Human Physiology: Fluid and Electrolyte Balance

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Questions and Answers

What is the typical daily loss of fluid through the gastrointestinal tract in healthy individuals?

200 to 300 mL

100 to 200 mL (correct)

50 to 100 mL

300 to 500 mL

Which of the following represents the normal serum osmolality range for healthy adults?

275 to 290 mOsm/kg (correct)

310 to 325 mOsm/kg

290 to 310 mOsm/kg

250 to 270 mOsm/kg

What is the normal range for urine-specific gravity?

1.025 to 1.035

1.000 to 1.010

1.010 to 1.025 (correct)

1.030 to 1.045

Which hormone, produced by the hypothalamus, is essential for water conservation in the body?

Antidiuretic hormone (ADH) Signup and view all the answers

What is the normal range for Blood Urea Nitrogen (BUN) levels in mg/dL?

10 to 20 mg/dL Signup and view all the answers

The volume percentage of red blood cells in whole blood is measured by which laboratory test?

Hematocrit Signup and view all the answers

What is the normal serum creatinine level range in mg/dL?

0.7 to 1.4 mg/dL Signup and view all the answers

What mechanism do baroreceptors primarily respond to in the body?

Changes in blood volume Signup and view all the answers

What is a potential nursing intervention for a patient with fluid overload?

Monitor vital signs regularly Signup and view all the answers

What does an acute weight gain of 1 kg correspond to in terms of fluid volume?

1 L of fluid Signup and view all the answers

Which grade of edema is characterized by a pit of 3 to 4 mm that rebounds in less than 15 seconds?

Grade 2 Signup and view all the answers

What underlying condition may cause increased capillary fluid pressure leading to edema?

Venous obstruction Signup and view all the answers

What should be avoided in patients with hypervolemia due to its sodium content?

Over-the-counter medications Signup and view all the answers

Which position is beneficial for a patient experiencing dyspnea or orthopnea?

Semi-Fowler position Signup and view all the answers

What does the assessment of breath sounds help to monitor in patients receiving IV fluids?

Fluid overload complications Signup and view all the answers

What is a characteristic symptom of localized edema?

Soft tissue swelling in a specific area Signup and view all the answers

Which diuretic is commonly administered for managing excess fluid volume?

Furosemide Signup and view all the answers

How often should skin care assessment be performed for patients with edema?

Daily Signup and view all the answers

What leads to hypovolemia in the fluid volume deficit (F.VD) condition?

Loss of extracellular fluid volume exceeding fluid intake Signup and view all the answers

Which condition is specifically characterized by loss of water alone?

Dehydration Signup and view all the answers

What is a primary cause of fluid volume deficit listed in the content?

Gastrointestinal (GI) suctioning Signup and view all the answers

Which sign or symptom is NOT typically associated with fluid volume deficit?

Increased skin turgor Signup and view all the answers

Which management method is preferred for correcting fluid loss if the deficit is not severe?

Oral intake, if the patient can drink Signup and view all the answers

What type of fluid shifts may contribute to fluid volume deficit, particularly in the presence of edema?

Third-space fluid shifts Signup and view all the answers

Which of the following laboratory findings would indicate fluid volume deficit?

Increased BUN and creatinine Signup and view all the answers

What effect does dehydration have on serum sodium levels?

Increases serum sodium levels Signup and view all the answers

What nursing intervention is specifically important for patients with edema?

Salt restricted diet Signup and view all the answers

Which symptom indicates severe fluid volume deficit?

Concentrated urine and oliguria Signup and view all the answers

What condition is characterized by increased thirst and dry mucous membranes?

Fluid volume deficit Signup and view all the answers

What type of intravenous solution would be most appropriate for a patient needing cellular fluid replacement?

Hypotonic fluids Signup and view all the answers

Which of the following actions should a nurse take to minimize the risk of infection when administering IV therapy?

Use sterile techniques for insertion Signup and view all the answers

What is a common complication that can occur if an intravenous access device dislodges from the vein?

Infiltration Signup and view all the answers

When monitoring a patient receiving intravenous therapy, which factor is not typically considered?

Patient's nutritional status Signup and view all the answers

Which nursing skill is essential for the initiation of infusion therapy?

Venipuncture technique Signup and view all the answers

What is the primary purpose of administering hypertonic intravenous fluids?

To draw water from cells to extracellular fluid Signup and view all the answers

What is a primary consequence of decreased plasma protein concentration?

Decreased capillary oncotic pressure Signup and view all the answers

Which condition is most likely to lead to increased interstitial oncotic pressure?

Inflammation or lymphatic obstruction Signup and view all the answers

Localized edema can be caused by which of the following?

Localized factors affecting fluid balance Signup and view all the answers

Anasarca is defined as:

Extreme generalized edema affecting multiple body areas Signup and view all the answers

What are common clinical manifestations of ascites?

Abdominal distension and shortness of breath Signup and view all the answers

Which of the following is NOT a cause of ascites?

Myocardial infarction Signup and view all the answers

What type of edema is characterized by swelling in multiple body areas simultaneously?

Anasarca Signup and view all the answers

Which of the following conditions can lead to capillary oncotic pressure reduction?

Malnutrition Signup and view all the answers

What can severe abdominal girth lead to in the context of ascites?

Altered body image Signup and view all the answers

What is the most common cause of localized edema due to injury?

Inflammation Signup and view all the answers

Study Notes

Fluid and Electrolyte Balance: Balance and Disturbance

Fluid and electrolyte balance is crucial for life and homeostasis
Disorders of fluid and electrolyte balance affect healthy people and those who are ill. Examples include strenuous exercise, increased fluid and sodium loss, and high environmental temperatures.
Homeostasis is the maintenance of a constant internal equilibrium in a biological system involving positive and negative feedback mechanisms.
Body fluid is distributed between Intracellular fluid (ICF), which is inside the cell (~67%) and Extracellular fluid (ECF), which is outside the cell (~33%). ECF further divides into interstitial fluid (~26%) and plasma (~7%).
Total body water = 60% of body weight. Adult body contains ~28 liters of intracellular water, ~10 liters of interstitial fluid, and ~3.5 liters of plasma.

Objectives

Identify the distribution of fluids and electrolytes throughout the body
Describe the causes, manifestations, management, and interventions for fluid/electrolyte abnormalities
Identify types and usage of I.V fluids
Identify complications related to I.V therapy
Identify nursing considerations for patients receiving I.V therapy

Outline

Definition of fluid & electrolyte balance, homeostasis
Distribution of body fluids
Factors affecting fluid & electrolytes in the body
Composition of body fluids
Processes of fluid & electrolyte balance regulation
Fluid imbalance - Fluid volume deficit(FVD) & dehydration, Fluid volume excess (FVE) & overhydration
Edema
Electrolyte imbalance
Nursing process for fluid & electrolyte imbalance

Introduction

Fluid and electrolyte balance depends on dynamic processes crucial for life and homeostasis.
Potential and actual disorders of fluid and electrolyte balance occur in every setting, affecting healthy people with diverse conditions including increased fluid/sodium loss with exercise and temperature, or inadequate fluid/electrolyte intake in ill people.
Homeostasis involves positive and negative feedback mechanisms.

Fluid distribution/Compartments

Intracellular fluid (ICF)
Extracellular fluid (ECF)
Intracellular fluid (2/3 of body water)
Extracellular fluid (1/3 of body water)
Blood (intravascular, 1/12 of ECF)
Interstitial (11/12 of ECF)

Systemic Routes of Gains and Losses

Healthy individuals gain and lose fluids nearly equal amounts daily.
Fluid intake orally, as water, in food, and from oxidation of food accounts for ~2500mL.
Fluid output through urine, stool, lungs, and skin (~2500 mL).

Systemic Routes of Gains and Losses (Further detail)

Kidneys - daily urine output ~1-2 liters
Skin - insensible perspiration accounts for ~300 mL
Lungs - insensible water loss from breathing is ~300 mL
Gastrointestinal tract - ~100-200 mL

Laboratory Tests for Evaluating Fluid Status

Osmolality: concentration of fluid affecting water movement between compartments (~275-290 mOsm/kg in healthy adults)
Urine-specific gravity: measures kidney's ability to excrete/conserve water (~1.010 to 1.025).
Blood Urea Nitrogen (BUN): end product of protein metabolism by liver (~10 to 20 mg/dL).
Creatinine: end product of muscle metabolism (~0.7-1.4 mg/dL).
Hematocrit % of red blood cells in whole blood (42% to 52% for men and 35% to 47% for women)

Homeostatic Mechanisms

Kidney functions: normally filters 180 L of plasma and excretes 1-2 L of urine daily
Heart and blood vessels: pumps blood through kidneys under enough pressure for urine formation
Lung function: Removes ~300 mL water daily through exhalation
Pituitary functions: ADH released from hypothalamus conserved water
Adrenal: Increased aldosterone causes retention of sodium and water

Other Mechanisms

Baroreceptors in atrium respond to changes in blood volume and regulate sympathetic and parasympathetic neural activity
Renin-Angiotensin-Aldosterone System (RAAS)
Antidiuretic Hormone (ADH) and Thirst
Osmoreceptors in hypothalamus senses change in sodium concentration
Natriuretic Peptides affect fluid volume and cardiovascular functions

Fluid Regulation Cycle

Relationship between variables like blood volume, serum osmolality, and ADH production for regulating fluid
Variables such as arterial blood pressure and renal perfusion.
Relationship between variables and factors like ADH, aldosterone, renal blood flow, GFR, urinary excretion of water and sodium, and blood pressure.

Fluid Volume Deficit (FVD), Hypovolemia

Loss of ECF volume exceeds fluid intake, ratio of electrolytes to water remains the same.
Conditions caused by vomiting, diarrhea, GI suctioning, sweating, decreased intake, third-space fluid shifts, Burns, ascites with liver dysfunction, diabetes insipidus, adrenal insufficiency, osmotic diuresis etc.

Signs and Symptoms of FVD

Weight loss
Decreased skin turgor (skin pinching does not rebound quickly).
Concentrated urine
Prolonged capillary filling time
Low central venous pressure (CVP)
Flattened neck veins
Tachycardia, Hypotension
Dry skin and cracked lips
Sunken eyes
Muscle cramps
Thirst
Weakness
Dizziness
Changes in mental status

Medical Management of FVD

Oral fluids for mild cases
I.V Fluids for acute cases (isotonic such as lactated ringers or 0.9% normal saline).
Switch to hypotonic solution (0.45%NS) once patient is normotensive.

Nursing Care of FVD

Monitor vital signs
Weigh daily
Monitor I&O
Assess ability to ambulate
Check skin/tongue turgor
Increase oral fluid intake
Offer oral rehydration solutions
Provide frequent mouth care

Hypervolemia (Fluid Volume Excess (FVE))

Abnormal retention of water and sodium in ECF, leads to an increase in total body sodium and water
Causes include excessive fluid intake, impaired kidney function, heart failure, cirrhosis of the liver etc.

Signs and Symptoms of FVE

Weight gain
Peripheral edema
Crackles (fluid in lungs)
Elevated CVP or distended neck veins
Shortness of breath
Hypertension
Tachypnea
Increased urine output

Medical Management of FVE

Limiting sodium and fluid intake
Administering diuretics (such as lasix)
Dialysis for severe cases
Treating underlying causes of fluid retention

Nursing Care for FVE

Monitor vital signs, weight, and I&O closely
Assess breath sounds
Assess for edema
Monitor serum electrolytes
Provide regular rest periods
Avoid medications containing sodium
Elevate affected limbs

Edema

Accumulation of fluid in interstitial space causing soft tissue swelling
Generalized: throughout the body
Localized: specific body part
Grade 1: Immediate rebound with 2 mm pit
Grade 2: Less than 15-second rebound with 3-4 mm pit
Grade 3: Rebound greater than 15 seconds but less than 60 seconds with 5-6 mm pit
Grade 4: Rebound between 2-3 minutes with 8 mm pit

Pathophysiology of Edema

Increased capillary fluid pressure (due to venous obstruction, heart failure)
Decreased capillary oncotic pressure (due to low albumin, liver disease, malnutrition)
Increased interstitial oncotic pressure (due to inflammatory conditions, lymphatic obstruction)

Types of Edema

Localized: restricted to a specific body part (e.g., ankle edema in rheumatoid arthritis)
Generalized: affecting multiple body areas (e.g., cardiac failure, kidney injury)
Anasarca: extreme form of generalized edema (e.g., severe heart failure, liver disease)

Ascites

Accumulation of fluid in the peritoneal cavity
Causes include cirrhosis, nephrotic syndrome, and certain malignancies
Clinical manifestations: abdominal distension, shortness of breath, discomfort, and respiratory difficulties
Management includes addressing underlying cause, sodium and fluid restriction, diuretic therapy, paracentesis, and nutritional support

Assessing and Monitoring Edema

Visual inspection: Swelling in dependent areas (feet, ankles, sacral region)
Pitting Test: Apply firm pressure for 5 seconds. Measures the depth of the pit and time of rebound.
Circumference Measurement: Use a tape measure to track changes in limb circumference.
Weight Monitoring: Daily weight measurements help track fluid retention.

Management Strategies for Edema in FVE

Diuretic Therapy: Medications like furosemide increase urine output and reduce fluid volume.
Sodium & Fluid Restriction: Limiting sodium and restricted fluid intake limits fluid retention.
Limb Elevation and Compression: Elevating affected limbs helps venous return and fluid mobilization while using compression stockings.
Advanced Interventions: Paracentesis for ascites and dialysis for severe cases

Nursing Care of Patients with Edema

Salt restricted diet
Using diuretics as ordered
Monitor I&O
Weigh daily
Positioning changes
Skin care
Elevation of edematous limbs
Avoiding prolonged sitting/standing

Parenteral Fluid Therapy

Purpose: Administer fluids when other routes are unavailable, to provide fluids, electrolytes & nutrients to meet daily requirements, replace water/electrolytes and administer medications or blood products
Types of Intravenous solutions
Isotonic: similar osmolality to ECF (e.g., 0.9% normal saline, D5W)
Hypotonic: lower osmolality than ECF (e.g., 0.45% normal saline)
Hypertonic: higher osmolality than ECF (e.g., 3% saline, D10W)

Nursing Management of the Patient Receiving Intravenous Therapy

Perform venipuncture to gain access to venous system, use appropriate cannula
Initiate infusion with correct fluid type, amount and rate
Closely monitor the patient's response to the fluids considering fluid volume, content and clinical status.

Complications of I.V. Therapy

Infiltration: Fluid leakage into surrounding tissues from vein
Infection: Signs of infection at the site (purulent drainage, erythema, warmth, hardness, fever)
Phlebitis: Inflammation of the vein (redness, swelling, tenderness, sluggish flow)
Air Embolism: Air entering vein (decreased blood pressure, increased pulse, respiratory distress, increased ICP, loss of consciousness)

Electrolytes Imbalances

Electrolytes are active chemical constituents in bodily fluids carrying positive or negative charges. Examples include sodium, potassium, calcium, magnesium, chloride, bicarbonate, sulfate and proteins.
Electrolyte concentration measured in milliequivalents(mEq or mmol per liter).

Roles of Major Electrolytes

Fluid balance in bodily fluids
Transmission of nerve impulses
Muscular function
Acid-base balance regulation
Blood clotting

Electrolyte Concentrations (Table)

Normal electrolyte concentrations for extracellular and intracellular fluids.

Sodium Imbalances

Sodium is the most abundant electrolyte in extracellular fluid (ECF).
Sodium deficit (hyponatremia):Serum sodium level less than 135 mEq/L. Causes include loss of GI fluids, excessive diuretic use, certain medications (anticonvulsants, such as carbamazepine), adrenal insufficiency, and excessive water supplements for patients receiving hypotonic tube feedings
Sodium excess (hypernatremia): Serum sodium level greater than 145 mEq/L due to water deprivation in patients unable to drink, hypertonic tube feedings, diabetes insipidus, and excessive use of corticosteroids

Potassium Imbalances

Potassium is an important electrolyte in intracellular fluid (ICF).
Potassium deficit (hypokalemia) : Serum potassium level less than 3.5 mEq/L. Causes include potassium-losing diuretics (thiazides, loop diuretics), GI losses (vomiting, diarrhea), hyperaldosteronism, and inadequate dietary consumption
Potassium excess (hyperkalemia):Serum potassium level greater than 5.0 mEq/L. Causes include renal failure, fluid volume deficit, iatrogenic administration of potassium, adrenal insufficiency, and use of potassium-sparing diuretics.

Calcium Imbalances

Calcium is essential for nerve impulse transmission, muscle function, and blood clotting
Calcium deficit (hypocalcemia):Serum calcium level less than 8.6 mg/dL. Causes include hypoparathyroidism, malabsorption, massive transfusion of citrated blood, pancreatitis, prolonged diarrhea, and diuretic phase of renal failure
Calcium excess (hypercalcemia): Serum calcium level greater than 10.2 mg/dL. Causes include renal failure, hyperparathyroidism, vitamin D excess, prolonged immobilization, overuse of calcium supplements, and corticosteroid therapy.

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Description

Test your knowledge on human physiology with a focus on fluid and electrolyte balance. This quiz covers topics such as normal ranges for serum osmolality, urine-specific gravity, and the roles of hormones in water conservation. Perfect for students studying human biology or health sciences.