Intermediate airways are those interventions that go beyond the maintenance of a patent airway. They represent a midpoint between airway establishment and true airway control. Airway control is secured by maneuvers such as tracheal intubation and tracheotomy, in which an endotracheal cuff isolates the trachea. The devices described in this section occlude the esophagus and allow ventilation across the larynx. The devices discussed are the esophageal obturator airway (EOA), the esophageal gastric tube airway (EGTA), the laryngeal mask airway (LMA) and the esophageal-tracheal Combitube (ETC) airway (Sheridan Catheter Corp., Argyle, NY). Two are designed to occlude only the esophagus (EOA and EGTA), one (LMA) seals the larynx at the hypopharynx level, and one ETC offers the versatility of use whether placed into the esophagus or the trachea. Each is designed for use in the unconscious patient who requires positive-pressure ventilation. The esophageal cuff or seal built into these devices reduces gastric content aspiration. The EOA and EGTA have fallen into general disfavor in recent years due to the gravity of errors in placement. Complications including esophageal rupture and tracheal intubation have led many to prefer the ETC or LMA as an intermediate airway.
Esophageal Obturator Airway and Esophageal Gastric Tube Airway
The EOA and the EGTA maintain airway patency in ways similar to the oral and nasal airways, but they also protect
the airway by occluding the esophagus to reduce gastric distention and regurgitation. The face mask permits use of these airways as positive-pressure ventilating devices. Air insufflated through the airway traverses the upper airway before crossing the larynx and entering the trachea. Ventilation from the EOA exits the airway through numerous ports in its hypopharyngeal portion . Ventilation from the EGTA is identical to mask ventilation, with the addition of esophageal occlusion. A port is available on the EGTA to vent the stomach. The attractiveness of the EOA and the EGTA for use in the apneic patient stems from their retention of much of the simplicity of the artificial airway with the addition of an important feature of more complicated airways--some protection against regurgitation and reduction of gastric distention.
Indications and Contraindications
Speed and simplicity are advantages of the esophageal airway over tracheal intubation. Trained individuals can successfully place an esophageal airway in an average of 5 seconds, whereas the same individuals may need 20 seconds to perform a tracheal intubation. In one out-of-hospital study, failure to intubate was much higher with the endotracheal tube (19.4%) than with the EOA (1.7%). [19] Neck motion is not as necessary with the esophageal airway as it is with tracheal intubation. For these reasons, the EOA may be an effective adjunct in the management of the unconscious injured patient who requires respiratory assistance. Hypercarbia may occur more commonly with EOA ventilation as compared with endotracheal ventilation. The most difficult aspect of this form of ventilation is securing a tight fit with the mask. Dentures should be left in place to give support to the lips. Adequate tidal volume must be delivered to ventilate the lungs.
There are various contraindications to the use of the EOA and the EGTA. Because the airway is not protected from pharyngeal secretions, the presence of active oropharyngeal bleeding and excessive secretions represent a relative contraindication to EOA and EGTA use. Because of attendant discomfort, the devices cannot be used in the awake patient. Size specifications preclude their use in the pediatric patient; 16 years is the age usually cited as the lower limit for EOA and EGTA use. The actual limiting factors are the size of the esophagus and the face; an adult-sized 14-year-old would certainly tolerate an EOA or EGTA if necessary. However, a small adult may not receive an appropriate fit. Other contraindications include esophageal injury or conditions predisposing to perforation. A patient who has ingested a caustic agent or one with a known esophageal stricture should not undergo esophageal intubation. As a precaution against pressure-related complications, it is recommended that the device not be left in place for longer than 2 hours. It must be recognized that the EOA and the EGTA are temporary forms of airway control. This form of airway control is most often used in out-of-hospital care.
Placement of EOA/EGTA
The head is in the neutral position during placement of the EOA and the EGTA. Neck motion is unnecessary. The rescuer grasps and pulls the jaw forward. At this point, the rescuer inserts the assembled airway with the mask attached. The obturator tip is directed into the patient's posterior pharynx with gentle, steady pressure. The obturator is advanced down the esophagus until the mask rests flush against the face of the patient. Figure 1-9 (Figure Not Available) A illustrates the correct position at placement. The cuff should lie in the esophagus just distal to the carina of the trachea. The rescuer postpones inflation of the balloon until proper position is confirmed. The patient is ventilated with a tight mask seal on the face, and the lungs are auscultated. For effective ventilation, the mask seal must be tight. Breath sounds should be audible bilaterally. Unilateral breath sounds or failure of auscultation should lead the rescuer to reassess the airway placement. Pneumothorax or hemothorax may explain unilateral sounds, as may inadvertent main stem bronchus intubation. Tracheal intubation will result in the absence of breath sounds. The possibility of bronchial or tracheal intubation requires removal and replacement of the airway. Once satisfactorily placed, the esophageal balloon is inflated to 20 to 25 mL.
Complications
A 5% incidence of inadvertent tracheal intubation has been reported by Don Michael in experience with 29,000 placements. In a subsequent smaller sample, a 2.9% (5 of 170) incidence was reported with a 100% mortality among the 5 patients. One study comparing out-of-hospital EOA placement with endotracheal tube placement found that the occurrence rate for complications of the EOA that prevented resuscitation (tracheal placement, tube kinking) was nearly three times higher for the EOA (8.7% vs 2.6%). If not quickly rectified, tracheal intubation with the EOA or tube kinking are disastrous complications that produce occlusion of the patient's airway. Disciplined examination for bilateral breath sounds is critical.
Esophageal lacerations of undetermined depth were found in 8.5% of autopsies of patients in whom the EOA was used.Esophageal rupture has been found and reported in case histories. Since Scholl and Tsai first reported esophageal ruptures in 1977, the recommended balloon inflation volume was reduced from 35 to 20 mL. No further ruptures or leakage around the cuff have been reported. However, factors other than balloon inflation volume that theoretically can contribute to rupture include careless balloon removal without deflation and forceful attempts at placement when obstruction is met.
Tracheal intubation should be performed BEFORE removal of the EOA, because vomiting often occurs following deflation of the balloon and EOA removal. If the EOA cuff has been overinflated, it may partially occlude the trachea and make intubation difficult. In such cases, the balloon is partially deflated to facilitate tracheal intubation.
The Laryngeal-Mask Airway
The laryngeal-mask airway (LMA) (Intavent International SA, Henley-on-Thames, England) functions intermediately between an oropharyngeal airway and an endotracheal tube. It was developed for use in the operating room as an alternative for endotracheal intubation, but it has also been recommended for use in difficult intubations. It consists of a tube fitted with an oval mask, rimmed with an inflatable cuff. Contrary to usual mask design, the mask is intended to reside in the hypopharynx rather than on the face. It is inserted digitally until its tip meets resistance in the upper esophageal sphincter. The cuff is then inflated, forming a seal around the glottic opening. The result is a relatively secure airway. However, it cannot be considered to protect against gastric regurgitation. Leakage of the hypopharyngeal mask allows aspiration of emesis and gastric distention may occur with misplacement. Although the device may be used for prolonged periods under appropriate conditions, it is usually considered a temporary adjunct until tracheal intubation is established.
Indications and Contraindications
The LMA is indicated for patients requiring an airway who cannot be endotracheally intubated. The most frequently cited example is a patient whose anatomy prevents visualization of the larynx. Contraindications include the inability to open the patient's mouth and vomiting.
Placement of LMA
The LMA is first checked for possible air leaks by inflating and deflating the cuff. If the patient has a gag reflex, deep oropharyngeal topical anesthesia or conscious sedation must be administered. With the patient's head in the sniffing position, the mask is lubricated and oriented so the mask opening is facing the tongue. With the index finger of the dominant hand placed on the proximal aspect of the mask, the mask is inserted into the mouth, firmly against the hard palate. The index finger (or thumb) may also be used as a guide during advancement. With one smooth motion, the mask is advanced until resistance is encountered. With the tip of the mask thus seated in the upper esophageal sphincter, the cuff is inflated. The lungs are auscultated to confirm correct placement.
While the sniffing position is desirable, it has been shown that LMA placement was 95% successful when the patient was placed in the neutral position with in-line immobilization, simulating a trauma setting.
After successful placement of the LMA, several methods are available to achieve subsequent endotracheal intubation. The first method is simply to pass an appropriately sized endotracheal tube down through the lumen of the LMA, rotate the tube 90° so that the tip easily passes through the fenestrations, and advance it through the larynx to the trachea . This has been found to be successful in 90% of attempted cases. The second method involves the use of a tracheal tube exchanger. The exchanger is passed blindly down the lumen of the LMA and into the trachea. The LMA is then removed and an endotracheal tube is passed over the tracheal tube exchanger. This method of tube placement must be combined with confirmation of exchanger location, because it has been shown to pass into the esophagus in up to 70% of attempts. Confirmation of endotracheal tube location should be made . The third and most dependable method of intubation with an LMA in place is via a fiberoptic scope. A lubricated, appropriately sized endotracheal tube is mounted over a fiberoptic scope, and this combination is advanced through the lumen of the LMA out through the mask and through the larynx. The scope is then removed, but the LMA may be left in place with the cuff deflated. If the LMA must be removed after a tracheal tube has been successfully placed through it, pass a tracheal tube exchanger down the tube, remove the tracheal tube/LMA combination, and replace it with a tracheal tube.
Complications
Although the LMA works well in most cases, this airway has several significant drawbacks. Aspiration is always a possibility, because the cuff does not provide a watertight seal. Laryngospasm can occur if adequate anesthesia is not achieved. A significant air leak around the cuff may occur when high airway pressures exist, leading to poor ventilation. Finally, success rates in the operating room range from 94 to 98%; success rates in difficult emergency airway management are unknown, but they are undoubtedly lower.
Conclusion
The LMA is a blindly placed intermediate airway that should be considered in patients who require establishment of an emergency airway but cannot receive endotracheal intubation. The technique is quick and simple, requires a minimum amount of training, and appears effective in the hands of paramedics, nurses, and respiratory therapists.
The Esophageal-Tracheal Combitube
The ETC is a noninvasive airway device that is placed blindly. It allows for effective ventilation and oxygenation when placed in either the esophagus or the trachea. The device has two lumina running parallel to each other. One is perforated at the level of the pharynx and occluded at the distal end, similar to the EOA. The second lumen is open at the distal end, resembling an endotracheal tube. The device has two balloons: a proximal pharyngeal balloon that occludes the oropharynx by filling the space between the base of the tongue and the soft palate and a smaller, distal cuff that serves as a seal in either the esophagus or trachea . The Combitube has compared favorably with the endotracheal tube with respect to ventilation and oxygenation in cardiac arrest situations. It is also placed more rapidly.
Indications and Contraindications
The ETC is superior to other intermediate airways, because no face mask seal is necessary. It may be preferable to tracheal intubation in certain situations, because it can be placed blindly and is also effective in the esophageal or tracheal position. It is, therefore, more easily placed than an endotracheal tube and is indicated in situations in which tracheal intubation is difficult, neck motion is impossible, or the rescuers are not skilled in tracheal intubation.
The ETC should not be used in patients with an intact gag reflex and is not recommended in patients younger than 16 years or less than 5 feet in height. It is contraindicated in suspected caustic poisonings or proximal esophageal disorders.
Placement of ETC
The device is held in the dominant hand and gently placed caudally into the pharynx while the nondominant hand grasps the tongue and jaw between the thumb and index finger. The tube is passed blindly to a depth where the printed rings on the proximal end of the tube lie between the patient's teeth or alveolar ridge. The pharyngeal balloon is then filled with 100 mL of air, and the distal cuff is subsequently filled with 10 to 15 mL of air. The large pharyngeal balloon serves to both securely seat the ETC in the oropharynx and to create a closed system in the case of esophageal placement. Because approximately three-quarters of placements are esophageal, ventilation is begun through the longer (blue plastic) connector associated with the esophageal lumen. Chest rise and good breath sounds without gastric insufflation confirms effective placement in the esophagus. However, gastric insufflation without breath sounds and chest rise indicate a tracheal positioning of the tube and require changing the ventilation to the shorter (clear plastic) tracheal lumen. Auscultation of breath sounds over the lateral lung fields confirms endotracheal placement of the Combitube. If the tube is in the esophageal position, gastric suctioning can be accomplished by passing a catheter through the open lumen into the stomach while the patient is being ventilated via the other port.
An alternative method to identify position is to attach an aspirating device to the tracheal or clear plastic shorter tube. The inability to easily aspirate air confirms esophageal placement necessitating ventilation via the longer blue esophageal tube. In the patient with ventilatory effort, CO2 detector devices also may be useful.
A patient who has been successfully resuscitated with an ETC positioned in the esophagus should ultimately receive a definitive airway. The steps required to place a tracheal tube in this setting are detailed in Chapter 2 but consist generally of deflating the large pharyngeal balloon and, with the distal balloon still inflated, intubating around the ETC.
Complications
Inappropriate balloon inflation and incorrect ETC placement can lead to air leaks during ventilation. The most common placement error is an improper insertion angle. A more caudal, longitudinal direction is recommended, as opposed to an anteroposterior direction of insertion. Another caveat is that the ETC must be maintained in the true midline position during insertion to avoid blind pockets in the supraglottic area, which prevent passage of the tube. Attention to the ring markings on the tube at the level of the incisors ensures proper positioning of the tube. One must remember to first inflate the oropharyngeal balloon before inflating the distal balloon. Although unlikely, esophageal injury is theoretically possible with the overinflation of the distal balloon.
Esophageal Obturator Airway and Esophageal Gastric Tube Airway
The EOA and the EGTA maintain airway patency in ways similar to the oral and nasal airways, but they also protect
the airway by occluding the esophagus to reduce gastric distention and regurgitation. The face mask permits use of these airways as positive-pressure ventilating devices. Air insufflated through the airway traverses the upper airway before crossing the larynx and entering the trachea. Ventilation from the EOA exits the airway through numerous ports in its hypopharyngeal portion . Ventilation from the EGTA is identical to mask ventilation, with the addition of esophageal occlusion. A port is available on the EGTA to vent the stomach. The attractiveness of the EOA and the EGTA for use in the apneic patient stems from their retention of much of the simplicity of the artificial airway with the addition of an important feature of more complicated airways--some protection against regurgitation and reduction of gastric distention.
Indications and Contraindications
Speed and simplicity are advantages of the esophageal airway over tracheal intubation. Trained individuals can successfully place an esophageal airway in an average of 5 seconds, whereas the same individuals may need 20 seconds to perform a tracheal intubation. In one out-of-hospital study, failure to intubate was much higher with the endotracheal tube (19.4%) than with the EOA (1.7%). [19] Neck motion is not as necessary with the esophageal airway as it is with tracheal intubation. For these reasons, the EOA may be an effective adjunct in the management of the unconscious injured patient who requires respiratory assistance. Hypercarbia may occur more commonly with EOA ventilation as compared with endotracheal ventilation. The most difficult aspect of this form of ventilation is securing a tight fit with the mask. Dentures should be left in place to give support to the lips. Adequate tidal volume must be delivered to ventilate the lungs.
There are various contraindications to the use of the EOA and the EGTA. Because the airway is not protected from pharyngeal secretions, the presence of active oropharyngeal bleeding and excessive secretions represent a relative contraindication to EOA and EGTA use. Because of attendant discomfort, the devices cannot be used in the awake patient. Size specifications preclude their use in the pediatric patient; 16 years is the age usually cited as the lower limit for EOA and EGTA use. The actual limiting factors are the size of the esophagus and the face; an adult-sized 14-year-old would certainly tolerate an EOA or EGTA if necessary. However, a small adult may not receive an appropriate fit. Other contraindications include esophageal injury or conditions predisposing to perforation. A patient who has ingested a caustic agent or one with a known esophageal stricture should not undergo esophageal intubation. As a precaution against pressure-related complications, it is recommended that the device not be left in place for longer than 2 hours. It must be recognized that the EOA and the EGTA are temporary forms of airway control. This form of airway control is most often used in out-of-hospital care.
Placement of EOA/EGTA
The head is in the neutral position during placement of the EOA and the EGTA. Neck motion is unnecessary. The rescuer grasps and pulls the jaw forward. At this point, the rescuer inserts the assembled airway with the mask attached. The obturator tip is directed into the patient's posterior pharynx with gentle, steady pressure. The obturator is advanced down the esophagus until the mask rests flush against the face of the patient. Figure 1-9 (Figure Not Available) A illustrates the correct position at placement. The cuff should lie in the esophagus just distal to the carina of the trachea. The rescuer postpones inflation of the balloon until proper position is confirmed. The patient is ventilated with a tight mask seal on the face, and the lungs are auscultated. For effective ventilation, the mask seal must be tight. Breath sounds should be audible bilaterally. Unilateral breath sounds or failure of auscultation should lead the rescuer to reassess the airway placement. Pneumothorax or hemothorax may explain unilateral sounds, as may inadvertent main stem bronchus intubation. Tracheal intubation will result in the absence of breath sounds. The possibility of bronchial or tracheal intubation requires removal and replacement of the airway. Once satisfactorily placed, the esophageal balloon is inflated to 20 to 25 mL.
Complications
A 5% incidence of inadvertent tracheal intubation has been reported by Don Michael in experience with 29,000 placements. In a subsequent smaller sample, a 2.9% (5 of 170) incidence was reported with a 100% mortality among the 5 patients. One study comparing out-of-hospital EOA placement with endotracheal tube placement found that the occurrence rate for complications of the EOA that prevented resuscitation (tracheal placement, tube kinking) was nearly three times higher for the EOA (8.7% vs 2.6%). If not quickly rectified, tracheal intubation with the EOA or tube kinking are disastrous complications that produce occlusion of the patient's airway. Disciplined examination for bilateral breath sounds is critical.
Esophageal lacerations of undetermined depth were found in 8.5% of autopsies of patients in whom the EOA was used.Esophageal rupture has been found and reported in case histories. Since Scholl and Tsai first reported esophageal ruptures in 1977, the recommended balloon inflation volume was reduced from 35 to 20 mL. No further ruptures or leakage around the cuff have been reported. However, factors other than balloon inflation volume that theoretically can contribute to rupture include careless balloon removal without deflation and forceful attempts at placement when obstruction is met.
Tracheal intubation should be performed BEFORE removal of the EOA, because vomiting often occurs following deflation of the balloon and EOA removal. If the EOA cuff has been overinflated, it may partially occlude the trachea and make intubation difficult. In such cases, the balloon is partially deflated to facilitate tracheal intubation.
The Laryngeal-Mask Airway
The laryngeal-mask airway (LMA) (Intavent International SA, Henley-on-Thames, England) functions intermediately between an oropharyngeal airway and an endotracheal tube. It was developed for use in the operating room as an alternative for endotracheal intubation, but it has also been recommended for use in difficult intubations. It consists of a tube fitted with an oval mask, rimmed with an inflatable cuff. Contrary to usual mask design, the mask is intended to reside in the hypopharynx rather than on the face. It is inserted digitally until its tip meets resistance in the upper esophageal sphincter. The cuff is then inflated, forming a seal around the glottic opening. The result is a relatively secure airway. However, it cannot be considered to protect against gastric regurgitation. Leakage of the hypopharyngeal mask allows aspiration of emesis and gastric distention may occur with misplacement. Although the device may be used for prolonged periods under appropriate conditions, it is usually considered a temporary adjunct until tracheal intubation is established.
Indications and Contraindications
The LMA is indicated for patients requiring an airway who cannot be endotracheally intubated. The most frequently cited example is a patient whose anatomy prevents visualization of the larynx. Contraindications include the inability to open the patient's mouth and vomiting.
Placement of LMA
The LMA is first checked for possible air leaks by inflating and deflating the cuff. If the patient has a gag reflex, deep oropharyngeal topical anesthesia or conscious sedation must be administered. With the patient's head in the sniffing position, the mask is lubricated and oriented so the mask opening is facing the tongue. With the index finger of the dominant hand placed on the proximal aspect of the mask, the mask is inserted into the mouth, firmly against the hard palate. The index finger (or thumb) may also be used as a guide during advancement. With one smooth motion, the mask is advanced until resistance is encountered. With the tip of the mask thus seated in the upper esophageal sphincter, the cuff is inflated. The lungs are auscultated to confirm correct placement.
While the sniffing position is desirable, it has been shown that LMA placement was 95% successful when the patient was placed in the neutral position with in-line immobilization, simulating a trauma setting.
After successful placement of the LMA, several methods are available to achieve subsequent endotracheal intubation. The first method is simply to pass an appropriately sized endotracheal tube down through the lumen of the LMA, rotate the tube 90° so that the tip easily passes through the fenestrations, and advance it through the larynx to the trachea . This has been found to be successful in 90% of attempted cases. The second method involves the use of a tracheal tube exchanger. The exchanger is passed blindly down the lumen of the LMA and into the trachea. The LMA is then removed and an endotracheal tube is passed over the tracheal tube exchanger. This method of tube placement must be combined with confirmation of exchanger location, because it has been shown to pass into the esophagus in up to 70% of attempts. Confirmation of endotracheal tube location should be made . The third and most dependable method of intubation with an LMA in place is via a fiberoptic scope. A lubricated, appropriately sized endotracheal tube is mounted over a fiberoptic scope, and this combination is advanced through the lumen of the LMA out through the mask and through the larynx. The scope is then removed, but the LMA may be left in place with the cuff deflated. If the LMA must be removed after a tracheal tube has been successfully placed through it, pass a tracheal tube exchanger down the tube, remove the tracheal tube/LMA combination, and replace it with a tracheal tube.
Complications
Although the LMA works well in most cases, this airway has several significant drawbacks. Aspiration is always a possibility, because the cuff does not provide a watertight seal. Laryngospasm can occur if adequate anesthesia is not achieved. A significant air leak around the cuff may occur when high airway pressures exist, leading to poor ventilation. Finally, success rates in the operating room range from 94 to 98%; success rates in difficult emergency airway management are unknown, but they are undoubtedly lower.
Conclusion
The LMA is a blindly placed intermediate airway that should be considered in patients who require establishment of an emergency airway but cannot receive endotracheal intubation. The technique is quick and simple, requires a minimum amount of training, and appears effective in the hands of paramedics, nurses, and respiratory therapists.
The Esophageal-Tracheal Combitube
The ETC is a noninvasive airway device that is placed blindly. It allows for effective ventilation and oxygenation when placed in either the esophagus or the trachea. The device has two lumina running parallel to each other. One is perforated at the level of the pharynx and occluded at the distal end, similar to the EOA. The second lumen is open at the distal end, resembling an endotracheal tube. The device has two balloons: a proximal pharyngeal balloon that occludes the oropharynx by filling the space between the base of the tongue and the soft palate and a smaller, distal cuff that serves as a seal in either the esophagus or trachea . The Combitube has compared favorably with the endotracheal tube with respect to ventilation and oxygenation in cardiac arrest situations. It is also placed more rapidly.
Indications and Contraindications
The ETC is superior to other intermediate airways, because no face mask seal is necessary. It may be preferable to tracheal intubation in certain situations, because it can be placed blindly and is also effective in the esophageal or tracheal position. It is, therefore, more easily placed than an endotracheal tube and is indicated in situations in which tracheal intubation is difficult, neck motion is impossible, or the rescuers are not skilled in tracheal intubation.
The ETC should not be used in patients with an intact gag reflex and is not recommended in patients younger than 16 years or less than 5 feet in height. It is contraindicated in suspected caustic poisonings or proximal esophageal disorders.
Placement of ETC
The device is held in the dominant hand and gently placed caudally into the pharynx while the nondominant hand grasps the tongue and jaw between the thumb and index finger. The tube is passed blindly to a depth where the printed rings on the proximal end of the tube lie between the patient's teeth or alveolar ridge. The pharyngeal balloon is then filled with 100 mL of air, and the distal cuff is subsequently filled with 10 to 15 mL of air. The large pharyngeal balloon serves to both securely seat the ETC in the oropharynx and to create a closed system in the case of esophageal placement. Because approximately three-quarters of placements are esophageal, ventilation is begun through the longer (blue plastic) connector associated with the esophageal lumen. Chest rise and good breath sounds without gastric insufflation confirms effective placement in the esophagus. However, gastric insufflation without breath sounds and chest rise indicate a tracheal positioning of the tube and require changing the ventilation to the shorter (clear plastic) tracheal lumen. Auscultation of breath sounds over the lateral lung fields confirms endotracheal placement of the Combitube. If the tube is in the esophageal position, gastric suctioning can be accomplished by passing a catheter through the open lumen into the stomach while the patient is being ventilated via the other port.
An alternative method to identify position is to attach an aspirating device to the tracheal or clear plastic shorter tube. The inability to easily aspirate air confirms esophageal placement necessitating ventilation via the longer blue esophageal tube. In the patient with ventilatory effort, CO2 detector devices also may be useful.
A patient who has been successfully resuscitated with an ETC positioned in the esophagus should ultimately receive a definitive airway. The steps required to place a tracheal tube in this setting are detailed in Chapter 2 but consist generally of deflating the large pharyngeal balloon and, with the distal balloon still inflated, intubating around the ETC.
Complications
Inappropriate balloon inflation and incorrect ETC placement can lead to air leaks during ventilation. The most common placement error is an improper insertion angle. A more caudal, longitudinal direction is recommended, as opposed to an anteroposterior direction of insertion. Another caveat is that the ETC must be maintained in the true midline position during insertion to avoid blind pockets in the supraglottic area, which prevent passage of the tube. Attention to the ring markings on the tube at the level of the incisors ensures proper positioning of the tube. One must remember to first inflate the oropharyngeal balloon before inflating the distal balloon. Although unlikely, esophageal injury is theoretically possible with the overinflation of the distal balloon.
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