Seppelt joins to dots on the big picture of neuro-critical airway management.

1. The Neurocritical Airway
Dr Ian Seppelt FANZCA FCICM
Dept of Intensive Care Medicine, Nepean
Hospital,
and George Institute for Global Health,
University of Sydney and
Neuroanaesthesia Division, Dept of
Anaesthesia,
Macquarie University

2. What might scare you?
1. Airway management with a broken neck
2. Airway management in acute SAH

6. Basic Principles
•
Stick to what you are used to and are good at
– Most experienced person available
•
Assess the airway properly first
•
Have Plan A, B and C prepared, articulated
and thought through
•
It is (almost) impossible to intubate with a
correctly fitting cervical collar
•
Consider what ‘neutral’ position means
– Get position right first [in sex, real estate and
anaesthesia]

7. Any history? MNO
Medic Alert/ Notes/ Old Trache
Predict Difficult Ventilation - BONES
Beard Obese No Teeth
Elderly Snores
Predict Difficult Laryngoscopy – Four Ds
Distortion Dentition
Disproportion Dysmobility
Airway Assessment

9. Plan A:
Initial tracheal
intubation plan
Plan B:
Secondary tracheal
intubation plan
Plan C:
Maintenance of
oxygenation, ventilation,
postponement of
surgery and awakening
Plan D:
Rescue techniques
for "can't intubate,
can't ventilate" situation
Direct laryngoscopy
failed intubation
succeed
succeed
succeed
Tracheal intubation
ILMATM
or LMATM
failed oxygenation
failed oxygenation
Revert to face mask
Oxygenate & ventilate
LMATM
increasing hypoxaemia
or
fail
Cannula
cricothyroidotomy
Surgical
cricothyroidotomy
improved
oxygenation
Awaken patient
Confirm - then
fibreoptic tracheal
intubation through
ILMATM
or LMATM
Postpone surgery
Awaken patient
failed intubation
http://www.das.uk.com

10. Unanticipated difficult tracheal intubation - during rapid sequence
induction of anaestheia in non-obstetric adult patient
failed intubation
Tracheal intubation
Direct
laryngoscopy
Any
problems
Call
for help
Plan A: Initial tracheal intubation plan
Plan B not appropriate for this scenario
failed oxygenation
(e.g. SpO2 < 90% with FiO2 1.0) via face mask
Pre-oxygenate
Cricoid force: 10N awake 30N anaesthetised
Direct laryngoscopy - check:
Neck flexion and head extension
Laryngoscopy technique and vector
External laryngeal manipulation -
by laryngoscopist
Vocal cords open and immobile
If poor view:
Reduce cricoid force
Introducer (bougie) - seek clicks or hold-up
and/or Alternative laryngoscope
Use face mask, oxygenate and ventilate
1 or 2 person mask technique
(with oral ± nasal airway)
Consider reducing cricoid force if
ventilation difficult
LMATM
Reduce cricoid force during insertion
Oxygenate and ventilate
failed ventilation and oxygenation
Plan D: Rescue techniques for
"can't intubate, can't ventilate" situation
Difficult Airway Society Guidelines Flow-chart 2004 (use wit h DAS guidelines paper)
Not more than 3
attempts, maintaining:
(1) oxygenation with
face mask
(2) cricoid pressure and
(3) anaesthesia
Maintain
30N cricoid
force
Verify tracheal intubation
(1) Visual, if possible
(2) Capnograph
(3) Oesophageal detector
"If in doubt, take it out"
Postpone surgery
and awaken patient if possible
or continue anaesthesia with
LMATM
or ProSeal LMATM
-
if condition immediately
life-threatening
Plan C: Maintenance of
oxygenation, ventilation,
postponement of
surgery and awakening
succeed
succeed
succeed
http://www.das.uk.com

11. Neutral position

12. Hyperextension

13. Hyperflexion

14. Morbidly Obese - Intubation
Morbidly obese patient, head on one pillow
(Anesthesia for Obstetrics, 3rd Ed, Sol M Shnider)

15. Same patient with shoulders and occiput elevated - can now
assume the “sniffing the morning air” position
(Anesthesia for Obstetrics, 3rd Ed, Sol M Shnider)
Morbidly Obese - Intubation

17. Incidence of cervical injury
•
Between 1 and 3% of pts admitted with
blunt trauma have a cervical fracture
– 20% are missed on lateral C/Spine
– 7% missed on trauma series
Baltimore Shock Trauma Database
•
SCIWORA
•
Ligamentous injury, esp transverse
ligament of dens, < 1:1000 incidence

18. No neurological sequelae …

19. Anaesthetic implications
•
Cervical spine is either definitively cleared
or it is not
•
If intubation or surgery is urgent then by
definition the neck is not clear
– Treat as if unstable cervical spine
– No well documented case of new spinal cord
injury after properly conducted trauma
intubation
– Large forces required to cause damage

20. Approach
•
Neutral position, remove collar
•
Manual in-line stabilisation
•
Pre-oxygenate
•
Drugs: thiopentone or (careful) propofol
•
NMBAs: suxamethonium or rocuronium
– Sugammadex available if using aminosteroids
•
Place of videolaryngoscopy
– Magrath Mac or Storz C-MAC [choice of Mac and
D blades]

21. Are nasal tubes an option?

24. The facts
•
3 reported cases of nasocranial intubation
– 2 uncontrolled tubes in acute trauma
Horellou et al, Anaesthesia, 1978, 33:73
Marlow et al, J Emerg Med, 1997, 15:187
– 1 routine neonatal intubation
Cameron, Arch Dis Child, 1993, 69:79
•
Inexperienced operators, unusual
circumstances

25. Planned maxillofacial surgery?
Goodisson, Shaw and Snape, Intracranial intubation in
patients with maxillofacial injuries associated with base of
skull fractures, J Trauma, 2001, 50:363
– Nasotracheal tubes are safe in absence of midline
anterior skull base fracture
– Even in these, gentle intubation over a bronchoscope
or bougie is safe in skilled hands
– Tracheostomy rarely required

26. •
(Awake) Blind nasal intubation
•
(Awake) Fibreoptic intubation
•
Retrograde intubation
•
Emergency or elective surgical airway
Other options?

28. Guiding ETT into the
nasopharynx
•
Do not use force (firm but gentle pressure)
•
Cephalad distraction of the tube
•
Rotation / Malleable introducers
•
Suction catheter brought out of the mouth

29. Retrograde intubation

31. ILMA
1
ILMA (Fastrach)
Easy insertion
No neck
movement
Tube insertion
easy
Airway
protected by
cuffed ETT

35. Principles of airway management
1. Secure definitive airway
2. Avoid hypoxia and hypotension
3. Avoid hypertensive response to
laryngoscopy
4. Basically, just keep the BP where it is,
okay (+/- 10%) ……

36. Preparation
•
Assessment, plans A,B,C,D
•
Some degree of hypertension is normal
physiological autoregulation
– Hypotension = brain ischaemia
•
Arterial line pre-induction if possible

37. Rebleeding
•
Unsecured aneurysms:
– 4% rebleed on day 0
– then 1.5%/day for next 13 days [ 27% for 2 weeks]
•
Not on my shift ….
•
Be ready to actively manage hypotension
AND hypertension
– SNP infusion, esmolol
– Nimodipine
– Noradrenaline infusion

39. BP in unsecured aneurysms

40. Choice of drugs for intubation
•
Pretreatment – lignocaine IV or tracheal?
•
Opioids – fentanyl, or remifentanil infusion
•
Induction agent – thiopentone or propofol or
ketamine
– Ketamine??? Are you serious??
•
Neuromuscular blocker – sux vs aminosteroid
•
Subsequent sedation – drugs that will wear off
– Neurological examination
– Propofol, remifentanil

41. Lignocaine pretreatment
•
Controversial – used to prevent BP and
ICP rises due to coughing and straining.
•
Contradictory evidence for neuroprotection
in cardiac surgery
•
Some evidence for neuroprotection in
decompression illness
Do the risks outweight the benefits?

42. Lignocaine in cardiac surgery

43. •
Answer: don’t know
•
Pro argument:
– Probably safe and possibly beneficial
•
Con argument:
– Evidence of hypotension lasting several
minutes
– Time-course to effect
– 1.5 – 2.0 mg/kg probably insufficient anyway
Lignocaine for neuroprotection
in TBI and SAH

44. Ketamine and ICP
•
Small series from 1970s suggest elevated ICP
•
More recent data contradicts this
•
Weak evidence of neuroprotection
But thiopentone and propofol have clear
evidence of neuroprotection

45. Harm from oversedation
•
‘Neuroemergency’ patients are best managed
with minimal sedation allowing clinical
examination
– After immediate resuscitation and stabilisation
phase complete
– Midazolam and esp ‘Morphazolam’ or
‘Fentazolam’ saturate fat stores and have very
long elimination times
– Adverse neurosychological effects of BZDs
– Propofol and remifentanil unique with
extrahepatic clearance and short T1/2cs

47. Summary
Airway management in neuroemergencies
1.Don’t panic
2.Proper assessment – right time, right place, right
people?
3.No clear indication for ‘neuroprotectants’
4.Maintain cerebral perfusion and keep BP close to
baseline
5.Do what you are good at.

49. seppelt@med.usyd.edu.au
Questions
?