What are the treatments for respiratory acidosis, constriction, and alkalosis?

Treatment of Respiratory Acidosis, Constriction, and Alkalosis

The primary treatment for respiratory acidosis is to address the underlying cause of alveolar hypoventilation, with non-invasive ventilation (NIV) being the first-line intervention for patients with pH <7.35 and pCO2 >6.5 kPa (>48.8 mmHg). 1

Respiratory Acidosis Treatment

Assessment and Diagnosis

• Respiratory acidosis occurs when pH falls below 7.35 with elevated PaCO2 (>6.1 kPa or >46 mmHg) 1
• Characterized by rapid shallow breathing pattern with increased respiratory rate and small tidal volumes 1
• Measure respiratory rate, observe chest/abdominal wall movement, and obtain arterial blood gas 1

Treatment Algorithm

1. Non-invasive Ventilation (NIV)

   • Indicated for pH <7.35 and pCO2 >6.5 kPa (>48.8 mmHg) 2
   • Initial settings:
     • IPAP: 8-12 cmH2O
     • EPAP: 4-5 cmH2O
     • Target respiratory rate: 15-20 breaths/min 2
   • Deliver in controlled environment (intermediate ICU or high-dependency unit) 2
   • Monitor for NIV failure:
     • Worsening ABGs/pH within 1-2 hours
     • No improvement in ABGs/pH after 4 hours 2

2. Oxygen Therapy

   • Target oxygen saturation of 88-92% to prevent worsening hypercapnia 2
   • Use controlled oxygen delivery methods:

     Method	Flow Rate	Target Saturation
     Nasal cannulae	1-2 L/min	88-92%
     24% Venturi mask	2-3 L/min	88-92%
     28% Venturi mask	4 L/min	88-92%

3. Pharmacological Management

   • Administer nebulized bronchodilators for 24-48 hours or until clinical improvement 2
   • Consider systemic corticosteroids (prednisolone 30 mg daily or hydrocortisone 100 mg IV) for 7-14 days 2
   • For COPD exacerbation:
     • Short-acting β-agonists and ipratropium
     • Prednisone 30-40 mg orally daily for 10-14 days
     • Antibiotics if indicated 2

4. Invasive Mechanical Ventilation

   • Consider if:
     • NIV failure occurs
     • Severe acidosis develops (pH <7.25)
     • Life-threatening hypoxemia occurs
     • Tachypnea >35 breaths/min persists 2

Special Considerations

• In chronic respiratory acidosis, kidneys retain bicarbonate to buffer acidity, producing "compensated respiratory acidosis" 1
• During COPD exacerbations, patients may develop "acute on chronic" respiratory acidosis despite high bicarbonate levels 1
• About 20% of patients with acute COPD exacerbations requiring hospitalization have respiratory acidosis 1

Respiratory Alkalosis Treatment

Assessment and Diagnosis

• Respiratory alkalosis occurs when pH >7.45 with decreased PaCO2 3
• Results from hyperventilation due to various pulmonary or extrapulmonary disorders 3

Treatment Algorithm

1. Identify and Treat Underlying Cause 3

   • Pulmonary causes (pulmonary embolism, pneumonia)
   • Extrapulmonary causes (anxiety, sepsis, liver disease)
   • Hyperventilation syndrome (diagnosis by exclusion)

2. Correct Metabolic Abnormalities

   • Monitor and correct electrolyte disturbances (potassium, phosphate, calcium) 3
   • Address mild lactic acidosis that may develop 3

3. Breathing Techniques (for hyperventilation syndrome)

   • Controlled breathing exercises
   • Paper bag rebreathing (in controlled settings only)

4. Pharmacological Management

   • Treat anxiety if present
   • Address pain if contributing to hyperventilation

Complications to Monitor

• Cardiac effects: tachycardia, ventricular and atrial arrhythmias, ischemic and non-ischemic chest pain 3
• Pulmonary vasodilation 3
• Gastrointestinal changes in perfusion, motility, and electrolyte handling 3

Constriction Management

Bronchial Constriction Treatment

1. Bronchodilator Therapy

   • Short-acting β-agonists (first-line)
   • Ipratropium bromide
   • Consider combination therapy for severe cases 2

2. Anti-inflammatory Treatment

   • Systemic corticosteroids for acute exacerbations
   • Consider inhaled corticosteroids for maintenance 2

3. Oxygen Therapy

   • Controlled oxygen delivery to maintain SpO2 88-92% 2

4. Additional Measures

   • Ensure appropriate ventilator settings with controlled modes to limit increases in hypercapnia 2
   • Monitor transcutaneous arterial oxygen saturation continuously 2
   • Measure blood pH, carbon dioxide tension, and consider lactate levels 2

Monitoring and Assessment

• Continuous monitoring of respiratory rate, oxygen saturation, level of consciousness 2
• Repeat arterial blood gases as needed 2
• Clinical improvement assessed through:
  • Resolution of symptoms
  • Normalization of respiratory pattern
  • Improvement in PCO2 levels 2

Pitfalls and Caveats

• Avoid excessive oxygen in COPD patients as it may worsen hypercapnia 1
• NIV contraindications include respiratory arrest, cardiovascular instability, impaired mental status, copious secretions with high aspiration risk, and recent facial surgery/trauma 2
• Avoid medications that may exacerbate respiratory conditions:
  • For MAT: theophyllines, β-adrenergic agonists, non-selective β-blockers 2
  • For respiratory acidosis: sedatives, narcotics without proper monitoring 4
• Beta-blockers should be used with caution in patients with severe pulmonary disease and only after correction of hypoxia 2