The reflex, protective, spasmodic closing of the vocal chords - partially, or fully.
Most dangerous when the patient is semi-conscious, because the protective airway
reflexes are heightened, and the reflexes to re-open the vocal chords are minimal.
The patient is semi-conscious during Stage II of anaesthesia - either induction or emergence.
Caused (during light anaesthesia) by:
- Irritation (stimulation) to vocal chords by trauma or obstruction (blood etc)
- Sensitivity to a drug
- Stimulation from the laryngoscope
- Reaction to endotracheal tube insertion/removal, when in Stage II, rather than when deeply anaesthetised, or awake..
- Chest movement with stridor, but little movement of air.
- In spontaneous ventilation, little bag movement.
- Chest movement without airway noise.
- No bag movement
- Not possible to provide ventilation.
Symptoms of airway obstruction:
- Paradoxical chest/abdomen movement (see-saw) on inspiration
- Tracheal tug
- Stridor (if only partial obstruction)
- Rib retraction
The resultant hypoxia (low oxygen) and hypercapnia (high
CO2) produces an increased
respiratory effort, with noisier breathing.
Violent coughing or breath holding indicates airway obstruction, which
requires suction. At induction: laryngospasm breaks up with deeper anaesthesia.
A forceful cough may dislodge foreign material.
Terminating the laryngospasm:
Take patient out of Stage II of anaesthesia:
- Deepen anesthetic with gas or I.V. agent (eg Propofol).
- Allow the patient to wake up - too long can result in hypoxia and cardiac arrest.
Breaking the laryngospasm:
- Stop the stimulation eg, laryngoscope.
- 100% oxygen via Mapleson C circuit, with valve partially closed.
- Jaw thrust.
- Ensure good mask seal.
- Call for help.
- Give continuous positive pressure, using reservoir bag.
- If laryngospasm persists, sedate with Propofol.
- Lignocaine IV (1mg/kg)?
Alternatively, apply pressure to the laryngospasm notch!
- Do not stimulate the vocal chords in a semi-conscious patient.
- Do not extbate in Stage II of anaesthesia.
- Extubate awake, or in a deep plane of anaesthesia.
- Clear the pharynx of secretions (suction).