Transport Mechanisms and Regulation

Transport Mechanisms

• Diffusion is the movement of solutes from an area of high concentration to an area of low concentration. It requires no energy (passive).
• Osmosis is the movement of water across a selectively permeable membrane from an area of high water concentration to an area of low water concentration. It also requires no energy (passive).
• Filtration is the movement of water and small solutes across a membrane due to hydrostatic pressure. It involves the squeezing of fluid through a membrane.
• Active transport moves solutes against their concentration gradient. This process requires energy (ATP).

Fluid and Electrolyte Regulation

Kidney Role

• Kidneys filter blood, regulating water and electrolyte balance, eliminating wastes.

Lung Role

• Lungs help regulate acid-base balance by removing carbon dioxide.

Endocrine Gland Role

• Endocrine glands (e.g., adrenal glands, parathyroid glands) regulate fluid and electrolyte balance through hormone secretion.

Fluid and Electrolyte Imbalances

Fluid Volume Deficit (FVD)

• Causes: Vomiting, diarrhea, excessive sweating, diuretic use.
• Manifestations: Thirst, decreased urine output, postural hypotension, weight loss.
• Management: Fluid replacement (oral or intravenous).
• Nursing Interventions: Monitor intake and output, vital signs, weight.

Fluid Volume Excess (FVE)

• Causes: Heart failure, kidney failure, excessive IV fluids.
• Manifestations: Edema, increased blood pressure, increased urine output.
• Management: Diuretics, restrict fluid intake.
• Nursing Interventions: Monitor daily weight, intake/output, lung sounds, and vital signs.

Sodium Imbalances

Hyponatremia

• Causes: Excessive water intake, loss of sodium through vomiting or diarrhea.
• Manifestations: Nausea, headache, confusion, seizures.
• Management: Correct underlying cause, administer sodium if needed.
• Nursing Interventions: Monitor neurological status, fluid balance.

Hypernatremia

• Causes: Dehydration, excessive sodium intake.
• Manifestations: Thirst, dry mucous membranes, elevated temperature.
• Management: Fluid replacement, correct underlying cause.
• Nursing Interventions: Monitor fluid status, intake, and output.

Potassium Imbalances

Hypokalemia

• Causes: Diuretic use, vomiting, diarrhea, inadequate potassium intake.
• Manifestations: Muscle weakness, fatigue, cardiac arrhythmias.
• Management: Potassium replacement, monitor cardiac rhythm.
• Nursing Interventions: Assess cardiac rhythm, monitor muscle strength, potassium intake.

Hyperkalemia

• Causes: Kidney failure, excessive potassium intake.
• Manifestations: Muscle weakness, paralysis, cardiac dysrhythmias.
• Management: Diuretics, dialysis.
• Nursing Interventions: Monitor cardiac rhythm, assess for neurological changes.

Other Electrolyte Imbalances

Calcium Imbalances

Hypocalcemia

• Manifestations: Muscle cramps, tetany, seizures.
• Management: Calcium replacement, vitamin D.
• Nursing Interventions: Monitor for muscle and nerve changes.

Hypercalcemia

• Manifestations: Nausea, vomiting, constipation.
• Management: Calcitonin, hydration.
• Nursing Interventions: Monitor for constipation/urinary stones.

Magnesium Imbalances

Hypomagnesemia

• Manifestations: Tremors, muscle spasms, cardiac dysrhythmias.
• Management: Magnesium replacement.
• Nursing Interventions: Monitor cardiovascular and neurological status.

Hypermagnesemia

• Manifestations: Bradycardia, hypotension (reduced heart rate and blood pressure).
• Management: Diuretics, calcium.
• Nursing Interventions: Monitor cardiovascular status, respiratory function.

Phosphorus Imbalances

Hypophosphatemia

• Manifestations: Muscle weakness, anorexia.
• Management: Phosphorus replacement.
• Nursing Interventions: Monitor for neuromuscular changes.

Hyperphosphatemia

• Manifestations: Tetany and muscle spasms.
• Management: Restrict phosphorus intake, phosphate binders.
• Nursing Interventions: Monitor for neuromuscular symptoms

Chloride Imbalances

Hypochloremia

• Manifestations: Weakness, nausea, vomiting.
• Management: Replace chloride.
• Nursing Interventions: Monitor for dehydration.

Hyperchloremia

• Manifestations: Thirst, lethargy, respiratory issues.
• Management: Correct underlying cause (e.g. dehydration).
• Nursing Interventions: Monitor respiratory status.

Acid-Base Balance

Lung, Kidney, and Buffer System Roles

• Lungs: Regulate CO2 levels through respiration.
• Kidneys: Regulate bicarbonate levels.
• Chemical buffers: Rapidly respond to pH changes.

Acid-Base Disorders

Metabolic Acidosis

• Causes: Diabetic ketoacidosis, kidney failure.
• Manifestations: Kussmaul respirations, headache, drowsiness.
• Management: Treat underlying cause, IV fluids.

Respiratory Acidosis

• Causes: Hypoventilation, opioid overdose.
• Manifestations: Headache, confusion, lethargy.
• Management: Improve ventilation, treat underlying cause.

Metabolic Alkalosis

• Causes: Vomiting, excessive use of bicarbonate antacids.
• Manifestations: Muscle weakness, tingling.
• Management: Treat the cause of excess bicarbonate.

Respiratory Alkalosis

• Causes: Hyperventilation.
• Manifestations: Lightheadedness, dizziness, tingling.
• Management: Treat the cause of excessive loss via respiration.

Arterial Blood Gas Interpretation

• Interpretation of arterial blood gas (ABG) values provides information about pH, PaCO2, HCO3, that helps assess acid-base balance and oxygenation status.
• ABG values can assist in identifying various acid-base imbalances including metabolic or respiratory acidosis and alkalosis.