Difficult airway is not anticipated
History of previous airway difficulty is present
Includes, Documented difficult mask ventilation; difficult laryngoscopy; failed intubation; emergency surgical airway.
Anticipated difficult mask ventilation or oxygenation
Includes, Age > 55 years; BMI ≥ 30 kg/m²; Beard / facial hair; Edentulous or poor dentition; History of snoring or obstructive sleep apnea; Reduced lung compliance (stiff lungs); Reduced chest wall or abdominal compliance; Central airway obstruction.
Anticipated difficult supraglottic airway device (SGA) insertion or ventilation
Includes, Reduced mouth opening (< 2.5 cm); Upper airway obstruction; Distorted upper airway anatomy; Reduced cervical spine mobility; Reduced lung compliance (stiff lungs); Reduced chest wall or abdominal compliance; Central airway obstruction.
Anticipated difficult laryngoscopy and tracheal intubation
Includes, Distorted airway anatomy; Upper airway obstruction; Mouth opening < 3 cm; Thyromental distance < 6 cm; Mallampati class III or IV; Anterior sliding of mandible absent on upper lip bite test (ULBT); Reduced neck mobility; Prior neck surgery or irradiation; "Woody" or indurated or edematous submental space; Tongue edema or macroglossia.
Anticipated difficult infraglottic airway (tracheostomy / cricothyrotomy)
Includes, Previous neck surgery; Neck edema or hematoma or infection; Obesity; Neck irradiation or fibrosis; Pre-tracheal or neck tumor.
Anticipated shared airway
Includes, Endo laryngeal procedures; Endo tracheal and endo bronchial interventions; Tracheal resection; Carinal resection; Foreign body airway removal; Tracheoesophageal fistula stenting or repair; Bronchopleural fistula repair.
Anticipated difficult extubation
Includes, Known difficult airway; Airway bleeding; Airway edema; Airway trauma; Obesity or obstructive sleep apnea; Restricted postoperative access to airway; High aspiration risk; Significant cardiovascular, respiratory, neurological, or metabolic risk.
Elevated cardiovascular or hypoxia risk during induction and intubation
Includes, Reduced FRC, Acute or Chronic Hypoxia; Shock; Heart failure; Severe metabolic acidosis; Pulmonary hypertension or right ventricular dysfunction.
Increased risk of pulmonary aspiration
Includes, Inadequate fasting; Intestinal obstruction; Gastric outlet obstruction; Recent trauma; Pregnancy; Obesity; Hiatus hernia; Symptomatic GERD; Conditions associated with delayed gastric emptying (e.g., diabetic gastroparesis, uremia)
Loose teeth
Artificial dentures