Exam 12 - Fluid Balance and Dehydration Quiz

Water

• Water is essential for carrying nutrients to body cells and waste products away from the cells
• Water serves as a medium for chemical reactions, acts as lubricant for tissues, helps maintain acid-base balance, and assists in heat regulation through evaporation
• Water comprises 50% to 80% of total body weight, depending on age, sex, and body fat
• Newborns have higher proportions of water in their bodies (70% to 80%), decreasing steadily with age
• Adults have 50% to 60% water, while older adults have 45% to 55%
• Women generally have less body fluid than men due to their higher body fat percentages
• Individuals with higher body weight, particularly obese individuals, have lower percentages of body water
• Infants are at a higher risk of dehydration due to more than half of their body fluid being located outside the cells (extracellular)

Dehydration in Older Adults

• Older adults are more susceptible to dehydration because of various factors
• Aging causes lean muscle to be replaced by fat, reducing total body fluid
• The aging kidney has difficulty concentrating urine, leading to increased fluid loss
• Decreased mobility and a weakened sense of thirst contribute to diminished fluid intake
• Incontinent individuals may restrict fluid intake to reduce the frequency of urination
• Older adults may add excess salt to their food to compensate for taste changes, causing electrolyte and fluid imbalances
• Dehydration can lead to orthostatic hypotension, constipation, and electrolyte imbalances
• Changes in skin and mucous membranes make them less reliable indicators of dehydration in older adults

Fluid Compartments

• Body fluids are found in two compartments: intracellular fluid (inside cells) and extracellular fluid (outside cells)
• The intracellular fluid compartment is larger, composing 66% of the body's fluid, containing dissolved particles called solutes
• The extracellular fluid compartment includes fluids outside the cells, encompassing oxygen, carbon dioxide, glucose, amino acids, fatty acids, sodium, calcium, chloride, and bicarbonate
• The extracellular compartment is further divided into interstitial fluid (between cells) and intravascular fluid (within blood vessels)

Fluid Intake and Output

• The average adult fluid intake is approximately 2,200 to 2,700 mL/day
• The average adult consumes about 1,100 to 1,400 mL/day of fluids orally, 800 to 1,000 mL/day from solid food, and 300 mL/day produced from cellular metabolism
• Oral intake is regulated through the thirst mechanism
• Fluid loss from the body is classified as sensible (measurable) or insensible (not measurable)
• Sensible losses occur through urine, feces, vomiting, and wound drainage, while insensible losses are from perspiration and expiration
• The kidneys play a crucial role in fluid balance, filtering blood at a rate of 125 mL/min, resulting in a daily urine output of 1 to 2 L

Movement of Fluids and Electrolytes

• Body fluids are constantly moving within a healthy individual, facilitating balance between intracellular and extracellular compartments
• Extracellular fluid transports nutrients to cells and carries waste products away
• Substances cross cell membranes through two processes: passive transport and active transport
• Passive transport processes do not require energy from the cell, while active transport processes do utilize cellular energy
• Passive transport processes include diffusion, osmosis, and filtration
• Active transport processes involve the use of carriers and energy from the cell to move molecules against pressure

Diffusion

• Diffusion is the movement of a substance from a high concentration area to a low concentration area, resulting in an even distribution of solutes
• A concentration gradient drives the movement of molecules from a high concentration area to lower concentration area
• Oxygen and carbon dioxide exchange in the body occurs through diffusion

Osmosis

• Osmosis is the movement of water through a semipermeable membrane from a low concentration area to a high concentration area
• The movement of water continues until both solutions reach equal concentration, known as isotonic
• Osmosis is demonstrated in red blood cells, which shrink in hypertonic environments and enlarge in hypotonic environments

Filtration

• Filtration is the transfer of water and dissolved substances from a high pressure area to a low pressure area
• Hydrostatic pressure, the force of fluid pressing outward on a vessel wall, drives filtration
• An example is the movement of water and electrolytes from the arterial capillary bed to the interstitial fluid

Active transport

• Active transport is the movement of molecules against pressure through cell membranes, utilizing carriers and cell energy
• The sodium-potassium pump is an example, maintaining sodium-potassium balance by moving sodium out of the cell and potassium into the cell

Electrolytes

• Electrolytes are substances that develop an electrical charge when dissolved in water, forming ions with positive or negative charges
• Electrolytes are measured in milliequivalents (mEq), which is a measure of an ion's chemical activity
• Sodium is the primary extracellular electrolyte, while potassium is the primary intracellular electrolyte

Sodium

• Sodium is the most abundant electrolyte in the body, regulating fluid volumes through osmotic pressure
• Sodium plays a role in muscular contractility, neuromuscular irritability, and acid-base balance
• The primary source of all electrolytes, including sodium, is the diet
• The kidneys are the main excretion route for sodium
• The normal blood level of sodium is 135 to 145 mEq/L

Hyponatremia

• Low sodium concentration in the blood, below 135 mEq/L.
• Caused by sodium loss (vomiting, diarrhea) or excessive water intake.
• Body tries to compensate by reducing water excretion.
• Symptoms: weakness, anorexia, muscle cramps, confusion, fatigue, headache, edema, seizures.
• Treatment: sodium replacement, water restrictions.

Hypernatremia

• High sodium concentration in the blood, above 145 mEq/L.
• Caused by excess sodium or water loss.
• Body tries to compensate by conserving water.
• Symptoms: dry mucous membranes, firm tissue turgor, low urine output, restlessness, agitation, confusion, flushed skin.
• Treatment: gradual sodium level reduction through decreased sodium intake or increased water.

Hypokalemia

• Potassium deficiency in the body, less than 3.5 mEq/L.
• Major cause: renal excretion, excessive GI losses (vomiting, diarrhea).
• Symptoms: cardiac dysrhythmias, muscle weakness, lethargy, confusion, paralysis, coma.
• Treatment: potassium replacement (oral or IV), monitoring kidney and cardiac function.

Hyperkalemia

• Potassium excess in the body, greater than 5 mEq/L.
• Major cause: renal disease, tissue damage.
• Symptoms: cardiac dysrhythmias, diarrhea, weakness, irritability, numbness, tingling.
• Treatment: potassium restriction, IV calcium gluconate, sodium bicarbonate/insulin, sodium polystyrene sulfonate (Kayexalate).

Hypochloremia

• Low chloride levels in the blood, below 96 mEq/L.
• Usually occurs with sodium loss as they are frequently paired.
• Causes: vomiting, diarrhea, gastric suctioning, acute infections.
• Treatment: alleviating underlying cause, chloride replacement with sodium chloride IV solutions.

Hyperchloremia

• Rare, can occur with low bicarbonate levels and metabolic acidosis.
• Represents an attempt to compensate for imbalances.
• No specific symptoms, may be indicated by symptoms of acidosis.

Hypocalcemia

• Low calcium levels in the blood, below 4.5 mg/dL.
• Causes: vitamin D or parathyroid hormone deficiency, renal failure, malabsorption, etc.
• Symptoms: neuromuscular irritation, hyperactive reflexes, seizures, tetany (muscle cramps, spasms).
• Treatment: IV calcium gluconate, oral calcium supplements, parathyroid hormone replacement.

Hypercalcemia

• High calcium levels in the blood, above 5.6 mEq/dL.
• Causes: calcium release from bones, excessive calcium or vitamin D intake.
• Symptoms: fatigue, weakness, constipation, nausea, vomiting, confusion, polyuria, polydipsia, renal stones, etc.
• Treatment: medications to reduce calcium levels, fluids, bisphosphonates, etc.

Hypercalcemia

• Occurs when there is an excess of calcium in the blood.
• Can be caused by a variety of factors, including movement of calcium from bone to circulation, immobilization, metastatic bone cancer, multiple myeloma, excess intake of supplemental calcium, excess intake of dietary calcium, excess intake of antacids containing calcium, increased absorption of calcium, increased levels of parathyroid hormone, and increased levels of vitamin D.
• Symptoms include anorexia, nausea, vomiting, behavioral changes (confusion), thirst, polyuria, renal calculi, decreased deep tendon reflexes, constipation, paralytic ileus, lethargy, coma, cardiac dysrhythmias, cardiac arrest, hypertension, decreased muscle tone, decreased GI motility, and bone pain.
• Nursing interventions include administering diuretics as ordered by the health care provider, encouraging the patient to drink 3000 to 4000 mL of fluids per day, and monitoring I&O.

Phosphorus

• Makes up about 1% of a person's total body weight.
• Found in every cell of the body but mostly in bones and teeth.
• Has an inverse relationship with calcium.
• Normal values range from 2.4 to 4.1 mEq/dL.
• Contributes to the support and maintenance of bones and teeth, is a component of DNA and RNA, and is an essential component of phospholipids.
• Phosphorous compounds are used as a buffer system to maintain the pH of the blood, and phosphorus promotes the effectiveness of many of the B vitamins.
• Plays a role in normal nerve and muscle activity and is needed in carbohydrate metabolism.
• Found in foods such as beef, pork, fish, poultry, milk products, and legumes.
• An adequate intake of vitamin D is necessary for absorption.
• Excreted primarily by the kidneys (90%) with the remainder excreted in the feces.

Hypophosphatemia

• Occurs when blood phosphorus levels fall below 2.4 mEq/dL.
• Can be caused by dietary insufficiency, impaired kidney function, or maldistribution of phosphorus.
• Low phosphorus levels are associated with muscle weakness (especially of the respiratory muscles), bone and joint pain, disorientation, and confusion.
• Treatment involves replacing phosphorus with oral or IV supplementation and monitoring the patient.

Hyperphosphatemia

• Occurs when blood phosphorus levels exceed 4.1 mEq/dL.
• Most commonly caused by renal insufficiency but can occur with an increased intake of phosphate or vitamin D.
• Signs and symptoms include tetany, numbness and tingling sensation around the mouth, and muscle spasms.
• Treatment involves restricting phosphorus intake, treating the underlying cause, and potentially using phosphate-binding gels (e.g., aluminum hydroxide) and IV calcium supplementation.

Magnesium

• The fourth most abundant mineral and the second most abundant cation in the intracellular fluid.
• Found in small amounts in the blood
• Important in maintaining normal body function.
• The majority (60%) is found in bone, with lesser amounts in muscle and soft tissue; only 1% is in the extracellular fluid, mostly in the cerebrospinal fluid.
• Acts as a cofactor in the activation of many enzymes.
• Promotes regulation of serum calcium, phosphate, and potassium levels.
• Essential for the integrity of nerve tissue, skeletal muscle, and cardiac functioning.
• Normal blood values are 1.5 to 2.5 mEq/L.
• Found in foods such as whole grains, fruits, green vegetables, meat, fish, legumes, and dairy products.
• Vitamin B6 influences magnesium absorption.
• Excreted primarily through the kidneys.

Hypomagnesemia

• Occurs when blood magnesium levels fall below 1.5 mEq/L.
• Can be caused by conditions causing large losses of urine, decreased intake, diarrhea, draining intestinal fistulas, hypercalcemia, impaired absorption from the GI tract, prolonged IV feedings without magnesium supplementation, prolonged malnutrition, and starvation.
• Symptoms include agitation, depression, confusion, anorexia, ataxia, cardiac dysrhythmias, cramps, spasticity, dysphagia, hyperactive deep tendon reflexes, hypotension, mental changes, nausea and vomiting, paresthesia, seizures, tachycardia, tetany, and tremors.
• Treatment involves administering oral or IV magnesium supplements and monitoring the patient.

Hypermagnesemia

• Occurs when blood magnesium levels exceed 2.5 mEq/L.
• Rarely occurs in individuals with normal kidney function, but can develop due to impaired renal function, excessive magnesium administration, and diabetic ketoacidosis with severe water loss.
• Symptoms include heat, hypotension, loss of deep tendon reflexes, nausea and vomiting, respiratory depression, thirst, and vasodilation.
• In prolonged or severe cases, it can lead to cardiac arrest and coma.
• Treatment involves decreasing the patient’s intake of magnesium, supporting cardiac and respiratory function, and potentially using dialysis to remove excess magnesium.

Bicarbonate

• One of the main anions in the extracellular fluid.
• An alkaline electrolyte with a major role in regulating acid-base balance.
• Acts as a buffer to neutralize acids in the body.
• Maintains a 20:1 ratio of bicarbonate to carbonic acid for homeostasis.
• Normal bicarbonate level is 22 to 24 mEq/L.
• Regulated by the kidneys.

Acid-Base Balance

• Refers to the homeostasis of hydrogen ion (H+) concentration in bodily fluids.
• A solution with a high number of hydrogen ions is acidic, while a solution with a low number of hydrogen ions is alkaline (basic).
• The hydrogen ion concentration is determined by the ratio of carbonic acid (H2CO3) to bicarbonate (HCO3-) in the extracellular fluid.
• The ratio needed for homeostasis is 1 part carbonic acid to 20 parts bicarbonate.
• Measured using pH, which is a measure of hydrogen ion concentration.
• Arterial blood gas levels can reveal whether the blood is acidic, neutral, or alkaline.
• Normal arterial blood pH is approximately 7.45, while venous blood and interstitial fluid pH are approximately 7.35.
• A pH lower than 6.8 or higher than 7.8 is usually fatal.
• Two types of disturbances can cause a pH imbalance:
  • Bicarbonate imbalance, leading to metabolic acidosis or alkalosis.
  • Carbonic acid imbalance, leading to respiratory acidosis or alkalosis.
• Three systems work to keep the pH in the normal range:
  • Blood buffers, respiratory system, and kidneys.

Blood Buffers (Physiologic Buffers)

• Composed of a weak acid and its base salt or a weak base and its acid salt.
• Include the bicarbonate/carbonic acid buffering system, intracellular protein buffers, and phosphate buffers in the bone.
• The bicarbonate/carbonic acid system is the most important, buffering blood and interstitial fluid.
• Function as chemical sponges, neutralizing excess acids or bases by contributing or accepting hydrogen ions.
• Work within a fraction of a second to prevent excessive changes in hydrogen ion concentration.
• The kidneys assist in regulating bicarbonate production.

Respiratory System

• The second line of defense in regulating hydrogen concentration.
• Adjusts acid-base balance by speeding up or slowing down respirations, which affects carbon dioxide levels in the blood.
• Removing carbon dioxide from the blood decreases carbonic acid levels and increases pH, making the environment more alkaline.
• Retaining carbon dioxide lowers pH (acidosis) by increasing carbonic acid levels.
• Takes 1 to 2 minutes to adjust acid-base balance compared to blood buffers, which take seconds.
• Chemoreceptors in the medulla of the brainstem stimulate increased respirations when hydrogen ion concentration is high.
• Can eliminate large amounts of acid (as carbon dioxide) and maintain normal pH levels.

Kidneys

• The third line of defense in regulating hydrogen ions.
• Regulate pH by excreting acids or bases as needed.
• In acidosis, the kidneys excrete hydrogen in urine and retain bicarbonate.
• In alkalosis, the kidneys excrete bicarbonate and retain hydrogen.
• Normal urine pH tends to be more acidic due to the body's constant elimination of excess acids produced in metabolic processes.
• The slowest of the systems to balance hydrogen concentration, potentially taking hours or days to compensate, but are efficient in returning pH to normal.
• Work closely with the blood buffers and the respiratory system to maintain a normal hydrogen ion concentration.

Types of Acid-Base Imbalances

• Occur if regulatory systems fail.
• Result in acidosis (blood pH less than 7.35) or alkalosis (blood pH greater than 7.45).
• Primarily caused by imbalances in lung or kidney function or both.
• Many diseases can predispose patients to acid-base imbalances, including diabetes mellitus, chronic obstructive pulmonary disease, end-stage renal disease, severe vomiting, and diarrhea.
• Four primary types:
  • Respiratory acidosis
  • Respiratory alkalosis
  • Metabolic acidosis
  • Metabolic alkalosis

Respiratory Acidosis

• Caused by any condition impairing ventilation and preventing the elimination of carbon dioxide.
• Carbon dioxide is retained, increasing carbonic acid levels.
• Decreases pH and disrupts the normal bicarbonate to carbonic acid ratio.
• Body attempts to compensate by increasing respirations to eliminate excess carbon dioxide.
• Central nervous system activity is depressed, leading to lethargy and confusion.
• Heart rate increases, possibly causing palpitations and dizziness.
• Kidneys attempt to compensate by retaining bicarbonate and excreting hydrogen, but this can take 24 hours or more.
• Treatment involves improving ventilation, treating the underlying cause, and providing respiratory support.
• Techniques like IPPB or CPAP may be used to promote exhalation of carbon dioxide.
• Antibiotics may be administered for respiratory infections.
• Adequate hydration is crucial.
• Bronchodilators can reduce bronchial spasms.
• Intubation and mechanical ventilation may be necessary.

Respiratory Alkalosis

• Most commonly caused by hyperventilation secondary to anxiety, adult respiratory distress syndrome, congestive heart failure, head trauma, severe blood loss, or pneumonia.
• Increased respiratory rate, depth, or both lead to excessive carbon dioxide loss, reducing carbonic acid levels.
• Increases pH due to low carbonic acid.
• Kidneys attempt to compensate by conserving hydrogen ions and excreting bicarbonate, but this can take 24 hours or more.
• Symptoms include lightheadedness, numbness and tingling sensation in extremities, tinnitus, blurred vision, increased heart rate, and irritability.
• In extreme cases, confusion, seizure activity, and loss of consciousness may occur.
• Treatment involves treating the underlying cause.
• Anxiety-related cases may be managed by making the patient aware of the abnormal breathing pattern and instructing them to breathe slowly to retain carbon dioxide.
• Breathing into a paper bag may also be helpful.
• Sedation may be necessary in severe cases.

Water

• Water is essential for many bodily functions, including nutrient transport, waste removal, metabolic reactions, tissue lubrication, acid-base balance, and heat regulation.
• Water constitutes 50% to 80% of total body weight, varying by age, sex, and body fat.
• Infants have a higher water percentage (70-80%) which gradually decreases with age.
• Adults have a water percentage of 50-60%, while older adults have 45-55%.
• Fat contains less water than muscle, so women generally have less body fluid than men.
• Obesity leads to a smaller percentage of body water.
• Dehydration is a greater risk for older adults and obese individuals due to reduced fluid reserves.
• Infants are more susceptible to dehydration because a significant portion of their body fluid is outside cells (extracellular).
• Extracellular fluid is lost more quickly than intracellular fluid (fluid inside cells).
• A 10% loss of body fluid is serious in adults, while a 20% loss is fatal.
• Infants are even more vulnerable: a 5% loss is serious, 10% is very serious, and 15% or more can be fatal.

Lifespan Considerations: Older Adults

• Older adults are more at risk for dehydration due to several factors.
• Fat replaces muscle with age, resulting in lower total body fluid.
• Aging kidneys are less efficient at urine concentration, increasing fluid loss.
• Reduced mobility and diminished thirst sensation can lead to decreased fluid intake.
• Incontinence may cause individuals to restrict fluids, exacerbating dehydration.
• Excessive salt intake to compensate for taste changes can disrupt electrolyte and fluid balance.
• Skin and mucous membrane changes make it difficult to assess dehydration reliably.
• Early signs of dehydration in older adults can include mild disorientation.
• Dehydration can increase the risk of orthostatic hypotension and constipation.
• Intravenous fluids or supplements containing sodium or potassium can lead to electrolyte imbalances in older adults.
• Closely monitor complete blood cell counts to check hematocrit changes related to dehydration.

Fluid Compartments

• Body fluids are found in two compartments: intracellular (inside cells) and extracellular (outside cells).
• These compartments are interconnected and constantly interact.
• The larger compartment is intracellular, accounting for 66% of the body's fluid.
• Intracellular fluid contains dissolved particles called solutes.
• Extracellular fluid, found outside cells, contains vital components such as oxygen, carbon dioxide, glucose, amino acids, fatty acids, and electrolytes.

Intake and Output

• The body maintains fluid balance by replacing lost water through various routes.
• Fluid is lost through the kidneys, lungs, skin, and GI tract.
• Homeostasis ensures stable fluid composition and volume.
• Average daily fluid intake for adults is 2200 to 2700 mL.
• Oral fluid intake should be 1100 to 1400 mL daily, while solid foods contribute 800 to 1000 mL.
• Cellular metabolism produces approximately 300 mL of fluid daily.
• The thirst mechanism regulates fluid intake.
• Individuals unable to perceive or respond to thirst are at higher risk for dehydration.

Fluid Loss

• Fluid loss can be sensible (measurable) or insensible (not measurable).
• Sensible losses occur through urine, feces, vomiting, and wound drainage.
• Insensible losses include perspiration and expiration.
• Accurate record-keeping of fluid intake and sensible output is essential to determine fluid needs.

Kidney Function in Fluid Balance

• Kidneys play a crucial role in fluid balance.
• Nephrons, functional units of the kidneys, filter approximately 180 L of blood daily.
• This filtration rate (glomerular filtration rate, GFR) leads to 1 to 2 L of urine output per day.
• Nephrons reabsorb excess fluid based on bodily needs.
• The body conserves fluids by reabsorbing more water from renal filtrate during dehydration, leading to concentrated urine.
• The kidneys need to excrete at least 30 mL/h of urine to eliminate waste products.
• In overhydration, kidneys excrete more dilute urine to eliminate excess fluid.
• Regularly weighing patients under controlled conditions helps assess water balance.

Urine Specific Gravity

• Urine specific gravity indicates urine concentration and provides insights into fluid balance.
• A specific gravity exceeding 1.030 suggests concentrated urine, as seen in dehydration.
• A value below 1.003 to 1.000 indicates dilute urine, as in overhydration.

Movement of Fluids and Electrolytes

• Fluids are constantly in motion throughout the body, contributing to fluid balance.
• Extracellular fluid transports nutrients to cells and carries waste products via the capillary bed.
• Movement of substances across cell membranes occurs through passive transport or active transport.

Passive Transport

• Diffusion involves the movement of a substance from an area of higher concentration to lower concentration, resulting in an even distribution of particles.
• Osmosis is the movement of water across a semipermeable membrane from a low-concentration area to a high-concentration area.
• Filtration is the transfer of water and dissolved substances from an area of higher pressure to an area of lower pressure.

Active Transport

• Active transport requires the expenditure of cellular energy to move molecules against pressure.
• Sodium-Potassium Pump: This example of active transport maintains sodium and potassium balance, moving sodium out of the cell and potassium back in, preventing cell disruption.

Electrolytes

• Electrolytes are substances that develop an electrical charge when dissolved in water.
• Charged particles are called ions: cations have a positive charge, while anions have a negative charge.
• Common cations in the body: sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+).
• Common anions in the body: chloride (Cl−), bicarbonate (HCO3−), sulfate (SO4−), hydrogen phosphate (HPO4−).
• Electrolyte balance is essential for maintaining homeostasis.
• Milliequivalents (mEq) measure the chemical activity of ions, comparing activity to hydrogen.
• Electrolytes balance each other's chemical activity to maintain electrical neutrality.
• Each electrolyte has a primary location, such as sodium being predominantly extracellular and potassium intracellular.

Sodium

• Sodium is the most abundant electrolyte in the body, primarily extracellular.
• Sodium regulates fluid volume through osmotic pressure.
• It's essential for muscle contractility, especially in the heart, and nerve impulse conduction.
• Sodium is the primary electrolyte for maintaining acid-base balance.
• Dietary intake is the primary source of sodium, often exceeding recommended levels.
• Kidneys are the main excretion route for sodium.
• Sodium levels are tightly regulated, with a normal blood level of 135 to 145 mEq/L.

Hyponatremia

• Hyponatremia is a condition where the concentration of sodium in the blood is less than 135 mEq/L.
• It can be caused by sodium loss (e.g., vomiting, diarrhea) or excessive water intake which dilutes sodium.
• The body compensates for sodium loss by decreasing water excretion.
• Symptoms include weakness, anorexia, muscle cramps, confusion, fatigue, headache, edema, and seizures.
• Treatment involves sodium replacement and water restrictions.

Hypernatremia

• Hypernatremia is when the concentration of sodium in the blood exceeds 145 mEq/L.
• Caused by excess sodium or a decrease in body water.
• The body compensates by conserving water through renal reabsorption.
• Symptoms include dry mucous membranes, firm tissue turgor, low urinary output, restlessness, agitation, confusion, and flushed skin.
• Treatment focuses on gradually lowering sodium levels by decreasing intake or increasing water in the body.

Potassium

• Potassium (K+) is a major intracellular cation.
• 98% of potassium is inside cells with 2% in the extracellular fluid.
• Functions include regulating water and electrolyte content within the cell, promoting nerve impulses, skeletal muscle function, and cellular metabolism of carbohydrates and proteins.
• Adequate potassium is obtained through a balanced diet (e.g., fruits, legumes, leafy vegetables, potatoes).
• Excretion occurs primarily through the kidneys (80-90%).

Hypokalemia

• Hypokalemia is a decrease in potassium levels to less than 3.5 mEq/L.
• Primary cause is renal excretion where the kidneys don't conserve potassium.
• Other causes include excessive GI losses, severe diarrhea, fistulas, strenuous exercise, and diuretics.
• Can affect skeletal and cardiac function leading to muscle weakness and potentially life-threatening cardiac conduction abnormalities.
• Treatment involves potassium replacement and monitoring kidney and cardiac function.

Hyperkalemia

• Hyperkalemia is an increase in potassium levels above 5 mEq/L.
• Major cause is renal disease where potassium isn't adequately excreted.
• Other causes include tissue damage, excessive potassium intake, salt substitutes, and drugs like beta blockers.
• Can be dangerous as overstimulation of the cardiac muscle can cause cardiac arrest.
• Treatment involves restricting potassium intake, administering calcium gluconate, and using medications like insulin and sodium polystyrene sulfonate (Kayexalate).

Chloride

• Chloride (Cl-) is an extracellular anion that is rarely present alone.
• Usually bound to sodium or potassium.
• Necessary for hydrochloric acid formation in gastric secretions and regulation of osmotic pressure and acid-base balance.
• Main route of excretion is through the kidneys.

Hypochloremia

• Hypochloremia is a decrease in chloride levels below 96 mEq/L.
• Usually associated with sodium loss.
• Caused by conditions like vomiting, diarrhea, gastric suctioning, and infections.
• Symptoms include depressed respirations, tetany, and alkalosis.
• Treatment involves addressing the underlying cause and replacing chloride with intravenous sodium chloride solutions.

Hyperchloremia

• Hyperchloremia is rare and can occur when bicarbonate levels fall and metabolic acidosis occurs.
• An increase in chloride anions is an attempt to compensate for the imbalance in body fluids.
• Specific symptoms are not readily identifiable, but symptoms of acidosis may indicate high chloride levels.

Calcium

• Calcium (Ca2+) is a positively charged ion found mainly in bones and teeth.
• 99% of calcium is stored in bones and teeth, with the remaining 1% in soft tissue and extracellular fluid.
• The body regulates calcium levels based on bone deposition and resorption, absorption from the GI tract, and excretion in urine and feces.
• Vitamin D, calcitonin, and parathyroid hormone increase calcium absorption and utilization.

Hypocalcemia

• Hypocalcemia develops when calcium levels fall below 4.5 mg/dL.
• Causes include vitamin D deficiency, chronic renal failure, and parathyroid gland dysfunction.
• Symptoms involve neuromuscular irritation, hyperactive deep tendon reflexes, seizures, and tetany.
• Treatment involves calcium replacement with intravenous calcium gluconate and oral supplements.

Hypercalcemia

• Hypercalcemia is an elevation of calcium levels above 5.6 mEq/L.
• Can occur when calcium stored in bone enters circulation (e.g., immobilization).
• Excessive calcium or vitamin D intake also contributes.
• Symptoms include fatigue, muscle weakness, constipation, bone pain, kidney stones, and confusion.
• Treatment involves addressing the underlying cause and may involve medications like bisphosphonates or calcitonin.

Hypercalcemia

• Hypercalcemia causes neuromuscular activity depression and the formation of renal calculi.
• Causes include increased movement of calcium from bone to circulation, immobilization, metastatic bone cancer, multiple myeloma, excess intake of supplemental and dietary calcium, and increased levels of parathyroid hormone and vitamin D.
• Hypercalcemia symptoms include anorexia, nausea, vomiting, confusion, thirst, polyuria, renal calculi, decreased deep tendon reflexes, constipation, paralytic ileus, lethargy, coma, cardiac dysrhythmias, cardiac arrest, hypertension, decreased muscle tone, decreased GI motility, and bone pain.
• Nursing interventions include administering diuretics, encouraging fluid intake of 3-4 liters per day, and monitoring intake and output.

Phosphorus

• Represents about 1% of body weight and is found in every cell, mostly in bones and teeth.
• Phosphorus and calcium have an inverse relationship - an increase in one decreases the other.
• Normal values range from 2.4 to 4.1 mEq/dL.
• Supports bone and teeth maintenance, is a component of DNA and RNA, and is essential for cell membranes.
• It helps maintain blood pH and enhances the effectiveness of B Vitamins.
• Food sources include beef, pork, fish, poultry, milk products, and legumes.
• Adequate intake of vitamin D is necessary for phosphorus absorption.
• 90% of phosphorus is excreted by the kidneys, the remainder is excreted in feces.

Hypophosphatemia

• Seldom occurs due to the abundance of phosphorus in many foods.
• Caused by dietary insufficiency, impaired kidney function, or maldistribution of phosphorus.
• Symptoms include muscle weakness, bone and joint pain, disorientation, and confusion.
• Treatment includes replacing phosphorus with oral or IV supplementation and monitoring the patient.

Hyperphosphatemia

• Rarely occurs, most commonly caused by renal insufficiency, but can occur with increased intake of phosphate or vitamin D.
• Symptoms include tetany, numbness and tingling sensation around the mouth, and muscle spasms.
• Treatment includes restricting phosphorus intake, treating the underlying cause, and potentially using phosphate-binding gels and IV calcium supplementation.

Magnesium

• The fourth most abundant mineral and second most abundant cation in the intracellular fluid.
• Majority found in bone, lesser amounts in muscle and soft tissue, and only 1% in the extracellular fluid.
• A cofactor in the activation of many enzymes, promotes regulation of serum calcium, phosphate, and potassium levels, and is essential for nerve tissue, skeletal muscle, and cardiac function.
• Normal blood values are 1.5 to 2.5 mEq/L.
• Food sources include whole grains, fruits, green vegetables, meat, fish, legumes, and dairy products.
• The body needs vitamin B6 to absorb magnesium.
• Excreted primarily through the kidneys, correlated with potassium excretion.

Hypomagnesemia

• Occurs when blood levels fall below 1.5 mEq/L.
• Associated with decreased potassium levels as the kidneys conserve magnesium at the expense of potassium excretion.
• Symptoms include increased neuromuscular irritability, tremors, cramping, numbness, tingling sensation, disorientation, confusion, tetany, and seizures.
• Causes include increased renal excretion, impaired GI absorption, and prolonged malnutrition.
• Treatment includes oral or IV magnesium supplementation.

Hypermagnesemia

• Occurs when magnesium blood levels exceed 2.5 mEq/L.
• Rarely occurs with normal kidney function, but can develop with impaired renal function, excess administration, and diabetic ketoacidosis.
• Causes severe restriction of nerve and muscle activity, respiratory depression, hypotension, and potential cardiac arrest.
• Treatment includes decreasing magnesium intake, supporting cardiac and respiratory function, and potentially dialysis.

Bicarbonate

• A major anion in the extracellular fluid, important for acid-base balance regulation.
• Neutralizes acids in the body and maintains the 20:1 ratio of bicarbonate to carbonic acid for homeostasis.
• Normal bicarbonate level is 22 to 24 mEq/L.
• Kidneys regulate the amount of bicarbonate retained or excreted based on need.

Acid-Base Balance

• Refers to homeostasis of the hydrogen ion concentration in body fluids.
• Determined by the ratio of carbonic acid to bicarbonate in the extracellular fluid, with a 1:20 ratio needed for homeostasis.
• Measured by pH, which is the hydrogen ion concentration in the body.
• Arterial blood gas levels reveal whether the blood is acidic, neutral, or alkaline.
• Normal arterial blood pH is approximately 7.45, while normal venous blood and interstitial fluid pH is 7.35.
• Between 7.35 and 7.45 is considered normal.
• A pH imbalance can result from an increase or decrease in bicarbonate or carbonic acid.
• Metabolic acidosis or alkalosis is caused by a bicarbonate imbalance, while respiratory acidosis or alkalosis is caused by a carbonic acid imbalance.

Blood Buffers

• Also known as physiologic buffers.
• Consist of a weak acid and its base salt or a weak base and its acid salt.
• Include the bicarbonate/carbonic acid buffering system, intracellular protein buffers, and phosphate buffers in bones.
• The bicarbonate/carbonic acid system is the most important, buffering blood and interstitial fluid.
• Act like chemical sponges, neutralizing excess acids or bases by contributing or accepting hydrogen ions.
• Work within a fraction of a second to prevent excessive hydrogen ion concentration changes.

Respiratory System

• Second line of defense in regulating hydrogen concentration.
• Increased or decreased respirations impact carbon dioxide levels in the blood, which influence carbonic acid levels.
• Carbon dioxide acts as a potential acid forming carbonic acid when dissolved in water.
• Removing carbon dioxide from the blood lowers carbonic acid level and raises pH, creating a more alkaline environment.
• Slower than blood buffers but still efficient in eliminating large amounts of acid from the body.
• Chemoreceptors in the medulla of the brainstem stimulate increased respirations.

Kidneys

• Third line of defense in regulating hydrogen ions.
• Excrete acids or bases as needed.
• In acidosis, the kidneys excrete hydrogen in urine and retain bicarbonate.
• In alkalosis, the kidneys excrete bicarbonate and retain hydrogen.
• The slowest system to balance hydrogen concentration, but efficient in returning pH to normal.

Types of Acid-Base Imbalance

• Four possible imbalances - acidosis (pH below 7.35) and alkalosis (pH above 7.45).
• Caused primarily by imbalances in lung or kidney function.
• Predisposing conditions include diabetes mellitus, COPD, end-stage renal disease, severe vomiting, and diarrhea.
• Four types: respiratory acidosis, respiratory alkalosis, metabolic acidosis, and metabolic alkalosis.

Respiratory Acidosis

• Caused by conditions impairing ventilation and preventing elimination of carbon dioxide.
• Carbon dioxide is retained, increasing carbonic acid levels in the blood.
• Body attempts to eliminate excess carbon dioxide by increasing respirations.
• Kidneys attempt to compensate by retaining bicarbonate and eliminating hydrogen.
• Treatment aims at improving ventilation, addressing the underlying cause, and providing respiratory support.

Respiratory Alkalosis

• Most commonly caused by hyperventilation due to anxiety, ARDS, CHF, head trauma, severe blood loss, or pneumonia.
• Increased respiratory rate and depth cause carbon dioxide loss and low carbonic acid level in the blood.
• Kidneys attempt to compensate by conserving hydrogen ions and excreting bicarbonate ions.
• Treatment involves addressing the underlying cause.

Charts of Comparison

• Provides a comprehensive overview of the causes, clinical signs and symptoms, and laboratory data for various acid-base imbalances.
• Examples include causes like airway obstruction, COPD, or head injuries, and symptoms like coma, dyspnea, or tremors.
• The charts also highlight specific laboratory data related to each imbalance, such as bicarbonate and potassium levels.

Test your knowledge on fluid balance and dehydration, focusing on factors affecting water composition in adults. Explore the impact of age, body fat, and physiological changes on hydration levels. This quiz will also review the significance of measuring intake and output in renal patients.