Microlaryngoscopy & Airway Laser

 

 

Considerations

 

  • Indication for surgery, location of airway lesion, presence of obstruction

  • Potential for dynamic airway obstruction with induction, positive pressure ventilation & paralysis:

    • Double setup with rigid bronchoscope available 

  • Shared airway with need to optimize surgical conditions/safety

  • Individualized ventilation technique (communicate with surgeon): 

    • Closed system: laser-safe ETT

    • Open system: 

      • Low-frequency jet ventilation

      • High-frequency jet ventilation

      • Spontaneous ventilation (especially pediatrics) 

    • Total IV anesthetic (TIVA)

    • Motionless surgical field

  • Complications:

    • Airway obstruction, laryngospasm 

    • Laser: airway fire, burns, venous air embolism with YAG laser (deeper), pneumothorax

    • Jet ventilation: barotrauma, abnormal ventilation/oxygenation

    • Unprotected airway & aspiration risk

 

 

Goals

 

  • Optimize surgical conditions: motionless field, no risk of combustion

  • Adequate oxygenation & ventilation, secure airway

  • Depth of anesthesia sufficient to suppress hemodynamic response

  • Clear, constant communication with surgery team

  • Good postoperative care: prone to laryngeal spasm & edema

 

 

Conflicts

 

  • Contraindication to jet ventilation & need for airway laser

  • Full stomach & laser surgery: laser ETT vs jet ventilation

 

 

Airway Management Options

 

  • Broadly classified into 1) closed system, 2) open system

  • Closed system (intubation):

    • General anesthesia with ETT (microlaryngoscopy tube or laser tube)

  • Open system (no intubation, tubeless technique):

    • Topical/local anesthesia with sedation

    • General anesthesia without intubation

      • Apnea & intermittent intubation/bag mask ventilation

      • Tubeless spontaneous ventilation technique

      • Jet ventilation with Sanders technique: supraglottic vs subglottic, via catheter/rigid scope

      • High-frequency jet ventilation

  • Considerations:

    • ETT/microlaryngoscopy tube:  risk of airway fire & obstructs surgeon's visualization

    • Jet ventilation avoids the risk of ETT complications (kinked, obstructed, displaced, damaged, ignited)

      • Risks/complications:

        • Difficulty maintaining oxygenation/ventilation in morbid obesity, stiff thorax, restrictive/obstructive pneumopathy, lung fibrosis, reduced alveolar-capillary diffusion capacity (pulmonary edema)

        • Risk of dynamic hyperinflation if obstructed airway with barotrauma (subcutaneous emphysema, pneumothorax/pneumomediastinum, tracheobronchial injury), hypoxemia, hypercarbia/hypocarbia, gastric distension & regurgitation due to scope malalignment, possible vocal cord motion if supraglottic, drying of laryngeal mucosa, distal spread of particulate matter with potential tracheobronchial viral or tumor seeding

 

 

Safety Precautions

 

  • Locked doors, signs on doors 

  • N95 mask for everyone if risk of viral particles 

  • Eye protection for patient & personnel 

  • Fire safety equipment (laser tube with methylene blue & saline into cuff/saline for extinguishing fire) 

  • Difficult airway equipment 

  • ENT surgeon present with rigid bronchoscopy 

Further Reading 

  • Patel, A. Ch 70: Anesthesia for Otolaryngologic and Head-Neck Surgery. In Miller's Anesthesia, 2-Volume Set 2210-2235 (Elsevier, 2020)