Ian Seppelt: Time is Brain: The Neurocritical Airway
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Ian Seppelt: Time is Brain: The Neurocritical Airway

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

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

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Ian Seppelt: Time is Brain: The Neurocritical Airway Ian Seppelt: Time is Brain: The Neurocritical Airway Presentation Transcript

  • 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
  • What might scare you? 1. Airway management with a broken neck 2. Airway management in acute SAH
  • 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]
  • 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
  • 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
  • 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
  • Neutral position
  • Hyperextension
  • Hyperflexion
  • Morbidly Obese - Intubation Morbidly obese patient, head on one pillow (Anesthesia for Obstetrics, 3rd Ed, Sol M Shnider)
  • 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
  • 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
  • No neurological sequelae …
  • 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
  • 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]
  • Are nasal tubes an option?
  • 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
  • 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
  • • (Awake) Blind nasal intubation • (Awake) Fibreoptic intubation • Retrograde intubation • Emergency or elective surgical airway Other options?
  • 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
  • Retrograde intubation
  • ILMA 1 ILMA (Fastrach)  Easy insertion  No neck movement  Tube insertion easy  Airway protected by cuffed ETT
  • 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%) ……
  • Preparation • Assessment, plans A,B,C,D • Some degree of hypertension is normal physiological autoregulation – Hypotension = brain ischaemia • Arterial line pre-induction if possible
  • 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
  • BP in unsecured aneurysms
  • 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
  • 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?
  • Lignocaine in cardiac surgery
  • • 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
  • 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
  • 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
  • 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.
  • seppelt@med.usyd.edu.au Questions ?