Anatomy & Anatomy & PhysiologyPhysiology

Tri-State Business InstituteTri-State Business Institute

Micheal H. McCabe, EMT-PMicheal H. McCabe, EMT-P

Fluid & Electrolyte Fluid & Electrolyte Balance:Balance:

Locations of Body Fluids:Locations of Body Fluids:1.1. Intracellular Fluids (ICF) – fluids within Intracellular Fluids (ICF) – fluids within

body cellsbody cells

2.2. Extracellular Fluids (ECF) – fluids outside Extracellular Fluids (ECF) – fluids outside body cellsbody cells

A.A. Interstitial Fluids (IF) – fluid in the space Interstitial Fluids (IF) – fluid in the space between cellsbetween cells

B.B. Blood Plasma (BP) – fluids contained in blood Blood Plasma (BP) – fluids contained in blood vessels vessels

In total, body fluids account for 50% to In total, body fluids account for 50% to 60% of the weight in a healthy adult60% of the weight in a healthy adult

Distribution of Body Distribution of Body FluidsFluids

Plasma – approximately 4% of body Plasma – approximately 4% of body weight in a young adult.weight in a young adult.

Interstitial Fluid – approximately Interstitial Fluid – approximately 10% of body weight10% of body weight

Intracellular Fluid – approximately Intracellular Fluid – approximately 33% of body weight33% of body weight

Variations in Body FluidsVariations in Body Fluids

Variations in total body fluids relate Variations in total body fluids relate to:to:

1.1. Weight – the more a person weighs, the Weight – the more a person weighs, the more water the body containsmore water the body contains

2.2. Fat Content – fat is almost water-free; the Fat Content – fat is almost water-free; the higher the percentage of body fat, the less higher the percentage of body fat, the less the percentage of body weight is waterthe percentage of body weight is water

3.3. Sex – women normally have 10% less Sex – women normally have 10% less water than menwater than men

4.4. Age – in the newborn, over 80% of total Age – in the newborn, over 80% of total body weight is waterbody weight is water

Fluid Input & Output over Fluid Input & Output over 24 Hours24 Hours

Fluid InputFluid Input Food Food 700 700

mlml Liquid Liquid 1500 1500

mlml Water formed within Water formed within

the body the body 200 200 mlml

Total Input = 2400 Total Input = 2400 mlml

Fluid OutputFluid Output LungsLungs 350 ml350 ml Skin (diffusion)Skin (diffusion)

350 ml350 ml Skin (sweat)Skin (sweat) 100 ml100 ml KidneysKidneys 1400 ml1400 ml Intestines (feces)Intestines (feces)

200 ml200 ml

Total Output = 2400 Total Output = 2400 mlml

Regulation of Fluid Regulation of Fluid IntakeIntake

When dehydration starts to develop, salivary When dehydration starts to develop, salivary secretion decreases, producing a “dry mouth.”secretion decreases, producing a “dry mouth.”

The brain interprets this as a sensation of The brain interprets this as a sensation of thirst.thirst.

The individual is compelled to drink water.The individual is compelled to drink water. If the individual is unable to drink, urine If the individual is unable to drink, urine

production decreases or stops.production decreases or stops. Fluid loss continues from the skin, lungs, and Fluid loss continues from the skin, lungs, and

intestine. intestine. Despite compensatory mechanisms, Despite compensatory mechanisms,

dehydration will progress.dehydration will progress.

Mechanisms that Maintain Mechanisms that Maintain Fluid BalanceFluid Balance

Fluid output adjusts to fluid intake; Fluid output adjusts to fluid intake; ADH from posterior pituitary gland ADH from posterior pituitary gland increases kidney tubule reabsorbtion increases kidney tubule reabsorbtion of water, increasing extra-cellular of water, increasing extra-cellular fluid (ECF) volume.fluid (ECF) volume.

ECF electrolyte concentration ECF electrolyte concentration influences ECF volume. An increase influences ECF volume. An increase in Na+ tends to increase ECF in Na+ tends to increase ECF volume.volume.

Mechanisms that Maintain Mechanisms that Maintain Fluid BalanceFluid Balance

Capillary blood pressure pushes Capillary blood pressure pushes water out of blood into interstitial water out of blood into interstitial fluid; blood protein concentration fluid; blood protein concentration pulls water into blood from pulls water into blood from interstitial fluid; these two factors interstitial fluid; these two factors regulate plasma and IF fluid volume regulate plasma and IF fluid volume under usual conditions.under usual conditions.

Electrolytes in Body Electrolytes in Body FluidsFluids

Electrolytes – compounds that Electrolytes – compounds that dissociate when dissolved in water dissociate when dissolved in water into into ionsions – example: NaCl (Sodium – example: NaCl (Sodium Chloride) dissociates into Na+ and Chloride) dissociates into Na+ and CL- ions when dissolved in water.CL- ions when dissolved in water.

Non-Electrolytes – organic Non-Electrolytes – organic substances that do not dissociate substances that do not dissociate when dissolved in water - -example: when dissolved in water - -example: glucoseglucose

Electrolytes in Body Electrolytes in Body FluidsFluids

Ions – the dissociated particles of an Ions – the dissociated particles of an electrolyte that carry an electrical electrolyte that carry an electrical charge. Example: Sodium (Na+)charge. Example: Sodium (Na+)

Positively charged ions (Anions) Positively charged ions (Anions) include Potassium (K+) and Sodium include Potassium (K+) and Sodium (Na+)(Na+)

Negatively charged ions (Cations) Negatively charged ions (Cations) include Chloride (Cl-) and include Chloride (Cl-) and Bicarbonate (HC03-)Bicarbonate (HC03-)

Electrolyte Composition of Electrolyte Composition of Blood PlasmaBlood Plasma

Positively Charged Ions:Positively Charged Ions: Sodium (Na+) = 142 mEq / LiterSodium (Na+) = 142 mEq / Liter Potassium (K+) = 4 mEq / LiterPotassium (K+) = 4 mEq / Liter Calcium (Ca++) = 5 mEq / LiterCalcium (Ca++) = 5 mEq / Liter Magnesium (Mg++) = 2 mEq / LiterMagnesium (Mg++) = 2 mEq / Liter Total of Positively Charged Ions = 153 Total of Positively Charged Ions = 153

mEq / LitermEq / Liter

Electrolyte Composition of Electrolyte Composition of Blood PlasmaBlood Plasma

Negatively Charged Ions:Negatively Charged Ions: Chloride (Cl-) = 102 mEq / LiterChloride (Cl-) = 102 mEq / Liter Bicarbonate (HCO3-) = 26 mEq / LiterBicarbonate (HCO3-) = 26 mEq / Liter Protein (Cation) = 17 mEq / LiterProtein (Cation) = 17 mEq / Liter Phosphate (HPO4-) = 2 mEq / LiterPhosphate (HPO4-) = 2 mEq / Liter Other cations = 6mEq / LiterOther cations = 6mEq / Liter Total of Negatively Charged Ions = 153 Total of Negatively Charged Ions = 153

mEq / LitermEq / Liter

Functions of ElectrolytesFunctions of Electrolytes

Electrolytes are required for many Electrolytes are required for many cellular activities; particularly nerve cellular activities; particularly nerve conduction and muscle contraction.conduction and muscle contraction.

Electrolytes must Electrolytes must balancebalance for these for these functions to work properly functions to work properly

The concentration of positive ions in The concentration of positive ions in the blood plasma must equal the the blood plasma must equal the concentration of negative ions.concentration of negative ions.

SodiumSodium

Sodium is the most abundant and Sodium is the most abundant and important positively charged ion in blood important positively charged ion in blood plasmaplasma

Normal Plasma Level = 142 mEq / LiterNormal Plasma Level = 142 mEq / Liter Average Daily Intake = 100 mEqAverage Daily Intake = 100 mEq Chief Method of Regulation: KidneyChief Method of Regulation: Kidney Aldosterone increases Na+ reabsorbtion Aldosterone increases Na+ reabsorbtion

in kidney tubulesin kidney tubules Many internal secretions contain sodiumMany internal secretions contain sodium

Internal Secretions Internal Secretions Containing SodiumContaining Sodium

Saliva – 1500 ml / 24 hoursSaliva – 1500 ml / 24 hours Gastric Secretions – 2500 ml / 24 hrsGastric Secretions – 2500 ml / 24 hrs Bile – 500 ml / 24 hrsBile – 500 ml / 24 hrs Pancreatic Juice – 700 ml / 24 hrsPancreatic Juice – 700 ml / 24 hrs Intestinal Secretions – 3000 ml / 24 hrsIntestinal Secretions – 3000 ml / 24 hrs Total volume of secretions may reach Total volume of secretions may reach

8000 ml in 24 hrs.8000 ml in 24 hrs. Most internal secretions are Most internal secretions are

reabsorbed reabsorbed

Relationship between Relationship between Electrolyte Concentration Electrolyte Concentration

and Fluid Balanceand Fluid Balance ““Where salt goes, water will follow!”Where salt goes, water will follow!” Example: If the concentration of sodium Example: If the concentration of sodium

in the interstitial fluid rises, water moves in the interstitial fluid rises, water moves from the blood pasma into the IF. The from the blood pasma into the IF. The volume of IF soon rises causing edema.volume of IF soon rises causing edema.

A solution with a concentration of sodium A solution with a concentration of sodium greater than blood plasma is called greater than blood plasma is called hypertonic.hypertonic.

A solution with a concentration of sodium A solution with a concentration of sodium less than blood plasma is called less than blood plasma is called hypotonic.hypotonic.

A solution with a concentration of sodium A solution with a concentration of sodium equal to blood plasma is called equal to blood plasma is called isotonic.isotonic.

Fluid ImbalancesFluid Imbalances

Dehydration – total volume of body fluids is Dehydration – total volume of body fluids is smaller than normal; IF volume shrinks first; smaller than normal; IF volume shrinks first; if untreated, ICF and plasma volume if untreated, ICF and plasma volume decrease; dehydration occurs when fluid decrease; dehydration occurs when fluid output exceeds intake for an extended period.output exceeds intake for an extended period.

Overhydration – total volume of body fluids Overhydration – total volume of body fluids larger than normal; overhydration occurs larger than normal; overhydration occurs when fluid intake exceeds output; various when fluid intake exceeds output; various factors may cause this – giving excessive factors may cause this – giving excessive amounts of IV fluids or giving them too amounts of IV fluids or giving them too rapidly may increase intake above output.rapidly may increase intake above output.

EdemaEdema

Edema is the presence of abnormally Edema is the presence of abnormally large amount of fluid in the tissue spaces.large amount of fluid in the tissue spaces.

Edema is a classic example of fluid Edema is a classic example of fluid imbalance and can be caused by a imbalance and can be caused by a number of factors:number of factors:

1.1. Retention of electrolytes – especially sodium Retention of electrolytes – especially sodium in the extracellular fluidin the extracellular fluid

2.2. An increase in capillary blood pressureAn increase in capillary blood pressure

3.3. A decrease in the concentration of plasma A decrease in the concentration of plasma proteinsproteins

Some Types of Edema:Some Types of Edema:

Pulmonary Edema – fluid builds up in Pulmonary Edema – fluid builds up in the lungs; results from congestive heart the lungs; results from congestive heart failure (left heart)failure (left heart)

Peripheral Edema / Dependant Edema – Peripheral Edema / Dependant Edema – fluid builds up in the lower extremities fluid builds up in the lower extremities due to circulatory insufficiency, right due to circulatory insufficiency, right heart failure, or vascular diseaseheart failure, or vascular disease

Cerebral Edema – fluid builds up in Cerebral Edema – fluid builds up in brain tissue due to infection, trauma, or brain tissue due to infection, trauma, or systemic inflammatory responsesystemic inflammatory response

DiureticsDiuretics

A diuretic is a substance that promotes A diuretic is a substance that promotes or stimulates production of urine.or stimulates production of urine.

Diuretics are some of the most Diuretics are some of the most commonly prescribed drugs – used to commonly prescribed drugs – used to control hypertension, congestive heart control hypertension, congestive heart failure, renal insufficiency, and edema.failure, renal insufficiency, and edema.

Diuretics have an effect on tubular Diuretics have an effect on tubular function in the nephron and are often function in the nephron and are often classified as to major site of action.classified as to major site of action.

DiureticsDiuretics

Proximal Tube DiureticsProximal Tube Diuretics – act on the – act on the proximal tubule to prevent water proximal tubule to prevent water reabsorbtion. Acetazolamide (Diamox) is reabsorbtion. Acetazolamide (Diamox) is an example.an example.

Loop DiureticsLoop Diuretics – act on the loop of – act on the loop of Henle. Lasix (Furosemide) and Edacrin Henle. Lasix (Furosemide) and Edacrin (ethacrynic acid) are examples.(ethacrynic acid) are examples.

Distal Tubule DiureticsDistal Tubule Diuretics – act on the – act on the distal tubules. Chlorothiazide (Diuril) is distal tubules. Chlorothiazide (Diuril) is an example.an example.

DiureticsDiuretics

Some diuretics are classified as to Some diuretics are classified as to the effect the diuretic has on the effect the diuretic has on electrolyte concentration;electrolyte concentration;

Some diuretics target specific Some diuretics target specific electrolytes in the renal tubules:electrolytes in the renal tubules:

1.1. Sodium (Na+)Sodium (Na+)

2.2. Chloride (Cl-)Chloride (Cl-)

3.3. Potassium (K+)Potassium (K+)

4.4. Bicarbonate (HCO3-)Bicarbonate (HCO3-)

Clinical Considerations for Clinical Considerations for DiureticsDiuretics

Keep careful records of input and Keep careful records of input and output!output!

Assess the patient for signs and Assess the patient for signs and symptoms of electrolyte and water symptoms of electrolyte and water imbalance.imbalance.

Some signs and symptoms of Some signs and symptoms of dehydration include: headache, fever, dehydration include: headache, fever, tachycardia, tachypnea, hypotension, tachycardia, tachypnea, hypotension, paresthesia, and gait disturbances.paresthesia, and gait disturbances.