Difficult Airway Management for Intensivists

W1 Difficult Airway Management for Intensivists

Thomas C. Mort, Luke Aldo

Supraglottic Airway Placement: Before Procedure

Indications

• Supraglottic airway placement (SGA) use for managing the airway:

• Bag-mask ventilation is ineffective or impossible:

• Noninvasive maneuvers such as nasal and oral airway placement, jaw thrust, chin lift, two- or three-person efforts are ineffective or fail to maintain SpO₂ >90%.

• Decision to utilize a supraglottic airway (e.g., laryngeal mask airway [LMA]) should be made rapidly to avoid desaturation or endanger the patient’s safety.

Equipment

• Equipment for mask ventilation

• Induction medications, topical anesthesia medications, and equipment for intubation

• Disposable or reusable SGA device

• Lubricating jelly

• Syringe for cuff inflation/deflation

• Tape to secure SGA

• Bite block optional

• SGA includes many available models of the original LMA from LMA North America and the many available other brands with similar offerings.

• Choice of device is often based on cost, comfort with product.

• Evidence-based use exists for some but not all product offerings.

• Sizes range from neonatal to large adult, will vary by manufacturer.

• SGA sizes available should meet needs of patient population in your facility.

• SGA access in facility may be best on code cart, airway cart or bag, rapid-response care cart, resuscitation areas in any and all areas where airway management may take place, either elective, urgent, or emergent.

• Remote hospital locations may be covered by carrying SGA devices in a transportable airway bag or tackle box that is carried by the airway team.

Anatomy

Though there are a variety of SGAs that occupy the periglottic area and surround the glottic opening with a cuff, most models differ very little except in the manufactured materials, their flexibility or rigidity, ease of use, weight, and effectiveness. Most but not all (e.g., Igel laryngeal mask) have an inflatable cuff that lies in the hypopharynx and essentially seals the supraglottic region (from the epiglottis down the cricopharyngeal sphincter). A sealed airway allows positive pressure ventilation to be delivered but is limited by the effectiveness of the cuff seal/periglottic mucosal surface interface. Many will allow effective delivery of pressure breathing to 10 to 20 cm H₂O pressure before leaking, while other models are specifically designed to allow much higher sealing thresholds (25-35 cm). These latter models are particularly effective generating ventilatory support for the obese and morbidly obese patient and when confronted by low pulmonary compliance situations (congestive heart failure, acute respiratory distress syndrome, abdominal distention, pregnancy, ascites, and pulmonary fibrosis).

In general, placement of the SGA can be performed in the exaggerated “sniff” position to the other extreme, a neutral cervical spine. The SGA generally can be placed effectively when faced with little to no neck flexibility. The SGA is lubricated and then passed toward the roof of the mouth across the hard to soft palate, encouraging smooth advancement along the posterior throat so as to minimize getting hung up on the epiglottis. It typically comes to lie with its distal tip in the cricopharyngeal region. Unfortunately, the cuff end may buckle over on itself, come to lie over the glottic opening, or be displaced in a contorted position that impedes effective ventilation and oxygenation. The SGA may indeed be placed incorrectly but still function in near perfect form with effective ventilation; it is a peculiar airway device. It can be forgiving, yet it still requires skill and finesse to place it properly in most situations. Guidance by a skilled and frequent user is the best method to learn the details of its proper use. Ideally, it lies just over the glottic opening and allows access to the trachea. However, the SGA is frequently malpositioned or the epiglottis is folded over to a lesser or greater degree, partially or completely blocking the pathway to the glottic opening, yet ventilation and oxygenation remain unabated. This may be adequate for airflow to and fro but not for the passage of an ETT into the glottic opening. Hence, most generic SGA models do require fiberoptic-guided placement of an ETT because of the uncertain position of the SGA.

After Procedure

Postprocedure Care

• The SGA used in the semi-elective, urgent, or emergent setting is often of short duration (2-20 minutes), since the goal is typically to intubate the trachea. Hence the SGA acts as a rescue ventilation device and/or an intubation conduit.

Outcomes and Evidence

The LMA design offers a relatively short learning curve for the airway novice and affords fewer episodes of desaturation, less difficulty in maintenance of a patent airway, larger tidal volume than mask ventilation, and decreased arm and hand fatigue when compared with a conventional face mask. Its value in the ICU setting for assistance during emergency airway management is undeniable, especially during difficult intubation or when ventilation is not possible with a standard bag-mask assembly. Blind or fiberoptic-assisted tracheal intubation is an extremely attractive asset the SGA device offers the clinician and provides an entirely novel rescue approach when conventional laryngoscopy and tracheal intubation prove troublesome or impossible. It is also useful in maintaining airway support in the intensive care unit (ICU) setting for patients who require repetitive general anesthetic or heavy sedation-analgesia for brief procedures, fiberoptic bronchoscopy, or diagnostic visualization of the airway. Recent work suggests that the SGA is better tolerated and produces fewer cardiovascular side effects than tracheal intubation. Insertion in the patient with an unstable cervical spine may be far easier than direct laryngoscopy, because its insertion does not absolutely require neck manipulation.

The device may be difficult to place into the hypopharynx in the presence of a small mouth, a large tongue or tonsils, hypertrophied lingual tissue, or a posteriorly displaced pharynx. However, the SGA often proves easier to use than conventional methods of airway control such as direct laryngoscopy. The threat of gastric dilatation and regurgitation/aspiration may lead some to avoid its use in the critically ill, but its excellent track record and very low incidence of regurgitation/aspiration (0/278 emergency insertions, Hartford Hospital, TCM) supports its role as a primary airway rescue device when conventional methods fail. The role of the SGA as a rescue device in the elective and emergency setting is unparalleled, but further studies into its use in the emergency setting are needed to solidify its standing as the premier rescue airway device, regardless of which model is used.

Suggested Reading

Brain AI, McGhee TD, McAteer EJ, et al. The laryngeal mask airway: Development and preliminary trials of a new type of airway. Anaesthesia 1985;40:356-61.

Brimacombe J, Berry A. The laryngeal mask airway—the first ten years. Anaesth Intensive Care 1993;21:225-6.

Verghese C, Smith T, Young E. Prospective surgery of the use of the laryngeal mask airway in 2350 patients. Anaesthesia 1993;48:58-60.

Truhlar A, Ferson DZ. Use of the Laryngeal Mask Airway Supreme in pre-hospital difficult airway management. Resuscitation 2008;78(2):107-8.

Benumof J. Laryngeal mask airway: Indications and contraindications. Anesthesiology 1992;77:843-6.

Ferson DZ, Rosenblatt WH, Johansen MJ, et al. Use of the intubating LMA-Fastrach in 254 patients with difficult-to-manage airways. Anesthesiology 2001;95(5):1175-81.

Gerstein NS, Braude DA, Hung O, et al. The Fastrach Intubating Laryngeal Mask Airway: an overview and update. Can J Anaesth 2010;57(6):588-601.

Mort TC. Laryngeal mask airway and bougie intubation failures: the Combitube as a secondary rescue device for in-hospital emergency airway management. Anesth Analg 2006;103(5):1264-6.

Kim JA, Mort TC. The role of the LMA in emergency airway management of the obese patient outside of the OR. Anesthesiology 2010;24(5):811-4.

Farag E, Bhandary S, Deungria M, et al. Successful emergent reintubation using the Aintree intubation catheter and a laryngeal mask airway. Minerva Anestesiol 2010;76(2):148-50.

Bougie-Assisted Intubation: Before Procedure

Indications

• Exchange of tracheostomy tube

• Exchange of ETT (Warning: most bougie models are approximately 55-65 cm in length and are shorter than the recommended airway exchange catheters. This may present a problem with maintaining control of the bougie during the exchange, owing to its length [component within the airway and the length outside the mouth available to thread new ETT].)

• Assist with passing ETT into trachea when limited by the “line of sight”:

• Full view of laryngeal inlet (unable to pass ETT because of hang up on cricoid ring)

• Partially obstructed view of laryngeal inlet:

• Grade II or III view of the larynx with laryngoscopy (conventional)

• Grade II: posterior third of glottis visible (Lehane-Cormack classification). More detailed classification (Cook-Yentis):

• Grade IIa: arytenoids and posterior cords visible

• Grade IIb: only epiglottic edge and arytenoids visible

• Grade III: no cords visible, only epiglottis visible; Cook-Yentis classification:

• Grade IIIa: only epiglottic edge visible

• Grade IIIb: downfolded or floppy epiglottis is visible

• Grade IV: no view of any airway structure; bougie use not recommended (Figures W1-1 through W1-6)

Figure W1-1 Line of sight with direct laryngoscopy.

Figure W1-2 Lehane Cormack laryngeal view grading system with the Cook-Yentis modifications, grade I→IV.

Figure W1-3 Cook-Yentis grade IIb laryngeal view with direct laryngoscopy achieves a very high success rate with bougie-assisted intubation.

Figure W1-4 Cook-Yentis grade IIIa view with direct laryngoscopy achieves a respectable success rate with bougie-assisted intubation, especially when compared to blind passing of the endotracheal tube “around the corner.”

Figure W1-5 A grade IV view, essentially no view at all of the laryngeal structures. The bougie is not indicated for a grade IV view. It is best handled with the laryngeal mask airway, fiberoptic bronchoscopy, or VL.

Figure W1-6 Two bougie models are shown (tracheal tube introducer). Note the characteristic 30-degree angle. Coude tip allows manipulation of the bougie tip underneath the epiglottis to increase its rate of passage through the laryngeal opening.

• Use of the bougie to determine the location of the ETT (esophagus versus trachea):

• Hang-up test (Cheney’s sign)

• Bougie tip will hang up on carina or mainstem bronchus, compared to simply passing unimpeded into the esophagus.

• Useful in cardiac arrest or clinical situation in which it is difficult to discern proper ETT placement

Contraindications

• Unfamiliar with its use

• Recent tracheal-bronchial reconstruction

Anatomy

Though the bougie is capable of assisting intubation in nearly all airway situations except when “no view” is possible, it is most commonly used as an adjunct with Grade IIb, IIIa, and IIIb laryngeal views. Even when the laryngoscopy reveals a full view (grade I), the bougie may be useful when the hypopharyngeal opening is narrow (OSA, obesity, swelling) and passing the ETT may actually obstruct the view of the glottic opening. In this case, the narrower, more colorful tracheal tube introducer can be passed into the trachea with little visual obstruction taking place. Conversely, the floppy epiglottis is a challenge that may be technically difficult with many different airway adjuncts. The bougie may either be used to elevate the floppy epiglottis or be maneuvered around by virtue of the Coude tip. Though useful, the success rate is often less than 50%, and other alternatives may be needed (intubating laryngeal mask airway [ILMA], videolaryngoscope [VL], fiberoptic bronchoscope [FOB]) (Figure W1-7).

Figure W1-7 A grade IIIb view; floppy or overhanging epiglottis is relatively uncommon but may be difficult to navigate around with a variety of airway adjuncts. The bougie may be used to elevate the epiglottis and navigate into the trachea, but the success rate is substantially lower in the grade IIIb setting (30%-50%) compared to a grade IIIa (only leading edge of epiglottis visible, 80%-90%).

Procedure

• The bougie is grasped in the intubator’s right hand at the 20- to 25-cm mark.

• It is passed alongside the laryngoscope with the 30-degree angled tip (coude) anteriorly.

• The tip is advanced anterior to the arytenoids and into the larynx (grade IIa, IIb).

• The tip is advanced underneath the epiglottis and past the vocal cords blindly (grade IIIa).

• The tip lifts the floppy epiglottis and then is advanced blindly past the vocal cords (grade IIIb).

• Following advancement into the trachea to a depth of 22 to 26 cm in average adult:

• Tip may “bounce” or “click” past the tracheal rings, suggesting tracheal placement.

• This is a helpful sign but does not guarantee intratracheal placement.

• The lack of “clicks” does not guarantee the position of the bougie, nor does it rule out location within the trachea.

• 10%-50% of bougies passed into a grade III airway may enter the esophagus:

• Grade IIIa: 5%-12% may enter the esophagus

• Grade IIIb: 30%-50% may enter the esophagus:

• Quickly deploy backup strategy (SGA, ILMA, VL)

• Some may consider bougie as poor choice in grade IIIb view

• Decision time: passing the ETT:

• If time permits, generously lubricate the ETT.

• Smaller-sized ETT pass over the bougie more easily than larger ones.

• Maintain tongue displacement with laryngoscopy/hand grasp.

• Pass the ETT, but do not force the advancement (an assistant should grasp the proximal end of the bougie to stabilize it).

• Anticipate resistance at 16-17 cm depth due to impingement on arytenoid/vocal cord (2 methods to remedy this) (Figure W1-8):

Figure W1-8 Endotracheal tube (ETT) being passed over tracheal tube introducer (TTI, bougie) and getting hung up on the epiglottis and arytenoid. Continued advancement should be discouraged. Simply withdraw 1 to 2 cm, rotate ETT counterclockwise about 90 degrees, and readvance. VC, vocal cord.

• Preemptively advance ETT while rotating in the counterclockwise (CCW) direction to allow ETT to avoid impingement on the glottis.

• If resistance is encountered, stop and withdraw ETT 2 cm, then rotate CCW and advance the ETT into the airway.

• If ETT fails to pass, the patient may be ventilated and oxygenated with bag-mask ventilation (move the bougie to the corner of the mouth).

• Change to a smaller-diameter ETT (to ease advancement over the bougie) and assume the glottic opening may be swollen, impeding entry.

After Procedure

Postprocedure Care

• Following advancement of ETT into the trachea, stabilize the ETT in position, and remove the bougie.

• Standard methods of determining the ETT position are required.

Outcomes and Evidence

The simplicity of the trachea tube introducer makes it an attraction option for assisting with trachea intubation in the situation when a restricted laryngeal view is available with laryngoscopy. A variety of uses for the bougie make it a desirable addition to the difficult airway cart or bag, made accessible at the bedside in the ICU and other remote locations in the hospital. The bougie is a suggested option in the management algorithms offered by anesthesiology societies in the United States, Canada, the United Kingdom, Germany, and many other countries.

Suggested Reading

Orelup CM, Mort TC. Airway rescue with the bougie in the difficult emergent airway. Crit Care Med 2004;32(12) S:A118.

Jabre P. Use of gum elastic bougie for prehospital difficult intubation. Am J Emerg Med 2005;23(4):552.

Budde AO, Pott LM. Endotracheal tube as a guide for an Eschmann gum elastic bougie to aid tracheal intubation using the McGrath or GlideScope videolaryngoscopes. J Clin Anesth 2008;20(7):560.

Shah KH, Kwong BM, Hazan A, et al. Success of the gum elastic bougie as a rescue airway in the emergency department. J Emerg Med 2011;40:1-6.

Combes X, Le Roux B, Suen P, et al. Unanticipated difficult airway in anesthetized patients: prospective validation of a management algorithm. Anesthesiology 2004;100(5):1146.

Smith MD, Katrinchak J. Use of a gum elastic bougie during surgical cricothyrotomy. Am J Emerg Med 2008;26(6):738.

Detave M, Shiniara M, Leborgne JM. Use of Eschmann’s gum elastic bougie in difficult orotracheal intubation, an audit over eight years of clinical practice. Ann Fr Anesth Reanim 2008;27(2):154-7.

McNelis U, Syndercombe A, Harper I, et al. The effect of cricoid pressure on intubation facilitated by the gum elastic bougie. Anaesthesia 2007;62(5):456-9.

Use of the Intubating Model of the LMA for Emergency Airway Rescue (Fastrach) ILMA: Before Procedure

Anatomy

The ILMA is similar to other SGA devices that occupy the periglottic area and surround the glottic opening with a cuff. Passing the ILMA into the oral cavity is easier than the comparative standard LMA, since is designed with an intrinsic curve that allows easier passage into the hypopharynx. The inflatable cuff lies in the hypopharynx and essentially seals the supraglottic region (from the epiglottis down the cricopharyngeal sphincter). The rigid construction of the ILMA is limited by its diameter, so adequate mouth opening is a prerequisite. The sealed ILMA allows positive-pressure ventilation to be delivered. Occasionally, the ILMA will afford effective ventilation if the standard LMA model fails, and vice versa.

In general, placement of the ILMA can be performed in the exaggerated “sniff” position or the other extreme, a neutral cervical spine. The ILMA is lubricated and then passed along the roof of the mouth across the hard to soft palate, encouraging smooth advancement along the posterior throat so as to minimize getting hung up on the epiglottis or causing its downfolding. The distal tip of the ILMA typically comes to lie with its distal tip in the cricopharyngeal region. Unfortunately, the cuff end may buckle over on itself, come to lie over the glottic opening, or be displaced in a contorted position that impedes effective ventilation and oxygenation (Figures W1-9 through W1-16).

Figure W1-9 Deflate the cuff, and lubricate with a water-soluble lubricant on the posterior surface. The lubricated intubating laryngeal mask airway is passed over the hard to soft palate along the posterior pharyngeal wall to the point where gentle resistance is felt.

Figure W1-10 Swing the mask into place in a circular movement, maintaining contact against the palate and posterior wall of the pharynx. Do not use the handle as a lever.

Figure W1-11 Inflate the mask, without holding the tube or handle, with approximately 10 to 20 mL of airway to seal the airway. Apply a manual bag or anesthesia circuit to the intubating laryngeal mask airway (ILMA) and verify ventilation. If no ventilation (leak or resistance), assume misplacement of ILMA or downfolding of the epiglottis. Manipulate the ILMA in an up-and-down or in-and-out maneuver to optimize position. Recheck ventilation, and adjust location of the ILMA to optimize ventilation. Do not attempt passing the endotracheal tube until effective ventilation is ensured.

Figure W1-12 Hold the intubating laryngeal mask airway (ILMA) handle while gently inserting the lubricated endotracheal tube (ETT) into the airway shaft. The provided ILMA-ETT is best suited for this, though a well-lubricated standard ETT may be used with fiberoptic guidance or may be used (with proper training and experience) blindly by inserting it “backwards,” meaning the concave curve of the ETT faces the nose as it is advanced into the ILMA shaft.

Figure W1-13 Advance the endotracheal tube (ETT), inflate the cuff, and confirm intubation. If unable to pass, ensure adequate lubrication. If resistance is felt, the intubating laryngeal mask airway (ILMA) may be malpositioned or may have entrapped the epiglottis and thus may block the ETT advancement. Try the in-and-out maneuver to reposition the ILMA and free up the epiglottis if applicable.

Figure W1-14 Remove the endotracheal tube (ETT) connector, and place the provided stabilizing rod onto the end of the ETT. Then ease the intubating laryngeal mask airway (ILMA) over the existing ETT and rod by gently swinging the handle caudally (keeping the ETT stable in position) until the ETT can be grasped at the level of the incisors.

Figure W1-15 Remove the stabilizing rod, and gently unthread the inflation line and pilot balloon of the endotracheal tube (ETT). Replace the ETT connector, and confirm ventilation and position per standard intubation procedures. If the intubating laryngeal mask airway (ILMA) has been used on a very challenging airway or the patient is unstable, delay removal of the ILMA from the existing ETT until stabilization takes place. Extubation of the airway is possible, so this maneuver should only be performed by those skilled in its execution.

Figure W1-16 Cook Critical Care prepackaged retrograde wire intubation kit.

ILMA use should be learned prior to its deployment in an emergency airway crisis. Training on a mannequin or humans under elective conditions by a skilled practitioner is best.

Procedure

• The intubating model of the LMA is placed into the airway in a similar fashion as other LMA products. However, the shortened length of the ILMA model and its handle may be simpler to place than the standard LMA model. Placement is augmented by passing it along the hard to soft palate posteriorly into the hypopharynx, posterior to the epiglottis. It too comes to lie with its tip atop the cricopharyngeal area posterior to the arytenoids/glottis. The tip may fold over or under and impede air exchange or be sensed by an incomplete cuff seal (leak). This can be remedied by performing the “in-and-out” or “up-and-down” maneuver (simply moving the ILMA slightly inward and outward to free up the distal tip). Cuff inflation is followed by positive pressure oxygen delivery. Successful placement allows chest rise, ETCO₂ detection, with no audible air leak to approximately 15 to 25 cm H₂O pressure applied to the ILMA. Always confirm ventilation prior to attempting ETT advancement via the ILMA.

• Two maneuvers are handy to improve success in ILMA placement and intubation:

• Following ILMA placement, Chandy maneuver #1 involves using the ILMA handle to optimize the positioning of the ILMA within the airway, with the goal of maximizing tidal volume, ETCO₂, and the feel of “bagging.” The ILMA is held in this position in preparation for passing a lubricated ETT. The included LMA brand wire-reinforced ETT is an excellent ETT for passing, but it is suboptimal for long-term use in the ICU airway (if duration of intubation is >24-48 hours, one should consider changing the ETT over an airway exchange catheter to the standard ICU ETT model).

• Once effective ventilation/oxygenation is established, passing an ETT may be the next objective. With the ILMA in the best ventilating position (Chandy #1), Chandy maneuver #2 involves using the ILMA handle to slightly elevate or “lift” the ILMA (handle toward forehead, ILMA distal tip anteriorly) to improve the success rate of passing the ETT into the trachea, based on the ILMA portal being tilted toward the glottic opening and away from the esophagus. This lift increases seal pressure and improves the alignment of the ILMA to the glottic opening and corrects any flexion the mask has undergone following its placement. Malposition or flexion of the mask while in the ventilating position may alter the pathway of the ETT as it exits the ILMA. Generous lubrication of the ETT to ease passage through the ILMA lumen is an absolute. Intubation of the trachea may be performed blindly or with fiberoptic assistance. The skill to successfully intubate the trachea is attained by practice coupled with instruction by an experienced individual. Practicing the technique before an emergency situation arises is in the best interest of patient care.

• Troubleshooting in the event of failure to intubate (typically caused by a downfolded epiglottis, ETT impaction on the periglottic tissues, too large or too small ILMA, or patient is resisting intubation because of inadequate sedation/analgesia/muscle relaxation/anesthesia):

• If resistance is felt approximately 2 cm beyond the black transverse line marked on the ILMA ETT (or 15-16 cm marking on a standard ETT), the downfolded epiglottis may be blocking ETT advancement, as may the vestibular wall. Rotation of the ETT may allow passage if impeded by the vestibular wall. A downfolded epiglottis may need to be addressed by performing the “up-and-down” maneuver. This is a partial withdrawal of the inflated ILMA to a maximum of 6 cm, followed by reinsertion. This often frees the epiglottis from its downfolded position. Otherwise, FOB assistance is needed, or a different size ILMA may be tried.

• If the ETT meets immediate resistance at 15 to 16 cm (black mark) or at 4- to 5-cm depth past the black mark, then the ILMA is too large, and downsizing may help.

• If resistance is encountered at 3 cm past the black mark, the ILMA may be too small. If an alternative-size ILMA is not available, external manipulation of the larynx either downward or caudally may assist with passing the ETT. Likewise, ETT rotation may be helpful.

• Another miscellaneous yet quite important clinical situation that may prohibit intubation is excessive periglottic/glottic edema when viewing with the FOB. Massive airway edema may preclude advancement of the FOB-ETT owing to the inability to clearly identify the glottic opening; caution must be exercised to not advance the FOB tip into unrecognizable tissue planes. Excessive force on the FOB or ETT may lead to tissue injury and thus threaten the current airway patency by inducing further bleeding, edema, or swelling. Attaching a bronchoscopic swivel adapter to the ILMA itself or via the ETT may allow active application of positive pressure to the airway and promote lateralization of the edematous glottic tissues. This is analogous to the use of continuous positive airway pressure (CPAP) in OSA patients. The bronchoscopic adapter is too narrow to allow an ETT to pass through it. To remedy this, an Aintree catheter (bougie-type catheter with a lumen that allows a proper-sized FOB to be placed within the catheter) is sized to fit through the adapter and its diaphragm. The Aintree-FOB assembly may be passed through the bronchoscopic adapter, down the ILMA, and used to visualize the glottic opening. Once advanced into the trachea, the Aintree remains within the trachea as the FOB is withdrawn. The ILMA is then removed over the Aintree, and the ETT is advanced over the Aintree catheter in similar fashion to a bougie, tube exchanger, or FOB.

After Procedure

Postprocedure Care

• Following “blind” intubation of the trachea, standard methods to confirm ETT position are pursued (chest auscultation, ETCO₂ detection, ETT misting, chest rise, etc.).

• Following fiberoptic-assisted intubation, the same clinical confirmation of ETT position should be pursued, even though visualization of the ETT within the trachea with FOB is considered failsafe. The caveat here is that FOB confirmation, though failsafe under ideal conditions, may be limited by secretions, edema, soilage, operator inexperience, faulty battery power, and the like in the ICU airway.

• With the ETT-ILMA assembly in place, the ILMA has to be carefully removed from the patient while leaving the ETT within the trachea. Accidental tracheal extubation during ILMA removal could be disastrous.

• Step-by-step removal of the ILMA is outlined later.

• If one is unfamiliar with ILMA removal, a more experienced team should be summoned to assist with this task. Conversely, if the patient’s clinical condition needs to be stabilized prior to its removal, at a minimum, the air should be removed from the ILMA cuff to reduce the pressure effect on the pharyngeal mucosa.

Outcomes and Evidence

• The use of the ILMA has revolutionized airway management, especially in the emergency setting. It is an accepted component in the American Society of Anesthesiologists (ASA) airway management algorithm, as well as all other algorithms offered by medical societies throughout the world. The presence of videolaryngoscopy has potentially altered the ILMA’s role as a logical and rational first step toward airway rescue when conventional methods fail or are inappropriate. However, the clinician must be familiar with this device and have it readily available as a backup for VL difficulties or failures.

• In the elective setting, the ILMA has an excellent track record for a high level of successful ventilation coupled with blind and FOB assisted intubation. Its successful deployment in the acute care setting in the ICU, the emergency department, or other remote locations outside of the operating room has been well received, though the success rate for both ventilation and intubation is tempered to a more realistic success rate of nearly 8 to 9 out of 10 patient encounters. Thus, a backup plan must be in place to deal with ILMA failure and establish effective ventilation/oxygenation and ultimately tracheal intubation, either blindly or with FOB assistance.

Suggested Reading

Cinar O, Cevik E, Yildirim AO, et al. Comparison of GlideScope video laryngoscope and intubating laryngeal mask airway with direct laryngoscopy for endotracheal intubation. Eur J Emerg Med E-pub 2010 Sep 13.

Kamada M, Kouno S, Satake Y, et al. Use of intubating laryngeal mask airway in combination with fiberoptic intubation in a patient with morbid obesity and unexpected lingual tonsillar hypertrophy. Masui 2010 Apr;59(4):460-3.

Mort TC. Complications of emergency tracheal intubation: immediate airway-related consequences: part II. J Intensive Care Med 2007 Jul-Aug;22(4):208-15.

Mort TC. Anesthesia practice in the emergency department: overview, with a focus on airway management. Curr Opin Anaesthesiol 2007 Aug;20(4):373-8.

Mort TC. Complications of emergency tracheal intubation: hemodynamic alterations–part I. J Intensive Care Med 2007 May-Jun;22(3):157-65.

Mort TC. Laryngeal mask airway and bougie intubation failures: the Combitube as a secondary rescue device for in-hospital emergency airway management. Anesth Analg 2006 Nov;103(5):1264-6.

Mort TC. The incidence and risk factors for cardiac arrest during emergency tracheal intubation: a justification for incorporating the ASA Guidelines in the remote location. J Clin Anesth 2004 Nov;16(7):508-16.

Mort TC. Emergency tracheal intubation: complications associated with repeated laryngoscopic attempts. Anesth Analg 2004 Aug;99(2):607-13.

Burke EJ, Beyus CM, Mort TC. Super morbid obesity: emergency airway challenges. Anesthesiology, A1649, Epub 2010.

Kim JA, Mort TC. The role of the LMA in emergency airway management of the obese patient outside of the OR. Anesthesiology, A1576, Epub 2010.

Young B. The intubating laryngeal-mask airway may be an ideal device for airway control in the rural trauma patient. Am J Emerg Med 2003 Jan;21(1):80-5.

Gerstein NS, Braude DA, Hung O, et al. The Fastrach Intubating Laryngeal Mask Airway: an overview and update. Can J Anaesth 2010 Jun;57(6):588-601.

Ojeda A, López AM, Borrat X, et al. Failed tracheal intubation with the LMA-CTrach in two patients with lingual tonsil hyperplasia. Anesth Analg 2008 Aug;107(2):601-2.

Wender R, Goldman AJ. Awake insertion of the fibreoptic intubating LMA CTrach in three morbidly obese patients with potentially difficult airways. Anaesthesia 2007 Sep;62(9):948-51.

Blair EJ, Mihai R, Cook TM. Tracheal intubation via the Classic and Proseal laryngeal mask airways: a manikin study using the Aintree Intubating Catheter. Anaesthesia 2007 Apr;62(4):385-7.

Retrograde Wire Intubation: Before Procedure

Indications

• Secure the airway in the elective setting with the patient awake, with adequate topicalization of airway with local anesthetics or local nerve blocks

• Trismus, severe temporomandibular joint (TMJ) disease, limited cervical range of motion

• Known difficult mask ventilation, intubation

• Secure the airway emergently in the setting that mask ventilation/oxygenation is effective

• Retrograde wire-guided intubation, in the best situation, may require 2 to 5 minutes to complete, hence one must be able to sustain ventilation/oxygenation.

• Secure the airway electively when difficult airway factors are known or suspected to exist and intubation by other means may be difficult or impossible.

Anatomy

The cricothyroid membrane is located between the superior thyroid cartilage and the inferior cricoid ring. The cricothyroid membrane is located just 1.5 to 2 cm below the vocal cords, so care must be practiced when advancing a needle caudad, as the underside of the vocal cords could be impaled. Passing the ETT over the wire or obturator/wire may be met with resistance at the 16- to 17-cm depth, as the ETT tip may impinge on the vocal cords or arytenoids. This is the inherent danger of passing the ETT blindly over the wire or obturator/wire assembly. The location of the distal tip (having met resistance) may or may not be at the position below the vocal cords. This is the challenge of the retrograde wire method; knowing the location of the ETT tip is unknown when the decision is made to remove the wire. If the ETT tip is erroneously positioned above the glottis, then the access to the airway is denied with wire removal; hence, the advantage of using the FOB as an intubation guide (Figure W1-17).

Figure W1-17 Anatomical landmarks for access to the cricothyroid membrane.

Procedure

• Retrograde tracheal intubation:

• Needle insertion directed cephalad; operator should approach with dominant hand more caudad (e.g., right-handed operator on right side of patient)

• Puncture cricothyroid membrane with needle directed cephalad (Figure W1-18).

Figure W1-18 Puncture of cricothyroid membrane, with air aspiration reflected in bubbling in saline-filled syringe.

• Aspirate air with syringe to locate air column (1-2 mL of saline in syringe; allow bubbles to percolate to verify the air column).

• Three choices to pass ETT down the wire into the airway (nasal or oral): (1) wire assisted, (2) wire with obturator to reinforce wire, (3) flexible bronchoscope (loaded with ETT) passed over wire into airway

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Jul 7, 2016 | Posted by admin in CRITICAL CARE | Comments Off

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