Airway management - throat surgery

 

Airway options:

1.ETT

Contraindicated if posterior vocal cord lesion

·     Normal

·     RAE

·     MLT

·     Laser

2.Jet

Frequency:

·     High (Monsoon) – 150/min, 1.5atm

·     Low (Manujet) – 6-8/min, 4atm

Location:

·     Supraglottic (surgeon’s rigid bronch)

·     Transglottic (Hansaker, LaserJet)

·     Infraglottic (Ravussin)

3.HFNP

·     Spont vent (“STRIVE Hi”) – ok if lasering but novel technique

·     Apnoea (“THRIVE”) – contraindicated if lasering

4.Trachie

·     Surgeon’s decision

 

Airway timing:

Awake

·     VL

·     FOI

·     Trachie

Anaesthetised

·     Anything

 

Airway assessment:

Questions

Type:

o  Surgeon’s needs: tube-free? Oxygen-free?

o  Anaesthetist’s needs: Protection? Ventilation? Oxygenation?

Timing:

o  Will airway procedures will be difficult?

o  Any red flags? (infection, swelling, cancer, radioTx, trauma, congenital)

Source

·     Patient

·     Surgeon

·     Notes

History

·     HOPC: dyspnoea, postural symptoms, exercise tolerance, *time course*

·     Medical Hx: resp disease, CVS disease

·     Anaes Hx: prev BMV, LMA, laryngoscopy

·     Fasting status

Examination

Everything else:

·     General inspection: body habitus, WOB, colour, stridor

·     Vital signs

·     Resp

·     CVS

Airway procedures:

·     Difficult BMV: ↑age, no teeth, beard, obese, stiff jaw

·     Difficult LMA: small mouth

·     Difficult ETT: ↑MP, ↓TMD, ↓MO, ↓neck ROM, obesity

·     Difficult FONA: obesity

Investigations

·     Airway: nasendoscopy (bedside), CT neck

·     Breathing: spirometry

 

Use of HFNP:

Spont vent

Airway:

·     FiO2: 1.0 at induction, 0.3 if lasering

·     Flow rate: 50L/min awake, 70L/min upon LOC

·     Laryngoscopy + topicalization (Cophenylcaine forte) at 5mcg/mL

·     Suspension laryngoscopy at 6.5mcg/mL

·     LMA inserted upon completion

Drugs:

·     Propofol Cpt: start 2mcg/mL, ↑by 0.5-1 “Cp – Ce = 1”) – 15-20 mins
(would like to try ↑0.5mcg/mL q1 min – duration 8 mins)

·     Remifentanil 0.01-0.05mcg/kg/min

·     Metaraminol infusion PRN

Apnoea

Airway:

·     FiO2 1.0 throughout

·     Flow rate: 50L/min awake, 70L/min upon LOC

·     Paralysis -> apnoea

Drugs:

·     Propofol

·     Remifentanil

·     Metaraminol

·     Muscle relaxant

 

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