Pediatric Airway Management: Techniques and Considerations

1. Airway Management Philip Ukrainetz, MD, PGY5 Gord McNeil, MD, FRCPS Core Rounds, July 18, 2002

2. Case • 6 year old girl, MVA victim. She is stuporous, has a suspected head injury and is hypotensive. You have an IV and are giving a 20cc/kg NS bolus. What do you want to do?

3. Three indications to intubate • Failure to protect airway • Failure to oxygenate or ventilate • Anticipated course

4. Anatomy • Pediatric Airway Differences • Larger tongue • Large occiput • Anterior larynx • Larger epiglottis/floppier • Subglottic area narrowest • Less musculature • Shorter trachea • Narrower airway

5. Pediatric Pointers • Broselow tape • Avoid 2nd dose of sux • infants/children exquisitely sensitive  intractable brady/arrest • Pierre Robin and Treacher Collins’ syndrome • Small mandibles and posteriorly fixed tongues • Down syndrome - large tongue

6. Four Types of Airways • BVM • Crash - intubate • RSI – the “8 P’s” • Difficult – no paralytic, have a backup

7. 8 Steps to a Successful RSI • RSI 8 p’s: • Preparation • Peruse • Preoxygenate • Pretreatment • Paralysis • Protection • Placement • Post intubation management

8. Basic Airway Management - 8 P’s“Prepare” – SIGMA D What do you need for intubation? • SIGMA D • S = Suction • I = Intravenous • G= Gas • M = Mask/Bag • A =airway equipment (oral airway, laryngoscope, tubes, alternative) • D= Drugs

9. “Peruse” - LEMON LAW • L = Look: face, neck, chest • E = Examine: mouth, thyromental, floor of mouth to thyroid • M = Mallampatti: huge tongue?, back of throat? • O = Obstruction: tumor, epiglottitis • N = Neck mobility: OA, RA, syndromic

10. LEMON - Look • Look • Evaluate the pt. • Obesity • Micrognathia • High arched palate • Narrow face • Short or thick neck • Neck trauma • Large tongue • Presence of facial hair • Dentures • Large teeth

11. LEMON –Evaluate 3-3-2 • Evaluate 3-3-2 • Evaluate the anatomy • 3 fingerbreadths of mouth opening • 3 fingerbreadths between front of chin and hyoid • 2 fingerbreadths from mandible to thyroid cartilage • CAN I DISPLACE TISSUE SUB-MENTALLY?

12. Mallampati score Grade 1: entire post. Pharynx, visualized to tonsillar pillars No difficulty Grade 2: hard palate, soft palate and top of uvula only No difficulty Grade 3: hard and soft palate only Moderate difficulty Grade 4: no visualization post pharynx or uvula (hard palate only Severe difficulty LEMON – Mallampati score

13. LEMON -Obstruction • Obstruction • Look for upper and lower airway obstruction • foreign body aspiration • Epiglottitis • croup • Abscesses • others: surgery,tumors, radiation

14. LEMON –Neck Mobility • Neck Mobility • Collar, RA, degenerative arthritis, history of surgery • Note: get significant movement with BVM ventilation also!!

15. “Pre-oxygenate” - no bagging • Preoxygenate (nitrogen washout) • Saturate O2 reservoir, tissues and blood • 100% NRB (70%) • 5 min healthy adult • 2.5 min children • 8 VC breaths

16. How much time do I have? • 70kg adult maintains O2 sat >90% for 8 min • From 90% - 0% = < 120 seconds • Obese adult (>120kg) desaturate to 0% in less than 3 min • 10kg child desaturate <90 in 4 min • From 90% to 0% in 45 seconds

17. Walls graph

18. “Pre- medicate” - LOAD • Lidocaine: tight heads, tight lungs • Opioid: for blunting sympathetic response (ICP, IOP, aortic dissection, aneurysm, IHD) • Atropine: children <= 10 • Defasiculate: for increased ICP

19. Lidocaine ? • Premise • Laryngoscopy and Intubation • afferent stim. in post pharynx/ larynx • increased central stim • increased ICP • stim of autonomic system • increased HR / BP • upper and lower resp. tract leading to increased airway resistance

20. Lidocaine ? • Literature (supports) • suppresses cough reflex • attenuates increase in airway resistance (from ET tube irritation) • prevents increased ICP • prevents increased IOP • decreases dysrhythmias by 30-40%

21. Lidocaine ? • Literature (?doesn’t support) • use to attenuate sympathetic response to laryngoscopy • Use: tight lungs / tight brains • 1.5mg/kg 3 min prior • Topical 4% lidocaine and ICP ????

22. Drugs to Decrease Sympathetic Response to Intubation (LOAD) • Fentanyl • high dose 5-10 ug/kg (will unequivocally block sympathetic response - hypotension, apnea , chest wall rigidity) • 1.5-3ug/kg (2 min prior) blocks increase BP but no effect on HR • Beta-blockers • will decrease sympathetic response • prob: neg ionotrope, bronchoconstriction

23. Drugs to Decrease Sympathetic Response to Intubation • Helfman et al • compared 200 lido, 200 fentanyl, 150 esmolol • esmolol only reliably agent in preventing rise in HR and BP • Chung et al • combination esmolol and fentanyl (2ug/kg and 2mg/kg) best combo with limited side-effects

24. LOAD - Atropine • Use with SUX in children under the age of 8 and when giving repeat doses • Sinus brady, junctional, sinus arrest usually after a second dose • Reason: Sch mimicks action of Ach at the cardic muscarinic receptors • Dose 0.02mg/kg (no less than 0.1mg), 3 min prior to induction

25. LOAD - Atropine • Literature • Prevents brady in children • Reduces BUT doesn’t eliminate them in infants • No effect on older children • Anesthesia literature: volatile anesthetics in combination with atropine - increased risk of arrhythmias • Bottomline: Use atropine on children in the ED

26. Defasiculation • Decrease the rise in ICP from Sch induced fasciculation (animal data, limited human) • Does not attenuate the sympathetic response to intubation • Does not attenuate the increase in airway resistance with intubation • 1/10 intubating dose

27. RSI in Adults With Elevated Intracranial Pressure: A Survey of EmergencyMedicine Residency Programs • Am J Emerg Med :1995 • 100 programs surveyed • 67 responses, 65 used RSI in their programs!!! • Top NMB agents – Sux and vecuronium • Top induction agents - midazolam and thiopental • Lidocaine - was routine • Fentanyl - other pretreatment agent • Defasciculating dose used by most programs

28. “Paralysis with induction” • Rapid sequence - “intubation before aspiration” • Do not titrate • Midazolam, ketamine or thiopental • Succinylcholine

29. Case • A 6 year old has been seizing for 30 minutes and you have a vial of etomidate in your hand - should you use it?

30. Etomidate • Ultrashort acting non-barbiturate hypnotic agent (no analgesic effects) • Adv: • rapid onset and rapid recovery • hemodynamic stability • minimal resp depression • cerebral protection • Induction Dose: 0.3 mg/kg

31. Etomidate • Onset : one arm-brain circulation (within 1 min) • Duration : 3-5 min • Cerebral • decreases CBF by 35% - decr ICP • no change MAP • CPP increases (increased cerebral oxygen/demand ratio) - decr ICP

32. Etomidate • Resp • minimal effects • doesn’t release histamine • CV • no change in HR/ MAP/ CI/ PAWP • Endocrine • concern re: steroid depression

33. Etomidate • Dose dependant reversible inhibition of 11-beta- hydroxylase (converts 11-deoxycortisol to cortisol) • Studies: • transient drop in cortisol levels with induction of anesthesia (6hrs), back to normal in 20 hrs • no reported adverse outcomes

34. Etomidate • CI: < 10, known seizure disorder, pregnant • Adverse effects • nausea and vomiting (30-40%) • pain on injection (similar to propofol) • myoclonic movement • Pregnancy category C • embryocidal in rats

35. Case • A brittle asthmatic comes in obtunded and has a silent chest - you needed to intubate him yesterday? • What inductionagent shall you use?

36. Ketamine • Phencyclidine derivative (similar to Angel Dust) • Dissociative anesthetic (dissociation between the thalmus and limbic system) • Sympathomimetic (increased HR and BP) • Increases cerebral blood flow by 60% potentially elevating ICP! • Reduces airway resistance • Dose 1-2mg/kg IV, 4-5mg/kg IM • Onset: within 60s

37. Case • Head injured, hemodynamically stable 34 year old. Needs to be intubated what will you pre-medicate with and what is currently your induction agent of choice?

38. Thiopental • Barbituate, potentiates GABA • Cerebroprotective • Dose related potent venodilator and myocardial and resp depressant • Adult 1-4 mg/kg, child 1- 6 mg/kg • Onset 15 - 30 secs, duration 3- 5 min • Do not use in hypotension

39. Case • One hour ago a zoo keeper was welding in the elephant cage when the elephant panicked, sat on him, and they were both burnt severely. The patient has been crushed, paralyzed, head injured, has an open globe injury, but manages to squeak out that he had a stroke 4 days ago. You cannot get an IV - can you use succinylcholine?

40. Succinylcholine CI • History of MH • Burns > 24 hrs old until healed • Muscle damage (crush) > 7 days - completely healed • Spinal cord injury, stroke (denervation UMN, LMN) > 7 days - 6 months • Neuromuscular disease, myopathies: indefinately as long as disease is active • Intra-abdominal sepsis > 7 days - resolution of infection

41. Succinylcholine • Depolarizing NM agent • Onset: 30-45s • Duration: 5-10 min • Dosage (IV): • 1-1.5mg/kg adult • 2mg/kg child • 3mg/kg neonate • Can give IM at twice the dose

42. Succinylcholine • Side-effects? • Incr IOP, ICP • Bradycardia • Trismus-masseter muscle spasm • Fasciculations • Malignant Hyperthermia • Hyperkalemia • Prolonged blockade

43. Sux - Hyperkalemia • Literature • Case reports since 1960’s • No case reports of hyperkalemia in the ED (multiple trauma, burns, neurological disease) • Literature poor with chronic renal failure • Zink et al • 100 pts (no risk factors) • Max increase 1.0 meq/L (K increased in 46pts, dropped in 46 pts and unchanged in 8) • 1 pt found to be in a wheelchair!, K dropped from 4.6 to 4.1

44. Sux - Hyperkalemia • Mechanism: ? Increased receptor density (extra-junctional), more sensitive, depolarize for long periods, release of K • ? Increased K of approx 0.5 meq/L • Risk factors/guidelines : • Burn victims >24hrs to 1-2 yrs post healing? • Crush injuries >7 days post lasting up to 60-90 days • Spinal cord injury/ stroke (denervation injury) >7 days to 6 months • Neuromuscular disorders (MS, ALS) indefinitely

45. Sux - Hyperkalemia • Conclusion • Non high risk pts • No problems with administration • High risk pts • CRF probably okay • Others : literature is not great but we have good NDNM blockers, therefore no point to take risk

46. Sux – Raised IOP • Thought to be a contraindication to an open globe injury! • Pressure elevations do occur, are transient, maximal for 2-4 min post administration • Pressure elevations of 3-8mmHg (never been shown to worsen globe injury • Comparison: normal blink – increases IOP by 10-15mmHg, forceful closure of the eyelid >70 mmHg • Anesthesia continues to use Sux in OR with globe injuries • Chiu et al: • if you want to prevent increase in IOP, can give defasciculating dose of a NDNM blocker (rocuronium 2 min pre RSI)

47. Case • During the G8 summit a cocaine addict comes in SLUDGING. Is it safe to use succinylcholine?

48. Sux – Prolonged blockade • Pseudocholinesterase Deficiency • Congenital • Heterozygous : up to 25 min, homozygous up to 5 hrs after a single dose • Homozygous : 1 in 3000 pts • Acquired • Organophosphate poisoning • Cocaine use • CRF, severe liver disease, hypothyroidism,malnutrition, pregnancy, cytotoxic drugs, metoclopramide, bambuturol(long acting beta 2 anonist) • Note: above none have prolonged blockade over 20-25 min

49. Sux – Trismus/Masseter muscle Spasm • Occasionally can get spasm • Especially in children • Transient • If prolonged, severe and other muscle involved should think of MH

50. Malignant Hyperthermia • Genetic skeletal muscle membrane abnormality - never been an ED case reported • Onset acute or delayed - 60% mortality • Clinically • Muscle rigidity • Autonomic instability • Hypoxia • Hypotension • Hyperkalemia • Lactic acidosis • Temp. elevation is a late sign