Airway Management in a Comatose patient

1. HKCEM College Tutorial Airway Management in a Comatose patient AUTHOR DR. LAM PUI KIN, REX OCT 2013

2. Objectives • Recognise indications for intubation • Anticipate difficult airway • Preparation for RSI • Procedure of RSI • How to handle if you fail to intubate

3. Triage • M/34 • presented to ED 2 hours post-ingestion of 20 tablets of psychiatric drug • GCS 8 • BP 149/91 P146 • RR 20/min • Temp 37.3°C Triage Category I

4. How would you manage him? How would you manage his airway? Start with ABC

5. Protection of airway GCS only 8 Lavage may be needed Prevent aspiration Other common indications Airway obstruction Respiratory Failure Adjuncts to therapy Provide hyperventilation Reduce work of breathing (e.g. decompensated shock) Situational need Indications for intubation Other general indications for intubating a patient

6. Why rapid sequence intubation (RSI) ? • Rapidly create controlled clinical environment for ETI • Reduce stimulation of potentially harmful autonomic reflexes associated with ETI • Reduce risk of aspiration Any absolute contraindication? No … However

7. Relative contraindications to RSI • Operator concern that both intubation and mask ventilation may not be successful • Major laryngeal trauma • Upper airway obstruction • Distorted facial or airway anatomy predict difficult airway before initiation of paralytic agent to prevent the situation of cannot ventilate and cannot intubate (CVCI)

8. Clinical Assessment before RSI • AMPLEhistory: Allergies Medication Past history Last meal Event- trauma, increased ICP, asthma • Neurological assessment before RSI

9. LEMON LAW • Look externally • Evaluate the 3-3-2 rule • Mallampati score • Obstruction • Neck mobility

10. MOANS – mnemonic for difficult BVM • Mask seal beards, facial trauma • Obesity/obstruction BMI > 26, airway obstruction, obstetric patients • Age > 55 yrs • No teeth • Stiffness Increase airway resistance (asthma, COPD), stiff lungs (pulmonary edema)

11. RSI is decided for this patient How do you prepare for RSI? Drugs Personnel Equipment

12. Personnel • A team effort • Junior doctor should be covered by a senior who is well versed in RSI • Help from an on-call anesthetist should be available when needed

13. Equipment – LAST SOB Not to forget! Full PPE in high risk cases • L Laryngoscope • A Airway • S Suction • T Tracheal tube • S Stylet, syringe • O Oxygen, Oximeter • B Bag, eosphageal bulb, bougie Do you know where is the difficult airway kit in your ED ? Do you know what is inside?

14. Drugs • Premedications • prevent bradycardia • prevent raised ICP • prevent bronchospasm • Induction agent • Muscle relaxant • Consider sedation and long acting muscle relaxant after RSI Now, take us through the steps of RSI.

15. The Seven Ps of RSI • Preparation zero minus 10 min • Pre-oxygenation zero minus 5 min • Premedication zero minus 3 min • Paralysis with induction zero • Protection and position 20 to 30 seconds (after succinylcholine) • Placement with proof 45 seconds (after succinylcholine) • Post-intubation management 1 min

16. How do you pre-oxygenate? • IPPV? • Any problems? IPPV will blow up stomach and increase risk of aspiration. If time allows, spontaneous respiration is better.

17. Pre Oxygenation + Monitoring • to wash out nitrogen from lung • High conc O2 mask (near 100%) x 5 minutes (SR) • Near 100% O2 x 4 max breath over 30 s (IPPV) • especially important in patient with  FRC • obese • distended abd • pregnancy Benumof JL et al. Anesthesiology 1997;87:979

18. Premedication – “LOAD” Lignocaine 1 - 1.5mg/kg • Mitigate bronchospasm in severe asthma • Blunt ICP rise • Controversial Opioids - Fentanyl 1-2 mcg/kg • Blunt sympathetic discharge and ICP rise • E.g. raised ICP, aortic dissection, ruptured aortic aneursym, IHD

19. Premedication – “LOAD” Atropine 0.02 mg/kg (min 0.1mg) • To prevent bradycardia (sux used in a child) Defasciculation (rarely done in ED) • Non-depolarising relaxant • 1/10 of paralysing dose

20. What induction agent would you use? • Why? • Dosage? • Adverse effects?

21. Induction Agents

22. How do you perform cricoid pressure?

23. Cricoid pressure • Prevent aspiration of stomach content • also prevent insufflation of stomach if IPPV is needed • Apply till ETT position confirmed

24. Cricoid pressure • Around 10 pounds of force over cricoid cartilage • force enough to • stop swallowing • indent a ping-pong • cause pain over nose bridge

25. Which muscle relaxant to use? • Why? • Dosage? • Adverse effects?

26. Muscle relaxants

27. What are the side effects of sux?

28. Side effects of sux • CVS • bradycardia, junctional, sinus arrest • tachycardia (gangionic stimulation) • Increase in ICP, IOP, IGP • Trismus (patient with myoclonus) • Myalgia • Histamine release

29. Side effects of sux • Hyperkalemia • normal increase 0.5 mmol/L • massive release in • burn (day 3 till to 1 yr after healing) • massive trauma (day 3 to 3 months) • neuromuscular-disorders: CVA, cord injury, tetanus (day 5 - 6 months) • muscular dystrophy • Malignant hyperthermia

30. Sux-- Phase II block • Prolonged NMB resembling those of non-depolarising agents • Occurs with intermittent/infusion of sux • Lower pseudocholinesterase level • Hepatic dx, uremia, severe malnutrition, pregnancy, congenital • Myasthenia gravis • partially reversed by anticholinesterase

31. How to assist the intubator in visualization of cord?

32. Optimal E xternal Laryngeal Manipulation Operator manipulates and obtains view of larynx, then asks assistant to hold B ackward U pward Right ward P ressure Assistant performs BURP for operator OELM vs BURP(optimal external laryngeal manipulation)(backward upward rightward pressure)

33. Cormack-Lehane system

34. How do you confirm tube position? Primary Secondary

35. Confirming Tube Position Esophageal Intubation (EDD) • Aspiration test • Self-inflating bulb • ETCO2

36. Monitor patient • Make sure tube is fixed securely • monitor patient • pulse oximeter • end tidal CO2 • BP/P

37. Look at this CXR What is the problem? Remember DOPE when anything goes wrong Right Main Bronchus Intubation

38. Post-intubation management • Bite block • Maintenance of sedation and NMB • Midazolam 0.05 – 0.1 mg/kg IV per dose, titrated • Recuronium 0.6 mg/kg IV of vecuronium 0.1 mg/kg IV as • Beaware of under-sedation with concomitant use of NMB • Consider titrating dose of morphine 0.025-0.05 mg/kg • Continuous monitoring • Reassess tube position after transfer

39. What if you fail to intubate? • Reoxygenate should take priority over repeated DL attempts • Ventilate with BVM • Evaluate cause of failure • Positioning? Equipment? Inadequate muscle relaxation? etc • Call for help from seniors +/- anaesthetist • Consider alternatives (Plan B & C) • Consider needle & surgical cricothyroidotomy

40. Repositioning

41. Gum Elastic Bougie

42. McCoy Laryngoscope

43. Supraglottic devices LMA Combitube Intubating LMA King airway

44. Videolaryngoscopes Glidescope

45. ASA Airway Management Guidelines

46. Summary We have covered: • Indications for intubation • How to assess difficult airway • How to perform RSI • How to handle if you fail to intubate

47. The end