Assessing the Patient

To avoid catastrophes secondary to difficult intubations, any patient that may require intubation should first undergo a historical and physical airway exam if the situation allows.

AIRWAY HISTORY: If possible, attain and review prior anesthesia records.  Ask the patient:

  • about problems with prior anesthesia such as jaw pain, hoarse voice, dental injury – any thing that may suggest the anesthesiologist had difficulty intubating or providing positive pressure ventilation or that the patient has an anatomic abnormality. 
  • if they have ever been informed by an anesthesiologist that they were difficult to intubate or ventilate. 
  • if they have dentures, sleep apnea, TMJ problems or history of prior airway surgery or trauma (including burns). 
  • if they have a history of head and neck tumors or infection.

PHYSICAL EXAM: Your physical exam will be your most reliable tool for anticipating difficulties in airway management.  Start by reviewing vital signs, particularly oxygen saturation.  Then, commence your exam with a general assessment:

  • is the patient obese or morbidly obese?
  • do they appear to have a short chin or an over-bite?
  • are there any signs of previous head, neck or thorax surgery?
  • is the patient pale or cyanotic?
  • is the patient able to sit up?
  • is the patient breathing comfortably?
  • does the patient require supplemental oxygen? 
  • is the patient appropriate and able to follow commands? 
  • does the patient have full range of motion of the neck?

 

In addition to a cardiovascular and pulmonary exam, a focused airway exam should be conducted.    Detailed evaluation and documentation of pre-procedure abnormalities is imperative:

  • examine the mouth and oral cavity (the best combination for east airway management is a large oral cavity with a small mobile tongue)  
  • evaluate the extent and symmetry of mouth opening (three finger breadths is optimal) 
  • check for loose, missing or cracked teeth
  • note any prominent buck teeth or particularly large incisors that may interfere with laryngoscopy (dental and oral injuries are common complications of laryngoscopy) 
  • note the size of the tongue (large tongues may interfere with use of the laryngoscope) 
  • note the arch of the palate (high arched palates have been known to hamper visualization of the larynx) 
  • examine the chin: the two important features of the chin include mandibular space and tissue compliance.   Predicted airway risk is low if the thyromental space (distance from the mandible to the thyroid) is three finger breadths or greater and tissue compliance is high.
  • examine the pharynx.  The appearance of the posterior PHARYNX may predict ease of laryngoscopy and visualization of the LARYNX.  Malampatti has classified patients in classes I-IV based on visualization of structures during pre-operative evaluation.  The patient is asked to open the mouth wide, stick out the tongue, and extend the neck to allow for maximal visualization of the PHARYNX.
    • If the whole of the tonsillar pillars are visualized, the airway is rated Class I and intubation is likely to be uncomplicated. 
    • If the uvula, but not the tonsillar pillars can be visualized, the airway is rated as Class II. 
    • Class III is characterized by visualization of part of the uvula and soft palate.  
    • An airway is characterized as Class IV if the tongue obstructs view of any structures beyond the hard palate.  Class IV is associated with increased risk of difficult intubation.

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