What are the Global Initiative for Asthma (GIA) 2025 guidelines for managing severe asthma exacerbations in the Intensive Care Unit (ICU)?

Global Initiative for Asthma 2025 ICU Management Guidelines

Immediate ICU Admission Criteria

Patients with severe asthma exacerbations require ICU admission when they exhibit deteriorating peak flow, worsening or persisting hypoxia (PaO₂ <8 kPa) despite 60% inspired oxygen or hypercapnia (PaCO₂ >6 kPa), onset of exhaustion with feeble respiration, confusion or drowsiness, or coma/respiratory arrest. 1

Additional life-threatening features mandating ICU-level care include: 2

• PEF <33% of predicted or personal best
• Silent chest, cyanosis, or feeble respiratory effort
• Altered mental status, confusion, or coma
• PaCO₂ ≥42 mmHg or rising
• Inability to speak in complete sentences
• Bradycardia, hypotension, or exhaustion

First-Line ICU Pharmacologic Management

Oxygen Therapy

Administer high-flow oxygen (40-60%) immediately via face mask or nasal cannula to maintain SaO₂ >90% (>95% in pregnant patients or those with cardiac disease). 2 Continue oxygen therapy throughout the treatment course. 1

Bronchodilator Therapy

Nebulized albuterol 2.5-5 mg combined with ipratropium bromide 0.5 mg should be administered every 20 minutes for 3 doses. 2 If the patient's condition has not improved after 15-30 minutes, give nebulized β-agonists more frequently, up to every 15 minutes. 1

For patients with life-threatening features, consider continuous nebulization of albuterol. 3

Systemic Corticosteroids

Administer systemic corticosteroids immediately—either prednisolone 30-60 mg orally or intravenous hydrocortisone 200 mg every 6 hours in patients who are seriously ill or vomiting. 1, 2 Clinical benefits may not appear for 6-12 hours, making early administration essential. 2

Monitoring Parameters in the ICU

Measure and record the following at 15-30 minute intervals initially: 1, 2

• Peak expiratory flow or FEV₁
• Oxygen saturation via continuous pulse oximetry
• Respiratory rate and heart rate
• Accessory muscle use
• Arterial blood gas if PEF <25% predicted, severe distress, or suspected hypoventilation

Escalation for Refractory Cases

Intravenous Magnesium Sulfate

For life-threatening exacerbations or severe exacerbations remaining after 1 hour of intensive conventional treatment, administer intravenous magnesium sulfate 2 g IV over 20 minutes (pediatric dose: 25-75 mg/kg, maximum 2 g). 2, 3

Aminophylline

If progress is still unsatisfactory after the above interventions, consider giving aminophylline or a parenteral β-agonist. 1 For patients with life-threatening features, give intravenous aminophylline 5 mg/kg over 20 minutes followed by maintenance infusion of 1 mg/kg/h; omit the loading dose if the patient is already receiving oral theophyllines. 1

Heliox Therapy

Consider heliox-driven albuterol nebulization for severe refractory cases to decrease work of breathing, though evidence is limited. 2

Mechanical Ventilation Indications and Management

Intubation Criteria

Not all patients admitted to the ICU need ventilation, but those with worsening hypoxia or hypercapnia, drowsiness, unconsciousness, or those who have had a respiratory arrest require intermittent positive pressure ventilation. 1

Specific signs requiring immediate intubation consideration include: 2

• Inability to speak
• Altered mental status or worsening confusion
• Intercostal retraction with worsening fatigue
• PaCO₂ ≥42 mmHg or rising
• Exhaustion despite maximal therapy

Intubation should ideally be performed by an anesthetist and should be done semi-electively before respiratory arrest occurs. 1

Ventilation Strategy

Use "permissive hypercapnia" ventilator strategy with low tidal volumes and low respiratory rates to allow for prolonged expiratory time and reverse dynamic hyperinflation. 2, 4, 5 This approach reduces the risk of barotrauma while maintaining PaO₂ and pH, allowing PaCO₂ to rise. 6

Ensure adequate intravascular volume replacement and consult with or comanage by a physician expert in ventilator management. 2

Critical Pitfalls to Avoid

Any sedation is contraindicated in acute severe asthma. 1 Additional interventions to avoid include: 3

• Antibiotics (give only if bacterial infection is present)
• Percussive physiotherapy (unnecessary)
• Aggressive hydration in older children and adults
• Methylxanthines as routine therapy (increased side effects without superior efficacy)

ICU Discharge Criteria

Patients should not be discharged from the ICU until: 1

• Peak expiratory flow above 75% of predicted value or best level
• Diurnal variability below 25%
• No nocturnal symptoms
• Symptoms have stabilized or returned to normal function

All patients should be discharged taking prednisolone tablets (30 mg daily or more) for 1-3 weeks, inhaled steroids at a higher dosage than before admission, and inhaled or nebulized β-agonists for use as necessary. 1