AIRWAY Assessment

AIRWAY Assessment

There are various definitions of “the difficult airway”, with no definition universally accepted : 

• In general terms, an airway is considered difficult when oxygenation and ventilation cannot be achieved in the desired manner
  
• ‘The difficult airway’ represents a complex interaction between patient factors, the clinical setting, and the skills and preferences of the practitioner

American Society of Anaesthesiologists Task Force definitions : 

• The difficult airway is “the clinical situation in which a conventionally trained Anesthesiologist experiences difficulty with facemask ventilation, difficulty in supraglottic device ventilation, difficulty in tracheal intubation or all three”

1. Difficulty with facemask ventilation is the inability of an unassisted anesthesiologist :
   
   
   a) to maintain oxygen saturation, measured by pulse oximetry, 92%; or
   b) to prevent or reverse signs of inadequate ventilation during positive-pressure mask ventilation under general anesthesia
   
   
2. Difficult laryngoscopy occurs when “it is not possible to visualize any portion of the vocal cords with conventional laryngoscopy.” This typically corresponds to a Cormack and Lehane Grade IV laryngoscopy view
3. Difficult endotracheal intubation occurs when “proper insertion of the tracheal tube with conventional laryngoscopy requires more than three attempts or more than 10 minutes“

Risk factors for difficult airway management, including

• Infections of oropharynx and neck
• Previous surgery or radiotherapy to neck
• Problems with mouth opening – e.g. trauma, soft tissue disorders, arthridities
• Problems with neck mobility – e.g. cervical spine disruption, rheumatoid arthritis, cervical fusion (e.g. operative, ankylosing spondylitis, scleroderma)
• Obesity, OSA
• Oropharyneal or neck masses
• Difficult dentition
• Pregnancy
• Recent intubation (swelling, trauma)
• Angioedema
• Craniofacial syndromes
• Burns
• Airway trauma – blunt or penetrating
• Airway obstruction

Useful Mnemonics

Difficult intubation = LEMON

• Look externally
• Evaluate 3-3-2 rule
• Mallampati score
• Obstruction
• Neck Mobility

Difficult BVM = BONES

• Beard
• Obese
• No teeth
• Elderly
• Sleep Apnea / Snoring

Difficult LMA = RODS

• Restricted mouth opening
• Obstruction
• Distorted airway
• Stiff lungs or c-spine

Difficult surgical airway = SHORT

• Surgery
• Hematoma
• Obesity
• Radiation distortion or other deformity
• Tumor

Airway Grades

1.  Mallampati Score

2.  Cormack-Lehane Classification

Modified Mallampati Score

• Class I: Soft palate, uvula, fauces, pillars visible
• Class II: Soft palate, uvula, fauces visible
• Class III: Soft palate, base of uvula visible
• Class IV: Only hard palate visible

Cormack-Lehane Classification

• Grade 1: Full view of glottis
• Grade 2a: Partial view of glottis
• Grade 2b: Only posterior extremity of glottis seen or only arytenoid cartilages
• Grade 3: Only epiglottis seen, none of glottis seen
• Grade 4: Neither glottis nor epiglottis seen

Source :www.lifeinthefastlane.com