Combining techniques is recommended by major airway societies and in this text as part of the difficult airway algorithm to overcome certain anatomic or physiologic challenges to intubation by standard methods.^1,2 Combination techniques have been described in both awake and sedated patients for placement and safe removal of tracheal tubes.^3,4,5 These combinations are between devices where the strengths of one device overcome the limitations of the other to assist with tube direction and delivery. Several combinations are possible among airway devices, including supraglottic airway devices (SGD), direct and video laryngoscopes, optical stylets, laryngeal tubes, gum elastic bougies, and flexible endoscopic devices. Nevertheless, this chapter will focus on two combination techniques that are more prevalent in clinical practice as either primary or rescue strategies: the combination of a flexible endoscope with either a SGD or a direct or video laryngoscope. The concept of using a combination of airway devices is based on their ability to complement each other and be critical in situations where the devices could fail or have already failed when employed alone.⁶

SGDs have been approved for clinical use by FDA since 1991.^7,8 Although the terms extraglottic and supraglottic devices are commonly used interchangeably—not all extraglottic devices (EGDs) are SGDs. A Combitube and King Laryngeal Tube are examples of retroglottic devices (EGD but not SGD), which do not facilitate passing an endotracheal tube (ETT) through their lumen (see Chapter 22, Extraglottic devices). However, several manufacturers produce SGDs, which allow passage of an ETT through the lumen. LMA^® Fastrach™, LMA^® Unique EVO™, Intersurgical i-gel^®, CookGas Air-Q^®, and Ambu^® AuraGain™ are examples (Fig. 28.1). SGDs may be used as a primary device for “mask” ventilation and/or for preoxygenation in the induced patient, but are most commonly used in the critically ill patient for rescue oxygenation/ventilation. Once in place, they provide a conduit to the airway opening that can be used to pass an ETT (assuming the correct SGD is used). Since their invention in 1966, flexible fiberoptic bronchoscopes have been extensively used in respiratory medicine and are the gold standard for intubation of the predicted difficult airway. Most modern single-use endoscopes now use distal chip technology and not fiberoptics, thus we use the term endoscope in an all-encompassing manner.

Whether an SGD is used as a primary device or for rescue ventilation, conversion to a “definitive airway” by placing an ETT is necessary for most scenarios involving critically ill patients. Establishing a “definitive airway” is essential to decrease the risk of aspiration and to prepare for
an anticipated long duration of mechanical ventilation with higher sealing pressures or prone positioning.

Once a SGD is placed and gas exchange is restored, the plan to convert to an ETT must ensure adequate ventilation and the availability of appropriate equipment and skilled personnel. SGD manufacturers frequently indicate the appropriately sized tube that may be used through the lumen. In rare cases, the provider may not know the type of SGD placed, and communication with the initial team or steps to identify the SGD may be required.