fluid (edema)(edema)

• 3rd space shifting- fluid accumulation 3rd space shifting- fluid accumulation in areas that are normally have no or in areas that are normally have no or little amounts of fluids (ascites) little amounts of fluids (ascites)

REGULATION OF FLUID REGULATION OF FLUID VOLUMEVOLUME

Diagnostic Tests for F/EDiagnostic Tests for F/E

• Urine studiesUrine studies– Urine pH Urine specific gravityUrine pH Urine specific gravity– Urine osmolarityUrine osmolarity– Urine creatinine clearanceUrine creatinine clearance– Urine sodiumUrine sodium– Urine potassiumUrine potassium

Blood StudiesBlood Studies

• Serum Hematocrit = 40-54%/men, Serum Hematocrit = 40-54%/men, 38-47% for women38-47% for women

• Serum Creatinine = 0.6 – 1.5 mg/dlSerum Creatinine = 0.6 – 1.5 mg/dl

• BUN = 8-20 mg/dLBUN = 8-20 mg/dL

• Serum osmolalitySerum osmolality

• Serum Albumin – 3.5-5.5 g/dLSerum Albumin – 3.5-5.5 g/dL

• Serum ElectrolytesSerum Electrolytes

ASSESSMENT FOR F/E ASSESSMENT FOR F/E BALANCEBALANCE• History of potential factors which place History of potential factors which place

patient at riskpatient at risk

• Vital signsVital signs

• I/OI/O

• Body weightBody weight

• Skin Skin

• Mucus membranesMucus membranes

• Vascular systemVascular system

FLUID VOLUME DEFICITEFLUID VOLUME DEFICITE

Hypovolemia: isotonic Hypovolemia: isotonic extracellular fluid extracellular fluid deficitdeficit

• Deficiency of both Deficiency of both water & electrolyteswater & electrolytes

• Caused by Caused by decreased intake, decreased intake, vomiting, diarrhea, vomiting, diarrhea, fluid shiftfluid shift

Dehydration: Dehydration: hypertonic hypertonic extracellular fluid extracellular fluid deficitdeficit

• Deficiency of water Deficiency of water • Caused by water loss Caused by water loss

related to high blood related to high blood glucose, inadequate glucose, inadequate ADH production, high ADH production, high fever, excess fever, excess sweatingsweating

Assessment of Fluid DeficitAssessment of Fluid Deficit

• HypotensionHypotension• Weak rapid pulseWeak rapid pulse• Temperature decreased if hypovolemic, Temperature decreased if hypovolemic,

and increased in dehydrationand increased in dehydration• Weight lossWeight loss• Skin turgor poor in dehydration and Skin turgor poor in dehydration and

possible edema in hypovolemicpossible edema in hypovolemic• Concentrated urine and blood Concentrated urine and blood

Treatment of DeficitTreatment of Deficit

• Correct causeCorrect cause

• IV fluidsIV fluids

• I and OI and O

• Skin careSkin care

• Assist with ADL’sAssist with ADL’s

FLUID VOLUME EXCESSFLUID VOLUME EXCESS

Extracellular: isotonic Extracellular: isotonic fluid excessfluid excess

• Excess of both water Excess of both water and electrolytesand electrolytes

• Caused by retention of Caused by retention of water and electrolytes water and electrolytes related to kidney related to kidney disease; overload with disease; overload with isotonic IV fluidsisotonic IV fluids

Intracellular: water Intracellular: water excessexcess

• Excess of body water Excess of body water without excess without excess electrolyteselectrolytes

• Caused by over-Caused by over-hydration in the hydration in the presence of renal presence of renal failure; administration failure; administration of D5Wof D5W

FLUID VOLUME FLUID VOLUME EXCESS/AssessmentEXCESS/Assessment

• IsotonicIsotonic– HypertensionHypertension– Bounding pulseBounding pulse– Crackles, dyspneaCrackles, dyspnea– Weight gainWeight gain– Edema in Edema in

extremitiesextremities– JVDJVD– Irritable, confusedIrritable, confused

• Hypotonic Hypotonic – Systolic B/P ^Systolic B/P ^– Decreased pulseDecreased pulse– Increased Increased

respirationsrespirations– Weight gainWeight gain– Cerebral edemaCerebral edema– Irritable, confusedIrritable, confused

FLUID VOLUME EXCESS/ FLUID VOLUME EXCESS/ TreatmentTreatment

• IsotonicIsotonic– Correct causeCorrect cause– Restrict H2O and Restrict H2O and

NaNa– DiureticsDiuretics– DigitalisDigitalis– Possible dialysisPossible dialysis

• HypotonicHypotonic– Correct causeCorrect cause– Restrict H2O intakeRestrict H2O intake– IV fluids with E-lytesIV fluids with E-lytes

FLUID VOLUME FLUID VOLUME EXCESS/Nursing CareEXCESS/Nursing Care

• IsotonicIsotonic– Monitor for excess Monitor for excess

excretion of H2O R/T excretion of H2O R/T diureticsdiuretics

– Maintain fluid restrictionMaintain fluid restriction– Consult dietary for salt Consult dietary for salt

restrictionsrestrictions– Watch for skin problemsWatch for skin problems– HOB ^ 30 degreesHOB ^ 30 degrees

• HypotonicHypotonic– IV’s and meds as IV’s and meds as

orderedordered– I/OI/O– Oral care and ice chipsOral care and ice chips– Safety precautionsSafety precautions– Seizure precautionsSeizure precautions