A supraglottic airway (SGA) is a medical device designed to assist a patient with breathing, particularly during general anesthesia or in urgent medical situations. The name “supraglottic” describes its placement: “above” the “glottis,” which refers to the vocal cords and the opening to the windpipe. These devices are positioned in the upper throat, creating a pathway for air and gases to reach the lungs without direct insertion into the trachea. SGAs provide a less invasive approach to managing breathing compared to methods that pass a tube through the vocal cords.
How Supraglottic Airways Function
A supraglottic airway device is inserted into the patient’s mouth and advanced until it rests in the pharynx, above the larynx. These devices create a seal around the laryngeal inlet, the opening to the windpipe. This seal is usually achieved either by inflating a cuff or using a soft, pre-formed gel-like material that conforms to the surrounding anatomy.
Once the seal is established, the device acts like a funnel over the entrance to the lungs, allowing oxygen and anesthetic gases to be delivered directly into the respiratory system. This design allows for effective ventilation and oxygenation without passing a tube between the vocal cords. The device’s placement above the glottis simplifies the insertion process while maintaining an open passage for breathing.
Common Medical Applications
Supraglottic airways are widely used in two main clinical environments. In planned surgical procedures, they serve as a common choice for delivering general anesthesia, especially for shorter or routine operations. Their ease and speed of insertion make them a preferred option in these controlled settings.
Beyond the operating room, these devices play a significant role in emergency medicine, both in hospitals and pre-hospital settings. Paramedics and first responders often use SGAs because they can be placed more quickly and with less specialized training compared to other airway management techniques. This rapid placement is especially beneficial in urgent situations, such as cardiac arrest, where securing a patient’s airway swiftly is paramount to providing oxygen and ventilation.
Types of Supraglottic Devices
The term “supraglottic airway” encompasses a variety of devices, each with distinct features. The Laryngeal Mask Airway (LMA) stands as a pioneering example, introduced in the early 1980s. The classic LMA features an elliptical mask with an inflatable cuff that, once inserted and inflated, creates a seal around the laryngeal inlet.
A more modern development is the i-gel, which utilizes a soft, pre-formed gel-like material instead of an inflatable cuff. This thermoplastic elastomer material is designed to conform precisely to the perilaryngeal anatomy, providing an anatomical seal without the need for air inflation. The i-gel also often includes a gastric channel, allowing for the drainage of stomach contents and potentially reducing the risk of aspiration. Many variations exist, with some devices incorporating features like intubating channels to facilitate the placement of an endotracheal tube if needed.
Comparison to Endotracheal Intubation
Supraglottic airways differ significantly from endotracheal (ET) intubation, which involves passing a tube directly through the vocal cords and into the trachea. SGAs are less invasive, as they rest above the larynx and do not traverse the vocal cords. This positioning results in less irritation to the throat and vocal cords post-procedure.
Supraglottic airways are faster and require less specialized skill to insert correctly than an ET tube. Despite their advantages in ease and speed, ET tubes provide a more secure and definitive airway. An ET tube offers superior protection against aspiration, the inhalation of stomach contents into the lungs, making it the preferred choice for patients with a high risk of aspiration or those requiring prolonged mechanical ventilation.