Acidosis, respiratory (Acidosis)

Introduction
Respiratory acidosis is an acid–base disturbance resulting from inadequate alveolar ventilation, leading to elevated arterial carbon dioxide (PaCO₂ > 45 mmHg) and decreased blood pH (< 7.35). It may develop acutely (e.g., respiratory failure, airway obstruction) or chronically (e.g., chronic obstructive pulmonary disease). Treatment focuses on reversing hypoventilation, correcting underlying causes, and stabilizing gas exchange while avoiding rapid shifts that may destabilize compensatory mechanisms.

1. Immediate Stabilization

• Airway management: Ensure patency; intubation and mechanical ventilation may be required in severe cases.

• Oxygen therapy: Administer supplemental oxygen, carefully titrated in chronic CO₂ retainers (e.g., COPD) to avoid worsening hypercapnia.

• Ventilatory support:

  • Non-invasive ventilation (NIV, e.g., BiPAP): First-line in acute exacerbations of COPD or neuromuscular weakness.

  • Invasive mechanical ventilation: For patients with severe respiratory failure, inability to protect airway, or refractory hypercapnia.

2. Treat Underlying Causes

• Chronic Obstructive Pulmonary Disease (COPD):

  • Bronchodilators (e.g., inhaled β₂-agonists, anticholinergics).

  • Systemic corticosteroids during acute exacerbations.

  • Antibiotics if bacterial infection is suspected.

• Asthma exacerbation: High-dose inhaled β₂-agonists, systemic corticosteroids, and oxygen therapy.

• Neuromuscular disorders (e.g., myasthenia gravis, Guillain–Barré syndrome): Immunotherapy (IVIG, plasmapheresis), ventilatory support.

• CNS depression (opioids, sedatives): Naloxone for opioid overdose; discontinuation of sedatives.

• Airway obstruction: Bronchoscopy, suctioning, or surgical intervention if required.

3. Pharmacologic Adjuncts

• Reversal agents: Naloxone for opioid-induced hypoventilation, flumazenil for benzodiazepine overdose (with caution).

• Diuretics: In cases of respiratory acidosis due to pulmonary edema.

• Acetazolamide: Occasionally used in chronic hypercapnia to stimulate ventilation, though not routine.

4. Supportive and Monitoring Measures

• Frequent monitoring of arterial blood gases and electrolytes.

• Correct associated electrolyte imbalances (e.g., hyperkalemia).

• Avoid excessive bicarbonate therapy; it is generally not indicated in pure respiratory acidosis, as it can worsen CO₂ retention.

5. Lifestyle and Preventive Measures

• Smoking cessation in chronic lung disease.

• Vaccinations (influenza, pneumococcal) to reduce risk of respiratory infections.

• Pulmonary rehabilitation and exercise conditioning.

• Weight management and treatment of sleep apnea (e.g., CPAP therapy).

6. Multidisciplinary Care

• Pulmonologists for chronic respiratory disease management.

• Critical care specialists for acute respiratory failure.

• Neurology input for neuromuscular causes.

• Long-term respiratory therapy support for rehabilitation and patient education.