University Health Network
University of Toronto
University Health Network
University of Toronto
Endotracheal intubation remains the standard of care when definitive control of the airway is required.1 Unlike intubation in elective anesthesia, patients in an emergency department requiring airway access are assumed to have a full stomach and are therefore at risk for aspiration during intubation.2
In these patients, laryngoscopy itself may cause fluids from the esophagus to flood the pharyngeal cavity.1 Indeed, pulmonary aspiration occurs in 4% to 20% of all emergency intubations.3,4 This is especially a risk in patients with acute epistaxis, gastrointestinal bleeding, or a history of airway trauma.5-7
Aspiration of as little as one fourth of a mouthful (0.4 mL/kg) of stomach contents may cause severe pulmonary injury or even death.8 Moreover, the presence of oropharyngeal fluids in the airway obstructs the view of the vocal cords, resulting in repeated and often unsuccessful attempts at direct visualization of the larynx, interrupted by urgent suctioning of the oropharynx. Attempts at mask ventilation to maintain oxygenation may force fluids and particles into the lung. Standard airway management algorithms deal with this scenario in a cursory manner or not at all.9,10
Defaulting to the emergency establishment of surgical airway through a cricothyroidotomy—a procedure not practiced commonly by many emergency physicians—may also not be a suitable alternative. Even with successful cricothyroidotomy, air leaks from the larynx may prevent adequate lung ventilation. A cricothyroidotomy airway does not protect the lungs from aspiration of blood, airway secretions and stomach contents. There may not be any alternative but to deal with the massive fluid accumulation.
In this manuscript, we present 4 maneuvers to resolve the problem of rapid fluid accumulations in the pharynx obscuring laryngeal visualization. We expect that at least some of these methods are known to many critical care workers, but we suspect that few know them all. Indeed, we did not find them in our review of the published literature and standard textbooks. Our aim is to present the methods together to enlarge the repertoire of front-line health care workers in managing heavy secretion loads during attempts at airway access.
Murphy Eye Suction
The Murphy “eye” is a port at the distal end of an endotracheal tube (ETT) that was historically intended to provide right upper lobe lung ventilation in the case of inadvertent right main bronchus intubation. Although this port is unlikely to provide any benefit for its intended use, it can be used to hold a tracheal suction catheter while an assistant occludes the catheter’s bypass port to provide suction at the tip (Figures 1 and 2). The ETT is then used as a wand to direct the suction ports of the suction catheter. When the larynx is in clear view, the suction tip can be passed through the larynx and act as a guide for the ETT. The tracheal suction catheter can then be withdrawn before the ETT cuff is inflated. Alternatively, when there is good visualization, an assistant can withdraw the suction catheter immediately prior to passing the ETT through the laryngeal opening.
ETT as a Suction Wand
Should fluid accumulation exceed the suctioning capacity of the tracheal catheter or contain suspended solid food particles and/or clots, the ETT itself can be turned into a suction wand by attaching its proximal end directly to the suction tubing (Figure 2 and Appendix). Note that there is no suction applied to the lung when the ETT is in the trachea if the proximal hole is not occluded. If tracheal suction is required, it should be performed with a tracheal suction catheter passed down the ETT to avoid atelectasis and lung damage.
It may be difficult to decide on optimal patient positioning during laryngoscopy. Head-up tilt may reduce fluid being regurgitated from the stomach. The disadvantage of this position is that fluid coming from the nasopharynx or mouth will pool in the pharynx. Very little accumulation of fluid is required to obstruct the view of the larynx. Furthermore, if the operator is standing at the head of the bed, it is much more difficult to view the larynx during laryngoscopy if the head of the patient’s bed is tilted up.
Consider instead tilting the patient’s head down. Until the nasopharynx is filled with fluid, the air-fluid level will be in the nasopharynx, leaving the larynx exposed, and reducing the risk for aspiration. If there are no contraindications (such as craniofacial trauma11), one can additionally pass a nasopharyngeal airway and attach suction tubing with a hole cut in the distal portion of the tubing to provide continuous drainage (Figure 3). The tip of the nasopharyngeal airway can remain in the nasopharynx during attempts at laryngeal intubation, as it does not obscure the view of the larynx or obstruct the advancement of the ETT. Continuous suction at the level of the pharynx may allow continued visualization of the larynx with less head-down tilt.
The “Blind” Advance
The fourth strategy is most suitable if the source of the fluid is the gastrointestinal tract, especially in the presence of a large amount of particulate material in the pharynx. In this case, the ETT is advanced blindly and the cuff is inflated (Figure 4). A suction catheter is then passed down the ETT and aspirated. If air is aspirated (confirming that the ETT is in the trachea), then after suitable airway toilet, the patient may be ventilated by applying positive pressure to the self-inflating bag. If gastric fluid is aspirated, or if the catheter tip becomes occluded (indicating that the esophagus has collapsed around the suction catheter openings), then:
- a piece of tape is placed over the ETT connector, occluding the lumen of the tube;
- the ETT is advanced so that the ETT connector is flush with the mouth;
- the cuff is inflated with at least 10 cc of air;
- the pharynx is suctioned thoroughly;
- the patient is ventilated by applying positive airway pressure to the face mask with a self-inflating bag; and
- position is confirmed by listening for air entry in the lungs and over the stomach.
Once the patient is adequately ventilated, then:
- a gastric tube is passed through the ETT to decompress the stomach; and
- the ETT is left in place to prevent regurgitation of stomach contents.
This optimizes the conditions for a second attempt at endotracheal intubation using a direct or indirect method.
The 4 methods that we describe are designed to supplement the standard repertoire of methods of managing difficult airways and potentially circumvent the need for a surgical airway. Passing the tracheal suction catheter through the Murphy eye is certainly the fastest to implement. Its major limitation, however, is the diameter of the suction tubing, which limits the rate of fluid aspiration.
Using the ETT itself as a suction wand provides a larger bore for aspiration in the presence of massive pharyngeal flooding from the stomach, large particles such as food, or viscous mucous secretions12 that tend to clog even the standard Yankauer suction wand. Moreover, by modifying the ETT such that it also acts as a suction device, the clinician is able to maintain constant visualization of the vocal cords while advancing an ETT.
Placing the patient in a steep head-down tilt reduces pooling at the larynx and may also decrease the likelihood of aspiration of fluid. Its major limitations are that it may not be useful for viscous secretions, and head-down tilt makes the operator position for laryngoscopy more awkward.
Finally, the improvised combined airway can actually be a first-line approach with massive flooding of the airway, especially with vomit. The ventilation approach is similar in concept to several commercially available double-lumen endoesophageal tubes (Combitube).
A major concern during all emergency endotracheal intubations is the risk for aspiration of fluids or particulate matter into the lungs. In a study examining the incidence of cardiac arrest during emergency intubations, it was found that 83% of cases were associated with profound hypoxemia (oxygen saturation <70%) during the airway procedure,13 which is likely to occur with fluid aspiration after multiple failed intubation attempts. The airway maneuvers presented here may be considered in all emergency patients who are at risk for fluid aspiration, as the time taken to switch between an ETT and a suction wand may be the determining factor for the success of laryngeal intubation or the extent of aspiration.
While clearly these are improvised methods that require some time to assemble, they can be prospectively assembled and placed on designated airway carts throughout the emergency department to allow their use when needed, with minimal disruption.
In summary, we present 4 airway maneuvers intended to help manage fluid accumulations in the pharynx during attempts at endotracheal intubation. Our intention is to increase the repertoire of techniques for managing difficult airways of front-line health care workers in the emergency department.
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