1. Anatomy & Physiology Tri-State Business Institute Micheal H. McCabe, EMT-P

2. Fluid & Electrolyte Balance: Locations of Body Fluids: Locations of Body Fluids: 1. Intracellular Fluids (ICF) – fluids within body cells 2. Extracellular Fluids (ECF) – fluids outside body cells A. Interstitial Fluids (IF) – fluid in the space between cells B. Blood Plasma (BP) – fluids contained in blood vessels In total, body fluids account for 50% to 60% of the weight in a healthy adult In total, body fluids account for 50% to 60% of the weight in a healthy adult

3. Distribution of Body Fluids Plasma – approximately 4% of body weight in a young adult. Plasma – approximately 4% of body weight in a young adult. Interstitial Fluid – approximately 10% of body weight Interstitial Fluid – approximately 10% of body weight Intracellular Fluid – approximately 33% of body weight Intracellular Fluid – approximately 33% of body weight

4. Variations in Body Fluids Variations in total body fluids relate to: Variations in total body fluids relate to: 1. Weight – the more a person weighs, the more water the body contains 2. Fat Content – fat is almost water-free; the higher the percentage of body fat, the less the percentage of body weight is water 3. Sex – women normally have 10% less water than men 4. Age – in the newborn, over 80% of total body weight is water

5. Fluid Input & Output over 24 Hours Fluid Input Food 700 ml Food 700 ml Liquid 1500 ml Liquid 1500 ml Water formed within the body 200 ml Water formed within the body 200 ml Total Input = 2400 ml Fluid Output Lungs350 ml Skin (diffusion)350 ml Skin (sweat)100 ml Kidneys1400 ml Intestines (feces)200 ml Total Output = 2400 ml

6. Regulation of Fluid Intake When dehydration starts to develop, salivary secretion decreases, producing a “dry mouth.” When dehydration starts to develop, salivary secretion decreases, producing a “dry mouth.” The brain interprets this as a sensation of thirst. The brain interprets this as a sensation of thirst. The individual is compelled to drink water. The individual is compelled to drink water. If the individual is unable to drink, urine production decreases or stops. If the individual is unable to drink, urine production decreases or stops. Fluid loss continues from the skin, lungs, and intestine. Fluid loss continues from the skin, lungs, and intestine. Despite compensatory mechanisms, dehydration will progress. Despite compensatory mechanisms, dehydration will progress.

7. Mechanisms that Maintain Fluid Balance Fluid output adjusts to fluid intake; ADH from posterior pituitary gland increases kidney tubule reabsorbtion of water, increasing extra-cellular fluid (ECF) volume. Fluid output adjusts to fluid intake; ADH from posterior pituitary gland increases kidney tubule reabsorbtion of water, increasing extra-cellular fluid (ECF) volume. ECF electrolyte concentration influences ECF volume. An increase in Na+ tends to increase ECF volume. ECF electrolyte concentration influences ECF volume. An increase in Na+ tends to increase ECF volume.

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

9. Electrolytes in Body Fluids Electrolytes – compounds that dissociate when dissolved in water into ions – example: NaCl (Sodium Chloride) dissociates into Na+ and CL- ions when dissolved in water. Electrolytes – compounds that dissociate when dissolved in water into ions – example: NaCl (Sodium Chloride) dissociates into Na+ and CL- ions when dissolved in water. Non-Electrolytes – organic substances that do not dissociate when dissolved in water - - example: glucose Non-Electrolytes – organic substances that do not dissociate when dissolved in water - - example: glucose

10. Electrolytes in Body Fluids Ions – the dissociated particles of an electrolyte that carry an electrical charge. Example: Sodium (Na+) Ions – the dissociated particles of an electrolyte that carry an electrical charge. Example: Sodium (Na+) Positively charged ions (Anions) include Potassium (K+) and Sodium (Na+) Positively charged ions (Anions) include Potassium (K+) and Sodium (Na+) Negatively charged ions (Cations) include Chloride (Cl-) and Bicarbonate (HC03-) Negatively charged ions (Cations) include Chloride (Cl-) and Bicarbonate (HC03-)

11. Electrolyte Composition of Blood Plasma Positively Charged Ions: Positively Charged Ions: Sodium (Na+) = 142 mEq / Liter Sodium (Na+) = 142 mEq / Liter Potassium (K+) = 4 mEq / Liter Potassium (K+) = 4 mEq / Liter Calcium (Ca++) = 5 mEq / Liter Calcium (Ca++) = 5 mEq / Liter Magnesium (Mg++) = 2 mEq / Liter Magnesium (Mg++) = 2 mEq / Liter Total of Positively Charged Ions = 153 mEq / Liter Total of Positively Charged Ions = 153 mEq / Liter

12. Electrolyte Composition of Blood Plasma Negatively Charged Ions: Negatively Charged Ions: Chloride (Cl-) = 102 mEq / Liter Chloride (Cl-) = 102 mEq / Liter Bicarbonate (HCO3-) = 26 mEq / Liter Bicarbonate (HCO3-) = 26 mEq / Liter Protein (Cation) = 17 mEq / Liter Protein (Cation) = 17 mEq / Liter Phosphate (HPO4-) = 2 mEq / Liter Phosphate (HPO4-) = 2 mEq / Liter Other cations = 6mEq / Liter Other cations = 6mEq / Liter Total of Negatively Charged Ions = 153 mEq / Liter Total of Negatively Charged Ions = 153 mEq / Liter

13. Functions of Electrolytes Electrolytes are required for many cellular activities; particularly nerve conduction and muscle contraction. Electrolytes are required for many cellular activities; particularly nerve conduction and muscle contraction. Electrolytes must balance for these functions to work properly Electrolytes must balance for these functions to work properly The concentration of positive ions in the blood plasma must equal the concentration of negative ions. The concentration of positive ions in the blood plasma must equal the concentration of negative ions.

14. Sodium Sodium is the most abundant and important positively charged ion in blood plasma Sodium is the most abundant and important positively charged ion in blood plasma Normal Plasma Level = 142 mEq / Liter Normal Plasma Level = 142 mEq / Liter Average Daily Intake = 100 mEq Average Daily Intake = 100 mEq Chief Method of Regulation: Kidney Chief Method of Regulation: Kidney Aldosterone increases Na+ reabsorbtion in kidney tubules Aldosterone increases Na+ reabsorbtion in kidney tubules Many internal secretions contain sodium Many internal secretions contain sodium

15. Internal Secretions Containing Sodium Saliva – 1500 ml / 24 hours Saliva – 1500 ml / 24 hours Gastric Secretions – 2500 ml / 24 hrs Gastric Secretions – 2500 ml / 24 hrs Bile – 500 ml / 24 hrs Bile – 500 ml / 24 hrs Pancreatic Juice – 700 ml / 24 hrs Pancreatic Juice – 700 ml / 24 hrs Intestinal Secretions – 3000 ml / 24 hrs Intestinal Secretions – 3000 ml / 24 hrs Total volume of secretions may reach 8000 ml in 24 hrs. Total volume of secretions may reach 8000 ml in 24 hrs. Most internal secretions are reabsorbed Most internal secretions are reabsorbed

16. Relationship between Electrolyte Concentration and Fluid Balance “Where salt goes, water will follow!” “Where salt goes, water will follow!” Example: If the concentration of sodium in the interstitial fluid rises, water moves from the blood pasma into the IF. The volume of IF soon rises causing edema. Example: If the concentration of sodium in the interstitial fluid rises, water moves from the blood pasma into the IF. The volume of IF soon rises causing edema. A solution with a concentration of sodium greater than blood plasma is called hypertonic. A solution with a concentration of sodium greater than blood plasma is called hypertonic. A solution with a concentration of sodium less than blood plasma is called hypotonic. A solution with a concentration of sodium less than blood plasma is called hypotonic. A solution with a concentration of sodium equal to blood plasma is called isotonic. A solution with a concentration of sodium equal to blood plasma is called isotonic.

17. Fluid Imbalances Dehydration – total volume of body fluids is smaller than normal; IF volume shrinks first; if untreated, ICF and plasma volume decrease; dehydration occurs when fluid output exceeds intake for an extended period. Dehydration – total volume of body fluids is smaller than normal; IF volume shrinks first; if untreated, ICF and plasma volume decrease; dehydration occurs when fluid output exceeds intake for an extended period. Overhydration – total volume of body fluids larger than normal; overhydration occurs when fluid intake exceeds output; various factors may cause this – giving excessive amounts of IV fluids or giving them too rapidly may increase intake above output. Overhydration – total volume of body fluids larger than normal; overhydration occurs when fluid intake exceeds output; various factors may cause this – giving excessive amounts of IV fluids or giving them too rapidly may increase intake above output.

18. Edema Edema is the presence of abnormally large amount of fluid in the tissue spaces. Edema is the presence of abnormally large amount of fluid in the tissue spaces. Edema is a classic example of fluid imbalance and can be caused by a number of factors: Edema is a classic example of fluid imbalance and can be caused by a number of factors: 1. Retention of electrolytes – especially sodium in the extracellular fluid 2. An increase in capillary blood pressure 3. A decrease in the concentration of plasma proteins

19. Some Types of Edema: Pulmonary Edema – fluid builds up in the lungs; results from congestive heart failure (left heart) Pulmonary Edema – fluid builds up in the lungs; results from congestive heart failure (left heart) Peripheral Edema / Dependant Edema – fluid builds up in the lower extremities due to circulatory insufficiency, right heart failure, or vascular disease Peripheral Edema / Dependant Edema – fluid builds up in the lower extremities due to circulatory insufficiency, right heart failure, or vascular disease Cerebral Edema – fluid builds up in brain tissue due to infection, trauma, or systemic inflammatory response Cerebral Edema – fluid builds up in brain tissue due to infection, trauma, or systemic inflammatory response

20. Diuretics A diuretic is a substance that promotes or stimulates production of urine. A diuretic is a substance that promotes or stimulates production of urine. Diuretics are some of the most commonly prescribed drugs – used to control hypertension, congestive heart failure, renal insufficiency, and edema. Diuretics are some of the most commonly prescribed drugs – used to control hypertension, congestive heart failure, renal insufficiency, and edema. Diuretics have an effect on tubular function in the nephron and are often classified as to major site of action. Diuretics have an effect on tubular function in the nephron and are often classified as to major site of action.

21. Diuretics Proximal Tube Diuretics – act on the proximal tubule to prevent water reabsorbtion. Acetazolamide (Diamox) is an example. Proximal Tube Diuretics – act on the proximal tubule to prevent water reabsorbtion. Acetazolamide (Diamox) is an example. Loop Diuretics – act on the loop of Henle. Lasix (Furosemide) and Edacrin (ethacrynic acid) are examples. Loop Diuretics – act on the loop of Henle. Lasix (Furosemide) and Edacrin (ethacrynic acid) are examples. Distal Tubule Diuretics – act on the distal tubules. Chlorothiazide (Diuril) is an example. Distal Tubule Diuretics – act on the distal tubules. Chlorothiazide (Diuril) is an example.

22. Diuretics Some diuretics are classified as to the effect the diuretic has on electrolyte concentration; Some diuretics are classified as to the effect the diuretic has on electrolyte concentration; Some diuretics target specific electrolytes in the renal tubules: Some diuretics target specific electrolytes in the renal tubules: 1. Sodium (Na+) 2. Chloride (Cl-) 3. Potassium (K+) 4. Bicarbonate (HCO3-)

23. Clinical Considerations for Diuretics Keep careful records of input and output! Keep careful records of input and output! Assess the patient for signs and symptoms of electrolyte and water imbalance. Assess the patient for signs and symptoms of electrolyte and water imbalance. Some signs and symptoms of dehydration include: headache, fever, tachycardia, tachypnea, hypotension, paresthesia, and gait disturbances. Some signs and symptoms of dehydration include: headache, fever, tachycardia, tachypnea, hypotension, paresthesia, and gait disturbances.