Sedation and Paralysis in Asthmatic Patients
Sedation is absolutely contraindicated in asthmatic patients, particularly those with acute severe or life-threatening asthma, as it can cause respiratory depression and death. 1, 2, 3
Critical Contraindication
The British Thoracic Society explicitly states that "any sedation is contraindicated" in the management of acute asthma. 1 This is a firm, non-negotiable guideline that applies across all severity levels of acute asthma exacerbations. The rationale is straightforward: sedatives suppress respiratory drive, mask deteriorating clinical status, and can precipitate respiratory arrest in patients whose respiratory mechanics are already compromised. 2, 3
When Intubation and Paralysis Are Necessary
If a patient requires intubation, do not attempt it until the most expert available doctor (ideally an anaesthetist) is present. 1
Indications for mechanical ventilation include:
- Worsening hypoxia or hypercapnia (PaCO₂ >6 kPa) 1
- Drowsiness, confusion, or unconsciousness 1
- Exhaustion with feeble respiration 1
- Coma or respiratory arrest 1
Critical procedural points:
- Call the intensive care anaesthetist immediately for unconscious or confused patients 1
- Maintain uninterrupted high-flow oxygen administration 1
- Intubation should ideally be performed by an anaesthetist, as this is a high-risk procedure in asthmatics 1
The Rare Exception: Severe Agitation
There is emerging evidence for intranasal dexmedetomidine in pediatric patients with acute asthma who present with severe, treatment-interfering agitation. 4 Dexmedetomidine is unique among sedatives because it has minimal effect on respiratory function and does not suppress respiratory drive. 4 However, this represents a highly specialized intervention for a specific clinical scenario (severe agitation preventing treatment delivery) and should only be considered by experienced clinicians in monitored settings. 4
Common Pitfalls to Avoid
Never use benzodiazepines (midazolam, lorazepam, diazepam) in acute asthma, despite their common use in other emergency settings. 2, 3, 5 While one study showed midazolam was safe in mild-to-moderate asthmatics undergoing elective dental procedures, 6 this does NOT apply to acute exacerbations where respiratory reserve is compromised.
Do not use propofol, thiopentone, or other general anesthetics outside of controlled intubation by an anesthesiologist. 7 These agents reduce oxygen consumption but also suppress respiratory drive. 7
Avoid opioids (fentanyl, morphine) as they can increase CO₂ retention and worsen bronchospasm. 7
Alternative Management Strategy
Instead of sedation, address the underlying causes of agitation or anxiety:
- Optimize bronchodilator therapy: Nebulized salbutamol 5 mg or terbutaline 10 mg every 15-30 minutes 2
- Administer systemic corticosteroids: Prednisolone 30-60 mg orally or hydrocortisone 200 mg IV every 6 hours 1, 2
- Ensure adequate oxygenation: High-flow oxygen via face mask to maintain SpO₂ >92% 2
- Provide reassurance and positioning: Sitting upright reduces work of breathing 8
The anxiety and agitation often seen in acute asthma typically resolve once bronchodilation and oxygenation improve. 5, 8 Treating the underlying asthma is the definitive management for associated anxiety, not sedation. 5