INTRODUCTION
Extraglottic devices (EGDs) are being used increasingly often in emergency settings, especially in the prehospital environment, as many emergency medical service (EMS) companies are promoting them as the principal mode of airway management. Because most EGDs need to be converted to a definitive airway, providers must be comfortable assessing and managing a patient once an EGD is in place, whether placed in the emergency department (ED) or before arrival. An EGD may have been used as a primary airway without prior attempts at intubation or secondarily in the event of a failed intubation, which can have important clinical implications. Hospital-based providers should become familiar with devices used within their agency/institution and by EMS agencies in their catchment area. This should include hands-on practice whenever possible. Intensive care units (ICUs), EDs, and critical care transport agencies should consider keeping samples of devices on hand for rapid reference. In-depth knowledge of the various EGDs in use will improve patient care and facilitate further management.
MANAGING A PATIENT WITH AN EGD IN PLACE
Although EGDs are not definitive airways—they are not cuffed tubes that exist within the tracheal lumen—they are reliable conduits for oxygenation and ventilation and offer variable degrees of aspiration protection. Therefore, the provider’s initial thought process should focus on confirming and optimizing gas exchange rather than on immediate exchange for an endotracheal tube (ETT). Most critically ill or injured patients with an EGD in situ have other competing priorities; if further airway interventions can be safely deferred for even a few minutes, it will allow the provider to address these other issues. We provide Figure 12-1 to help think through the process.
• FIGURE 12-1. Management Algorithm for an in situ EGD.
Assessment
Rapid assessment of gas exchange (both ventilation and oxygenation) should be the first step. Adequate gas exchange is confirmed in the same way as for an ETT. Clinical observations such as breath sounds, chest rise, and gastric distension are important, but waveform capnography is paramount (Fig. 12-2). If the provider concludes that ventilation is taking place, then oxygenation should next be considered. Simultaneously, the provider should visually assess whether or not the device appears to be sized correctly and is sitting in a grossly appropriate position, whether or not the pilot balloon pressures seem appropriate (if present), and whether or not a substantial air leak is present. Any correctable issues should be rapidly addressed, such as repositioning the device or adding/removing air from inflatable cuffs. If any major issues that cannot be quickly corrected are present, the device should be removed and rescue bag mask ventilation (BMV) initiated (Chapter 9).
• FIGURE 12-2. Ventilator tubing as well as waveform capnography equipment attached to an EGD, specifically the King LTS-D (seated in mannequin). The device has been secured with a commercially available tube holder.
Optimization
Once general function has been assessed and assured, the provider can focus on optimizing the situation. Ventilators may be employed just as if the patient were intubated. A ventilator will free up hands and assure consistent, lung protective ventilation as appropriate for the patient’s condition; tens of thousands of patients are managed in this fashion in the operating room every day. Reassessment for air leak should take place after any changes in ventilator parameters. Patients should receive appropriate analgesia and sedation, and occasionally neuromuscular blockade, just as if they were intubated with an ETT. Patients should be routinely monitored for common complications of any positive pressure ventilation, such as pneumothorax. If not already present, a gastric tube should be inserted if a conduit exists. All “second-generation” EGDs facilitate gastric tube placement, but not all EMS providers that place these devices are allowed to perform gastric decompression or stock the appropriate-sized gastric tubes, especially in pediatrics. Bite blocks should be used for spontaneously breathing patients if the EGD does not have one built-in.
TROUBLESHOOTING
If ventilation is adequate but oxygenation is poor, hypoxemia is more likely on account of patient pathology than device failure. The provider should seek to intervene by increasing positive end expiratory pressure if not contraindicated, increasing the FIO2, adding sedation and analgesia and possibly neuromuscular blockade, and treating pneumothorax if present. If such maneuvers are successful, semielective exchange can be considered. If such maneuvers are unsuccessful, then the provider should err on the side of rapid exchange to ensure that the device was not contributing to oxygenation failure. An option for this type of exchange is rapid sequence intubation (RSI) with a “double setup” for surgical airway. After induction and neuromuscular blockade, the EGD can be pulled and one best attempt at laryngoscopy made before moving to a cricothyrotomy because rescue with another EGD is assumed to be unreliable. Another option in this situation is to continue ventilating via the EGD to oxygenate as well as possible while performing a surgical airway with the EGD in situ.
If ventilation is inadequate in the setting of a well-sized and positioned EGD, the next task is to determine whether the problem is intrinsic to the patient or the device. Patient issues that can be rapidly corrected include tension pneumothorax, mucus plugging, and bronchospasm. Device issues that may be rapidly addressed include obstructing secretion or blood clots or herniation of the epiglottis into the outlet of the supraglottic airway; both will become apparent and possibly solved with passage of a suction catheter. If these maneuvers improve air movement, then oxygenation can be addressed as described above. If these maneuvers do not improve air movement, the device should be immediately removed, BMV commenced, and definitive airway management performed according to the Difficult and Failed Airway Algorithms (see Chapter 3).
WHEN TO CONSIDER SEMI-ELECTIVE EXCHANGE
When a device is clearly not working and troubleshooting, as discussed earlier, is unsuccessful, the decision to remove it is easy. However, the decision to remove a functioning EGD (i.e., a semi-elective exchange) is much more challenging. Semi-elective exchange for an ETT is not without risk and is a decision that should not be taken lightly.
The reason the device was initially placed should be considered. If the EGD was placed as a matter of protocol, then a routine airway assessment should be performed using the LEMON, ROMAN, and SMART mnemonics (see Chapter 2). If the EGD was placed by an experienced provider after a failed intubation, then the airway should be considered difficult regardless of other predictors.
The expected clinical course for the patient must also be considered. If the patient requires urgent imaging or a critical procedure, these should not be delayed if the device is functioning and adequate gas exchange is taking place. If the patient has a deteriorating upper airway condition, such as a thermal inhalation injury that is anticipated to eventually preclude EGD functioning, then the EGD should be exchanged as soon as possible. If the patient is headed emergently to the operating room, then it may be reasonable to defer exchange to anesthesia providers. If, on the other hand, the patient is going to the interventional radiology suite or the cardiac catheterization lab, then the threshold to exchange for an ETT should probably be lowered. These are all decisions that should be made in consultation with the providers accepting the patient.
Finally, if the patient is being transferred between institutions, the threshold for intubation is also lowered, although it is very reasonable to transfer a patient with a well-functioning EGD in place if: (1) the exchange is predicted to be difficult; (2) the clinical condition is not likely to change over the course of transport such that the EGD would no longer be expected to provide effective oxygenation and ventilation; and (3) it is expected the device would remain in place no longer than 4 hours, after which the risk of ischemic mucosal injury (even with properly inflated devices) increases. This decision should be made in conjunction with the receiving hospital, transport team, and transport agency medical director whenever possible.
HOW TO PERFORM A SEMI-ELECTIVE EXCHANGE FOR AN ETT
We strongly discourage rushing to remove an EGD until the airway is thoroughly assessed and device-specific plans can be made. The techniques available for exchange will vary according to the attributes of each device (Table 12-1), available equipment, expertise, and the clinical situation.
Removal with Routine Intubation via Direct/Video Laryngoscopy
An EGD can always be deflated and removed. This approach may be utilized with any EGD when a difficult airway is not anticipated, patient physiology is favorable, and sufficient equipment for a more secure exchange is not available. It is advisable to decompress the stomach first when possible. The patient should be appropriately sedated and paralyzed as during an RSI procedure. Reinsertion of the same EGD is a consideration if intubation proves difficult or impossible, provided that it was not damaged when removed. Reinsertion does not guarantee success, however, with a number of anecdotes and case reports describing both intubation difficulty and subsequent EGD use after removal.
Attributes of Common EGDs and Selected Exchange Techniques |
Device | Type | Blind Passage of ETT through EGD Lumen | Visualized Passage of ETT through Lumen Using Endoscope or Intubating Stylet | Use of the Aintree Catheter for Exchange |
Combitube | Dual balloon Dual lumen Retroglottic | Not possible | Not possible | Not possible |
King Larygneal Tube | Dual balloon Single lumen Retroglottic | Not possible | Not possible | Possible |
King iLT-D | Dual balloon Single lumen Retroglottic | Possible Reliability not established |
