acid-base disorders

Four Primary Acid-Base Disorders

Respiratory Acidosis, Respiratory Alkalosis, Metabolic Acidosis, and Metabolic Alkalosis

Respiratory Acidosis

Definition: CO2 is retained due to hypoventilation

Respiratory Acidosis

Definition: This leads to increased carbonic acid and decreased blood pH

Respiratory Acidosis

Parameter: pH ↓ (< 7.35)

Respiratory Acidosis

Parameter: PaCO2 ↑ (> 45 mmHg)

Respiratory Acidosis

Parameter: HCO3- Normal (acute) or ↑ (chronic compensation)

Respiratory Acidosis

Cause: Hypoventilation

Respiratory Acidosis

Cause: Chronic COPD

Respiratory Acidosis

Cause: Emphysema

Respiratory Acidosis

Cause: Asthma

Respiratory Acidosis

Cause: Airway obstruction

Respiratory Acidosis

Cause: Respiratory depression (e.g., narcotics, anesthesia)

Respiratory Acidosis

Cause: Chest trauma

Respiratory Acidosis

Cause: Neuromuscular disease

Respiratory Acidosis

Sign/Symptom: Confusion

Respiratory Acidosis

Sign/Symptom: Drowsiness

Respiratory Acidosis

Sign/Symptom: Headache

Respiratory Acidosis

Sign/Symptom: Dyspnea, shallow respirations

Respiratory Acidosis

Sign/Symptom: Cyanosis

Respiratory Acidosis

Sign/Symptom: Hypotension

Respiratory Acidosis

Management: Improve ventilation (airway clearance, bronchodilators, oxygen, mechanical ventilation)

Respiratory Acidosis

Management: Monitor ABGs and respirations

Respiratory Acidosis

Management: Hydrate (helps eliminate CO2)

Respiratory Acidosis

Management: Treat underlying cause

Respiratory Alkalosis

Definition: CO2 is excessively exhaled due to hyperventilation

Respiratory Alkalosis

Definition: This leads to decreased carbonic acid and increased blood pH

Respiratory Alkalosis

Parameter: pH ↑ (> 7.45)

Respiratory Alkalosis

Parameter: PaCO2 ↓ (< 35 mmHg)

Respiratory Alkalosis

Parameter: HCO3- Normal or ↓ (compensation)

Respiratory Alkalosis

Cause: Anxiety, panic attacks

Respiratory Alkalosis

Cause: Fever, pain

Respiratory Alkalosis

Cause: Hypoxemia (e.g., high altitude)

Respiratory Alkalosis

Cause: Pulmonary embolism

Respiratory Alkalosis

Cause: Excessive mechanical ventilation

Respiratory Alkalosis

Cause: Early salicylate (aspirin) toxicity

Respiratory Alkalosis

Sign/Symptom: Lightheadedness, dizziness

Respiratory Alkalosis

Sign/Symptom: Tingling of fingers and toes (paresthesia)

Respiratory Alkalosis

Sign/Symptom: Confusion, restlessness

Respiratory Alkalosis

Sign/Symptom: Tachypnea

Respiratory Alkalosis

Sign/Symptom: Tetany or muscle cramps

Respiratory Alkalosis

Management: Encourage slow breathing (e.g., paper bag rebreathing)

Respiratory Alkalosis

Management: Treat underlying cause (pain, fever, anxiety)

Respiratory Alkalosis

Management: Sedatives if anxiety-induced

Respiratory Alkalosis

Management: Monitor ABGs and vital signs

Metabolic Acidosis

Definition: Acid accumulates or bicarbonate is lost

Metabolic Acidosis

Definition: This leads to decreased pH

Metabolic Acidosis

Parameter: pH ↓ (< 7.35)

Metabolic Acidosis

Parameter: PaCO2 ↓ (compensatory)

Metabolic Acidosis

Parameter: HCO3- ↓ (< 22 mEq/L)

Metabolic Acidosis

Cause: Diabetic ketoacidosis (DKA)

Metabolic Acidosis

Cause: Renal failure (impaired acid excretion)

Metabolic Acidosis

Cause: Severe diarrhea (loss of bicarbonate)

Metabolic Acidosis

Cause: Lactic acidosis (shock, sepsis)

Metabolic Acidosis

Cause: Salicylate overdose (late phase)

Metabolic Acidosis

Sign/Symptom: Kussmaul respirations (deep, rapid)

Metabolic Acidosis

Sign/Symptom: Weakness, fatigue

Metabolic Acidosis

Sign/Symptom: Headache, confusion

Metabolic Acidosis

Sign/Symptom: Hypotension, cardiac arrhythmias

Metabolic Acidosis

Sign/Symptom: Nausea, vomiting

Metabolic Acidosis

Management: Treat the cause — insulin for DKA, dialysis for renal failure, fluids and bicarbonate if severe

Metabolic Acidosis

Management: Monitor K+ levels (hyperkalemia often occurs)

Metabolic Acidosis

Management: Monitor ABGs and vital signs

Metabolic Alkalosis

Definition: Acid is lost or bicarbonate is gained

Metabolic Alkalosis

Definition: This leads to increased pH

Metabolic Alkalosis

Parameter: pH ↑ (> 7.45)

Metabolic Alkalosis

Parameter: PaCO2 ↑ (compensatory)

Metabolic Alkalosis

Parameter: HCO3- ↑ (> 26 mEq/L)

Metabolic Alkalosis

Cause: Prolonged vomiting or gastric suction

Metabolic Alkalosis

Cause: Diuretic therapy (loss of H+ and K+)

Metabolic Alkalosis

Cause: Excess antacid intake

Metabolic Alkalosis

Cause: Hypokalemia

Metabolic Alkalosis

Cause: Cushing's syndrome

Metabolic Alkalosis

Sign/Symptom: Muscle cramps, tremors

Metabolic Alkalosis

Sign/Symptom: Weakness, confusion

Metabolic Alkalosis

Sign/Symptom: Hypoventilation (compensation)

Metabolic Alkalosis

Sign/Symptom: Nausea, vomiting

Metabolic Alkalosis

Sign/Symptom: Dysrhythmias (due to low K+)

Metabolic Alkalosis

Management: Treat the cause

Metabolic Alkalosis

Management: Stop gastric suction

Metabolic Alkalosis

Management: Replace electrolytes (K+, Cl-)

Metabolic Alkalosis

Management: Administer IV fluids (NaCl + KCl)

Metabolic Alkalosis

Management: Monitor ECG, ABGs, and fluid balance

ROME Mnemonic for ABG Interpretation

R.O.M.E.

ROME Mnemonic for ABG Interpretation

pH and PaCO2 move OPPOSITE directions → the problem is RESPIRATORY

ROME Mnemonic for ABG Interpretation

pH ↓ with PaCO2 ↑

ROME Mnemonic for ABG Interpretation

pH ↑ with PaCO2 ↓

ROME Mnemonic for ABG Interpretation

pH and HCO3- move the SAME (EQUAL) direction → the problem is METABOLIC

ROME Mnemonic for ABG Interpretation

pH ↓ with HCO3- ↓

ROME Mnemonic for ABG Interpretation

pH ↑ with HCO3- ↑