Difficult airway

a budding anaesthetist out here to help my juniors anf fellow anaesthetists

1. DIFFICULT AIRWAY PREPARATION Dr ASHISH NAIR MD ANAESTHESIA

2. What is Difficult Airway? Clinical Situation in which conventionally trained anaesthesiologist experiences difficulty in Mask ventilation Tracheal intubation Placement of supraglottic airway device(SAD) Creating Surgical airway

3. DIFFICULT TO MASK VENTILATE PATIENTS Definition: A situation in which it is not possible for the unassisted anaesthesiologist to maintain SPO2 >90 % using 100 % O2 and positive pressure mask ventilation in a patient whose SPO2 was 90% before anaesthetic intervention.

4. Difficult Bag Mask Ventilation(BMV) B earded individual O besity N o teeth E lderly S norer

5. SIGNS OF INADEQUATE MASK VENTILATION: Absent or inadequate chest movement Absent breath sounds Gastric insufflation Decreasing oxygen saturation Absent or inadequate ETCO2

6. What is Difficult Intubation? Conventionally trained anaesthesiologist needs more than 3 attempts 10 minutes for a successful tracheal intubation Best attempt at laryngoscopy – Laryngoscopy performed with patient in optimal sniff position having no significant muscle tone and laryngoscopist has an option of change of blade type and length

7. Difficult placement of SAD Predictors of difficult placement /subsequent ventilation with SAD R estricted mouth opening O bstructions of the Upper airway D isrupted upper airway following trauma, burns etc S tiff lung

8. Difficult Surgical airway access Presence of any of following factors predict difficulty in performing surgical airway – cricothyrotomy or tracheostomy B leeding tendency inherent or as a result of anticoagulants A gitated patient N eck scarring,neck flexion deformity G rowth or vascular abnormalities in the region of surgical airway

9. AIRWAY ASSESSMENT WHY TO ASSESS ?? Optimal patient preparation Proper selection of equipments and techniques Participation of personnel experienced in the difficult airway management .

10. HISTORY Difficult intubation Airway trauma Broken tooth Airway surgery Radiation Burns Tumor Joint pathology(Rheumatoid arthritis,TMJ ). Cervical spine pathology. Difficulty in positioning the patient for laryngoscopy ( Ankylosing spondylitis ). Congenital syndromes & facial dysmorphism .

11. EXAMINATION c.

12. PHYSICAL EXAMINATION 1.MOUTH OPENING: Inter- incisor distance should be 5 cm or more ( > 3 fingers) in adults. For easy insertion of 3cm deep flange of laryngoscope blade. <3 cm:Difficult laryngoscopy <2cm:Difficult LMA insertion.

13. EXAMINATION 2.MALLAMPATTI CLASSIFICATION: Frequently performed. To examine the size of tongue in relation to the oral cavity. Describes the re lationship between mouth opening, tongue size and pharyngeal space. More the tongue obstruct the view of pharyngeal structures, more difficult the intubation will be.

14. Samsoon & Youngs modified MP Grading Test for assessing the adequacy of oropharynx for laryngoscopy . MP GRADE I : Faucial pillars, uvula,soft and hard palate are visible. MP GRADE II : uvula ,soft and hard palate are visible MP GRADE III : Base of uvula or none, soft and hard palate are visible MP GRADE IV : Only hard palate is visible.

15. EXAMINATION MP grade 0(zero) : when epiglottis is visualized during examination of oropharynx.

16. EXAMINATION 3. ASSESSMENT OF MANDIBULAR SPACE : Thyromental distance Hyomental distance Sternomental distance

17. EXAMINATION a) THYROMENTAL DISTANCE : Measured by Patil's test. Distance between mentum and thyroid notch. Ideally done with neck fully extended. Helps determine how readily laryngeal axis will fall in line with pharyngeal axis. >6.5 cm ( > 3 finger bridth ) - normal 6- 6.5 cm - less difficult airway < 6 cm - difficult airway

18. EXAMINATION b) HYOMENTAL DISTANCE : Distance between mentum and hyoid bone. GRADE I : > 6 cm GRADE II : 4-6 cm GRADE III : <4 cm GRADE III associated with difficult laryngoscopy & intubation.

19. EXAMINATION C) STERNOMENTAL DISTANCE : Assessed by SAVVA test. Distance between mentum and sternal notch > 12.5 cm is normal. < 12.0 cm associated with difficult intubation. Measured when neck is fully extended and mouth closed.

20. COOKS MODIFIED CORMACK-LEHANS CLASSIFICATION Class I : Visualisation of entire vocal cords Class II a : Visualization of posterior part of vocal cord. Class II b:Visualisation of arytenoids only. Class III a : Epiglottis liftable Class III b:Epiglottis adherent or only tip visible. Class IV : No glottic structures seen

21. EXAMINATION 4. TEMPOROMANDIBULAR JOINT Put the middle finger of each hand inferior and posterior to patient's earlobe. Place the index finger just anterior to tragus. Instruct the patient to open mouth widely. TWO distinct movement should be felt : The first is rotational The second is advancement of condylar head . If presence of clicks or crepitus , suggest TMJ dysfunction.

22. EXAMINATION 5) NOSE & ORAL CAVITY Deformities of nose Patency of nostrils Macroglossia High arched palate/ cleft palate Micrognathia / retrognathia Large central incisors , edentulous,loose or poor dentition

23. 6.HEAD AND NECK EXAMINATION: Neck circumference > 40 cm predicts 5% difficult intubation > 60 cm predicts 35% difficult intubation. Laryngoscopic view becomes easier when neck is flexed on chest by 25-35̊ and atlanto occipital joint extended by 85̊- Magills sniffing position. Assess flexion by asking the patient to touch his manubrium sternii with his chin, this assures flexion of 25-35̊ Extension assessed by asking the patient to look at ceiling without raising eyebrows.

24. MAGILLS SNIFFING POSITION A- Neutral head position: OA, PA and LA are at greater angle. B- Pillow under head - flexing lower cervical spine and aligning PA and LA C- Head has been extended over cervical spine aligning OA, PA and LA and creating optimum “SNIFFING “ position.

25. LEMON scoring system L : Look externally E : Evaluate 3-3-2-1 rule M : Mallampati score O : Obstruction N : Neck mobility

26. LEMON scoring system EVALUATE 3-3-2-1 RULE : Mouth opening : < 3 fingers Hyo -mental distance : < 3 fingers Thyro -mental distance : < 2 fingers Lower jaw anterior subluxation : < 1 finger

27. Concerns of Unanticipated DA Expert help may not be available Special equipment non availability General anesthesia and long acting muscle relaxant may have been given Backup airway management plan may not be thought of

28. Unanticipated difficult airway

29. DIFFICULT AIRWAY CART

30. Organisation,design & standardisation of Difficult airway trolley According to four plans of Difficult airway algorithm of DAS guidelines. Helps in improving the adherence to step wise progression to alternative airway rescue plan Immediate availability of equipments. Movable,portable storage space with 4-5 drawers Individual drawers clearly labelled Contents checked once daily, or after every use. Individual variations can be made according to local availability and requirement. Laminated charts of algorithm or printed images to be displayed on side of trolley. Familiarity with equipment It can be a cart/trolley/grab bag with essential equipments for remote locations.

31. Top of trolley Difficult airway algorithm flow chart Direct access phone numbers to ENT and anaesthesiology , icu physician Stopwatch Monitors for videolaryngoscope / fibreoptic brochoscope Side of trolley Introducers, bougie /ventilating bougie Videobronchoscope Airway exchange catheter

32. Drawer 1- (Plan A) Intubation Contents Laryngos cope handles-standard, stubby handle, Howland lock Laryngoscope blades-Macintosh sizes 3 & 4, Miller sizes 2 & 3, McCoy . Videolaryngoscope blades ETT of assorted sizes Stylet : Shroders stylet / light wand Lubrication gel Syringe 5, 10 ml Magill forceps Adhesive tape, wide and narrow Cognitive aid indicating the importance of continous waveform capnography . Printed labels “ Rocuronium ” Aspiration cannula

33. HOWLAND LOCK LIGHT WAND

34. Drawer 2- (Plan B) Oxygenation via a Supraglottic Airway Device Contents Two different types of second generation SADs(IGEL, Proseal ), sizes 3,4,5 Lubrication gel Syringe 20 ml(cuff inflation) Orogastric tubes size 12 & 14

35. Drawer 3 –(Plan C) mask ventilation Contents Neonatal facemask size 0 Facemaks - Various sizes Oropharyngeal airways – various sizes Nasopharyngeal airways – various sizes Syringe 10 ml Aspiration cannula Prepinted labels “ sugammadex ”

36. Drawer 4 –(Plan D)Emergency invasive airway access Surgical cricothyroidotomy Contents Emergency Cricothyroidotomy catheter set Endotracheal tube size 6 Scalpel blade 10

37. Drawer 5- Optional , customized equipment Specialized equipments, pertinent to specific areas of hospital Contents Equipment for management of tracheostomies Left hand laryngoscope blades: Mirror image version of macintosh blade for use with right hand Reverse configuration of the flange Used for patients with right sided facial or oropharyngeal abnormalities, when ETT should be located on left side of mouth. Combitube

38. Left handed laryngoscope Mirror image version of macintosh blade for use with right hand. Identical to the regular macintosh blade except for the reversed configuration of flange. Used for procedures in those with right sided facial abnormalities , in which ETT should be located on the left side of the mouth.

39. COMBITUBE

40. Combitube Large proximal oropharyngeal cuff inflated with 100 ml air. Distal esophageal/tracheal cuff inflated with 15 ml air. Two lumens, one opens beyond the distal cuff , while the other lumen ends between two cuffs and has 8 ventilating ports. Used for emergency airway management. Primarily used as an alternative airway device in pre hospital setup in CPR,in difficult airway. Can be inserted blindly , mostly enters esophagus (95% cases)

41. Cricothyrotomy - Needle cricothyrotomy Percutaneous cricothyrotomy Surgical cricothyrotomy Immediate preparation of FONA to be done as soon as it is declared as “CICO” Equipment-Scalpel(10), Bougie , ETT 6

42. Laryngeal Handshake

43. Needle cricothyroidotomy Equipment-14 G cannula , 5 ml syringe, saline,O2 source Laryngeal handshake Insert cannula at 45 degree while aspirating Advance cannula of trocar Remove trocar Reattach syringe to confirm aspiration Supply O2 and secure cannula

44. Ventilating with cricothyroid cannula Bag valve assembly with oxygen Modified oxygen tubing- hole near the end of oxygen tubing, connect to 50 psi oxygen source ,ventilate by intermittenly opening and closing the hole. Jet ventilation.

45. Scalpel/ Bougie Palpable membrane Transverse stab Turn blade 90 degree Slide bougie tip along blade into trachea Railroad 6mm ETT into trachea Ventilate ,inflate cuff and confirm position Secure tube

46. Pre oxygenation Pre oxygenation and face mask ventilation are primary methods to preserve oxygenation until airway is secured Pre oxygenation should be done for a min of 3 to 5 min with tidal volume breathing 8 vital capacity breaths for 60 s is more effective method Target End Tidal Oxygen>90% and End tidal nitrogen<4%

47. Positioning for intubation Best position- Sniffing position ( Flexion at the neck and extension at the atlanto occipital joint)achieved by keeping a pillow of 10 cm thickness under the head, C/I in suspected cervical spine injury. Ramped position / HELP - In obese patients sniffing position is achieved by placing blankets or towel below scapula,shoulder,neck,head until external auditory meatus and sternum are in horizontal line

48. Other Equipments 1)AMBU(Artificial manual breathing unit) Ventilating device used for resuscitation,transport,standby for non functioning of anesthesia machine 2) Functioning suction machine 3)Emergency drugs 4)Extra set of batteries. 5) Pillows and towels for positioning of patient.

49. Trans tracheal jet ventilation Used for percutaneous transtracheal ventilation (PTV) Attach jet ventilation assembly to 50 psi oxygen source with regulator so that pressure can be titrated. 14G catheter at 50 psi will deliver a gas flow of 1600 ml/s for normal compliant lung( so keep a longer expiration time). Patency of upper airway should be ensured before doing jet ventilation to avoid barotrauma . Avoid jet ventilation whenever there is doubt regarding patency and also in children < 5 years. Delivering breaths without ensuring full expiration will lead to barotrauma . Transtracheal jet ventilation is a rescue and temporary maneuver until a more secure permanent airway is established.

50. Anticipated Difficult Airway Preparation of patient, counselling , explaining procedure and risk of difficult airway. Preparation of anesthetic team, familiarity with equipments. Back up plan, senior help. Consider the merits and demerits of basic management choices- Awake intubation Vs Intubation after induction of GA Non invasive technique for initial approach to intubation Vs invasive technique. Preservation of spontaneous respiration Vs abolition of spontaneous respiration. Videoassisted laryngoscopy as an initial approach to intubation.

51. Advantages of Awake Intubation Preserves spontaneous respiration. Airway potency and tone of pharyngeal muscles maintained Options for awake intubation- Blind nasal Fibreoptic bronchoscope Retrograde intubation.

52. Premedication i ) Antisialogogues - inj. Glycopyrrolate 4mcg/kg Helps in drying of secretions & visualisation of FOB. Minimise the dilution of local anesthetic and formation of barrier between L.A & Mucosa. ii)Nasal mucosa decongestants: Vasoconstrictor like Xylometazoline Spray Widens the space and reduces risk of bleeding iii)Identify risk factors for aspiration and give aspiration prophylaxis.

53. Premedication iv)Sedatives : Dexmedetomidine , Midazolam , Fentanyl are Commonly used. Aim is to preserve spontaneous respiration Given in titrated doses Use one or two agents , not more. Patient should be co operative and also able to control their airway throughout procedure. v) Topicalisation of airway: Lignocaine 4% Nebulisation , Lignocaine with adrenaline 2% patties in nostril, lignocaine 10% spray Lignocaine dose Infiltration: Plain lignocaine 5 mg/kg. Topical:British thoracic society recommends maximum dose of 8.2 mg/kg

54. Glossopharyngeal Nerve Block Internal Approach:Bilateral glossopharyngeal nerve block - 2 ml lidocaine can be injected at base of anterior tonsillar pillar on each side.

55. Extra oral approach of Glossopharyngeal nerve block

56. Superior laryngeal nerve block Sensory supply to epiglottis, arytenoids, vocal cords Technique 1occ syringe with 6 cc 1% lidocaine attached to 23G needle,inserted until lateral most part of hyoid bone and then it is withdrawn and walked off greater cornu in inferior direction. Needle is then advanced and passed through thyrohyoid membrane(felt as slight resistance, aspirated and then 2 cc of L.A injected. Procedure is then repeated on the opposite side.

57. Transtracheal block Provides anesthesia of entire trachea between carina to vocal cord Complications- bleeding,tracheal injury and subcutaneous emphysema Technique 2-4 ml 4% lidocaine in 10 cc syringe with 23G needle Cricothyroid membrane is identified, syringe directed posteriorly perpendicular to the floor Sudden LOR felt when needle in trachea, position confirmed by aspiration of air through syringe, lidocaine injected & needle withdrawn quickly

58. Standard reporting of unanticipated difficult intubation Complete details of nature of difficulty, airway management plan & complication if any to be documented in standard format. Copy should be available in case note and should be given to patient or relative for future reference. A Standard difficult airway alert form ideally , which can be modified according to requirements of workplace. This will be useful to the doctor treating them in future.

59. CONCLUSION Examples of equipments given in DAS guidelines should serve only as guide and should not be considered as absolute recommendations. Most Important is Right equipment Right time Right place Remember to Plan, communicate, prepare and Train

60. ThankYou