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1. Unit III: Basic Nursing Concepts Lecture I: Fluids and Electrolytes Lecture II: Acid-Base Balance and Imbalance Dr Naiema Gaber Fundamentals of Nursing.

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Presentation on theme: "1. Unit III: Basic Nursing Concepts Lecture I: Fluids and Electrolytes Lecture II: Acid-Base Balance and Imbalance Dr Naiema Gaber Fundamentals of Nursing."— Presentation transcript:

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2 Unit III: Basic Nursing Concepts Lecture I: Fluids and Electrolytes Lecture II: Acid-Base Balance and Imbalance Dr Naiema Gaber Fundamentals of Nursing II 2 nd year

3 Fluid and Electrolyte Objectives nExplain homeostasis nDiscuss homeodynamics of 1-Water Balance (ECF/ICF volumes) 2-Electrolyte Balance (Na + and K +) nIdentify nursing interventions for clients with altered fluids and electrolytes balance nIdentify nursing interventions for clients with altered fluids and electrolytes balance.

4 Fluids –Substances composed of freely moving molecules –Have the ability to conform to the shape of the container that holds it –There are different types of fluids in our bodies

5 What is homeostasis? n It is physiologic processes that regulate fluids intake & output as well as movement of water & substances dissolved in it (fluids)between the body compartments

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7 What are the factors that influence body fluids? Age body fluids ↑ in younger than older Body fat content Thin people > obese as fat cells contain little water Sex Male>Female Environmental factors

8 The body fluid composition of tissue varies by –Tissue type (lean tissues have higher fluid content than fat tissues) –Gender (males have more lean tissue and therefore more body fluid) –Age (lean tissue is lost with age and body fluid is lost with it)

9 Water is essential for life, HOW??? Water is vital to health and normal cellular function as it is a n medium for metabolic reactions within cells. n transporter for nutrients and waste products. n lubricant. n Help in regulating and maintaining body temperature. 60% of the average healthy adult’s weight is water

10 Major Compartments for Fluids (Distribution of body fluids) n INTRACELLUL AR FLUID (ICF 63% of fluids) n Inside cell n Most of body fluid (40% weight) n Decreased in elderly n EXTRACELLULAR FLUID ECF (37 % of fluids is Outside cell) n Intravascular fluid - within blood vessels (5%) n Interstitial fluid - between cells & blood vessels (15%) n Trancellular fluid - cerebrospinal, pericardial, synovial

11 Fluids Figure 7.1a

12 Fluids Figure 7.1c

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14 Distribution of body fluids Total body fluids = 40 liters Extracellular Fluid (ECF) 15 L Interstitial Fluid 75% Intravascular Fluid 20% Lymph + Trans-cellular fluid 5% Intracellular Fluid (ICF) 25 L

15 Fluids n Extracellular fluids include –Tissue fluid found between the cells within tissues and organs of the body (interstitial) –Plasma, the fluid portion of blood that carries the blood cells (intravascular) –Trans-cellular fluid - cerebrospinal, pericardial, synovial

16 Electrolytes n Body fluid is composed of –Electrolytes which are mineral salts dissolved in water, including for example: »Sodium »Potassium »Chloride »Phosphorus

17 What is meant by ELECTROLYTES? *Substance when dissolved in body fluids charged ions & is able to carry an electrical current conducting electricity. * It can be: n CATION - positively charged electrolyte n ANION - negatively charged electrolyte *No. Cations = No. Anions for homeostasis *Commonly measured in milliequivalents / liter (mEq/L)

18 WHAT IS THE IMPORTANCE OF ELECTROLYTES  Maintaining fluids balance  Contributing to acid-base regulation  Facilitating enzyme reaction  Transmitting neuromuscular reactions

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20 MILLIEQUIVALENT (mEq) n Unit of measure for an electrolyte n Describes electrolyte’s ability to combine & form other compounds n Equivalent weight is amount of one electrolyte that will react with a given amount of hydrogen n 1 mEq of any cation will react with 1 mEq of an anion

21 DEFINITIONS n SOLUTE - substance dissolved n SOLVENT - solution in which the solute is dissolved n SELECTIVELY PERMEABLE MEMBRANES - found throughout body cell membranes & capillary walls; allow water & some solutes to pass through them freely

22 Movement of Body Fluids and Electrolytes It can be by: Osmosis? Diffusion? Filtration? Active transport

23 METHODS OF FLUID & ELECTROLYTE MOVEMENT 1- Passive Transport n Diffusion n Osmosis n Filtration 2- Active Transport using energy (ATP)

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25 DIFFUSION n Process by which a solute ( ions and molecules) in solution moves as gas or substance n Molecules move from an area of higher concentration to an area of lower concentration to evenly distribute the solute in the solution n It can be simple or facilitated diffusion

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28 FACILITATED DIFFUSION n Involves carrier system that moves substance across a membrane with simple diffusion, (from area of higher concentration to one of lower concentration) n Example is movement of glucose with assistance of insulin across cell membrane into cell

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30 OSMOSIS n Movement of the solution =solvent = water across a membrane to equalizes the concentration of ions (solute)on each side of membrane n Movement of solvent molecules across a membrane to an area where there is a higher concentration of solute that cannot pass through the membrane

31 Osmosis Figure 7.4

32 OSMOSIS OSMOSIS cont.

33 OSMOTIC PRESSURE n Pull that draws solvent through the membrane to the more concentrated side (or side with solute ) n It is determined by relative number of particles of solute on side of greater concentration

34 COLLOID OSMOTIC PRESSURE OR ONCOTIC PRESSURE n Special kind of osmotic pressure Created by substances with a high molecular weight (like albumin)

35 ISOTONIC n ISO - means alike n TONICITY - refers to osmotic activity of body fluids; tells the extent that fluid will allow movement of water in & out cell n Means that solutions on both sides of selectively permeable membrane have established equilibrium n Any solution put into body with the same osmolality as blood plasma.

36 ISOTONIC SOLUTIONS EXAMPLES: n 0.9% sodium chloride solution n 5% glucose n Ringer’s Solution n Lactated Ringer’s Solution

37 HYPOTONIC HYPERTONIC n Solution of lower osmotic pressure n Less salt or more water than isotonic n If infused into blood, RBCs draw water into cells ( can swell & burst ) n Solutions move into cells causing them to enlarge n Solution of higher osmotic pressure n 3% sodium chloride is example n If infused into blood, water moves out of cells & into solution (cells wrinkle or shrivel) n Solutions pull fluid from cells

38 HYPOTONIC SOLUTIONS n 5% DEXTROSE & WATER n 0.45% SODIUM CHLORIDE n 0.33% SODIUM CHLORIDE

39 HYPERTONIC SOLUTIONS n 3% SODIUM CHLORIDE n 5% SODIUM CHLORIDE n WHOLE BLOOD n ALBUMIN n TOTAL PARENTERAL NUTRITION n TUBE FEEDINGS n CONCENTRATED DEXTROSE (>10%)

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42 OSMOLALITY n Measure of solution’s ability to create osmotic pressure & thus affect movement of water (tonicity) n Number of osmotically active particles per kilogram of water n Plasma osmolality is 280-300* mOsm/ kg n ECF osmolality is determined by sodium n MEASURE used in clinical practice to evaluate serum & urine

43 IV Fluid Tonicity !!!! n TONICITY n Hypotonic n Isotonic n Hypertonic n OSMOLALITY CELL n < 270 mOsm/kg Swelling n 275-295 mOsm/kg Nothing n > 300 mOsm/kg Shrinking

44 Osmolality In Clinical Practice * n Serum 280-300mOsm/kg n Urine 50-1400mOsm/kg n Serum osmolality can be estimated by doubling serum sodium n Urine specific gravity measures the kidneys’ ability to excrete or conserve water

45 Osmolality In Clinical Practice * n BUN - blood urea nitrogen; made up of urea an end-product of protein metabolism. n inc. with protein intake, fever, & sepsis; dec. with starvation, end-stage liver n dx., low protein diet, expanded fluid vol. (as with pregnancy)

46 Osmolality In Clinical Practice * n Creatinine - end product of muscle metabolism; better indicator of renal function; normal level 0.7-1.5 mg/d L n Hematocrit - vol. % of RBCs in whole blood; normal level in male- 44-52% n In female- 39-47%

47 FILTRATION n Movement of fluid and solutes together through a selectively permeable membrane from an area of higher hydrostatic pressure to an area of lower hydrostatic pressure n Arterial end of capillary has hydrostatic pressure > than osmotic pressure so fluid & diffusible solutes move out of capillary

48 HYDROSTATIC PRESSURE n Force of the fluid pressing outward against vessel wall n With blood not only refers to weight of fluid against capillary wall but to force with which blood is propelled with heartbeat n “Fluid- pushing pressure inside a capillary”*

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50 ACTIVE TRANSPORT SYSTEM n Moves molecules or ions uphill against concentration & osmotic pressure n Requires specific “carrier” molecule as well as specific enzyme (ATP) n Hydrolysis of adenosine triphosphate (ATP) provides energy needed n Sodium-potassium pump is an active transport system. It moves substances from area of low solutes concentration to a higher one

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52 REMEMBER MOVEMENT OF SOLUTE ONLY (SUBSTANCE) DEFUSION MOVEMENT OF SOLVENT ((SOLUTION OR WATER ONLY OSMOSIS MOVEMENT OF BOTH SOLUT AND SOLVENT from area of higher hydrostatic pressure to lower one FELTERATION MOVEMENT OF ION OR MOLECULES AGAINST CONCENTRATION OR OSMOTIC PREASSURE ACTIVE TRANSPORT

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54 Regulating Body Fluids I- Fluid intake: In health by: n Drinking n Eating In illness by: n Parenteral route (IV – SC) n Enteral feeding (in the stomach or intestine)

55 II- Fluid output: Organs of fluids loss: Skin Lungs G I T Kidney

56 Homeostatic Mechanisms Kidneys: The kidneys are functioning under the mastering of aldosterone and antidiuretic hormone (ADH). Regulate electrolytes levels in the ECF by selective retention of needed substances and excretion of unneeded substances. Regulate pH of ECF by excretion or retention of hydrogen ions. Heart and Blood Vessels: If pumping action of the heart fails, it will interfere with the renal perfusion and thus water and electrolytes regulation.

57 Homeostatic Mechanisms cont. Lungs: Remove 300 ml of water daily. Cough will ↑ the loss of water. Mechanical ventilation + excessive moisture ↓ loss. Parathyroid Gland: Parathyroid gland secretes parathyroid hormone: It regulates calcium and phosphate balance. It influences Ca++ reabsorption from interstitial and renal tubules

58 Pituitary Gland: Hypothalamus manufactures antidiuretic hormone (ADH) which is stored in the pituitary gland as needed for the maintenance of osmotic pressure of the cells by controlling renal water retention or excretion and control blood volume. Adrenal Gland: Adrenal gland secretes aldosterone ↑ Secretion of aldosterone → sodium retention → water retention → potassium loss. ↓ Secretion of aldosterone → sodium loss→ water loss→ potassium retention. Homeostatic Mechanisms cont.

59 INTAKE FLUIDS OUT n Ingested liquids 1500 n Water in foods 800* n Water from oxidation 300* n TOTAL 2600* n INSENSIBLE n Skin 600* n Lungs through expired air 300* n Feces 200 n Kidneys 1500* n TOTAL 2600*

60 INTAKE & OUTPUT n INTAKE n Oral fluids - including ice, gelatin, etc. n Parenteral fluids n Tube feedings with flushes n Catheter irrigants that are not withdrawn n OUTPUT n Urine output n Liquid feces n Vomitus n NG drainage n Excessive sweating n Wound drainage n Draining fistula n Rapid or labored RR

61 Quiz ???? n 1. Who has the highest body % of water? Infant? Adolescent? 50 year old? Elderly? n 2. The chief cation of the ICF is Sodium? Chloride? Potassium? Phosphorus

62 More Questions ???? n 4. If you don’t drink any water or have lost a lot of water, what do you think will happen to: renal blood flow, renal BP, Glomerular filtration rate (GFR), ADH, Urine output n 5. Your patient’s blood volume is low due to hemorrhage. What do you expect to see with: BP ? HR ? Skin hot or cool ? Urine output ?

63 You just ate 4 bags of potato chips so what would you expect? n THIRST ? n ADH ? n OSMOLALITY ? n ALDOSTERONE ? n URINE OUTPUT ?

64 You decide to drink 5 gallons of water so what do you expect ? n THIRST ? n ADH ? n OSMOLALITY ? n BLOOD VOLUME ? n RENAL BLOOD VOLUME ? n URINE OUTPUT ?

65 Fluids Disturbances 1. ECF deficit → both Na + and water loss (hypovolemia or dehydration). In the strict sense dehydration is not an ECF deficit but water deficit only. 2. ECF excess → both Na + and water retention (hypervolemia or edema). Over hydration is an ↑ only in the amount of water only not electrolytes.

66 Assessment of Fluid Balance n Health History n Daily Weight n Thirst n Intake and Output n Vital Signs n Skin Turgor n Mucous Membranes n Hand Vein Filling/Emptying n Labs – Urine SG; H&H; Sodium; Total Protein; Albumin; Serum Osmolality; BUN; Creatinine

67 THIRST n Conscious desire for water n Major factor that determines fluid intake n Initiated by the osmoreceptors in hypothalamus that are stimulated by increase in osmotic pressure of body fluids to initiate thirst n Also stimulated by a decrease in the ECF volume

68 FLUID VOLUME DEFICIT (FVD n Hypovolemia or FVD is result of water & electrolyte loss n Compensatory mechanisms include: Increased sympathetic nervous system stimulation with an increase in heart rate & cardiac contraction; thirst; plus release of ADH & aldosterone n Severe case may result in hypovolemic shock or prolonged case may cause renal failure

69 CAUSES OF FVD n Abnormal GI fluid loss such as N&V or drainage of GI tract n Abnormal fluid loss from skin such as high temperature or burns n Increased water vapor from the lungs such as hyperpnea n Conditions that increase renal excretion of fluids such as diuretics & hypersomolar tube feedings n Decrease in fluid intake n Third-space shift such as ascites or trauma

70 LAB VALUES IN FVD n INCREASE IN: HEMATOCRIT nl 44*-52*% M nl 39*-47% F BUN nl 10*-20 mg/dl URINE SPECIFIC GRAVITY nl 1.010*-1.025*

71 SIGNS & SYMPTOMS OF FVD n Dry mucous membranes n Weight loss n Orthostatic hypotension & tachycardia n Subnormal Body temperature n Flat neck veins & decrease in CVP n Decreased urinary output & altered sensorium

72 NURSING MANAGEMEMT OF FVD n Monitoring I&O on a regular schedule depending on the patient n If urine output is below 30 mL / hr. notify the physician n May check urine specific gravity q 8hrs. n Weigh patient daily at the same time & recognize that a change of 2.2 lbs. represents a loss of 1000 mL n Monitor skin turgor, oral membranes, lab

73 Dehydration !!!! n Water isn’t replaced in body n Fluid shifts from cells to EC space n Cells lose water n Happens in confused, comatose, bedridden persons along with infants & elderly n May be treated with hypotonic sol (like dextrose 5% in water)

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75 Dehydration cont. n Risk Factors (Causes) n Insufficient intake due to anorexia, nausea, impaired swallowing, confusion, depression. n Loss of water and electrolytes from: vomiting, diarrhea, nasogastric suction, excessive sweating, fever, polyuria, abdominal drainage, or wound losses.

76 Nursing intervention in dehydration n Oral fluid is given at frequent intervals in a small amount. n Replace the lost electrolyte. n Frequent mouth care. n Replace fluids by enteral or parenteral route if oral replacement can not tolerate. n Prevent skin breakdown.

77 FLUID VOLUME EXCESS FVE n FVE is a result of expansion of fluid compartment due to increase in total sodium content. n Fluid excess in the intravascular space is called hypervolemia. n Fluid excess in interstitial space is called edema n Excess of extra cellular fluid in other body compartment Third space is called. Fluids may be trapped in abdomen, peritoneum (ascites) or plural space (plural effusion).

78 SIGNS & SYMPTOMS OF FVE n SOB & orthopnea n Edema & weight gain n Distended neck veins & tachycardia n Increased blood pressure n Crackles & wheezes n May be ascites & pleural effusion n Increase in CVP

79 NURSING MANAGEMENT OF FVE n Monitor I & O plus monitor for physical signs of hypervolemia n Check for edema & weigh patient daily n Restrict sodium intake as prescribed n Limit intake of fluids n Watch for signs of potassium imbalance n Monitor for signs of pulmonary edema n Place patient in semi-Fowler’s position

80 Nursing management in edema Assessment: n Measure intake and output at regular intervals. n Assess breath sound. n Monitor degree of edema at the most dependent parts of the body. n Assess the degree of pitting edema.

81 EDAEMA It is excessive accumulation of fluid isn the interstitial space it may be n localized edema if it due to trauma or inflammation. n Generalized edema involves the whole body. It is severe.

82 Pitting edema on the leg Pitting edema on the foot

83 Pitting odema

84 Water Intoxication !!!! n Excess fluid moves from EC space to IC space n Happens with SIADH, rapid infusion of hypotonic IV sol or tap water as NG irrigant or enemas; can happen with psychogenic polydipsia ( may drink 12-18 L/day ) n Findings Serum NA < 125 mEq/L Serum Osmolality < 280 mOsm/kg

85 Electrolyte Imbalances 1. Sodium – Hyponatremia – Hypernatremia 2. Potassium – Hypokalemia – Hyperkalemia 3. Calcium – Hypocalcemia – Hyperc alcemia 4. Magnesium – Hypomagnesemia – Hypermagnesemia 5. Phosphorus – Hypophosphatemia – Hyperphosphatemia

86 SODIUM (NA + ) n DOMINANT EXTRACELLULAR ELECTROLYTE n CHIEF BASE OF BLOOD n NL SERUM LEVEL 135-145 mEq/L

87 SODIUM (NA)* n Main extracellular fluid (ECF) cation n Helps govern normal ECF osmolality n Helps maintain acid-base balance n Activates nerve & muscle cells n Influences water distribution (with chloride)

88 SODIUM (NA + ) n SODIUM AFFECTS FLUID VOLUME & CONCENTRATION IN ECF n IS REGULATED BY: Aldosterone Renal blood flow Renin secretion Antidiuretic hormone (ADH) due to its effect on water Estrogen Carbonic anhydrase enzyme

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90 HYPERNATREMIA n Serum Na + level > 148 mEq/L serum osmolality > 295 mOsm/kg & urine sp gr > 1.030 with nl kidneys n Collaborative management tries to gradually lower serum sodium by *infusion of 0.45% NaCl *monitoring U/O & serum sodium level *administering fluids carefully * restricting sodium intake n The thirsty person will not get this !!!!

91 Memory Jogger Hypernatremia n S - skin flushed n A - agitation n L - low grade fever n T - thirst

92 Nursing Diagnosis in Hypernatremia n Fluid volume deficit r/t abnormal water loss, inadequate water intake n Fluid volume excess r/t excessive intake of salt, abnormal Na retention n Risk for injury r/t restlessness and agitation n Impaired oral mucous membrane r/t decreased salivation n Risk for aspiration r/t stupor

93 HYPONATREMIA n Serum Na + < 135 mEq/L (patient may be asymptomatic until level drops below 125) n Collaborative management seeks to correct cause & give sodium with caution due to possible rebound fluid excess by : *infusing isotonic saline in IV fluids *restricting oral & IV water intake *increasing dietary sodium *monitoring for signs of hypervolemia

94 Nursing diagnosis of Hyponatremia n Fluid volume excess r/t water intoxication, SIADH n Knowledge deficit r/t specific need to replace Na n Risk for injury r/t confusion, weakness, seizures

95 POTASSIUM (K + ) n DOMINANT INTRACELLULAR ELECTROLYTE n PRIMARY BUFFER IN CELL n NL SERUM LEVEL 3.5-5.5 *mEq/L

96 POTASSIUM (K)* n Dominant cation in intracellular fluid (ICF) n Regulates cell excitability n Permeates cell membranes, thereby affecting cell’s electrical status n Helps control ICF osmolality & ICF osmotic pressure

97 POTASSIUM (K + ) n MOVEMENT INFLUENCED BY:Changes in pH Insulin Adrenal hormones Changes in serum sodium n IMPORTANT IN: Neuromuscular irritability Intracellular osmotic activity Acid-base balance

98 HYPERKALEMIA n K + > 5.5 mEq/L n Dangerous due to potential for fatal dysrhythmias, cardiac arrest n Major cause is renal disease n EKG shows tall, peaked T waves & dysrthythmias n Beware of pseudohyperkalemia due to prolonged tourniquet, hemolysis of blood, sampling above KCl infusion

99 Nursing diagnosis in Hyperkalemia n Risk for injury r/t lower extremity weakness, possible seizures n Activity intolerance r/t neuromuscular weakness n Risk for decreased cardiac output r/t dysrhythmia and cardiac conduction changes

100 HYPERKALEMIA TX n Watch EKG for fatal dysrthymias or cardiac arrest n Collaborative management may include: Calcium to counteract effect on heart Sodium bicarbonate to alkalinize fluids Hemodialysis or peritoneal dialysis Cation exchange resins (Kayexalate) by mouth or enema Small dose of insulin & dextrose Restrict dietary K +

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102 HYPOKALEMIA n K + < 3.5mEq/L n Most common type of electrolyte imbalance n Major cause is increase renal loss most often associated with diuretics n EKG shows dysrhythmias, flattened T wave n Can increase the action of digitalis n NEVER GIVE K + IV PUSH & ALWAYS DILUTE IN IV FLUIDS

103 Memory Jogger Hypokalemia n S - skeletal muscle weakness n U - U wave (ECG changes) n C- constipation, ileus n T - toxicity of digitalis glycosides n I - irregular, weak pulse n O - orthostatic hypotension n N- numbness

104 Nursing diagnosis in hypokalemia n Altered nutrition, less than body requirements n Risk for injury, vessels, tissues, GI track n Altered urinary elimination of K+ n Risk for decreased C.O. r/t dysrhythmia from electrolyte imbalance, cardiac arrest

105 HYPOKALEMIA TX n Correct the cause n Oral or IV administration of potassium n Salt substitutes containing K + n Foods high in potassium : bananas, pears, dried apricots; fruit juices; tea, cola beverages; milk; meat, fish; baked potato; dried beans (cooked); ANYTHING THAT TASTES GOOD LIKE CHOCOLATE !!

106 www.peditips.com106

107 Summary of the lecture

108 Fluids represent 60 % of weight Distributed as n INTRACELLULAR FLUID (ICF 63% of fluids) n Inside cell n Most of body fluid here - 40% weight n Decreased in elderly n EXTRACELLULAR FLUID ECF (37 % of fluids is Outside cell) n Intravascular fluid - within blood vessels (5%) n Interstitial fluid - between cells & blood vessels (15%) n Transcellular fluid - cerebrospinal, pericardial, synovial

109 Electrolytes n Body fluid is composed of –Water –Electrolytes: mineral salts dissolved in water, including »Sodium »Potassium »Chloride »Phosphorus

110 Movement of Body Fluids and Electrolytes It can be by: Osmosis? Diffusion? Filtration? Active transport

111 IV Fluid Tonicity !!!! n TONICITY n Hypotonic n Isotonic n Hypertonic n OSMOLALITY CELL n < 270 mOsm/kg Swelling n 275-295 mOsm/kg Nothing n > 300 mOsm/kg Shrinking

112 Fluids Disturbances 1. ECF deficit → both Na + and water loss (hypovolemia or dehydration). In the strict sense dehydration is not an ECF deficit but water deficit only. 2. ECF excess → both Na + and water retention (hypervolemia or edema). Over hydration is an ↑ only in the amount of water only not electrolytes.

113 Electrolyte Imbalances 1. Sodium – Hyponatremia – Hypernatremia 2. Potassium – Hypokalemia – Hyperkalemia 3. Calcium – Hypocalcemia – Hyperc alcemia 4. Magnesium – Hypomagnesemia – Hypermagnesemia 5. Phosphorus – Hypophosphatemia – Hyperphosphatemia

114 n Patient with hypervolemia should be in which position? –Lying –b- flat –C-Semifowler’s –d-lateral –(C)

115 n Why we should put patient with hypervolemia in Smi-Fowler’s position bescause he has –a- orthopnea –b-

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118 UNIT III: BASIC NURSING CONCEPTS Lecture II: Acid-Base Balance and Imbalance Dr Naiema Gaber Fundamentals of Nursing II 2 nd year

119 Acid-Base Balance Objectives n Describing the regulation of acid-base balance in the body n Identifying nursing interventions for clients with altered acid-base balance.

120 Which way will the scale tip???* Acidosis vs. Alkalosis

121 Definitions n Acid: is a substance that can donate hydrogen ions in solution. Strong acid such as hydrochloric acid (HCl)release all the H +. Weak acids like carbonic acid (H 2 CO 3 ) release some H +. n Base or Alkali: is a substance that can accept hydrogen ions in solution. n Acidity or alkalinity is measured by pH.

122 Definitions n pH: means the concentration of hydrogen ions [H + ] of the solution. n In the body, weak acids and weak bases regulate acid-base balance to prevent sudden changes in the pH of the body fluids. n Normal pH= 7.35 – 7.45. n 7.45 = alkalosis

123 ACID-BASE BALANCE n Governed by the regulation of hydrgen ion (H + ) concentration in the body n pH = negative logarithm of the H + concentration n Acids - proton donors & give up H + n Bases - H + acceptors n Acidic - inc. in concentration of H + n Basic - dec. in concentration of H +

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125 HENDERSON - HASSELBALCH EQUATION n Expresses that the ratio of base to acid or HCO 3 - to H 2 CO 2 * ( 20: 1) determines the pH n pH < 7.35 ACIDOSIS n pH > 7.45 ALKALOSIS

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127 ACID-BASE REGULATORY MECHANISMS n CHEMICAL BUFFER SYSTEMS - bicarbonate, phosphate, protein, hemoglobin n LUNGS - carbonic acid broken down into CO 2 & H 2 O n KIDNEYS - increasing or decreasing bicarbonate ions

128 Regulation of Acid-Base Balance Review of definitions n Base – accepts or removes hydrogen ion n Buffer- controls the hydrogen ion concentration: »Absorbing hydrogen ions when an acid is added OR »Releasing hydrogen ions when base is added. n Three Buffer Systems: –Bicarbonate – operates in lungs & kidneys –Phosphate – renal tubules –Protein – Hgb, plasma proteins, & intracellular protein

129 I. Buffer mechanisms 1. The bicarbonate buffer system (HCO 3 - ). important in controlling the pH of extracellular fluids. 2. The phosphate buffer system (HPO 4 2- and H 2 PO 4 - ) important in controlling pH of intracellular fluids 3. The protein buffer system. The largest buffer system inside the cells

130 II. Respiratory regulation n It controls the rate of CO 2 which reacts with water to give carbonic acid which ↑ or ↓ pH of the blood.

131 III. Renal regulation n The kidney excretes hydrogen ions (H + ) and forms bicarbonate ions (HCO 3 - ) in specific amounts as indicated by the pH of the blood.

132 Acid – Base Balance

133 Arterial Blood Gases (ABGs) n pH 7.35-7.45 n PaCO 2 35-45 mm Hg n Pa O 2 80-100 mm Hg n O 2 sat. 95-99% n HCO 3 - 22-26mEq/L

134 Regulation of Acid-Base Balance n Normal Values: pHPCO2HCO3 7.35 – 7.45 35 – 45 mm Hg 22 – 26 mEq / L

135 ACID-BASE PARAMETERS n ACID n pH <7.35 n PaCO2 >45 n HCO3 <22 n BASE n pH >7.45 n PaCO2 <35 n HCO3 >26

136 Acid-Base Imbalance 1. Acidosis n Respiratory acidosis n Metabolic acidosis 2. Alkalosis n Respiratory alkalosis n Metabolic alkalosis

137 Respiratory Acidosis* n pH < 7.35 n PaCO 2 > 45mm Hg n Due to inadequate alveolar ventilation n Tx aimed at improving ventilation n Respiratory Opposite

138 Respiratory Alkalosis* n pH > 7.45 n PaCO 2 < 35mm Hg n Due to alveolar hyperventilation & hypocapnia n Tx depends on underlying cause

139 Regulation of Acid-Base Balance Respiratory Function pHPC02Condition DecreasedIncreased Respiratory acidosis IncreasedDecreased Respiratory alkalosis

140 Pair Share – Critical Thinking n What acid-base imbalance would you suspect for the patient having respiratory problems with respiratory rate: 28/min and expiratory wheezing?

141 Pair Share – Critical Thinking n What acid-base imbalance would you suspect for the post-operative patient with respiratory rate 10/min, difficulty to arouse, but arouses with verbal stimuli

142 Metabolic Acidosis* n pH < 7.35 n HCO 3 < 22mEq/L n Due to gain of acids or loss of base (like excessive GI loss from diarrhea) n May have associated hyperkalemia n Tx aimed at correcting metabolic defect n Metabolic Even

143 Metabolic Alkalosis* n pH > 7.45 n HCO 3 > 26 mEq/L n Due to loss of acid or gain of base (most common is vomiting or gastric suction) n Hypokalemia may produce alkalosis n Tx aimed at underlying disorder

144 Regulation of Acid-Base Balance Metabolic FunctionpHHC03Condition DecreasedDecreased Metabolic acidosis IncreasedIncreased Metabolic alkalosis

145 Regulation of Acid-Base Balance > = increased; < = decreasedABGCondition Metabolic process >PCO2Metabolicacidosis < HCO3- elimination by the kidneys – increased acid HCO3- elimination by the kidneys – increased base

146 Regulation of Acid-Base Balance Arterial Blood Gas Interpretation n Step 1: Evaluate the pH –pH <7.35 = acidosis –pH >7.45 = alkalosis n Step 2: Evaluate Respiratory Function –Paco2 >45 mm HG = ventilatory failure & respiratory acidosis –Paco2 <35 mm HG = hyperventilation & respiratory alkalosis > = increased; < = decreased

147 Regulation of Acid-Base Balance Arterial Blood Gas Interpretation n Step 3: Evaluate Metabolic Processes –Serum bicarbonate HCO3 <22 mEq/L = metabolic acidosis –Serum bicarbonate HCO3 >26 mEq/L = metabolic alkalosis n Step 4: Determine the Primary Disorder –When Paco2 & HCO3 are both abnormal: »Determine which follows the deviation from the pH and »Deviates the most from normal

148 Respiratory acidosis Risk FactorsClinical Manifestation Nursing Intervention Acute lung disease: pneumonia, acute pulmonary edema, aspiration of foreign body… Chronic lung disease: asthma, cystic fibrosis, emphysema Overdose of narcotics Brain injury Airway obstruction Chest injury Increased pulse Increased respiratory rate Headache Confusion Convulsions Warm flushed skin Assess respiratory status and lung sound Monitor air way and ventilation Inhalation therapy Percussion and postural drainage Monitor fluid intake and output Measure vital signs Measure arterial blood gases

149 Respiratory alkalosis Risk FactorsClinical ManifestationNursing Intervention Hyperventilation due to: -Extreme anxiety -Elevated body temp. -Overventilation -Hypoxia -Salicylate overdose Brain energy Fever Increased basal metabolic rate Shortness of breath Chest tightness Numbness and tingling of extrimities Difficulty concentrating Blurred vision Monitor vital signs and ABGs Assist client to breath more slowly Help client breath in a paper bag

150 Metabolic acidosis Risk FactorsClinical Manifestation Nursing Intervention Increase of non volatile acids in blood: -renal impairment -DM Decrease in bicarbonates: -Prolonged diarrhea Excessive NaCl infusion Salicylates overdose Cardiac arrest Deep rapid respiration Lethargy, confusion Headache Weakness Nausea and vomiting Monitor ABG values Monitor intake and output Monitor of LOC Administer IV sodium bicarbonate

151 Metabolic alkalosis Risk FactorsClinical Manifestation Nursing Intervention Excessive acid base due to: -Vomiting -Gastric suction Excessive use of K-losing diuiretics Excessive adrenal corticoid hormones due to: -Cushing’s syndrome -Hyperaldosteronism Excessive bicarbonate intake from: -Antacids -Parenteral NaHCO 3 Increase respiratory rate and depth Dizziness Numbness and tingling of the extremities Hypertonic muscles, tetany Monitor intake and output Monitor vital signs especially respiration and LOC Administer IV fluid carefully

152 EVALUATING ABGs* n 1. List pH, P a CO 2, & HCO 3 - n 2. Compare to normals & rate as ACID, BASE OR NORMAL. Write A (acid), B (base), or N (normal) or think ROME n 3. Circle any two letters that are the SAME to tell IMBALANCE. n pH 7.10 P a CO 2 80mmHg HCO 3 - 25mEq/l ???? IMBALANCE ???? n Look at P a O 2 & S a O 2 for oxygenation

153 ABG ASSESSMENT* n 36 yo pt. complains of acute SOB, R sided pleuritic pain n pH 7.50 n P a CO 2 29 mmHg n P a O 2 60 mmHg n HCO 3 - 24 mEq/l n S a O 2 78% n ? Meaning ? n 32 yo pt. with drug OD & breathing 5 times / minute n pH 7.25 n P a CO 2 61 mmHg n P a O 2 74 mmHg n HCO 3 - 26 mEq/l n SaO 2 89% n ? Meaning ?

154 ABGs* n 70 year old diabetic with hx of not taking insulin n pH 7.26 n PaCO 2 42 n HCO 3 17 n ???? n 58 year old pt. With CHF for 6 mos. & placed on digoxin & Lasix n pH 7.48 n PaCO 2 45 n HCO 3 26 n ????

155 Resp Failure – Medical Tx Goals n Maintain adequate oxygenation & ventilation –Oxygen therapy –Mobilization of secretions »Effective coughing and positioning »Hydration & humidification –Chest physical therapy –Airway suctioning –Positive pressure ventilation –Relief of bronchospasm –Reduction of airway inflammation –Reduction of pulmonary congestion –Treatment of pulmonary infections –Reduction of severe anxiety, pain, and agitation –Treat underlying cause –Maintain adequate cardiac output –Maintain adequate hemoglobin concentration

156 Nursing Diagnosis 66-year old man with shortness of breath, dyspnea, orthopnea, profuse perspiration, feeling like he can’t catch his breath. You observe him to have prolonged expiration. Breath sounds: expiratory wheezing – upper lung fields bilaterally; rhonchi hear in right lung field ABGs:Pulse Oximetry: 89 pH -7.28 Paco2 – 50 B/P: 160/90 HR: 110 Resp: 14 HCO3- - 26 Pao2 – 66 Priority Nsg Actions? Top Three Nsg Dx? Top Three Nsg Dx?

157 Nursing Diagnosis n Ineffective airway clearance n Ineffective breathing pattern n Risk for imbalanced fluid volume n Anxiety n Impaired gas exchange n Imbalanced nutrition: less than body requirements

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