Essentials of Airway Management, Oxygenation, and Ventilation: Part 2: Advanced Airway Devices: Supraglottic Airways
Offices and outpatient dental facilities must be properly equipped with devices for airway management, oxygenation, and ventilation. Part 1 in this series on emergency airway management focused on basic and fundamental considerations for supplying supplemental oxygen to the spontaneously breathing patient and utilizing a bag-valve-mask system including nasopharyngeal and oropharyngeal airways to deliver oxygen under positive pressure to the apneic patient. This article will review the evolution and use of advanced airway devices, specifically supraglottic airways, with the emphasis on the laryngeal mask airway, as the next intervention in difficult airway and ventilation management. The final part of the series (part 3) will address airway evaluation, equipment and devices for tracheal intubation, and invasive airway procedures.Abstract
American Dental Society of Anesthesiology unconscious patient airway algorithm.
Positioning of oropharyngeal airway. (A) Oropharyngeal airway does not seal glottis and requires caution when bag mask pressures exceed 20 cm H2O. (B) Epiglottis drops down over glottis when excessive bag mask pressure is used, potentially pressurizing the stomach.
Exemplary resuscitation bag manometers. Resuscitation bag manometers provide 3 colored zones indicating pressure being delivered during bag ventilation: (a) 0–20 cm H2O (green), safe for bag mask ventilation with or without oropharyngeal or nasopharyngeal airways; (b) 20–40 cm H2O (yellow), safe for bag ventilation with advanced airway (SGA or endotracheal tube); and (c) >40 cm H2O (red) unsafe pressure due to potential barotrauma.
Final positioning of supraglottic airway. (A) Laryngeal mask airway (LMA) slightly moved down to show direct seal over glottis, permitting pressures of 20–40 cm H2O without pressurizing the stomach. Note that the practitioner must always verify that the device is past the base of the tongue to have adequate depth for creating a seal over the glottis. (B) Bronchoscope visualization of LMA centered over and sealing patient's glottis.
Comparison of classic LMA (left side) versus i-gel (right side). Four beneficial features of i-gel not found in the classic LMA: (a) does not require air inflation to seal over the glottis; (b) tip does not flex forward or backward preventing seal over the glottis; (c) vents gastric pressure if prior bag mask ventilation has pressurized the stomach; and (d) has a bite block to prevent loss of airway if patient bites down during return to consciousness while still needing airway management and ventilation assistance.
i-gel supraglottic airway. (A) i-gel slightly moved down to show correct placement for seal over glottis permitting pressures up to 40 cm H2O without pressurization of stomach during ventilation. (B) i-gel patient placement with maxillary central incisors at the black line.
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