DIFFICULT AIRWAY

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• DIFFICULT AIRWAY
• PRESENTED BY
• DR DOUKUMO D.M.
• DEPARTMENT OF ANAESTHESIA
• OAUTHC, ILE-IFE

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• OUTLINE
• INTRODUCTION
• DEFINITIONS
• INCIDENCE
• AETIOLOGY
• EVALUATION/RECOGNITION
• MANAGEMENT
• FOLLOW-UP CARE
• RECOMMENDATIONS
• CONCLUSION
• TAKE HOME MESSAGE

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• INTRODUCTION
• Airway mgt is the primary
• responsibility of the anaesthetist.
• As Anaesthetists, we provide safe and effective
  airway management.
• Is easily safely achieved in most patients.
• Difficulties occur infrequently.

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• Poor preparation and planning can lead to
  disastrous outcome Regurgitation, aspiration,
  hypoxic brain damage
• Morbidity and Mortality is a major concern
  worldwide
• DEFINITIONS
• Difficult airway is defined as the clinical
  situation in which a conventional trained
  anaesthetist experiences difficulty with face
  mask ventilation of the upper airway, difficulty
  with tracheal intubation or both

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• The difficult airway represents a complex
  interaction b/w pt factors, the clinical setting,
  and the skill of the practitioner
• Difficult face-mask ventilation It is not
  possible for the anaesthetist to provide adequate
  face mask ventilation due to one or more of the
  following problems
• Inadequate mask seal
• Excessive gas leakage
• Excessive resistance to the ingress of gas

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• Signs of inadequate face mask ventilation
  include
• Absent or inadequate chest movement
• Absent or inadequate breath sounds
• Auscultatory signs of severe obstruction
• Cyanosis
• Gastric air entry or dilatation
• Decreasing or inadequate SPO2
• Absent or inadequate exhaled CO2

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• Absent or inadequate spirometric measures of
  exhaled gas flow, and
• Haemodynamic changes associated with hypoxaemia
  or hypocarbia (HT, tachycardia, arrhythmia)
• Difficult laryngoscopy It is not possible to
  visualize any portion of the vocal cords after
  multiple attempts at conventional laryngoscopy

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• Difficult tracheal intubation When an
  experienced laryngoscopist, using direct
  laryngoscopy requires
• More than 2 attempts with the
• same blade or
• A change in the blade or an adjunct to a direct
  laryngoscopy (i.e. Bougie)
• Use of an alternative device or technique
  following failed intubation with direct
  laryngoscopy
• Failed intubation placement of the endotracheal
  tube fails after multiple attempts.

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• INCIDENCE
• Not well defined. Conclusions from work.
• Achieving poor view at laryngoscopy 2-8
• Difficulty with intubation, although associated
  with poor view 0.8
• Failure to intubate 1-3 per 1000 attempts
• Unable to ventilate with bag mask 1-3 per
  10,000
• 28 of all anaesthetic deaths related to
  inability to mask ventilate or intubate
• Local incidence

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• AETIOLOGY
• Anatomical
• Congenital
• Acquired- Often follows trauma
• Pathological
• Congenital
• Syndrome- Syndromes with associated abnormal
  airway (Pierre-Robin, Treacher-Collins e.t.c.)
• Non-syndrome-abnormal airway features not
  associated with syndromes.

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• Abnormal anatomic airway features
• Length of upper incisors-relatively long
• Relation of maxillary and mandibular incisors
  during-prominent overbite (maxillary incisor
  anterior or mandibular incisors)
• Relation of maxillary and mandibular incisors
  during voluntary protrusion- pt cannot bring
  mandibular incisors anterior to ( in front of)
  maxillary incisors
• Shape of palate- Highly arched or very narrow

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• Tongue Large
• Small mouth/short neck
• Pathological factors Usually following
• Trauma
• Infection/ inflammation
• Neoplasm
• degenerative dx Calcification of the thyroid
  ligament
• Endocrine- Morbid obesity, D.M., Acromegaly

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• Other Factors
• Large breasts
• Pregnancy
• Heavy beard
• African hair-do
• Wrong positioning
• Wrong/faulty equipment
• Inadequate depth of anaesthesia
• Inadequate muscle relaxants

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• EVALUATION/ RECOGNITION
• Adequate preparation and planning is the key to
  recognition of a difficult airway
• Personnel
• Equipment
• Assessment

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• HISTORY/PHYSICAL EXAMINATION
• The intent of the airway hx is to detect medical,
  surgical, and anaesthetic factors that may
  indicate the presence of a difficult airway.
• Examination of previous anaesthetic records, if
  available in a timely manner, may yield useful
  information (about airway mgt).
• Physical exam will help to detect physical xtics
  that may indicate the presence of a difficult
  airway. Multiple airway features should be
  assessed.

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• AIRWAY ASSESSMENT
• Predictive Test
• Effective mandibular length lt 9cm
• Inter-incisor gap lt 2.5cm
• Relation of the uvula to the oro-pharynx
  (Mallampati Classification)
• Sterno-mental (Savvas) distance lt 6 finger
  breaths
• Thyromental (Patils) distance lt 3 finger breaths

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• M Mallampati score. The Mallampati rule states
  that there is a relationship between what is seen
  on direct peroral pharyngeal visualization and
  that seen with laryngoscopy.
• patient extends his neck, open his mouth fully,
  protrude his tongue
• Visualize the airway, looking for the tongue,
  soft and hard palate, uvula, and tonsillar
  pillars.
• 3 Mallampati grade tend to have poorer
  visualization during direct laryngoscopy.
• The exam can be approximated in supine and
  comatose patients using a tongue blade.

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• View obtained during Mallampati test
• 1. Faucial pillars, soft palate and uvula
  visualized
• 2. Base of Uvula, soft palate visualized, hard
  palate
• 3. Soft palate, hard visualized
• 4. Hard palate only.

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• Cormack and Lehane Grading system

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• Range of motion of head and neck patient cannot
  touch tip of chin to chest or cannot extend neck
• Positive prayer sign
• Wilsons Risk Score
• Based on wt, head neck movt, jaw movt, receding
  mandible IIG

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• Upper lip bite test
• Class I lower incisors can bite the upper lip
  above the vermilion line,
• Class II lower incisors can bite the upper lip
  below the vermilion line,
• Class III lower incisors cannot bite the upper
  lip
• Class III suggest difficult intubation

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• Radiological
• Plain X-ray
• Reduced atlanto-occipital extension
• Calcification of styloid ligament
• PREDICTIVE VALUE OF TESTS
• Safe outcome of anaesthetic remains the goal of
  every anaesthetist. There is still no test or
  group of tests that can predict 100 of difficult
  laryngoscopies.

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• Modified MT, TMD and inter-incisor gap appear to
  provide the optimal combination in prediction of
  DL in WA population Merah et al. 2005
• MANAGEMENT
• Basic preparation for difficult Airway Management
• Inform the patient ( or responsible person) of
  the special risk and procedures
• Additional assistant

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• Consider the feasibility of supplemental oxygen
  adm during the process of difficult airway mgt
• Opportunities for supplement oxygen
• Administration
• Mask pre-oxygenation
• Oxygen delivery by mask
• Insufflation or Jet Ventilation during intubation
  attempts
• Oxygen delivery by nasal cannula, face mask,
  laryngeal mask airway (LMA)
• Oxygen delivery by face mask, or nasal cannulae
  after extubation of the tracheal.

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• DIFFICULT AIRWAY CART
• Rigid laryngoscope blades of alternate design and
  size from those routinely used this may include
  a rigid fibre optic laryngoscope
• Tracheal tubes of assorted sizes
• Tracheal tube guide. Examples (semi-rigid
  stylets, ventilating tube changer, light wands,
  and forceps designed to manipulate the distal
  portion of the tracheal tube.
• Laryngeal Mask Airways of assorted sizes, this
  may include the LMA-proseal
• Flexible fibre optic intubation equipment

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• Retrograde intubation equipment
• At least, one device suitable for emergency
  non-invasive airway ventilation. E.g. an
  oesophageal tracheal combitube, hollow jet
  ventilation stylet, and a trans-tracheal jet
  ventilator.
• Equipment suitable for emergency invasive airway
  access ( e.g. cricothyroidotomy)
• An exhaled CO2 detector
• The contents of the portable storage unit should
  be customized to meet the specific needs,
  preferences, and skill of the practitioner and
  health care facility.

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• STRATEGY FOR INTUBATION
• The strategy for intubation of the difficult
  airway should include
• 1.An assessment of the likelihood and
  anticipated clinical impact of 4 basic problems
  that may occur alone or in combination
• difficult ventilation
• difficult intubation
• difficulty with patient co-operation or consent
• difficult tracheostomy

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• 2.A consideration of the relative clinical merits
  and feasibility of three basic management choices
• -awake intubation versus intubation after
  induction of GA
• -use of non-invasive techniques for the
  initial approach to intubation versus the use of
  invasive technique (surgical or percutaneous
  tracheostomy or cricothyroidectomy)
• -preservation of spontaneous ventilation during
  intubation attempts versus ablation of
  ventilation during intubation attempts.

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• 3.A consideration of a primary or preferred
  approach to
• -awake intubation
• -pt who can be adequately ventilated
  but is difficult to intubate
• -the life-threatening situation in
  which the pt cannot be ventilated or intubated.
• 4.The consideration of alternative approaches if
  the primary fails or is not feasible(unco-operati
  ve or paediatric pt restricts options for the
  airway management)
• -local anaesthetic infiltration
  -regional nerve
  blockade, but this approach does not represent a
  definitive solution to the presence of a
  difficult airway, nor does it obviate the need
  for a preformulated strategy for intubation of
  the difficult airway.

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• TECHNIQUES FOR DIFFICULT AIRWAY
• Alternative laryngoscope blades
• Awake intubation
• Blind intubation(oral or nasal)
• Fibreoptic intubation
  
• Intubating stylet or tube changer
• Laryngeal Mask Airway as an intubating conduit
• Light wand
• Retrograde intubation
• Invasive airway access

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• TECHNIQUES FOR DIFFICULT VENTILATION
• Two-person mask ventilation
• Oropharyngeal or nasopharyngeal airways
• Laryngeal mask airway
• Oeosophageal tracheal combitube
• Intratracheal jet stylet
• Rigid ventilating bronchoscope
• Invasive airway access
• Transtracheal jet ventilation

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• BLUE PRINT FOR MANAGEMENT
• PLAN A Initial tracheal intubation plan
• PLAN B Secondary tracheal intubation plan, when
  plan A has failed
• PLAN C Maintenance of oxygenation and
  ventilation, postponement of surgery, and
  awakening the patient when earlier plans fail.
• PLAN D Rescue techniques for cant intubate,
  cant ventilate (CICV) situation.

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• FIG 4 Management of unanticipated difficult
  intubation guidelines

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• FIG 5 Unanticipated difficult intubation
  during routine induction of anaesthesia in an
  adult patient

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• STRATEGY FOR EXTUBATION
• Consideration of relative merits/demerits of
  awake extubation versus extubation from loss of
  consciousness.
• Evaluation of general features that may produce
  adverse impact on ventilation post extubation of
  patient
• Preformulated plan in the event of postoperative
  ventilation problems
• Device that can serve as a guide for expedited
  re-intubation

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• COMPLICATIONS
• Laceration of soft tissues
• Laryngospasm
• Vocal cord paralysis
• Dislocation of arytenoid cartilages or mandible
• Perforation of the trachea or oesophagus
• Endobronchial or oesophageal intubation
• Dental damage
• Haemorrhage
• Aspiration of gastric content or foreign bodies

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• Increased ICP or IOP
• Hypoxaemia or hypercarbia
• Fracture or dislocation of the cervical spine
• Spinal cord damage
• Trauma to the eyes
• Adverse reflexes- Bronchospasm
• Apnoea
• Arrhythmias
• Vomiting

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• FOLLOW-UP CARE
• Document presence and nature of the airway
  difficulty in the medical record
  
  
  
  
• Aim- Guide and facilitate the delivery of future
  care
• -Description of the airway difficulties that were
  encountered
• -Description of the various techniques that were
  employed
• -Inform the patient/responsible person

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• The information presence of a difficult
  airway, the apparent reasons for difficulty, and
  the implication of future care.
• Evaluate and follow up the patient for potential
  complications of the difficult airway management
• Oedema, bleeding, tracheal and
  oesophageal perforation, pneumothorax and
  aspiration

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• RECOMMENDATIONS
• A pre-anaesthetic airway air evaluation should be
  carried out on all patients and conclusion drawn
  regarding the likelihood of airway difficulties
• The anaesthetic plan should reflect the
  conclusions drawn from the pre-anaesthetic airway
  evaluation.
• All clinical care areas should be equipped with
  alternatives to face mask-bag ventilation and
  direct laryngoscopy for tracheal intubation

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• Physician providing airway care to patients
  should be familiar with and practised in
  alternative technique to face mask-bag
  ventilation
• In event that anticipated difficulty is
  encountered with face mask-bag ventilation, an
  alternative to ventilate the lungs should be
  utilized
• Physicians providing airway care to patients be
  familiar with and practised in alternative
  techniques to direct laryngoscopy
• In event that unanticipated difficulty is
  encountered with direct laryngoscopy for
  tracheal, an alternative technique to intubate
  the trachea should be considered

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• A strategy should be in place to ensure
  continuous patency of the airway before
  extubation of a trachea which was previously
  difficult to intubate
• Patients should be advised when unanticipated
  airway difficulties were encountered
• A note should be entered on the patients record
  when unanticipated airway difficulties were
  encountered, detailing the nature of the
  difficulties and how they resolved
• Training programmes in anaesthesia should develop
  a curriculum to ensure graduate physicians are
  skilled in alternative techniques for airway
  management

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• CONCLUSION
• There is increased knowledge of airway
  management in the last decade
• New tools and techniques have been introduced
• -but many anaesthetists have
  failed to keep their skills up to date
• -this may be due to either
  lack of facilities or lack of training
  opportunities
• Risk prevention can only be implemented with a
  sufficient range of skills
• These skills can only be gained with the right
  attitude towards training and learning and should
  be our immediate goal to enhance safe airway
  management.

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• TAKE HOME MESSAGE
• He who fails to prepare, prepares to fail

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THANK YOU FOR LISTENING