Routine Mask Ventilation
Adrian A. Matioc
1 Describe in detail the device or technique.
The standard face mask (FM) in use today is a disposable device consisting of a transparent dome with a 22-mm universal connector and a soft cushion as the interface between the device and the patient’s face. The generic one-handed face mask ventilation (FMV) technique is implemented with the “E-C” grip. The face-seal is applied by the thumb and index finger on the dome of the mask (“C”) while the remaining three fingers spread over the mandible (“E”), with the fourth finger applied at the angle of the jaw, instituting the airway maneuver. The FMV technique is optimized by placing the patient in the sniffing position and by the use of oropharyngeal and the nasopharyngeal airways.
2 Where or when is this device or technique used in airway management?
The FM is a ubiquitous tool readily available in any circumstance where oxygenation/ventilation may be needed. In the OR it is used for preoxygenation, ventilation after induction and before insertion of an advanced airway device, for general anesthesia in short procedures, after emergence from general anesthesia, and in any emergent situation where oxygenation is needed.
3 What distinguishes this device or technique from similar airway management methods?
The FM’s effectiveness relies on the provider’s skill and knowledge to provide a seal with the face and to relieve airway obstruction both during inspiration and expiration.
Airway patency is affected by the manipulation of two movable bony structures: the cervical spine (chin lift/head extension) and the temporomandibular joints (mandibular advancement/jaw thrust). Both maneuvers stretch the anterior neck structures and, by increasing the distance between the chin and sternum and the chin and cervical spine, respectively, pull the tongue, larynx, epiglottis, hyoid bone, and associated soft tissues off the posterior pharynx, increasing the cross-sectional area of the upper airway (“active” increase of pharyngeal airway). The most effective airway maneuver is the two-handed triple-airway maneuver (chin lift/head extension, jaw thrust and opening the mouth).
FMV is a dynamic process with the potential for airway obstruction to occur during inspiration and/or expiration. During inspiration (without an oro- or nasopharyngeal airway) the nasal route may be obstructed at the nasal passages, soft palate, tongue, epiglottis, and/or glottis. Insertion of an oropharyngeal airway will support some of the obstructing soft tissues (tongue) and will commit to an oral route of ventilation bypassing superior obstruction sites. During expiration (without an oro- or nasopharyngeal airway) the primary site of obstruction is the soft palate. As the egress of air is blocked, the chest rises but does not fall (breath stacking), there is no expiratory end-tidal CO2, and when the mask is removed, a forceful egress of gas occurs through the mouth. The use of an oropharyngeal airway will bypass the soft-palate obstruction during expiration. An optimal FMV technique includes strategies to improve ventilation and to limit stomach inflation by keeping PAP low (˜20-25 cm H2O). An inadequate technique increases the risks for gastric insufflation, regurgitation and aspiration, generates hypoventilation, and causes facial, eye, and nerve injuries.