Timby/Smith: Introductory Medical-Surgical Nursing, 10/e

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Timby/Smith: Introductory

Medical-Surgical

Nursing, 10/e

Timby/Smith: Introductory

Medical-Surgical

Nursing, 10/e

Chapter 16: Caring for Clients with Fluid, Electrolyte, and

Acid-Base Imbalances


Fluid and Electrolyte BalanceFluid and Electrolyte Balance• Human body is 60% water

– Intracellular (mostly); Extracellular

• Average oral fluid intake-2500ml; primary sources of body fluid is food and liquids

• Functions: Maintain or restore equilibrium in fluid volume

• Translocation: Fluid and chemical exchange

– Electrolytes; Acids and bases; Fluid balance

• Physiologic processes

– Osmosis; Filtration; Passive and facilitated diffusion; Active transport


QuestionQuestion

Is the following statement true or false?

A function of fluid and electrolyte balance is to maintain or restore equilibrium.


AnswerAnswer

True.

A function of fluid and electrolyte balance is to maintain or restore equilibrium, promoting homeostasis.


Fluid and Electrolyte RegulationFluid and Electrolyte Regulation

Distribution of body fluid at the cellular level, pg 182


• Osmosis

– Water movement through semi-permeable membrane; Tonicity (concentration of substances); Osmotic pressure (power to draw H2O toward an area of grater concentration)

– Fluid distribution: Flows from dilute (low) to concentrated (high); Figure 16-3 pg 183

• Filtration

– Movement: Fluid, dissolved substances through semi-permeable membrane; Relocates: Water; Chemicals

• From high pressure to low pressure

– Affects kidney function; kidneys filter abt 180 L of fluid from blood daily; all but 1 – 1.5 L is reabsorbed

Fluid and Electrolyte BalanceFluid and Electrolyte Balance



In osmosis, the fluid flows from the dilute to the concentrated.

QuestionQuestion


True.

In osmosis, the fluid flows from the dilute to the concentrated.

AnswerAnswer



• Passive Diffusion

– Movement: Dissolved substances

• High to low concentration

– Remains fairly static (post-equilibrium)

• Facilitated Diffusion

– Certain dissolved substances require assistance

• Carrier molecule

• To pass through semipermeable membrane



• Active Transport

– Energy source

– Adenosine triphosphate (ATP): Drives dissolved chemicals; low-to-high concentration

• Sodium-potassium pump system

– Metabolic disorders: Diminish ATP

– Significant change in fluid volume


Fluid-Electrolyte Regulation MechanismsFluid-Electrolyte Regulation Mechanisms

• Maintain normal fluid volume and electrolyte concentrations

– Urine formation; Thirst promotion

• Osmoreceptors

– Fluid volume regulation

– Located: Hypothalamus; Senses serum osmolality

– Sensitive: Changes in blood volume and BP

– Baroreceptors (stretch receptors in aortic branch that signals brain to release ADH when blood volume decreases OR to inhibit release if blood volume is increased)


QuestionQuestion


The body is without regulatory mechanisms to maintain fluid-electrolyte balance.


AnswerAnswer

False.

The body has several regulatory mechanisms to maintain fluid-electrolyte balance, including thirst and urine formation.


Fluid-Electrolyte Regulation MechanismsFluid-Electrolyte Regulation Mechanisms• Renin-Angiotensin-Aldosterone System

– Chain of chemicals

• Increase: BP; Blood volume

• Juxtaglomerular apparatus (Cells)

– Angiotensin II: Raises BP via vasoconstriction

– Aldosterone: causes kidneys to reabsorb Na which in turn increases blood volume & BP

• Natriuretic Peptides: Hormone-like substances

– Works the opposite to renin-angiotensin-aldosterone system; reduce blood volume = urine release


Fluid ImbalancesFluid Imbalances

• Is a general term describing any of several conditions in which the body’s water/fluid is not in the proper volume or location

• Common fluid imbalances:

- Hypovolemia

- Hypervolemia

- Third-spacing


Fluid Imbalances: HypovolemiaFluid Imbalances: Hypovolemia• Fluid imbalance: Fluid volume deficit (Table 16-2, pg 185)

– Hypovolemia: Only blood volume low

– Dehydration: All fluid compartments deficient

• Pathophysiology and Etiology

– Inadequate fluid intake; Fluid loss in excess of intake; Translocation

• Assessment Findings

– Thirst – earliest

– Hemoconcentration; Concentrated urine (high specific gravity)

– Serum electrolyte levels normal


Fluid Imbalances: HypovolemiaFluid Imbalances: Hypovolemia• Medical Management

– Treat etiology (cause)

• Increasing oral intake volume

• IV fluid replacement

• Controlling fluid loss

• Nursing Management

– Gather assessment data

– Fluid deficit: Measures to restore balance

– Teaching plan: Prevent hypovolemia

– REVIEW: Nsg Care Plan 16-1 pg 187

– REVIEW: Nsg Guidelines 16-1 pg 188


• High volume of water: Intravascular fluid compartment

• Pathophysiology and Etiology

– Fluid intake > fluid loss

• Heart failure

• Renal disease

• Corticosteroid drugs

• Fluid retention

– Circulatory overload

Fluid Imbalances: HypervolemiaFluid Imbalances: Hypervolemia



– Weight gain; Elevated BP; Dependent edema, Fig 16-7 pg 188

– Low blood cell count; Hemodilution; Dilute urine (low specific gravity)

• Medical Management

– Treat etiology; Daily weight

– Restrict fluids; Medications: Diuretics

– Limit: Salt (sodium) intake

Fluid Imbalances:HypervolemiaFluid Imbalances:Hypervolemia


• Nursing Management

– REVIEW: Nursing Process, pg 186-190

– Daily weight (same time/ same clothes, etc)

– Accurate I & O’s; Restrict fluids per Dr’s order – maintain oral hygiene

– Monitor v/s; check for edema; administer prescribed diuretics

– Limit: Salt (sodium) intake: Refer to Box 16-1, Foods high in Salt or Sodium

Fluid Imbalances: HypervolemiaFluid Imbalances: Hypervolemia



The treatment for hypovolemia and hypervolemia are the same.

QuestionQuestion


True.

While the steps taken during treatment may differ, the treatment principle is the same – you treat the cause (etiology).

AnswerAnswer


Fluid Imbalances: Third-spacingFluid Imbalances: Third-spacing

• Fluid translocation to intracellular compartments

– Trapped, useless; Colloid loss


– Hypovolemia symptoms (except weigh loss); Ascites; Generalized edema


– Restore circulatory volume

– Eliminate trapped fluid;

• IV solutions

• Blood products, albumin

• IV diuretic


Electrolyte ImbalancesElectrolyte Imbalances• Electrolytes

– Ions (including Bicarbonate; Protein; Organic acids)

– Extracellular fluid (more concentrated): Sodium, Calcium; Chloride

– Intracellular fluid (more concentrated): Potassium; Magnesium; Phosphate

– Imbalances; Identified – blood labs

• Electrolyte imbalances: Deficit or excess of electrolytes; Electrolyte translocation

– Sodium; Potassium; Calcium; Magnesium of particular concern


Sodium ImbalancesSodium Imbalances• Hyponatremia: Sodium deficit (Na <135 mEq/L)

– Etiology

• Inadequate food intake; excessive water intake

• Administration of certain meds

• Profuse diaphoresis or diuresis• Loss of GI secretions (Prolonged vomiting; GI

suctioning, etc)

– Assessment Findings

• Mental confusion; Elevated body temp; Tachycardia; N/V; Personality changes; Coma

– Medical Management

• Treat underlying cause; Sodium administration


Sodium ImbalancesSodium Imbalances• Hypernatremia: Sodium excess (Na > 145 mEq/L)

– Etiology

• Overabundance of orally consumed or IV electrolytes

• Kidney Failure; Endocrine dysfunction

• Profuse watery diarrhea; Decreased H2O intake

• High fever

– Assessment Findings

• Dry, sticky mucous membranes; Decreased urine output; Fever; Lethargy

– Medical Management

• Treat underlying cause; Restrict sodium


Sodium ImbalancesSodium Imbalances• Nursing Management for Sodium Imbalances

– Assess sodium imbalances – EARLY detection!

– Monitor: Laboratory findings - serum potassium

– Monitors oral and IV fluid therapy closely

– Accurate I & O’s

– Assess vital signs q 1 to 4hrs

– Client education

• Review dietary restrictions: Nutrition Notes 16-1, pg 191

• Review: Pharmacy Considerations, pg 191


Potassium ImbalancesPotassium Imbalances• Hypokalemia: Potassium deficit (K+ <3.0 mEq/L)

– Potassium-wasting diuretics (Lasix, Hyrdodiuril); Loss of fluid from the GI tract; Large corticosteroid doses


– Fatigue; N/V; Cardiac dysrhythmias; Paresthesias; Leg cramps


– Treat underlying cause; Potassium sparing diuretic substitution

– Potassium-rich foods; Oral potassium supplement


Potassium ImbalancesPotassium Imbalances• Hyperkalemia: Potassium excess (K+ >5.5 mEq/L)

– Severe renal failure; Severe burns; Overuse of potassium supplements; Potassium-sparing diuretics; Addison’s disease


– Diarrhea, Nausea; Muscle weakness; Paresthesias; Cardiac dysrhythmias (Tall T wave)


– Treatment dependent on cause, severity: Decrease potassium-rich foods; Kayexalate

– IV-insulin; Peritoneal dialysis; Hemodialysis


Potassium ImbalancesPotassium Imbalances

Top left: Normal tracingTop right: Serum potassium level

below normal results in U wave

Lower Right: High potassium on ECG produces a tall T wave


Potassium ImbalancesPotassium Imbalances• Nursing Management for Potassium Imbalances

– Assess potassium imbalances

– Monitor: Laboratory findings - serum potassium

– Consults with the physician: Prolonged IV fluid therapy without added potassium


• Potassium-excreting medications

• Pharmacy Considerations: pg 193

• Food sources: Vegetables, dried peas and beans, wheat bran, bananas, oranges (and juice), melon, prune juice, potatoes, milk

• Supplements


Calcium ImbalancesCalcium Imbalances• Hypocalcemia: Calcium deficit (Ca++ < 8.8 mg/dL)

– Vitamin D deficiency; Hypoparathyroidim; Severe burns; Acute pancreatitis; Corticosteroids


– Tingling in extremities, around mouth; Abdominal and muscle cramps; Trousseau’s sign; Mental changes; Positive Chvostek’s sign; Tetany (Figure 16-9, pg 193)


– Mild: Oral calcium, Vitamin D

– Severe: Calcium salt (IV)


Calcium ImbalancesCalcium Imbalances• Hypercalcemia; Calcium excess ( Ca++ >10 mg/dL)

– Parathyroid gland tumors; Paget’s disease; Hyperparathyroidism; Chemotherapeutic agents; Specific malignancies; Prolonged immobilization


– Polyuria; Constipation; N/V; Thirst; Mental changes


– Treat underlying cause when possible; Oral fluid intake; Limit calcium consumption


Calcium ImbalancesCalcium Imbalances

• Nursing Management for Calcium Imbalances

– Assess closely for neurological manifestations: tetany, seizures, spasms

– Monitor: Laboratory findings; watch for signs of bruising or bleeding

– Consults with the dietician: limit Ca intake w/ increased Ca; increase w/low CA


• Take medications as ordered

• Pharmacy Considerations: pg 194


Magnesium Imbalances Magnesium Imbalances

• Hypomagnesemia: Magnesium deficit (Mg++< 1.3 mEq/L)

– Conditions: Excessive diuresis; Prolonged gastric suction; Chronic alcoholism; Severe burns and renal disease


– Cardiac dysrhythmias; Paresthesias; Leg and foot cramps; Hypertension; Mental changes; Positive Chvostek’s, Trousseau’s signs


– Dietary; Severe: Magnesium sulfate (IV)


Magnesium ImbalancesMagnesium Imbalances

• Hypermagnesemia: Magnesium excess (Mg++ > 2.1 mEq/L)

– Renal failure; Excessive antacid or laxative use


– Flushing, warmth; Hypotension; Lethargy; Bradycardia; Depressed respirations; Coma


– Decrease magnesium intake; Discontinue parenteral replacement; Hemodialysis


Magnesium ImbalancesMagnesium Imbalances

Hypermagnesemia: Magnesium excess (Mg++ > 2.1 mEq/L)

• Nursing Management for Magnesium Imbalances

– Monitor vital signs closely


• REVIEW Pharmacy Considerations, pg 195

• REVIEW Stop, Think & Respond, pg 195


Acid-Base BalanceAcid-Base Balance

• Chief acid: Carbonic acid (H2CO3) - Lungs

• Chief base (alkaline): Bicarbonate (HCO3) - Kidneys

– Acid, base content: Influence pH; pH values (7 is neutral)

– Normal plasma pH (7.35-7.45) maintained by

• Chemical regulation; Organ regulation

• Figure 16-10, pg 195

• Chemical Regulation

– Add Hydrogen ions: Increases acidity

– Eliminate Hydrogen ions: Promotes alkalinity


Acid-Base BalanceAcid-Base Balance• Chemical Regulation (Cont’d)

– Major chemical regulator of plasma pH

• Bicarbonate–carbonic acid buffer system

• Oxygen Regulation

– Lungs, kidneys facilitate: Ratio of bicarbonate to carbonic acid

• Lungs: Regulate carbonic acid levels by releasing or conserving CO2: (quickly by breathing faster or slower)

• Kidneys: regulate bicarbonate ion retention or excretion (slower process)

– Compensation: Regulatory processes


Acid-Base ImbalancesAcid-Base Imbalances

• Life-threatening

• Acidosis: Excess acids OR Excess loss of bicarbonate

• Alkalosis: Excess bases OR Excess loss of acids

– Four sub-types of acid-base imbalances

• Metabolic Acidosis: Increase in acids or decreased bicarbonate

– Occurrence: Shock; Cardiac arrest; Starvation; Diabetic ketoacidosis; Renal failure

– Assessment Findings: Kussmaul’s breathing; N/V; Headache; Confusion; Lethargy; Dangerous cardiac dysrhythmias



• Metabolic Acidosis (Cont’d)

– Diagnostic Findings: ABG values; Decreases in pH


– Eliminating cause

– Replacing lost fluids and electrolyte

– Severe cases: IV bicarbonate


Acid-Base ImbalancesAcid-Base Imbalances• Metabolic Alkalosis: Increased plasma pH; Rapid

decrease in extracellular fluid volume

– Causes: Diuretic therapy; Prolonged gastric suctioning; Vomiting; Hypokalemia


– Circumoral paresthesias; Confusion; N/V; Carpopedal spasm; Hypertonic reflexes; Tetany

– ABGs; Compensatory respiratory mechanisms


– Eliminating cause; Sodium chloride solutions



• Respiratory Acidosis: Excess carbonic acid

– Causes: Pneumo-hemothorax; Pulmonary edema; Asthma; Atelectasis; Pneumonia; COPD; Cystic fibrosis


– Extreme respiratory insufficiency; Decreased expiratory volumes; Cyanosis; Behavioral changes due to CO2 accumulation

– ABG values; Compensatory mechanism


– Individualized treatment dependent upon cause, acute or chronic


Acid-Base ImbalancesAcid-Base Imbalances• Respiratory Alkalosis: Carbonic acid deficit from deficient

CO2 due to rapid breathing


– Increased respiratory rate; Lightheadedness; Numbness, tingling of hands and feet; Circumoral paresthesias; Sweating; Panic

– Kidney excretes bicarbonate ions: HCO3 falls

– ABG values


– Treat cause: (Temporary) Breathe into paper bag and rebreathe expired air; Sedation


Documents

Timby/Smith: Introductory Medical-Surgical Nursing, 10/e