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Preop eval and airway management

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Didactics in our rotation in the Department of Anesthesiology. …

Didactics in our rotation in the Department of Anesthesiology.
Source: Miller's Textbook of Anesthesiology

Published in Health & Medicine
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  • Pertinent Medical history: Asthma, Metabolic, endocrine diseases..hx of drug abuse
  • The reduction in consciousness produced by general anesthesia (or trauma or disease) is necessarily associated with depression of other physiologic systems. The depressant effects on airway, respiratory, and cardiovascular function can cause immediate threats to the patient. Airway management differs from management of other depressed function in that it requires a range of manual skills, as well as knowledge and judgment.
  • Includes the upper airwayNasal and oral cavityPharynxLarynxTracheaPrincipal bronchi
  • Prominent aortic arch, congenital vascular anomalies, anterior mediastinal masses, enlarged lymph nodesCan compress trachea and interfere with respiration
  • Aspirated materials and/or deeply inserted tubes tend to enter the right principal bronchus
  • identify any possible problem with maintaining, protecting, and providing a patent airway during anesthesia.performed with the aid of physical examination and a review of the patient’s history and anesthetic records.
  • Class I: soft palate, fauces, uvula, pillars Class II: soft palate, fauces, portion of uvula Class III: soft palate and base of uvula Class IV: hard palate onlyA high Mallampati score (class 3 or 4) is associated with more difficult intubation
  • In an awake patient, airway patency is maintained by muscle tone in the head and neck, particularly the pharynx and tongue. As consciousness is lost and muscle tone is reduced, tissues fall backward under the influence of gravity in a supine patient and can obstruct the upper airway.

Transcript

  • 1. PRE-OPERATIVE EVALUATION AND AIRWAY MANAGEMENT CC Jackie Lou C. Acha Department of Anesthesiology West Visayas State University Medical Center August 27, 2013
  • 2. Objectives of Preoperative Evaluation • To establish a medical, anesthesia and medication history • To perform a physical exam • To establish a doctor-patient relationship • To obtain consent • To make an anesthesia plan
  • 3. Goals of Pre-operative Evaluation • Inform the patient of the risks • Educate the patient regarding anesthesia and perioperative events • Answer question and reassure the patient and family • Notify NPO status • Instruct allowable and prohibited medications
  • 4. Pre-Anesthetic Evaluation Purpose: Review of Database 1. MEDICAL HISTORY a. Current Problem b. allergies c. drug intolerances d. present therapy e. illicit drug use f. previous anesthetic experience
  • 5. 2. PHYSICAL EXAMINATION  Vital Signs  Airway  Heart  Lungs  Extremities  Neurologic Examination
  • 6. 3. ASA Classification Class Definition 1 A normal healthy patient 2 A patient with mild systemic disease and no functional limitations 3 A patient with moderate-severe disease that limits activity 4 A patient with severe systemic activity that is a constant threat to life 5 A moribund patient who is equally likely to die in the next 24 hours with or without surgery 6 A brain-dead patient for organ donation “E” Added for Emergency operations
  • 7. • AIRWAY EXAMINATION Mallampati Classification Class Direct Visualization I Soft palate, fauces, uvula, pillars II Soft palate, fauces, uvula III Soft palate, uvular base IV Hard palate Only
  • 8. Routine Pre-Operative Laboratory Evaluation Hemoglobin or Hematocrit -All menstruating women -All patients over 60 years of age -All patients likely to experience significant blood loss and may require transfusion Serum Glucose and Creatinine -All patients over 60 years of age -Diabetic patients
  • 9. Electrocardiogram (ECG) -patients > 40 yo -specific indications – HPN, palpitations, previous MI Chest Radiograph -patients > 60 yo -specific clinical indications – HPN, malignancy, acute pulmonary symptoms
  • 10. • Urinalysis • T3, T4, TSH
  • 11. Preoperative Fasting • Recommended fasting period – 2 hours for clear liquids in all patients – > 6 hours after a light meal – 8 hours after a meal that includes fried or fatty foods
  • 12. PRE-OPERATIVE MEDICATION • Psychological Preparation • Pharmacologic Preparation
  • 13. Primary Goals of Pharmacologic Premedication 1. Relief of anxiety 2. Sedation 3. Amnesia 4. Analgesia 5. Prevention of airway secretion 6. Prevention of autonomic reflex responses 7. Reduction of gastric fluid volume 8. Increase in gastric fluid pH 9. Reduction of anesthetic requirements 10. Prophylaxis against allergic reaction
  • 14. Secondary Goals of Pharmacologic Premedication 1. Decrease vagal activity 2. Facilitation of smooth induction of anesthesia 3. Post-operative analgesia 4. Prevention of post-operative nausea and vomiting
  • 15. Drug Classes for Premedication o Benzodiazepines o Opioids o Anthihistamines o Anticholinergics o Histamine receptor antagonists (H2 antagonists) o Antacids o Proton pump inhibitors o Antiemetics o Gastrokinetic agents o A2-adrenergic agonists
  • 16. Airway Management • For successful airway management  Anatomy of airway  Evaluation of airway  Proper equipments  Adequate skills
  • 17. Anatomy of the Airways
  • 18. Nasal and Oral Cavity • Warms and humidifies the air • Provides 2/3 of airway resistance
  • 19. Pharynx • Anteriorly communicate with nasal and oral cavity and larynx • 3 parts of pharynx: – Nasopharynx – Oropharynx – at the level of C2-C3 – Hypopharynx - at the level of C4-C6 • Epiglottis – demarcate oropharynx and hypopharynx – Adults – crescent shape – Infants – u-shape
  • 20. Larynx • Cartilaginous skeleton • 9 cartilages (3 paired and 3 unpaired) – 3 paired • Arytenoid • Corniculate • Cuneiform – 3 unpaired • Thryroid • Cricoid • Epiglottis
  • 21. Larynx
  • 22. Trachea • ~15 cm in adults • Supported by 17-18 C- shaped cartilages • 1st tracheal ring – anterior of 6th cervical vertebrae • Ends at the carina at the level of 5th thoracic vertebra
  • 23. Primary Bronchi • Right principal bronchus – 1.8 cm long – larger than the left – deviates less from the axis of the trachea • Left principal bronchus – 5 cm long
  • 24. Adult vs Pediatric Airway
  • 25. Evaluation of the Airway • PATIENT HISTORY – Symptoms related to the airway should be elicited • Snoring • Chipped teeth • Changes in voice • Dysphagia • Stridor • Bleeding • Cervical spine pain or limited ROM • TM joint pain/dysfunction – Previous problems with airway
  • 26. Evaluation of the Airway • PHYSICAL EXAMINATION – Thyromental distance – measure mentum to thyroid notch in the neck extended position • <6-7 cm or 3 fingerbreadth – poor laryngoscopic view – Interincisor gap • interincisor distance with the mouth fully opened • <3 cm – poor laryngoscopic view
  • 27. Evaluation of the Airway – Atlanto-Occipital Extension/Neck Mobility • Flexion of the neck and elevating head ~3cm – aligns laryngeal and pharyngealaxis to obtain line of vision during laryngoscopy – Submandibular compliance • Area in which pharyngeal soft tissue must be displaced to obtain the line of vision during laryngoscopy
  • 28. Evaluation of the Airway – Mallampati Classification • Correlation of oropharyngeal space with ease of direct laryngoscopy and intubation • Observer at eye level, head in neutral position, maximal mouth opening and tongue protrusion without phonating • Examination of oropharyngeal structure
  • 29. Mallampati Airway Classification • Class I: soft palate, fauces, uvula, pillars • Class II: soft palate, fauces, portion of uvula • Class III: soft palate and base of uvula • Class IV: hard palate only A high Mallampati score (class 3 or 4) is associated with more difficult intubation
  • 30. Evaluation of the Airway • The efficacy of direct laryngoscopy is measured in terms of the best view of the larynx achieved • Cormack and Lehane Score • Laryngoscopic view • Visualization of the entire laryngeal aperture
  • 31. Cormack and Lehane Score • Grade 1: most of glottis visible • Grade 2: only posterior portion of glottis • Grade 3: only epiglottis • Grade 4: no airway structures visible
  • 32. Upper Airway Obstruction
  • 33. Signs of Upper Airway Obstruction • Hoarse voice • Decreased air in and out • Stridor • Retraction of suprasternal/supraclavicular/intercostal space • Cyanosis
  • 34. Upper Airway Obstruction • Head extension and jaw thrust – move the hyoid bone and attached structures anteriorly and relieve airway obstruction to a variable extent
  • 35. Head Extension
  • 36. Jaw Thrust • Achieved by exerting anterior pressure behind the angles of the mandible • Uses the sliding component of the TMJ to move the mandible, hyoid bone, and attached structures anteriorly
  • 37. Oxygenation and Preoxygenation • A.K.A. denitrogenation • Maximize O2 stores before induction to prolong the period before the onset of hypoxemia in the event of serious difficulty with airway management • 100% O2 from a close-fitting facemask before induction of anesthesia
  • 38. Breathing 100% O2 – Three minutes of tidal volume breathing – Deep breathing with a high fresh gas flow for 1.5 minutes 5 minutes of 100% O2, via tight fitting face mask – furnish up to 10 minutes of O2 reserve after apnea
  • 39. Airway Management Techniques Face Mask Ventilation – simplest and least invasive anesthesia technique – suitable for short operations – also used for controlled ventilation before and after the use of tracheal tubes
  • 40. Face Mask • should fit over the bridge of the nose with the upper border aligned with the pupils • Sides should seal just lateral to the nasolabial folds • Bottom should seat between the lower lip and chin • Ventilating pressure < 20cm H2O
  • 41. Sealing the Mask to the Face • 1st requirement to ensuring good fit – Air-filled cushion that does not leak • Hypothenar eminence – Used to draw the soft tissue of the left cheek to meet the cushion • Ulnar 3 fingers of the left hand – Grip the mandible to displace anteriorly • Thumb and index finger – Holds the mask on the face
  • 42. Assessment of Ventilation Adequate Ventilation Inadequate ventilation Normal breath sounds Stridor, phonation, snoring Sequential rise and fall of the subcostal region Motionless subcostal region Upper chest expansion before or during subcostal expansion Upper chest retraction during subcostal expansion; intercostal or supraclavicular retraction, tracheal tug, flaring nasal alae Prompt refilling of the reservoir bag during exhalation Depleted reservoir bag Appropriate tidal volume measured with each breath Reduced tidal volume measure Square shaped capnogram with normal end-expiratory CO2 Capnogram without plateau; large or small end expiratory CO2 SpO2>97% SpO2<97% Normal VS and ECG Abnormal VS and ECG
  • 43. • If head extension and jaw thrust fail to maintain an unobstructed airway – oropharyngeal airway – nasopharyngeal airway – SAD – tracheal intubation
  • 44. Oropharyngeal Airway • Keep the tongue from blocking the airway • Allow for easier suctioning of the airway • Used on unconscious patients without a gag reflex • Used in conjunction with bag valve mask
  • 45. Nasopharyngeal Airways • Conscious patient who cannot maintain airway • Can be used with intact gag reflex • Should not be used with head injuries or nosebleeds
  • 46. Endotracheal Intubation • Indications - Provide a patent airway - Prevent aspiration of gastric contents - Need for frequent suctioning - Facilitate positive-pressure ventilation of the lungs - Operative position other than supine - Operative site near or involving the upper airway - Airway maintenance by mask difficult
  • 47. Equipments for ET Insertion • Endotracheal tube • Suction catheter • Laryngoscope • Laryngoscope blades • Equipment for providing positive-pressure ventilation of the lungs with oxygen
  • 48. Technique • Elevate head 8-10 cm • Extend head at atlanto-occipital joint => “Sniff position” • Patient’s face near intubator’s xiphoid cartilage • Counter pressure of the right thumb on mandibular teeth and right index finger on the maxillary teeth => Scissors maneuver
  • 49. Sniff Position
  • 50. Scissors Maneuver
  • 51. Sellick Maneuver • Exert downward external pressure to displace the cartilaginous cricothyroid ring posteriorly • Compress esophagus against cervical vertebrae • Prevent spillage of gastric contents into pharynx • 30 to 40 Newtons or 8-9 pounds weight force • Pressure released once the airway is secured & cuff inflated
  • 52. Endotracheal Intubation
  • 53. Laryngoscopy – positioning of head & insertion of blade • Laryngoscope is held in the left hand • Blade inserted on the right of the patient’s mouth • Pressure on the teeth and mouth must be avoided while advancing the blade forward
  • 54. Laryngoscopy – lifting the handle • Depression or lateral movement of the patient’s thyroid cartilage externally on the neck (OELM) or backward upward rightward pressure (BURP) may facilitate exposure of the glottic opening
  • 55. Laryngoscopy – continue to lift the blade towards roof
  • 56. Insertion of endotracheal tube • Tube is held in the right hand like a pencil • Curve directed anteriorly • Advance toward the glottis from the right side of the mouth • Tube is advance until proximal end is 1-2cm past the vocal cords
  • 57. Laryngoscopic view
  • 58. • Remove laryngoscope blade • Inflate ET cuff to create a seal against the tracheal mucosa
  • 59. Laryngoscopic view
  • 60. Post-intubation auscultation 1. Right infra- clavicular 3. Right infra- mammary 5. Gastric 2. Left infra- clavicular 4. Left infra- mammary
  • 61. Laryngoscope
  • 62. Curved Macintosh Laryngoscope
  • 63. Curved Macintosh Laryngoscope • Tip is advanced into the space between the base of the tongue and pharyngeal surface of the epiglottis • Forward and upward movement stretches the hypoepiglottic ligament, elevates the epiglottis and exposes the glottic opening • Blade 3 or 4 standard for adult
  • 64. Straight (Miller) blade • Tip is passed beneath the laryngeal surface of the epiglottis • Forward and upward movement directly elevates the epiglottis to expose the epiglottic opening
  • 65. Curved vs. Straight Blade • Curved blade – less trauma to the teeth with more room for passage of ET and less bruising of the epiglottis • Straight blade – better exposure of the glottic opening
  • 66. Endotracheal Tube • Specified according to internal diameter • Made of clear, inert polyvnyl chloride plastic that molds to the contour of the airway after softening on exposure to body temperature
  • 67. ET Sizes Age Weight (Kg) ET (mm) Premature <1.5 2.5 Premature 1.5 – 2.5 3.0 Newborn 3.5 3.5 1 10 4.0 2-3 15 4.5 4-6 20 5.0 7-9 30 5.5 10-12 40 6.0 13-15 50 6.5 >16 >60 7.0
  • 68. • Rigid implement made of flexible metal • Inserted inside endotracheal tube to maintain chosen shape • It is bent over the tube to prevent protrusion beyond the endotracheal tube & cause injury • Facilitates intubation when glottis visualization is minimal / absent & a semi- blind or blind insertion is attempted Stylet
  • 69. Stylet
  • 70. Complication of ET intubation • Direct trauma • Dental injury • Systemic hypertension and tachycardia
  • 71. Extubation • Either deeply anesthetized or fully awake • If under light anesthesia ( disconjugate gaze, breath-holding or coughing and not responsive to command) – laryngospasm • Preferred if at risk from increased intracranial or intraocular pressure, surgical wound bleeding, or wound dehiscence
  • 72. Checklist for Extubation  No medical indication for continued intubation  Muscle relaxants fully reversed  Spontaneous ventilation is adequate  Desired level of consciousness achieved  All equipment for airway management present  Denitrogenate with high flow oxygen  Clear pharynx for suction  Deflate the cuff  Apply positive pressure to the breathing system and gently remove the tracheal tube  Clear the pharynx by suction again  Reassess airway patency and ventilation  Apply mask with high flow oxygen  Check vital signs
  • 73. Extubation complications • Laryngospasm • Inhalation of gastric contents • Pharyngitis (disappears after 48-72H) • Damage to tracheal mucosa • Tracheal stenosis
  • 74. THANK YOU!