Predicting difficulty in mask ventilation Mask ventilation is the most basic, and arguably most impoant, skill in airway management. Patients who have been identified as having DMV, or who are predicted to be difficult, are, or potentially are, at the highest risk in airway management. It is this facet of management that should influence our decision-making the most, potentially with consideration given to awake techniques. DMV can also be suggestive of difficulty in subsequent laryngoscopy. DMV occurs in up to 5% of patients, and there are several factors that are known to be predictive of this. An early study highlighted five independent factors Mnemonic OBESE to be used. Fuher study of DMV added modified Mallampati class of 3 or 4, limited jaw protrusion, and the male sex. Neck irradiation is the most significant predictor of impossible mask ventilation, defined as an inability to achieve gas exchange despite the use of adjuncts, multiple providers, and neuromuscular block, as it causes development of fibrotic non-compliant tissue affecting the airway. BMI itself is not a very useful predictor, although it can be a marker for potential oxygenation issues (due to reduced FRC) and increased aspiration risk. In predicting DA, the actual distribution of body fat should be considered, with fat deposition in the parapharyngeal tissues increasing airway collapsibility, predisposing to OSA. This is seen more in android pattern obesity with distribution of adipose tissue around the trunk, upper body, and neck. The increased fat deposits in neck tissue can fuher narrow the airway. OSA, snoring without apnoea, and increasing neck circumference, above 40 cm, are associated with DMV. The probability of DMV increases with increasing neck circumference. Age >55 BMI > 26 (obesity) Beard Lack of teeth(edentulous) History of snoring (OSA) Neck circumference (>17 inches in men and > 16cm in women) Thyromental distance Large tongue facial and neck deformity Cervical spine disease or previous cervical spine surgery