Bronchospasm is is a reversible reflex spasm of the smooth muscle in the bronchi.
Bronchospasm is vagally mediated and caused by histamine, or one of many noxious stimuli, including cold air, inhaled irritants, and instrumentation (eg, tracheal intubation).
Bronchospasm is mediated by vagal afferents which result in an increase in cyclic guanosine monophosphate (cGMP).
It is more common in asthmatics.
- Rapidly increasing peak inspiratory pressure (plateau pressure unchanged)
- Slowly increasing wave on the capnograph
- Decreasing exhaled tidal volumes
Bronchospasm: Acute Treatment
- Supplemental Oxygen
- Inhaled β2 -agonists
- Intravenous Steroids
1) Deepen anesthetic – increase volatile anesthetic concentration
- All volatile anesthetic agents are bronchodilators
- Ketamine is the only intravenous anesthetic agent with bronchodilating properties
2) Consider alternative causes of high airway pressures eg. kinked tube, endobronchial intubation, etc.
3) Inhaled β2 -agonists – delivered to the inspiratory limb of the circuit through a meetered dose inhaler or nebulized. If the severity of bronchospasm prohibits delivery of inhaled beta agonists, consider infusions of IV agonists such as terbutaline or epinephrine.
4) Consider administering intravenous steroids