Bronchospasm represents a lower airway obstruction marked by the contraction of smooth muscles, leading to heightened resistance to airflow within the bronchial tree. This condition predominantly affects patients with hyperreactive airways, such as those with asthma, bronchitis, a history of tobacco use, or those recently recovering from an upper respiratory infection (URI), often triggered by sputum or secretions present in the pulmonary tree. In patients under anesthesia, bronchospasm can be identified by a notable increase in peak airway pressures, indicative of reduced lung compliance. Clinically, it manifests as wheezing audible during both inspiration and exhalation, a decline in oxygen saturation levels, and a reduction or complete absence of exhaled carbon dioxide (ETCO2), signaling a critical need for immediate medical intervention to restore adequate ventilation and airflow.
Prevention
- Preoperative bronchodilators
- Avoid histamine-releasing drugs (morphine; muscle relaxants such as atracurium and mivacurium) and use anticholinesterase reversal agents cautiously; propofol, etomidate, and ketamine are acceptable choices
- Beware of giving dexamethasone (Decadron) to an awake patient; rapid injection causes perineal burning.
- Lidocaine pre ETT insertion
- Sevoflurane is a preferred volatile anesthetic
- Consider deep extubation
Treatment
- Give 100% oxygen
- Remove the trigger of the attack, if possible
- Administer a short-acting beta-2 agonist (e.g., albuterol; terbutaline 0.25 mg subcutaneously or intravenously)
- Use an inhaled anticholinergic (e.g., ipratropium bromide)
- Provide corticosteroids
- Deepen the anesthetic:
- Increase volatile anesthetic concentration
- Administer IV propofol
- Consider using Lidocaine IV (1.5 mg/kg)
- Use Ketamine for its bronchodilator properties
- Epinephrine dosing:
- Adult:
- 0.1 – 0.5 ml (1:1000) SQ
- 10 – 50 mcg IV slow push, titrated and repeated as needed (0.5 – 1 mg IV is reserved for cardiac arrest)
- 0.1 – 1.0 μg/kg/min IV infusion
- Pediatric:
- 0.01 mL/kg (10 μg/kg) of 1:1000 SQ or IM
- 0.01 - 0.1 μg/kg/min IV infusion
- Adult:
- *Succinylcholine is not helpful in treating bronchospasm
| Feature | Laryngospasm | Bronchospasm |
|---|---|---|
| Site | Glottic adductor contraction — cricoarytenoid, arytenoid, and the cord tensor cricothyroid; the larynx can also occlude reflexively at levels other than the true vocal cords, which is why mask positive-pressure ventilation does not reliably relieve it | Lower airway smooth muscle contraction raising resistance within the bronchial tree |
| Typical setting | Post-extubation airway obstruction; a particular concern in pediatric cases | Hyperreactive airways — asthma, bronchitis, tobacco history, recent URI — often triggered by sputum or secretions |
| Presentation | Partial spasm with some air movement, crowing or phonation, and paradoxical chest movement; complete spasm with no air movement | Wheezing on inspiration and exhalation, rising peak airway pressures, falling oxygen saturation, reduced or absent ETCO2 |
| Immediate risk | Hypoxia, negative-pressure pulmonary edema, hypoxemia, cardiac arrest | Reduced lung compliance and inadequate ventilation requiring immediate intervention |
| Succinylcholine | 0.1–0.2 mg/kg IV, or 4–5 mg/kg IM when IV access is not available | Not helpful in treating bronchospasm |
| Onset of that dose | IV within 30–60 seconds, lasting a few minutes; IM onset is rapid but slower than IV | — |
