Please take this very serious one of our groups lost a pt that could not be reintubated after being extubated.
Sally Stander, MD
Assistant Professor of Anesthesiology
Department of Anesthesiology
University of North Carolina at Chapel Hill School of Medicine
“Please come exchange the endotracheal tube in the ICU. We think there is a cuff leak.”
I was called to the ICU for an endotracheal tube (ETT) exchange on a patient weighing 312 kg because ventilation was intermittently inadequate. According to the report, the patient became bradycardic when the tidal volume diminished and the saturations dropped. Upon my arrival, the saturations were at 100% with adequate tidal volume. I would be hard-pressed to manipulate the ETT given the patient’s size and potential for loss of airway. I was curious whether the situation was caused by a mucous plug, malposition, or perhaps a cuff leak. The respiratory therapist informed me that she had inflated the cuff with greater than 70 mL of air and that there was a leak. Then, while I was still in the room, ventilation began to fail and I knew I had to come up with a plan.
Managing airways outside the operating room (OR) presents unique challenges that are not typical in the OR environment, and may require thinking beyond the American Society of Anesthesiologists (ASA) Difficult Airway Algorithm.1Anesthesiologists are often the personnel to respond to codes and intubations in the hospital units, ICUs, emergency departments, and clinics. Performing emergent intubations in unfamiliar locations increases the complexity and creates a higher incidence of difficult intubations and complications.2
ETT exchange with an airway exchange catheter seems like a straightforward procedure, but it should be approached with caution, as there are several case reports of complications related to the procedure.3-5 Devising a well-developed plan is necessary to reduce the need to default to the end point of the ASA Difficult Airway Algorithm warranting an emergent invasive surgical airway.
As airway experts, anesthesiologists reviewed airway assessment data and determined the safety of intubation techniques leading to the development of the ASA Difficult Airway Algorithm. There is a paucity of data on the safety of techniques for airway exchange and no algorithm to use as a resource. This narrative review focuses on strategies for safe airway exchange techniques, particularly those occurring outside the OR environment.
Airway Management in Non-OR Settings
Airway management complications and unanticipated failures in the OR are rather uncommon. The opportunity for a preoperative airway assessment, optimal positioning, preoxygenation, proper equipment, skilled assistants, and backup plans all regularly lead to success.
Airway management in non-OR settings does not provide the same opportunities for preparedness, and the rate of complications and failures increases.6Exchanging ETTs, while not an uncommon procedure, may take place as a result of scenarios including the following: 1) exchanging a double-lumen tube for a single-lumen ETT, or vice versa; 2) upsizing an ETT for bronchoscopy; and 3) upsizing an ETT to reduce resistance for weaning from a ventilator. These examples are more controlled, nonurgent exchanges.
Exchanging an ETT because of tube malfunction is often needed in an urgent situation for a patient who has reduced physiologic reserves. These patients have an airway that is functional—at least to some capacity—so blindly forging ahead to exchange an ETT or reintubate is cavalier. Because patients are often compromised beyond respiratory failure—whether that be altered mental status, sepsis, cardiovascular instability, or sequelae from other chronic illnesses—it is prudent to be aware of the barriers to safe airway management in remote locations. Familiarity with equipment and having quick access to airway devices, tools, and medications are critical.
In reviewing the literature on ETT exchanges, case reports of complications were most commonly published. Mort published two studies in 2009 and 2015 supporting the use of video laryngoscopy for glottis visualization during an ETT exchange over an airway exchange catheter.7,8 Review articles related to airway complications and management in critical care—not specifically ETT exchanges—provide insight into the risks and address ways to minimize poor outcomes with adequate training, equipment, and vigilance.2,9,10 Research into this specific area of airway exchange management is lacking.
When approaching the ETT exchange conundrum, there is no evidence-based algorithm. Several points must be addressed before moving forward with an exchange: First is the differential diagnosis of why the ETT is not functioning as expected. Perhaps it is a cuff leak, but that is not the only possibility. In a study by Kearl and Hooper, 18 ETTs were exchanged over a 2-year period for massive air leaks. Only 5 (28%) ETTs that were exchanged actually had a confirmed cuff perforation, demonstrating that a leak is not necessarily a torn cuff, and an exchange may not be necessary.11
The second step is confirming the diagnosis and resolving the issue from step 1, but only if the situation permits. Considerations at this point are diagnostic methods, the mechanism of exchange, drugs to administer, and the patients’ comorbidities. There are many approaches and adjuncts to facilitate an airway exchange, and it is a good idea to review and be familiar with what is available. Lastly, consider the long- or short-term ventilation plan, and be prepared for a lost airway.
Diagnosis of the ETT Malfunction
Determining the diagnosis is key because the ETT does not always need to be replaced, thereby avoiding risk. Most requests from the ICU are for an ETT exchange because of a cuff leak or the need for an increase in size of the ETT before bronchoscopy. An algorithm for the management of a displaced ETT was published by Nolan and Kelly based on the 4th National Audit Project.10 When monitoring a ventilated patient in the ICU, airway managers should consider ETT tube displacement or malfunction if there is hypoxia, cardiovascular instability, inadequate ventilation, or loss of pressure in the cuff.
The next steps should be to call for help, monitor end-tidal carbon dioxide tracing, and support with 100% oxygen.10 Check the position of the ETT at the teeth, and review a recent chest radiograph to assess the ETT position. Often the lack of pressure in the cuff is due to herniation of the cuff above the vocal cords rather than a cuff leak. Pass a suction catheter to clear any secretions or blockages. Assess the patient’s sedation status. An agitated patient may bite the tube or fight the ventilator, causing problems with ventilation. If a new oral or nasogastric tube has been placed, it may be interfering with ventilation and should be removed. A displaced ETT does not need to be exchanged to become functional after proper repositioning. It needs to be correctly positioned above the carina.
If the initial assessment is inconclusive, it may be necessary to explore the diagnostic possibilities with visualization, and exchange the tube if necessary. Viewing of the glottis and the tracheal tube passing through the vocal cords is important for diagnosis. During a first look, valuable information of the airway is obtained, and the position of the ETT may be confirmed. This first view is recommended before placing an airway exchange catheter. There are several modes of visualization: direct laryngoscopy, fiber-optic bronchoscopy, and video laryngoscopy. Starting with video laryngoscopy is a good choice due to the increased difficulty and complication rates associated with intubations in the ICU.8 Several portable devices are available that function well in this situation, such as the King Vision (Ambu), McGrath MAC (Medtronic), C-MAC (KARL STORZ), and C-MAC D-Blade (KARL STORZ). The portability and rapid availability of video laryngoscopy are features that make it a practical option, so having easily accessible video laryngoscopy is crucial.
If viewing the ETT passing through the vocal cords is unsuccessful, using a fiber-optic bronchoscope (FOB) passing through the ETT can confirm positioning within the trachea. The FOB can be used to guide a malpositioned ETT into place. The FOB may be a necessity when difficult airways are not adequately visualized with video laryngoscopy.
Ultrasound is quickly becoming a great perioperative diagnostic tool. Its role in airway management has been reviewed by Chou et al.12 The prevalence of the use of ultrasound for airway diagnostics, although not currently common, may soon increase and become another valuable tool in airway management.
Mechanisms for Exchange
Airway exchange catheters are long, semirigid, hollow tubes that pass through an ETT that can be used to supply oxygenation through an adapter (Figure 2). A thorough list of catheters and their properties was published by Hagberg in her most recent review in Anesthesiology News of the management of difficult airways.13 After passing a lubricated airway exchange catheter, while visualizing with direct or video laryngoscopy, the ETT is removed and a new ETT is placed, allowing confirmation of the endotracheal intubation. When an airway exchange catheter is passed and the tube exchanged without visualization, there is a significant risk for an esophageal intubation.5 If the ETT had herniated above the vocal cords, the airway exchange catheter may not advance between the vocal cords. The airway exchange catheter also could be displaced from the trachea during the exchange if it is not advanced far enough into the airway.
Using an airway exchange catheter serves as a conduit to facilitate ETT replacement, but its use does not come without risks. Reports of pneumothorax and mucosal trauma have occurred.4,14 An airway manager must be cognizant of the depth of insertion. It is recommended to insert the airway exchange catheter to a depth of no more than 20 to 25 cm. Also, if attempting to oxygenate through the airway exchange catheter, the airway manager must consider the airway pressure and potential for barotrauma.15 On occasion, the ETT will not pass smoothly along the airway exchange catheter, most likely due to impingement on the arytenoids or glottic structures. Using an airway exchange catheter that has a closer outer diameter to the ETT inner diameter helps prevent this problem (Figure 3).8,16 When advancement is hindered, rotating the ETT 90 degrees counterclockwise will turn the bevel and assist in freeing passage through the vocal cords.
The Aintree Intubation Catheter (AIC; Cook Medical) is a specialized airway exchange catheter with a larger internal diameter to allow a pediatric FOB to pass through the center; it is more commonly used for intubation of difficult airways through supraglottic airway devices.17 An Aintree catheter also is beneficial for examining a nonfunctional ETT and having a way to place a catheter in the trachea at the same time. For this technique, passing the FOB beside the existing ETT allows external visualization of the ETT to determine the reason for the malfunction. As the FOB and AIC are advanced between the vocal cords, the in situ ETT can be removed. The Aintree exchange catheter and FOB can be advanced to the carina. The FOB is removed while securing the position of the AIC.
An ETT can then be advanced over the catheter using the Seldinger technique, followed by reinsertion of the FOB via the AIC, to reconfirm position as the ETT is advanced into the trachea. This is similar to a technique described by Hou et al for exchanging an ETT with the use of 2 airway exchange catheters.18 That is, the first airway exchange catheter is advanced through the existing ETT, and the second airway exchange catheter of a smaller caliber is preloaded with another ETT positioned under visualization through the vocal cords while desufflating the tracheal cuff. Having a preloaded ETT at the glottis allows for minimal time from extubation to reestablishing the airway. This is beneficial in patients who may desaturate quickly. Also, when the original tube is removed, the larger airway exchange catheter is kept in place so that the airway is protected with 2 catheters and a means of oxygenation if any mishaps occur.18
These techniques allow for continued ventilation through the existing tube, thereby reducing the time for desaturation to occur, and FOB placement of a catheter that can be used for oxygenation if there is difficulty during the exchange. This type of exchange requires more equipment and coordination, but can be valuable in difficult airway situations.
In addition to the technical aspects of exchanging an ETT, pharmacologic management requires thoughtful consideration. For sedation, propofol, ketamine, and etomidate are commonly used drugs. Deciding on an induction agent is highly dependent on patient comorbidities and the current status of patient sedation. When not contraindicated, succinylcholine is a reasonable option in a straightforward exchange. If it is anticipated to be a difficult exchange, or if there are contraindications to succinylcholine use, a non-depolarizing agent should be used. Rocuronium can be quickly reversed with sugammadex (Bridion, Merck), and for this reason is another practical option.19 The use of neuromuscular blockers (NMBs) provides optimal intubating conditions and has been shown to improve success rates of emergency intubations.20 Also, NMBs prevent coughing or bucking, which may lead to dislodging the airway exchange catheter and a lost airway. The use of remifentanil (Ultiva, Mylan) as an alternative to an NMB has been used.21 Having immediate access to pressors and code medications is crucial in this environment. A useful emergency induction checklist was published as an appendix in Nolan and Kelly’s review.10
Failure of an ETT Exchange
Despite all the advances in airway equipment and products to facilitate airway exchange, there will be failures. In any airway exchange situation, airway managers should be cognizant of the potential for complications and disaster and prepared to move quickly. Being in an unfamiliar location with unfamiliar personnel and limited resources is difficult. Add to that an acutely ill, potentially decompensating patient and the situation is dire. A well-thought-out plan, backup plan, and emergency preparedness will help to mitigate the risks. Having surgical colleagues present at the bedside is valuable in difficult airway situations. Depending on the urgency, consideration of the long-term ventilation plan is helpful when deciding whether to exchange the ETT or to proceed with a tracheostomy in a controlled environment. The optimal controlled setting may be the OR.
Learning how to use equipment and common techniques for various airway exchange scenarios should be part of anesthesia and critical care training. As with any technique, user familiarity and clinical judgment are invaluable during an exchange procedure. When addressing the ETT exchange, having a pragmatic plan is essential.
We are resourceful, and as anesthesiologists, we react quickly to solve problems creatively. But in the context of patient safety and airway management, we must be expertly prepared.
If patient parameters are favorable—nonobese, adequate oxygenation, history of easy intubation, and no obvious airway challenges—a low-risk exchange strategy is indicated. With a known easy airway from a recent intubation, or a first view with laryngoscopy, it is reasonable to simply extubate and reintubate the patient and avoid the risks associated with airway exchange catheters. This is more common in an OR setting. Most often in the ICU, the patient does not meet the favorable parameters noted above and more thoughtful means of managing the airway are necessary.
In the initial case scenario, the reason for inadequate ventilation was not certain. It was not possible to pass a suction catheter beyond the tube. The initial plan was to visualize with video laryngoscopy, to see whether the ETT had passed through the vocal cords. Before proceeding, surgical colleagues were present in case an emergent surgical airway was necessary. During video laryngoscopy, only soft tissue was visualized due to body habitus and a large tongue.
Recognizing the potential risk for trauma with an airway exchange catheter, a fiberoptic scope was passed down the ETT. Again, nothing but pink tissue was noted at the end of the ETT; no recognizable airway structures were visualized. In between these maneuvers, we were able to ventilate again and saturations improved. The working hypothesis was that the ETT had migrated above the vocal cords or there was a large, partially obstructing soft tissue mass in the airway. An attempt was made to visualize the ETT by passing the FOB through an oral airway alongside the tube, which was unsuccessful again due to a large tongue and redundant oropharyngeal tissue. Passing the FOB through the nasal passage finally revealed a herniated, overfilled cuff and an ETT that was acting more like a laryngeal mask airway.
The cuff was deflated, and a view of the glottis became evident. At that point, the ETT was advanced between the vocal cords without the need for an exchange catheter.
Because there is no current airway exchange catheter algorithm, criterion, and/or evidence-based research, it is important to have a methodical, systematic approach to managing ETT exchanges. Perhaps this guideline will lead to safer outcomes.
- Apfelbaum JL, Hagberg CA, Caplan RA, et al. Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology. 2013;118(2):251-270.
- Martin LD, Mhyre JM, Shanks AM, et al. 3,423 emergency tracheal intubations at a university hospital: airway outcomes and complications. Anesthesiology. 2011;114(1):42-48.
- Benumof JL. Airway exchange catheters: simple concept, potentially great danger. Anesthesiology. 1999;91(2):342-344.
- de Almeida JP, Hajjar LA, Fukushima JT, et al. Bronchial injury and pneumothorax after reintubation using an airway exchange catheter. Braz J Anesthesiol. 2013;63(1):107-109.
- Hwang SM, Lee JJ, Jang JS, et al. Esophageal misplacement of a single-lumen tube after its exchange for a double-lumen tube despite the use of an airway-exchange catheter. Saudi J Anaesth. 2013;7(2):194-196.
- Lapinsky SE. Endotracheal intubation in the ICU. Crit Care. 2015;19:258.
- Mort TC. Tracheal tube exchange: feasibility of continuous glottic viewing with advanced laryngoscopy assistance. Anesth Analg. 2009;108(4):1228-1231.
- Mort TC, Braffett BH. Conventional versus video laryngoscopy for tracheal tube exchange: glottic visualization, success rates, complications, and rescue alternatives in the high-risk difficult airway patient. Anesth Analg. 2015;121(2):440-448.
- Cook TM, Woodall N, Harper J, et al. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 2: intensive care and emergency departments. Br J Anaesth. 2011;106(5):632-642.
- Nolan JP, Kelly FE. Airway challenges in critical care. Anaesthesia. 2011;66(suppl 2):81-92.
- Kearl RA, Hooper RG. Massive airway leaks: an analysis of the role of endotracheal tubes. Crit Care Med. 1993;21(4):518-521.
- Chou EH, Dickman E, Tsou PY, et al. Ultrasonography for confirmation of endotracheal tube placement: a systematic review and meta-analysis. Resuscitation. 2015;90:97-103.
- Hagberg CA. Current concepts in the management of the difficult airway. Anesthesiology News. 2017;43[suppl 14(1)]:1-32.
- Harris K, Chalhoub M, Maroun R, et al. Endotracheal tube exchangers: should we look for safer alternatives? Heart Lung. 2012;41(1):67-69.
- Benumof JL. Management of the difficult airway. Ann Acad Med Singapore. 1994;23(4):589-591.
- Udomtecha D. Airway tube exchanger techniques in morbidly obese patients. Anesthesiol Res Pract. 2012;2012:968642.
- Wong DT, Yang JJ, Mak HY, et al. Use of intubation introducers through a supraglottic airway to facilitate tracheal intubation: a brief review. Can J Anaesth.2012;59(7):704-715.
- Hou RM, Crooke B, Greenland KB, et al. A technique for safe endotracheal tube exchange in difficult airway patients. Anaesth Intensive Care. 2013;41(5):684-685.
- Chambers D, Paulden M, Paton F, et al. Sugammadex for reversal of neuromuscular block after rapid sequence intubation: a systematic review and economic assessment. Br J Anaesth. 2010;105(5):568-575.
- Wilcox SR, Bittner EA, Elmer J, et al. Neuromuscular blocking agent administration for emergent tracheal intubation is associated with decreased prevalence of procedure-related complications. Crit Care Med. 2012;40(6):1808-1813.
- Gulhas N, Topal S, Erdogan Kayhan G, et al. Remifentanil without muscle relaxants for intubation in microlaryngoscopy: a double blind randomised clinical trial. Eur Rev Med Pharmacol Sci. 2013;17(14):1967-1973.