These generally consist of two groups of devices, oral airways and nasopharyngeal airways or nasal 'trumpets'.
Simple airway adjuncts are invaluable in increasing the success rate of basic airway maneuvers, which aim to create and maintain airway patency, allowing spontaneous respiration or facilitating bag-mask ventilation. They basically work by stenting open the obstruction in the upper airway which invariably occurs with a reduced level of consciousness, unconsciousness and general anesthesia, when the base of the tongue falls backwards against the posterior pharyngeal wall in the supine patient.
Also discussed under the 'oral airways' heading below are the Ovassapian and Berman oral airways.
Oral airways
FEATURES
The standard oral or oropharyngeal airways are rigid plastic tubes which are shaped according to the outline of the hard and soft palate as well as the tongue, against which they sit inside the mouth if placed correctly. They have a flange that should rest against the patient's lips and prevent the device from being inserted too deeply into the mouth. Most manufacturers adhere to a standardized color-coding system of sizes. The typical adult sizes are green, yellow, and red by increasing size.
Oral airways; common adult sizes
Oral airways
Other types of oropharyngel airway are available, which, in addtition to creating and maintaining airway patency, are specifically designed to facilitate oral fiberoptic intubation, which means they can accomodate (and guide) an ET tube inside a semi-closed channel. Here we will briefly desctibe the Berman and Ovassapian airways.
Berman and Ovassapian airways
The Berman airway is a very helpful device for oral fiberoptic intubation. It has a channel accomodating the bronchoscope and/ or ET tube which is open at one side. After successful intubation the Berman airway can be 'broken' open and removed from the ET tube.
Berman and Ovassapian oral airways (side view)
Berman and Ovassapian airways (top down view)
Berman and Ovassapian airways (proximal view)
The Ovassapian airway is also used for oral fiberoptic intubation. It features some plastic ridges in its design which guide the ET tube in the midline. A disadvantage of this airway in comparison with the Berman airway is the fact that there is no 'channel' for the distal half of the airway, where it is pretty much just a flat plastic blade. This means that the Ovassapian airway does not create a channel for the fiberoptic bronchoscope to pass through the oropharynx. The tongue can still occlude the airway against the soft palate which causes poor visiblity during advancement of the fiberoptic scope.
Berman airway (bottom) and Ovassapian airway (top) with missing channel for distal half of the airway
USES
These devices are used to help with creating and mainaining a patent upper airway, in conjunction with the basic airway maneuvers. Chosing the correct size and insertion of oropharyngeal airways is descibed in the 'Basic airway maneuvers' article.
The Berman and Ovassapian airways are really only useful for oral fiberoptic intubation. How to use the Berman and Ovassapian airways is described in the article on 'Oral fiberoptic intubation'.
Nasopharyngeal airways/ nasal 'trumpets'
FEATURES
Unlike the rigid oral airways, these devices are soft. They have a bevelled tip to reduce the risk of trauma to the nasal passage during insertion. Still, the possibility of causing trauma inside the nasal cavity and nosebleeds is a definite disadvantage of these devices.
Devices differ slightly between manufacturers, with the biggest distinguishing feature being the flange design.
Two types of nasopharyngeal airways
USES
These devices are used to help with creating and mainaining a patent upper airway, often in conjunction with the basic airway maneuvers.
CAUTION: Be very careful with using these devices in patients with narrow nasal passages or nasal congestion (which is also a feature of late pregnancy!). Never forecefully introduce these! There is a definite risk of causing significant epistaxis, which can make ariway management much more difficult.
Sizing and insertion are described in the 'Basic airway maneuvers' article.
