Comprehensive Review of Acid-Base Imbalances

Overview of Respiratory Acidosis

• Cause: Decrease in lung ventilation, retention of CO2.
• Result: Drop in blood pH.

Causes of CO2 Retention

• Low breathing rate (bradypnea): Less than 12 breaths/min in adults.
• Damage to lungs: Affects gas exchange structures like alveolar sacs.
• Weak respiratory muscles: Conditions like neuromuscular disorders.

Carbon Dioxide and Gas Exchange

• CO2: Waste product from cell metabolism.
• Normal CO2 range: 35-45 mmHg.
• Increased CO2: Levels higher than 45 mmHg.
• Exchange process: CO2 in blood -> heart -> lungs -> exhaled.

Acid-Base Chemistry

• CO2 + H2O: Forms carbonic acid (weak), dissociates into hydrogen ions and bicarbonate.
• Blood pH measurement: Concentration of hydrogen ions.
• Normal blood pH: 7.35-7.45.
• Acidosis: pH less than 7.35, excess hydrogen ions.

Diagnosis and Causes

• Arterial Blood Gas Values: Low pH, high CO2 (>45 mmHg), and variable bicarbonate levels.
• Causes: Use mnemonic "DEPRESS" (Drugs, Edema, Pneumonia, Respiratory center damage, Emphysema, Spasms, Sacs elasticity).

Signs and Symptoms

• Neuro changes: Confusion, drowsiness.
• Hypoxia: Low oxygen levels, increased heart rate.
• Clinical observations: Neuro changes and hypoxia.

Nursing Role

• Oxygen administration: Be cautious with COPD patients.
• Monitor respiratory status: Rate and neuro status.
• Interventions: Coughing, deep breathing, mouth care, and bronchodilators.
• Electrolyte monitoring: Hyperkalemia risk.

Overview of Respiratory Alkalosis

• Cause: Increased lung ventilation, loss of CO2.
• Result: Rise in blood pH.

Causes of Increased Ventilation

• Tachypnea: Fast breathing rate, >20 breaths/min.
• Conditions: Fever, aspirin toxicity, mechanical ventilation, hyperventilation (anxiety), pain, pneumothorax, brain injury, embolism, altitude.

Acid-Base Chemistry

• Low CO2 levels: Less carbonic acid, fewer hydrogen ions, increased pH.

Diagnosis

• Arterial Blood Gas Values: High pH, low CO2 (<35 mmHg), variable bicarbonate levels.

Signs and Symptoms

• Increased respiratory rate.
• Neuro changes: Anxiety to seizures.
• ECG changes: Due to hypocalcemia and hypokalemia.

Nursing Role

• Interventions: Find and treat cause, encourage rebreathing, monitor electrolytes.
• Education: Teach relaxation and stress techniques.

Overview of Metabolic Acidosis

• Cause: Excess acids or failure to excrete acids.
• Result: Low blood pH, low bicarbonate.

Causes

• Mnemonic "ACIDS": Accumulation of lactate, Chronic diarrhea, Impaired renal function, DKA, Salicylate toxicity.

Acid-Base Chemistry

• Acids: Hydrogen ions decrease pH.
• Body response: Uses bases to neutralize acids.

Diagnosis

• Arterial Blood Gas Values: Low pH, low bicarbonate, variable CO2.

Signs and Symptoms

• Kussmaul breathing: Fast, deep breaths.
• Neuro changes: Confusion, weakness.
• ECG changes: Hyperkalemia risk.

Nursing Role

• Identify cause and treat.
• Interventions: Fluids like sodium bicarbonate, dialysis if renal failure.

Overview of Metabolic Alkalosis

• Cause: Loss of acids or increase in bases.
• Result: High blood pH, high bicarbonate.

Causes

• Mnemonic "ALKALI": Acid loss (vomiting), Low chloride, Potassium loss, Aldosterone increase, Loop and thiazide diuretics, Sodium bicarbonate IV.

Acid-Base Chemistry

• Bases: Neutralize acids by binding with hydrogen ions.

Diagnosis

• Arterial Blood Gas Values: High pH, high bicarbonate, variable CO2.

Signs and Symptoms

• Bradypnea: Slow breathing, risk of respiratory failure.
• ECG changes: Hypokalemia risk.

Nursing Role

• Monitor ECG, respiratory, and neurostatus.
• Address vomiting, diuretic use.
• Administer medications as needed.

ABG Sample Collection and Analysis

• Modified Allen Test: Ensure collateral blood flow before collecting ABG from radial artery.
• Tic-Tac-Toe and ROME Methods: Solve ABG problems, identify compensations.
• Practice Problems: Use provided practice problems to master ABG interpretation.