chapter 37 fluid, electrolyte, and acid-base balance fundamentals of nursing: standards &...

Chapter 37

Fluid, Electrolyte, and Acid-Base Balance

Fundamentals of Nursing: Standards & Practices, 2E

Copyright 2002 by Delmar, a division of Thomson Learning 37-2

Physiology of Fluid and Acid-Base Balance

Fluid Compartments• Cells, blood vessels and tissue space

contain the body’s fluid• Terms used to described

compartmentalized body fluid are Intracellular fluid: within the cell Extracellular fluid: within the blood vessels Interstitial fluid: between cells; fluid that

surrounds cells


• Terms used to describe movement of molecules in body fluids are Solute: substance dissolved in a solution Solvent: liquid that contains a substance

in solution Permeability: capability of a substance,

molecule, or ion to diffuse through a membrane (covering of tissue over a surface, organ, or separating spaces)


Semipermeable: selectively permeable (all membranes in the body allow some solutes to pass through the membrane without restriction but will prevent the passage of other solutes)

• Permeable membranes allow fluid and solutes to pass into and out of the cell.

• Blood vessels have permeable membranes that bathe and feed the cells.


Body Fluid Distribution• Water represents 45% to 75% of the

body’s total weight.• Body fat is essentially free of water,

making the ratio of water to body weight greater in leaner people than in obese people.

• Ingesting liquids and food products replenishes body fluid.


Electrolytes• An electrolyte is a compound that,

when dissolved in water or another solvent, forms or dissociates into ions.

• Review Table 37-1 regarding distribution of electrolytes in body fluids.


Movement of Body Fluids

Movement of Body Fluids• Physiological forces transport

molecules of water, foods, gases, wastes, and ions to maintain a balance between extracellular and intracellular fluid volumes.

• Review Table 37-2 regarding movement of body fluids.


Regulators of Fluid Balance• Fluid and Food Intake and Loss• Skin• Lungs• Gastrointestinal Tract • Kidneys


Acid-Base Balance• Acid-base balance refers to the

homeostasis of the hydrogen ion concentration in body fluids.

• Acid is a substance that donates hydrogen ions.

• Base is a substance that accepts hydrogen ions.


Regulators of Acid-Base Balance• Buffer Systems• Respiratory Regulation of Acid-Base

Balance• Renal Control of Hydrogen Ion

Concentration


Factors Affecting Fluid and Electrolyte Balance

AgeLifestyle


Disturbances in Electrolyte and Acid-Base Balance

Electrolyte Disturbances• Sodium

Hyponatremia is a deficit in the extracellular level of sodium.

Hypernatremia is an excess in the extrcellular level of sodium.

• Potassium Hypokalemia is a decrease in the

extracellular level of potassium.


Hyperkalemia is an increase in the extracellular level of potassium.

• Calcium Hypocalcemia is a decrease in the

extracellular level of calcium. Hypercalcemia is an increase in the

extracellular level of calcium.


• Magnesium Hypomagnesemia is a decrease in the

extracellular level of magnesium and usually occurs with hypokalemia and hypocalcemia.

Hypermagnesemia refers to an increase in the extracellular level of magnesium.


• Phosphate Hypophosphatemia is a decreased

extracellular level of phosphorus. Hyperphosphatemia is an increased

extracellular level of phosphorus.


• Chloride Hypochloremia is a decrease in the

extracellular level of chloride. Hyperchloremia is an increase in the

extracellular level of chloride.

• Review Table 37-3 The Clinical Management of Clients Experiencing Common Electrolyte Disturbances.


Acid-Base Disturbances• Laboratory Data• Respiratory Acidosis (Carbonic Acid Excess)• Respiratory Alkalosis (Carbonic Acid Deficit)• Metabolic Acidosis (Bicarbonate Deficit)• Metabloc Alkalosis (Bicarbonate Excess)• Review Table 37-4 Respiratory and

Metabolic Acidosis and Alkalosis


Assessment

Health HistoryPhysical Examination

• Daily Weight• Vital Signs• Intake and Output• Edema• Skin Tugor• Buccal (Oral) Cavity


• Eyes• Jugular and Hand Veins• Neuromuscular System

Diagnostic and Laboratory Data• Hemoglobin and Hematocrit Indices• Osmolality• Urine pH

Serum Albumin


Nursing Diagnosis

Excess Fluid Volume Deficient Fluid Volume Risk for Deficient Fluid Volume


Other Nursing Diagnosis• Impaired Gas Exchange• Decreased Cardiac Output• Risk for Infection• Altered Oral Mucous Membrane• Deficient Knowledge


Outcome Identification and Planning

Expected outcomes for clients with fluid imbalances are not only specific to their primary diagnosis, but also require inclusion of outcomes relative to interventions.

Achievement of the goals and the client’s expected outcomes indicates resolution of the problem.


Implementation

Monitor Daily WeightMeasure Vital SignsMeasure Intake and OutputProvide Oral HygieneReview Procedure 37-1 on

measuring intake and output


Oral Fluid Therapy• Nothing by Mouth• Restricted Fluids• Forced Fluids

Maintain Tube FeedingMonitor Intravenous Therapy


Monitor Intravenous Therapy• Parenteral Fluids• Equipment• Review Table 37-5 on common

intravenous solutions• Preparing an Intravenous Solution.


• Review Procedure 37-2 on preparing an intravenous solution.

• Initiating IV Therapy• Administering IV Therapy• Review Procedure 37-3 on

administering an IV solution.


• Managing IV Therapy• Review Procedure 37-4 on managing IV

therapy and dressing change.• Blood Transfusion• Review Procedure 37-5 on administering

a blood transfusion.• Complementary Therapy


Evaluation

Evaluation is an ongoing process for clients with fluid, electrolyte, and acid-base imbalances.

Nurse should focus on the client’s responses when evaluating whether timeframes and expected outcomes are realistic.

chapter 37 fluid, electrolyte, and acid-base balance fundamentals of nursing: standards &...

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cells fluid

cellextracellular fluid

body fat

body fluids aresolute

intracellular fluid

body weight greater

hydrogen ions