Airway evaluation and Management

1. Airway evaluation andManagement By :Dr. Adel Elshimy

2. Lecture Objectives Students at the end of the lecture will be able to : • Describe the applied anatomy of the airway. • Conduct a preoperative airway assessment . • Identify a potentially difficult airway. • Learn about management of airway obstruction. • Become familiar with airway equipment. • Understand issues around aspiration prophylaxis. • Become familiar with controlled ventilation. • Appreciate ways of monitoring of ventilation and oxygenation.

3. AIRWAY CONTROL Opening the Airway Jaw thrust Head tilt–chin lift

4. AIRWAY CONTROL Oropharyngeal Airway

5. Mask Ventilation • Oral airway • Two-handed technique

6. AIRWAY CONTROL Oropharyngeal Airway (cont.)

7. AIRWAY CONTROL Nasopharyngeal Airway (cont.)

8. OXYGENATION AND VENTILATION Bag-Valve-Mask (cont.) With oxygen reservoir

9. Esophageal-Tracheal Combitube A = esophageal obturator; ventilation into trachea through side openings = B C = tracheal tube; ventilation through open end if proximal end inserted in trachea D = pharyngeal cuff; inflated through catheter = E F = esophageal cuff; inflated through catheter = G H = teeth marker; blindly insert Combitube until marker is at level of teeth E Distal End A C H Proximal End B D F G

10. L M A

11. Usage L M A

12. Indications of intubation • Resuscitation (CPR) • Prevention of lung soiling • Positive pressure ventilation (GA) • Pulmonary toilet • Patent airway (coma or near coma) • Respiratory failure(CO2 retention )

13. Airway Anatomy • Innervation • Vagus n. • Superior laryngeal n. • External branch – motor to cricothyroid m. • Internal branch – sensory larynx above TVC’s • Recurrent laryngeal n. • Right – subclavian • Left – Aortic arch (board question) • Motor to all other muscles, Sensory to TVC’s and trachea

15. Airway

16. Management I-History: previous history of difficulty is the best predictor Inquire about:-Nature of difficulty -No of trials -Ability to ventilate bet trials -Maneuver used -Complications II-Snoring and sleep apnea( prdictors of DMV)

17. LEMON -Look for any obvious anomaly • Morbid obesity(BMI) • Skull • Face • Jaw • Mouth,teeth • Neck

18. Examination I-The 3 joints movements • A-O joint(15-20 degrees) Presence of a gap bet the Occiput and C1 is essential • The cervical spine(range>90) • T.M joint: • Subluxation (1 finger)

19. Examine Airway The 3 – 3 – 2 rule • Mouth open: 3 fingers • Mentum to hyoid: 3 fingers • Floor of mouth to thyroid cartilage: 2 fingers LEMON

20. Mallampatti Mallampatti test: Based on the hypothesis That when the base of the Tongue is disproportionally Large it will overshadow the larynx

21. -Simple easy test,correlates with what is seen during laryngoscopy or Cormack-Lehene grades ,but 1-moderate sensitivity and specificity(12% false +ve) 2-Inter observer variation 3-Phonation increases false negative view

22. II-Wilson test -Consists of 5 easily assessed factors • Body wight(n=0 ,>90=1,>110=2) • Head and neck movement • Jaw movement • Receding jaw • Buck teeth Each factor assigned as o ,1 ,2 max is 10

23. Obstruction • Apparent cause e.g. goitre • OSA • Noisy breathing or stridor • Signs of upper airway obstruction • Other causes

24. Neck Mobility Prior condition • Surgery • Rheumatoid arthritis • Osteoarthritis • Others LEMON

25. Proper Equipment -Bag and mask,oxygen source -Airways oro and nasopharyngeal -Laryngosopes different blades -ETT different sizes -suction on

26. Airway gadgets

27. Mask Ventilation • Induction of anesthesia produces upper airway relaxation and possible collapse • Downward displacement of mask with thumb and index finger

28. Requirement of successful intbation • 1-Normal roomy mandible • 2-Normal T-M, A-O , and C-spine

29. Positioning for successful intubation 3-Alignment of 3 axes or Assuming sniffing position -Any anomaly in these 3 joints A-O, T-M or C-spine can result In difficult intubation

30. Endotracheal Intubation • Look for epiglottis • If initially not found insert laryngoscope further • If this maneuver does not work slowly pull laryngoscope back • Once epiglottis visualized, push laryngoscope into vallecula and apply traction at 45 degree angle to “push” epiglottis up and out of the way

31. Confirm tube position • Direct visualization of ETT between cords • Bronchoscopy ;carina seen • Continuous trace of capnography • 3 point auscultation • Esophageal detector device • Other as bilateral chest movement,mist in the tube,CXR

32. Rapid sequence induction • Indications • Technique: -Preoxygenation -IV induction with sux -Cricoid pressure -Intubate, inflate the cuff ,confirm position -Release cricoid and fix the tube

33. Cricoid pressure Cricoid Pressure

34. Complications of intubation 1-Inadequate ventilation 2-Esophageal intubation 3-Airway obstruction 4-Bronchospasm 5-Aspiration 6- Trauma 7-Stress response

35. Problems with ETT and Cuff ❏ Too long - endobronchial intubation ❏ Too short - accidental extubation ❏ Too large - trauma to surrounding tissues ❏ Too narrow - increased airway resistance ❏Too soft - kinks ❏ Too hard - tissue damage ❏ Prolonged placement - vocal cord granulomas, tracheal stenosis ❏ Poor curvature - difficult to intubate ❏ Cuff insufficiently inflated - allows leaking and aspiration ❏ Cuff excessively inflated - pressure necrosis

36. Difficult airway • Causes -Congenital -Acquired

38. Airway gadgets

39. Bullard Wu Scope Rigid Fiberoptic Scope Fiberoptic

40. Upsher GlideScope Rigid Fiberoptic Scope Fiberoptic

41. L M A

42. Difficult airway • Expected from history,examination Secure airway while awake under LA • Unexpected different options Priority for maintenance of patent airway and oxygenation

44. Transtracheal Jet Ventilation TTJV

45. Ventilation • Spontaneous ventilation • Controlled ventilation Pressure cycled and volume cycled ventilator -Tidal volume 10 mls/kg -Respiratory rate to maintain normocarbia -I:E ratio -PEEP

46. Recommendations • Adequate airway assessment to pick up expected D.A to be secured awake • Difficult intubation cart always ready • Pre oxygenation as a routine • Maintenance of oxygenation not the intubation should be your aim • Use the technique you are familiar with • Always have plan B,C,D in unexpected D.A

47. EXTUBATION General guidelines: • check that neuromuscular function and hemodynamic status is normal • check that patient is breathing spontaneously with adequate rate and tidal volume • allow patient to breathe 100% O2 for 3-5 minutes • suction secretions from pharynx • deflate cuff, remove ETT on inspiration (vocal cords abducted) • ensure patient breathing adequately after extubation • ensure face mask for O2 delivery available • proper positioning of patient during transfer to recovery room, e.g. sniffing position, side lying.

48. Oxygen Therapy • Aim • to prevent or at least minimize tissue hypoxia. • Indications: • When oxygen tension is less than 60 mmHg in a healthy patient. • N.B If patient has chronic lung disease may accept a lower oxygen tension before treatment. • Post operatively supplemental oxygen may be given if SaO2<92% especially if anemic, hypotensive, septic • Delivery of medication (e.g. nebulized salbutamol) • Treatment of carbon monoxide poisoning

49. Hypoxemia Causes of tissue hypoxia: • Low inspired oxygen tension • Hypoventilation • Poor matching of ventilated areas of lung with those areas being perfused • Impaired blood flow to tissues: • Low cardiac output -Hypotension -Arterial occlusion • Impaired oxygen carrying capacity: Low hemoglobin concentration • Abnormal hemoglobin (e.g. sickle cell) • Poisoned hemoglobin (methemoglobin, carboxyhemoglobin) • Impaired oxygen utilization by tissues: cyanide poisoning • Excess oxygen utilization: Thyrotoxicosis - Malignant hyperthermia

50. Delivery systems: • Nasal cannulae • inspired oxygen concentration is dependent on the oxygen flow rate, the nasopharyngeal volume and the patient’s inspiratory flow rate. • Increases inspired oxygen concentration by 3-4%. • Oxygen flow rates greater than 3 liters are poorly tolerated by patients due to drying and crusting of the nasal mucosa.