Difficult mask ventilation

A comprehensive review of difficult mask ventilation (DMV) reports that the incidence of DMV varies widely (from 0.08% to 15%) depending on the criteria used for its definition. It reminds us that the independent predictors of DMV are:

  • Obesity
  • Age older than 55 yr
  • History of snoring
  • Lack of teeth
  • The presence of a beard
  • Mallampati Class III or IV
  • Abnormal mandibular protrusion test

The review also points out that DMV does not automatically mean difficult laryngoscopy, although it does increase its likelihood.
In addition to positioning, oral and nasal adjuncts, two person technique, and jaw thrust, the application of 10 cmH20 CPAP may help splint open the airway and reduce the difficulty of mask ventilation in some patients.
Difficult mask ventilation
Anesth Analg. 2009 Dec;109(6):1870-80
Causes of DMV:
1) Technique-related

1. Operator: Lack of experience

2. Equipment

a. Improper mask size
b. Difficult mask fit: e.g., beard, facial anomalies, retrognathia
c. Leakage from the circuit
d. Faulty valve
e. Improper oral/nasal airway size
3. Position: Suboptimal head and neck position
4. Incorrectly applied cricoid pressure
5. Drug related
a. Opioid-induced vocal cord closure
b. Succinylcholine-induced masseter rigidity
c. Inadequate depth of anesthesia
d. Lack of relaxation?

2) Airway-related

1. Upper airway obstruction

a. Tongue or epiglottis
b. Redundant soft tissue in morbid obesity and sleep
apnea patients
c. Tonsillar hyperplasia
d. Oral, maxillary, pharyngeal, or laryngeal tumor
e. Airway edema e.g., repeated intubation attempts,
trauma, angioedema
f. Laryngeal spasm
g. External compression e.g., large neck masses and
neck hematoma

2. Lower airway obstruction

a. Severe bronchospasm
b. Tracheal or bronchial tumor
c. Anterior mediastinal mass
d. Stiff lung
e. Foreign body
f. Pneumothorax
g. Bronchopleural fistula

3) Severe chest wall deformity or kyphoscoliosis restricting chest expansion