Fluid and Electrolyte Imbalances: 1 Fluid and Electrolyte Imbalances


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Body Fluid Compartments: 3 Body Fluid Compartments 2/3 (65%) of TBW is intracellular (ICF) 1/3 extracellular water 25 % interstitial fluid (ISF) 5- 8 % in plasma (IVF intravascular fluid) 1- 2 % in transcellular fluids – CSF, intraocular fluids, serous membranes, and in GI, respiratory and urinary tracts (third space)


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Slide6: 6 Fluid compartments are separated by membranes that are freely permeable to water. Movement of fluids due to: hydrostatic pressure osmotic pressure\ Capillary filtration (hydrostatic) pressure Capillary colloid osmotic pressure Interstitial hydrostatic pressure Tissue colloid osmotic pressure


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Balance: 8 Balance Fluid and electrolyte homeostasis is maintained in the body Neutral balance: input = output Positive balance: input > output Negative balance: input < output


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Solutes – dissolved particles: 11 Solutes – dissolved particles Electrolytes – charged particles Cations – positively charged ions Na+, K+ , Ca++, H+ Anions – negatively charged ions Cl-, HCO3- , PO43- Non-electrolytes - Uncharged Proteins, urea, glucose, O2, CO2


Slide12: 12 Body fluids are: Electrically neutral Osmotically maintained Specific number of particles per volume of fluid


Homeostasis maintained by:: 13 Homeostasis maintained by: Ion transport Water movement Kidney function


Slide14: 14 MW (Molecular Weight) = sum of the weights of atoms in a molecule mEq (milliequivalents) = MW (in mg)/ valence mOsm (milliosmoles) = number of particles in a solution


Slide15: 15 Tonicity Isotonic Hypertonic Hypotonic


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Slide17: 17 Cell in a hypertonic solution


Slide18: 18 Cell in a hypotonic solution


Slide19: 19 Movement of body fluids “ Where sodium goes, water follows.” Diffusion – movement of particles down a concentration gradient. Osmosis – diffusion of water across a selectively permeable membrane Active transport – movement of particles up a concentration gradient ; requires energy


Slide20: 20 ICF to ECF – osmolality changes in ICF not rapid IVF → ISF → IVF happens constantly due to changes in fluid pressures and osmotic forces at the arterial and venous ends of capillaries


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Regulation of body water: 22 Regulation of body water ADH – antidiuretic hormone + thirst Decreased amount of water in body Increased amount of Na+ in the body Increased blood osmolality Decreased circulating blood volume Stimulate osmoreceptors in hypothalamus ADH released from posterior pituitary Increased thirst


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Slide24: 24 Result: increased water consumption increased water conservation Increased water in body, increased volume and decreased Na+ concentration


Slide25: 25 Dysfunction or trauma can cause: Decreased amount of water in body Increased amount of Na+ in the body Increased blood osmolality Decreased circulating blood volume


Slide26: 26 Edema is the accumulation of fluid within the interstitial spaces. Causes: increased hydrostatic pressure lowered plasma osmotic pressure increased capillary membrane permeability lymphatic channel obstruction


Slide27: 27 Hydrostatic pressure increases due to: Venous obstruction: thrombophlebitis (inflammation of veins) hepatic obstruction tight clothing on extremities prolonged standing Salt or water retention congestive heart failure renal failure


Slide28: 28 Decreased plasma osmotic pressure: ↓ plasma albumin (liver disease or protein malnutrition) plasma proteins lost in : glomerular diseases of kidney hemorrhage, burns, open wounds and cirrhosis of liver


Slide29: 29 Increased capillary permeability: Inflammation immune responses Lymphatic channels blocked: surgical removal infection involving lymphatics lymphedema


Slide30: 30 Fluid accumulation: increases distance for diffusion may impair blood flow = slower healing increased risk of infection pressure sores over bony prominences Psychological effects


Slide31: 31 Edema of specific organs can be life threatening (larynx, brain, lung) Water is trapped, unavailable for metabolic processes. Can result in dehydration and shock. (severe burns)


Electrolyte balance: 32 Electrolyte balance Na + (Sodium) 90 % of total ECF cations 136 -145 mEq / L Pairs with Cl- , HCO3- to neutralize charge Low in ICF Most important ion in regulating water balance Important in nerve and muscle function


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Regulation of Sodium: 34 Regulation of Sodium Renal tubule reabsorption affected by hormones: Aldosterone Renin/angiotensin Atrial Natriuretic Peptide (ANP)


Potassium: 35 Potassium Major intracellular cation ICF conc. = 150- 160 mEq/ L Resting membrane potential Regulates fluid, ion balance inside cell pH balance


Regulation of Potassium: 36 Regulation of Potassium Through kidney Aldosterone Insulin


Isotonic alterations in water balance: 37 Isotonic alterations in water balance Occur when TBW changes are accompanied by = changes in electrolytes Loses plasma or ECF Isotonic fluid loss ↓ECF volume, weight loss, dry skin and mucous membranes, ↓ urine output, and hypovolemia ( rapid heart rate, flattened neck veins, and normal or ↓ B.P. – shock)


Slide38: 38 Isotonic fluid excess Excess IV fluids Hypersecretion of aldosterone Effect of drugs – cortisone Get hypervolemia – weight gain, decreased hematocrit, diluted plasma proteins, distended neck veins, ↑ B.P. Can lead to edema (↑ capillary hydrostatic pressure) pulmonary edema and heart failure


Electrolyte imbalances: Sodium: 39 Electrolyte imbalances: Sodium Hypernatremia (high levels of sodium) Plasma Na+ > 145 mEq / L Due to ↑ Na + or ↓ water Water moves from ICF → ECF Cells dehydrate


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Slide41: 41 Hypernatremia Due to: Hypertonic IV soln. Oversecretion of aldosterone Loss of pure water Long term sweating with chronic fever Respiratory infection → water vapor loss Diabetes – polyuria Insufficient intake of water (hypodipsia)


Clinical manifestationsof Hypernatremia: 42 Clinical manifestations of Hypernatremia Thirst Lethargy Neurological dysfunction due to dehydration of brain cells Decreased vascular volume


Treatment of Hypernatremia: 43 Treatment of Hypernatremia Lower serum Na+ Isotonic salt-free IV fluid Oral solutions preferable


Hyponatremia: 44 Hyponatremia Overall decrease in Na+ in ECF Two types: depletional and dilutional Depletional Hyponatremia Na+ loss: diuretics, chronic vomiting Chronic diarrhea Decreased aldosterone Decreased Na+ intake


Slide45: 45 Dilutional Hyponatremia: Renal dysfunction with ↑ intake of hypotonic fluids Excessive sweating→ increased thirst → intake of excessive amounts of pure water Syndrome of Inappropriate ADH (SIADH) or oliguric renal failure, severe congestive heart failure, cirrhosis all lead to: Impaired renal excretion of water Hyperglycemia – attracts water


Clinical manifestations of Hyponatremia: 46 Clinical manifestations of Hyponatremia Neurological symptoms Lethargy, headache, confusion, apprehension, depressed reflexes, seizures and coma Muscle symptoms Cramps, weakness, fatigue Gastrointestinal symptoms Nausea, vomiting, abdominal cramps, and diarrhea Tx – limit water intake or discontinue meds


Hypokalemia: 47 Hypokalemia Serum K+ < 3.5 mEq /L Beware if diabetic Insulin gets K+ into cell Ketoacidosis – H+ replaces K+, which is lost in urine β – adrenergic drugs or epinephrine


Causes of Hypokalemia: 48 Causes of Hypokalemia Decreased intake of K+ Increased K+ loss Chronic diuretics Acid/base imbalance Trauma and stress Increased aldosterone Redistribution between ICF and ECF


Clinical manifestations of Hypokalemia: 49 Clinical manifestations of Hypokalemia Neuromuscular disorders Weakness, flaccid paralysis, respiratory arrest, constipation Dysrhythmias, appearance of U wave Postural hypotension Cardiac arrest Others – table 6-5 Treatment- Increase K+ intake, but slowly, preferably by foods


Hyperkalemia: 50 Hyperkalemia Serum K+ > 5.5 mEq / L Check for renal disease Massive cellular trauma Insulin deficiency Addison’s disease Potassium sparing diuretics Decreased blood pH Exercise causes K+ to move out of cells


Clinical manifestations of Hyperkalemia: 51 Clinical manifestations of Hyperkalemia Early – hyperactive muscles , paresthesia Late - Muscle weakness, flaccid paralysis Change in ECG pattern Dysrhythmias Bradycardia , heart block, cardiac arrest


Treatment of Hyperkalemia: 52 Treatment of Hyperkalemia If time, decrease intake and increase renal excretion Insulin + glucose Bicarbonate Ca++ counters effect on heart


Calcium Imbalances: 53 Calcium Imbalances Most in ECF Regulated by: Parathyroid hormone ↑Blood Ca++ by stimulating osteoclasts ↑GI absorption and renal retention Calcitonin from the thyroid gland Promotes bone formation ↑ renal excretion


Hypercalcemia: 54 Hypercalcemia Results from: Hyperparathyroidism Hypothyroid states Renal disease Excessive intake of vitamin D Milk-alkali syndrome Certain drugs Malignant tumors – hypercalcemia of malignancy Tumor products promote bone breakdown Tumor growth in bone causing Ca++ release


Hypercalcemia: 55 Hypercalcemia Usually also see hypophosphatemia Effects: Many nonspecific – fatigue, weakness, lethargy Increases formation of kidney stones and pancreatic stones Muscle cramps Bradycardia, cardiac arrest Pain GI activity also common Nausea, abdominal cramps Diarrhea / constipation Metastatic calcification


Hypocalcemia: 56 Hypocalcemia Hyperactive neuromuscular reflexes and tetany differentiate it from hypercalcemia Convulsions in severe cases Caused by: Renal failure Lack of vitamin D Suppression of parathyroid function Hypersecretion of calcitonin Malabsorption states Abnormal intestinal acidity and acid/ base bal. Widespread infection or peritoneal inflammation


Hypocalcemia: Hypocalcemia 57