L7. Disorders of Fluid and Electrolytes _ Acid Base Balance PDF

LECTURE-7 DISORDERS OF FLUID , ELECTROLYTES & ACID BASE BALANCE PATH 200 1  OUTLINE: Homeostasis Distribution of body fluids Movement of fluid Tonicity Regulating body fluid Fluid imbalance Edema Electrolytes Acid...

LECTURE-7 DISORDERS OF FLUID , ELECTROLYTES & ACID BASE BALANCE PATH 200 1  OUTLINE: Homeostasis Distribution of body fluids Movement of fluid Tonicity Regulating body fluid Fluid imbalance Edema Electrolytes Acid Base balance 2  OBJECTIVES: By the end of this lesson, the students will be able to: Define edema List 4-5 fluid imbalance disorders. Differentiate between the 3 passive transport systems. Describe 2-3 Electrolyte abnormalities Analyze the arterial blood gases 3  HOMEOSTASIS Balance of fluids, electrolytes, acids and bases Physiologic processes control intake and output Every illness has the potential to upset the balance Functions of body fluids Transport gases, nutrients, and wastes Help generate the electrical activity needed to power body functions Take part in the transformation of food into energy Maintain the overall function of the body 4  DISTRIBUTION OF BODY FLUIDS INTRACELLULAR COMPARTMENT (ICF) Consists of fluid contained within all of the billions of cells in the body Larger of the two compartments, with approximately two thirds of the body water in healthy adults HIGH CONCENTRATION OF K+ EXTRACELLULAR COMPARTMENT (ECF) Contains the remaining one third of body water Contains all the fluids outside the cells, including that in the interstitial or tissue spaces and blood vessels High concentration of Na+ 5  MOVEMENT OF FLUIDS PASSIVE TRANSPORT SYSTEMS OSMOSIS DIFFUSION FILTRATION ACTIVE TRANSPORT 6 DIFFUSION The movement of charged or uncharged particles along a concentration gradient from an area of higher concentration to one of lower concentration 7  OSMOSIS The movement of water across a semipermeable membrane from the side of the membrane with the lesser number of particles and greater concentration of water to the side with the greater number of particles and lesser concentration of water 8 FILTRATION Movement of solute and solvent across a membrane caused by hydrostatic (water pushing) pressure Occurs at the capillary level If normal pressure gradient changes (as occurs with right-sided heart failure) edema results from “third spacing” 9  ACTIVE TRANSPORT Solutes can be moved against a concentration gradient Also called “pumping” Dependent on the presence of ATP 10 TONICITY The tension or effect that the effective osmotic pressure of a solution with impermeable solutes exerts on cell size because of water movement across the cell membrane Solutions can be classified according to whether or not they cause cells to shrink: ISOTONIC: NEITHER SHRINK NOR SWELL HYPOTONIC: SWELL HYPERTONIC: SHRINK 11  REGULATING BODY FLUIDS Fluid intake – thirst , IV fluids Fluid output – urine – insensible loss – feces Homeostasis is maintained by Kidneys ADH Renin-angiotensin-aldosterone system Atrial natriuretic system 12 REGULATING BODY FLUIDS 13 REGULATING BODY FLUIDS 14  FLUID IMBALANCES DEHYDRATION HYPOVOLEMIA HYPERVOLEMIA 15  DEHYDRATION LOSS OF BODY FLUIDS ⇒ INCREASED CONCENTRATION OF SOLUTES IN THE BLOOD AND A RISE IN SERUM NA+ LEVELS Fluid shifts out of cells into the blood to restore balance Cells shrink from fluid loss and can no longer function normaly Clients at risk: confused, comatosed, bedridden, infants, elderly, enterally fed Clinical findings: dry skin/mucous membranes, poor skin turgor, weakness, extreme thirst, decreased urine output Treatment: Fluid replacement - oral or IV over 48 hrs 16  HYPOVOLEMIA Isotonic fluid loss from the extracellular space Can progress to hypovolemic shock Causes: Excessive fluid loss (hemorrhage eg: road traffic accidents),decreased fluid intake, third space fluid shifting Clinical findings: Mental status deterioration, thirst, tachycardia, delayed capillary refill, urine output less than 30 ml/hr, cool, pale extremities, weight loss Treatment: Fluid replacement 17  HYPERVOLEMIA Excess fluid in the extracellular compartment as a result of fluid or sodium retention, excessive intake, or renal failure Occurs when compensatory mechanisms fail to restore fluid balance Leads to heart failure and pulmonary edema Clinical findings: tachypnea, dyspnea, crackles, rapid, bounding pulse, hypertension, acute weight gain, edema Treatment: Fluid and Na+ restriction,diuretics 18  EDEMA Edema can occur as a result of : ✔ Increased capillary fluid pressure ✔ Decreased capillary oncotic pressure ✔ Increased interstitial oncotic pressure causing expansion of the interstitial fluid compartment Edema can be localized (eg, in the ankle, as in rheumatoid arthritis) or generalized (as in cardiac and renal failure). Severe generalized edema is called anasarca. 19  ELECTROLYTES Charged particles in solution Cations (+) Eg: sodium, potassium, calcium, magnesium Major cations: Extracellular - sodium (Na+) Intracellular- potassium (K+) Anions (-) Eg:chloride, bicarbonate,phosphate Integral part of metabolic and cellular processes 20  ELECTROLYTE IMBALANCES Hyponatremia/ Hypernatremia Hypokalemia/ Hyperkalemia Hypomagnesemia/ Hypermagnesemia Hypocalcemia/ Hypercalcemia Hypophosphatemia/ Hyperphosphatemia 21  SODIUM Attracts fluid and helps preserve fluid volume normal range of serum sodium 135 - 145 meq/L HYPONATREMIA HYPERNATREMIA Dilutional - results from Na+ loss, water gain Excess Na+ relative to body water Depletional - insufficient Na+ intake Occurs less often than hyponatremia Hypovolemic - Na+ loss is greater than water loss; can May be caused by water deficit or be renal (diuretic use) or non-renal (vomiting) over-ingestion of Na+ Hypervolemic - water gain is greater than Na+ gain; edema occurs Isovolumic - normal Na+ level, too much fluid 22  POTASSIUM Untreated changes in K+ levels can lead to serious neuromuscular and cardiac complications Normal K+ levels = 3.5 - 5 meq/L HYPOKALEMIA HYPERKALEMIA Serum K+ < 3.5 MEq/L Serum K+ > 5 Meq/L can be caused by GI losses, diarrhea, Less common than hypokalemia insufficient intake, non-k+ sparing Caused by altered kidney function, diuretics (thiazide, furosemide) increased intake (salt substitutes), blood transfusions, meds (k+-sparing diuretics), cell death (trauma) 23  MAGNESIUM Helps produce ATP Role in protein synthesis & carbohydrate metabolism Helps cardiovascular system function (vasodilation) Regulates muscle contractions Normal level 1.5-2.5 meq/L HYPOMAGNESEMIA HYPERMAGNESEMIA Serum Mg++ level < 1.5 meq/L Serum Mg++ level > 2.5 meq/L Caused by poor dietary intake, poor Not common GI absorption, excessive GI/urinary Renal dysfunction is the most losses common cause 24  CALCIUM 99% in bones, 1% in serum and soft tissue (measured by serum Ca++) Works with phosphorus to form bones and teeth Role in cell membrane permeability Affects cardiac muscle contraction Participates in blood clotting Normal level 8.9-10.1 mg/dl HYPOCALCEMIA HYPERCALCEMIA Serum calcium < 8.9 mg/dl Serum calcium > 10.1 mg/dl Caused by inadequate intake, Two major causes malabsorption, pancreatitis, thyroid or Cancer parathyroid surgery, loop diuretics, Hyperparathyroidism low magnesium levels 25  PHOSPHORUS Crucial to cell membrane integrity, muscle function, neurologic function and metabolism of carbs, fats and protein Functions in ATP formation, phagocytosis, platelet function and formation of bones and teeth Normal level 2.5-4.5 mg/dl HYPOPHOSPHATEMIA HYPERPHOSPHATEMIA Serum phosphorus Serum phosphorus < 2.5 MG/DL > 4.5 MG/DL Can lead to organ system failure Caused by impaired kidney function, cell Caused by respiratory alkalosis damage etc (hyperventilation), diuretics, extensive burns 26  ACID-BASE BALANCE An acid is a molecule that can release an H+. Base is an ion or molecule that can accept or combine with an H+. Balance depends on regulation of free hydrogen ions Concentration of hydrogen ions is measured in pH Arterial blood gases(ABG) are the major diagnostic tool for evaluating acid-base balance 27  MECHANISMS OF ACID–BASE BALANCE PH of extracellular fluid must be maintained within 7.35 to 7.45 for optimal functioning of body cells. PH is determined by the ratio of the bicarbonate base to the volatile carbonic acid The concentration of metabolic acids and bicarbonate base is regulated by the kidney. The concentration of CO2 is regulated by the respiratory system. Ph regulation Chemical buffer systems of the body fluids eg: proteins and organic molecules The lungs, which control the elimination of CO2 eg:bicarbonate buffering system The kidneys, which eliminate H+ and both reabsorb and generate HCO3− 28 NORMAL ABG (ARTERIAL BLOOD GASES) VALUES 29  ACIDOSIS PH < 7.35 Caused by accumulation of acids or by a loss of bases HIGH PCO2 ======> RESPIRATORY ACIDOSIS ▪ Any compromise in breathing can result in respiratory acidosis ▪ Causes: neuromuscular diseases, depression of the brain’s respiratory center, lung disease or airway obstruction LOW HCO3 ======> METABOLIC ACIDOSIS ▪ Characterized by gain of acid or loss of bicarbonate ▪ Causes: diabetes mellitus, alcoholism, starvation, hyperthyroidism 30  ALKALOSIS H > 7.45 P Occurs when bases accumulate or acids are lost LOW PCO2 ======> RESPIRATORY ALKALOSIS ▪ Most commonly results from hyperventilation caused by pain, salicylate poisoning, use of nicotine HIGH HCO3 ======>METABOLIC ALKALOSIS ▪ Commonly associated with hypokalemia from diuretic use ▪ Also caused by excessive vomiting, NG suction, kidney disease or drugs containing baking soda 31  PH :7.38 PACO2: 38 HCO3: 24 INTERPRETATION: NORMAL EXAMPLES PH: 7.22 PCO2: 55 HCO3: 25 Normal values INTERPRETATION: RESPIRATORY ACIDOSIS pH : 7.35 - 7.45 PaCO2: 35 - 45 HCO3: 22 - 26 PH : 7.48 PACO2: 25 HCO3: 24 INTERPRETATION: RESPIRATORY ALKALOSIS pH low- Acidosis pH High – Alkalosis PH: 7.28 PCO2: 42 HCO3: 20 PaCO2 low- Respiratory Alkalosis INTERPRETATION: METABOLIC ACIDOSIS PaCO2 High – Respiratory Acidosis HCO3 low – Metabolic Acidosis PH: 7.5 PCO2: 42 HCO3: 33 HCO3 High – Metabolic Alkalosis INTERPRETATION: METABOLIC ALKALOSIS 32  REFERENCES Norris, t. (2019). Porth’s pathophysiology concepts of altered health states. 10th ed. Wolters kluwer Ian peate, (2021) fundamentals of applied pathophysiology: an essential guide for nursing & healthcare students. 4th ed. Hoboken, nj : wiley-blackwell dignle, m., Mulvihill, M., Zelman, M. & Tompary, E. (2011). Introductory pathophysiology for nursing & healthcare professionals. |Pearson Nair, M., & Peate, I. (2015). Pathophysiology for nurses at a glance (nursing and healthcare). Publisher: west sussex, england: john wiley & sons, inc 33 ANY QUESTIONS? THANK YOU 34