CHAPTER 40

Airway Equipment Setup, Operation, and Maintenance Tools to Access the Glottic Opening

Brandon Minzer and Vicki E. Modest

Introduction

Expertise in airway management is at the core of anesthetic care. A wide range of equipment options are available to facilitate this essential task. The previous chapter, discusses airway devices that serve as pathways through which oxygen and other gases may be delivered. This chapter discusses the tools commonly used for placement of these devices. The clinical strengths and weaknesses, as well as setup and maintenance of these tools, are presented here. From this, technicians should better understand the role these tools play in airway management and be better able to provide support for routine and difficult intubations.

The anatomy and physiology of the airway have been discussed in Chapter 7; the basic techniques of airway management are discussed in Chapter 18; and the management of the emergency airway is discussed in Chapter 57. This chapter intersects with all these topics, but focuses on the tools themselves.

Equipment used to access the airway can be divided into two main classifications—ones that create a view of the larynx and ones that do not. Those that create a view of the larynx may be further divided into “direct” providing an unhindered line of sight from the mouth to larynx, or an “indirect” using fiberoptics or a video chip to obtain a view. Tools used to access the airway without providing a view of the larynx are discussed under the heading “airway adjuncts.” An overview of tools, manufacturer names when applicable, maintenance of components, and basic troubleshooting strategies are provided. Costs vary considerably, change frequently, and are readily available online. As such, this chapter may mention prices only to give a general sense of market value as of the date of publication.

Direct Laryngoscopy

Since the early 20th century, direct laryngoscopy has been and remains the standard and most common approach to endotracheal intubation. The laryngoscope is the tool used. It is simple in design, low tech, inexpensive, and ubiquitous (composed of a handle, bulb, rigid blade, and battery). To use, the blade is inserted into the mouth, and combined with proper patient positioning and correct technique, the glottic opening may be visualized.

Handles

During laryngoscopy, the handle allows the anesthesia provider to manipulate the blade. Historically, there are two types of laryngoscopy handles—standard and fiberoptic. These are most easily differentiated by the location and type of light source (i.e., bulb). There are also variously sized handles (standard, short, and pediatric).

Standard laryngoscopes have an incandescent light bulb comprised of a tungsten filament surrounded by a halogen gas incorporated into the blade. Standard laryngoscopy handles contain the batteries to power the bulb in the blade. Costs are low and range from $20 to $100.

Fiberoptic laryngoscopes, also known as “bulb-on-handle,” can be either halogen or light-emitting diode (LED) technology in which both the battery and light source are housed within the handle. The light is carried from the handle to the tip of the blade often by fiberoptics or via a clear plastic channel. Fiberoptic handles offer numerous advantages over standard laryngoscopes including improved battery life with longer life spans (up to 30,000 hours of use) and generate less heat. Such handles are more expensive than the standard type, ranging in cost from a hundred to several hundred dollars, and can be seen in Figure 40.1.

FIGURE 40.1. Fiberoptic laryngoscope handles.

Regardless of handle type (standard or fiberoptic), both require regular maintenance. All have either replaceable or rechargeable batteries. Depending on the manufacturer, replaceable batteries are commonly AA, C, or D sized. Rechargeable handles are typically housed in charging stations between uses to ensure adequate power during laryngoscopy. Prior to recharging, disinfect as per your institution’s protocol to eliminate the spread of organisms between patients. Once clean and charged, verify function.

Blades

An array of blades are available to accommodate differences in patient anatomy, facilitate ease of use, and increase laryngeal visualization success rates. These blades each have unique characteristics and advantages. Despite a multitude of variations, blades are either “straight” or “curved.” Straight blades such as the Miller function by directly contacting and lifting the posterior surface of the epiglottis away from the larynx. Curved blades such as the Macintosh achieve the same goal using a slightly different technique, sliding the tip of the blade into the vallecula and lifting the epiglottis indirectly. Both straight and curved blades come in various sizes based on patient size ranging from 0 (infants) to 4 (large adults). Table 40.1 describes the most commonly seen blades and provides brief descriptions of each, and Figure 40.2 has picture of the most commonly used blades. Notably, the most common laryngoscopic blades for adults are by far the Miller 2 and Macintosh 3.

Table 40.1. Many Laryngoscope Blade Types: Straight and Curved

FIGURE 40.2. Laryngoscope blades.

Indications for specific blade use are complex. Although that discussion is outside the scope of this text, it is important to recognize that the choice of blade typically depends on personal preference, clinical scenario, and patient anatomy. There is no direct blade type that is faultless for all laryngoscopies, and several blades may be tried during a challenging intubation attempt.

Laryngoscope blades are made in both reusable and disposable forms. Reusable blades have a bulb, frosted or clear, set into a supporting socket located approximately one-third of the distance from the tip. A battery located inside the handle powers it. The average bulb life span is approximately 1,000 hours with a replacement cost of $10-$30 per bulb. Fiberoptic blades are available for the “bulb on handle” type laryngoscopes; these have a life span of 4,000+ uses and as many as 20 years. Reusable blades on average cost between $50 and $150, while disposable blades run from $5 to $15 per blade.

Disinfection

Reusable blades require disinfection, but do not require sterilization between uses. Commonly, blades are soaked in disinfectant consisting of an enzyme detergent and brushed cleaned. Some institutions may use disposable plastic covers over reusable blades to minimize the spread of organisms. Bulb function must be ensured after each cleaning and may need tightening or replacement (see Chapter 47, Anesthesia Supply and Equipment Contamination, Sanitation, and Waste Management).

Special Circumstances

Additionally, independent of the handle and blade, laryngoscopes can be made magnetic resonance imaging (MRI) compatible. It is important to note that standard laryngoscopes should never be taken into close proximity of the MRI machine. Consult your institution’s policies for further discussion and clarification regarding MRI safety (see Chapter 52, MRI Safety).

Troubleshooting the Laryngoscope

If the laryngoscope fails to light, identify the malfunctioning component: handle versus blade.

If the problem is with the handle:

• Check the battery (replace or recharge).
• Clean the contacts.
• Make sure that the open blade is activating the power/light source.

If the problem is with the blade:

• Tighten or replace the bulb.

Indirect Laryngoscopy

Despite a high success rate with traditional laryngoscopy, there are instances where a direct line-of-sight from oral cavity to vocal cords is unachievable. Reasons for difficulty are many and include unfavorable body habitus, abnormal airway anatomy (e.g., tumors, masses), significant head or neck trauma, small mouth opening, poor patient positioning, or the need to minimize movement of the head and neck. This has led to development of indirect laryngoscopic methods and devices such as:

• Optical stylets
• Fiberoptic scopes (flexible or rigid)
• Rigid video laryngoscopes

Optical Stylets

Introduced in the late 1970s, this nearly 50-year-old technology has almost completely been replaced by easier to use, newer technologies. However, optical stylets are still around and have some nice features such as providing a view from the tip of the scope, ability to function with limited mouth opening, and ability to provide continuous oxygen flow during intubation. The components of these devices include an optical stylet (malleable or rigid), light source, optical fiber, viewing means (eyepiece or camera with monitor), and a power source. Rigid models (Bonfils intubation fiberscope, Karl Storz Endoscopy) and malleable versions (Shikani and Levitan optical stylets, Clarus Medical) are still manufactured and may be found at some American hospitals.

Fiberoptic Bronchoscopes

There are multiple commercially available fiberoptic scopes; a common setup is shown in Figure 40.3. Both flexible and rigid fiberoptic bronchoscopes are available. Although different in format, similarities in design include the following:

FIGURE 40.3. Fiberoptic scopes and airway cart.

• An illumination system that may be an external device connected to the scope via cable, or battery operated and directly attached the bronchoscope itself.
• A light bundle that relays light from the light source to the tip of the scope.
• Imaging fiberoptic bundles made of continuous strands of flexible glass fibers that transmit the image at the tip to the eyepiece or display.
  • Newer models have transitioned away from “fiberoptics” and use a digital camera. They have an internal light source and an imaging chip at the tip of the bronchoscope.
• An eyepiece or video monitor.
• Many scopes have a separate channel available for suctioning or delivery of oxygen or local anesthetic to numb the airway.

Flexible Fiberoptic Bronchoscopes

Clinicians have long regarded the flexible fiberoptic bronchoscope as the “go to” tool for difficult or special airway management given its versatility and maneuverability. The operator can rotate the scope 360 degrees and can flex the tip in either direction by using an integrated, thumb-operated, bar-shaped control located near the top of the scope. Its real-time adaptability makes it ideal for patients with difficulties such as airway tumors and cervical spine injuries. It is well suited for awake or asleep intubations. Additionally, this scope is the only device useful for indirect, guided nasal intubations, as well as entry into the airway through a nonroutine route such as a tracheal stoma. Most manufacturers offer three standard sizes of bronchoscopes—adult, pediatric, and neonatal as shown in Figure 40.4.

FIGURE 40.4. Flexible fiberoptic bronchoscopes.

When the scope is used for oral intubations, the clinician must obtain a clear view of the vocal cords. If the view is unobtainable, the scope likely will not be useful. For example, the fiberoptic scope loses its value if there is lens occlusion due to blood, gastric contents, and/or foreign objects in the oropharynx.

Preparation for fiberoptic-guided intubation of the trachea includes the following:

• Confirming proper function of the scope at the intended site of use
• Attaching suction to the scope
• Focusing and defogging the lens and white balancing the image if needed
• Mounting the selected endotracheal tube securely over the bronchoscope
• Ensuring that other endotracheal tube options are immediately available

If the patient will remain awake for intubation, the airway will need to be numbed by local anesthetic either by a nerve block, sprayed through the scope, or placed directly in the airway. Typically, 2%-4% lidocaine, viscous lidocaine, atomizer, Q-tips, and gauze may be requested. Additionally, if nasal intubation is planned, decongesting nasal spray is often used to help prevent bleeding. Responsibility for stocking the numbing and nasal spray medications vary between institutions but may fall under the responsibility of the technicians. Bite blocks should be available to use to protect the scope and the clinician. Several commercially available disposable bite blocks are available such as the Ovassapian Fiber Optic Intubating Airway. In lieu of that, a hand-made bite block may be used. Preoxygenation and continued oxygenation delivery during the awake intubation is essential. Specialized masks for awake intubations are on the market, but nasal cannula or a modified facemask will suffice.

Rigid Fiberoptic Bronchoscopes

In the late 1980s, rigid bronchoscopes were introduced as a device that combined the best available features of direct and indirect laryngoscopes with a less fragile format compared with flexible scopes. These scopes have been largely displaced by newer technology (see below, “Rigid Video Laryngoscopes”). Although these scopes are no longer readily available for new purchase, they may still be found in some clinical settings. The Bullard scope (ACMI Corp., acquired by Olympus 2008) was the first on the market shortly followed by the WuScope (Achi Corp.) and the UpsherScope (Mercury Medical). Minor differences aside, the Bullard, Wu, and UpsherScope are all reusable devices comprised of a power source, a special standard-like laryngoscope handle, fiberoptic blade, handle, eyepiece, and endotracheal tube stylet and guide. The fiberoptic blade may contain three channels that function as the light bundle, image bundle, and a working channel to accommodate a stylet (can also serve as a suction port to clear secretions or instill oxygen insufflation).

Disinfection and Care

After each use, disinfect fiberoptic bronchoscopes in a disinfecting solution and clean as described in the device’s manual. Cleaning the working channel of the bronchoscope is essential; debris is removed with flushes and a long thin brush, thereby preventing solidification of the material within the channel. Afterward, the imaging bundle is disconnected from the illumination device, and the entire scope is wiped off or soaked in an antimicrobial solution, rinsed with water, and dried.

Flexible fiberoptic bundles are fragile and prone to damage from excessive bends or unintentional crimps, like catching in a closing drawer. When enough of the fibers get broken, the scope becomes unusable. To avoid this, hang flexible fiberoptic bronchoscopes in storage cabinets or place individually in trays to protect the scope between uses. Clinicians may need to be reminded to handle the scope with care. After cleaning, prior to returning the scope to circulation, check the quality of the image. If too many optical fibers are broken, the scope will need to be removed from use and sent for repair. These devices are expensive to purchase or repair. Cost for new scopes vary by manufacturer and range from $10,000 to $20,000.

Rigid Video Laryngoscopes

Rigid video laryngoscopes (RVLs) are a group of devices that resemble traditional laryngoscopes but integrate a small camera, light source, video connector, and display. Some are battery operated. Some have the video display attached to the device, while others have a separate monitor. They are relatively basic to operate and are rapidly and easily mobilized into use with little preparation. These devices provide an excellent view of the laryngeal inlet while reducing the need for excessive head and neck manipulation. As such, many clinicians value these devices and look to them as the preferred tool to use for anticipated difficult airways or as a rescue device after failed intubations; however, these devices may fail in the setting of limited oral access or excessive material in the oropharynx that would result in lens obstruction.

There are two types of RVLs—“channeled” and “nonchanneled.” The primary difference pertains to handling of the endotracheal tube. Channeled devices have a slot into which the endotracheal tube is secured. After obtaining a view of the vocal cords, the endotracheal tube is slid off the scope into the airway. A gum elastic bougie should accompany channeled RVLs since the bougie may facilitate endotracheal tube insertion if the blade is too short to access the laryngeal inlet. Some nonchanneled scopes recommend that the endotracheal tube be loaded onto a nondisposable proprietary stylet for advancement into the airway.

Channeled RVLs

Several manufacturers have offerings. Two commonly found examples are the Airway Scope AWS-S200 (Pentax Medical Company) and Airtraq Avant (Prodol Meditec). Other companies of note are Pentax Medical Company and Prodol Meditec.

The Airway Scope AWS-S200 is battery operated and uses a disposable rigid blade. This RVL can accommodate a variety of endotracheal tube sizes and has a video screen on the handle. One of the limitations to the device is that the blade is only manufactured in one size for the adult, pediatric, and neonate populations. Maintenance of the device focuses largely on ensuring the availability of the disposable plastic blades, cleaning between uses with alcohol wipes or cleaning solution as described by the manufacturer, and replacing the batteries as needed.

The Airtraq Avant uses an eyecup or optional video camera and attached display, disposable blades (size 2 and 3 for endotracheal tubes 6.0-7.5 and 7.0-8.5, respectively), a rechargeable battery, and docking station. There are two separate tracks: one for the endotracheal tube and the other for the optics. There is an antifog system that is activated by the LED, requiring 30-60 seconds before use to warm the lens. The Airtraq Avant has been certified MRI conditional up to 3T. Overall, the system requires minimal maintenance similar to other RVLs, and technologists should ensure accessibility of blade sizes, cleaning between patient contacts, and adequate battery charge.

Nonchanneled Video Laryngoscopes

The most commonly used nonchanneled RVLs are the GlideScope AVL (Verathon), McGrath MAC (Medtronic), and C-MAC (Karl Storz); see Figure 40.5.

FIGURE 40.5. Nonchanneled video laryngoscopes.

The GlideScope, made commercially available in 2001, has several current models that utilize a digital color monitor. The GlideScope AVL is a reusable video baton/disposable blade system with two sizes of baton available. Additionally, there are six sizes of disposable blade ranging from the neonate GVL 0 (<1.5 kg) up to GVL 5 for large or morbidly obese. Two sizes are shown in Figure 40.6. The GlideScope Titanium is a reusable titanium alloy blade with integrated camera and light source. The titanium is available in four sizes, two angled sizes, and tow MAC-style blades. Verathon also produces a semirigid stylet that matches the curve of the GlideScope blades. The stylet is an essential part of the GlideScope and should always accompany it. Most difficulties with GlideScope intubations are not with seeing the glottic opening but with getting the tube into it, which is facilitated by the proper stylet. GlideScope stylets should neither be discarded, nor bent.

FIGURE 40.6. GlideScope video laryngoscope.

The McGrath MAC may be used as a direct line-of-sight laryngoscope using the curved, Macintosh-shaped blade while simultaneously capturing an indirect view of glottic opening from the tip of the blade. The McGrath MAC consists of an integrated 2.5-inch screen, in-line anterior camera, rechargeable battery pack, compact cable-free design, and single-use blades with antifog coating in three sizes. Unlike the GlideScope, no specialized stylet is required. The rechargeable battery has a reported life of 250 minutes. Maintenance of the McGrath MAC is similar to other RVLs.

The Karl Storz C-MAC video laryngoscope, introduced in 2003, is similar to the McGrath MAC as it can also be used as a direct or indirect laryngoscope. The components of the C-MAC include a high-resolution monitor, electronic cable module (interface between the camera and the monitor unit), reusable standard steel blade shapes (Macintosh 2-4, Miller 0-1, and the D-Blade), and rechargeable lithium ion battery as seen in Figure 40.7. The D-Blade has an acute curve to facilitate visualization of anterior airways. This device does not require a specialized stylet. The C-MAC S model uses disposable blades (Macintosh 3-4 and D-Blade). The reported battery life of the C-MAC is approximately 120 minutes.

FIGURE 40.7. C-MAC video laryngoscope.

Indirect Laryngoscope Troubleshooting

Immediately prior to clinical use, function of all these devices should be re-confirmed. Failure of image retrieval may be due to many issues. Given the numerous indirect laryngoscope offerings on the market, the most complete troubleshooting specifics will be found by consulting the manufacturer’s manual; however, in general, if there is difficulty with the image, the technologist should:

• Ensure that the device is properly assembled.
• Ensure all contacts and cables are clean and fully engaged.
• Verify the power source. Check function of outlet. Verify battery life.
• Verify that monitor is properly connected and selected for viewing.
• Provide sufficient warm-up time to prevent camera fogging.
• Check white balance and focus on fiberoptic bronchoscopes.

Tools for Blind Techniques

Intubating Stylets

These devices are low tech, inexpensive devices that have a special role in securing an airway. These are often used to instrument the trachea when visualization is poor or nonexistent. The call for one signifies a difficult intubation is expected or in progress and possibly that visualization attempts have failed. The two most common types of intubating stylets are as follows:

• Gum elastic bougies
• Lighted stylets

Gum Elastic Bougies

Also termed “introducer” or “bougie,” a gum elastic bougie is a single-use, long, thin, moderately flexible, radiopaque straight tube with position markings along the length and an angled tip, as shown in Figure 40.8. The bougie is typically inserted orally, and the tip is directed into the airway by tactile feedback. Once in the airway, an endotracheal tube can slide over it into position. Bougies are often used along with other intubation methods (either direct or indirect). Some bougies are simple flexible stylets, others have a central lumen with a side port that can connect to an oxygen source for use during bougie placement. The Aintree Intubation Catheter (Cook Medical) is a 19F airway exchange catheter with several versatile uses. Like a bougie, it can be placed, using tactile feedback, via direct laryngoscopy into a suboptimal view of the glottis. Unlike the gum elastic bougie, it has a channel, with both a Luer-Lock and a standard airway connector. If needed, it can be connected to a jet ventilator or an anesthesia machine (though its resistance is too high for routine prolonged ventilation). It can over a fiberoptic bronchoscope as well as through an ETT and can facilitate endotracheal tube placement through the fenestrations of a laryngeal mask airway (LMA) with or without the assistance of a flexible fiberoptic bronchoscope. Manufacturers produce many sizes and designs that are commercially available for clinical use. Costs range from $5 to $25 per bougie.

FIGURE 40.8. Gum elastic bougie.

Lighted Stylets

These flexible stylets have a protected bulb at the tip. To use, an endotracheal tube is placed over the stylet, inserted orally and advanced, sometimes with the assistance of direct laryngoscopy. The functional premise is that a bright glow from the bulb will glow through the anterior neck when it is properly placed in the trachea. If malpositioned in the esophagus, little or no light will be visible. This technique has a low overall success rate and requires room darkness to see the glow.

There are many lighted stylets available including Trachlight (Laerdal), Light Wand (Vital Signs), Trachlight (Rusch), Surch-Lite (Aaron Medical Industries), Tube-Stat lighted stylet (Xomed), and an array of other manufacturers. Lighted stylets may have a reusable battery pack handle with a disposable lighted stylet, or they might be fully disposable. Both forms have adult and pediatric sizes. Disposable units cost $30-$50 each, while the partially reusable models run for $20-$30 for the battery pack handle and $10-$20 for the detachable stylet.

Airway Exchange Catheters

On occasion, the need to exchange an endotracheal tube arises such as in the setting of a defective endotracheal tube pilot balloon, ruptured cuff, nonideal size, or type of tube. Regardless of reason, airway exchange catheters are designed to facilitate this undertaking. One example is the Cook Airway Exchange Catheter (Fig. 40.9). This single-use device is a blunt-tipped, plastic, radiopaque catheter accompanied by position markings along its length. The hollow catheter is equipped with an adapter (either a 15-mm or a Luer-Lock connector), allowing oxygenation or ventilation assistance during the exchange. (The Aintree catheter, optimally sized to assist with intubation, is the shortest and largest diameter of the many sizes of airway exchange catheters.) The Arndt Airway Exchange Catheter Set permits the exchange of LMAs or endotracheal tubes using a flexible fiberoptic bronchoscope, bronchoscopic port, wire guide, and exchange catheter. The Arndt device resembles the Cook Airway Exchange catheter but includes an additional stiff wire guide with positioning marks, connector, removable adapter, and a bronchoscopic port.

FIGURE 40.9. Airway exchange catheter.

Intubating the Airway

The vast majority of intubations are done on anesthetized, asleep patients and proceed in a routine manner. However, not all do. In that setting, the clinician will need to change their airway management plan, and technologists must rapidly present and setup fully functional equipment. Anesthesia technicians play a significant role in successful airway management through a combination of overall situational awareness, equipment familiarity, and readiness.

Preparing for Endotracheal Intubations

Routine

Straightforward endotracheal intubations often require slight modifications to plans made prior to induction. These changes are made during the induction. To optimize care, the OR cart must contain necessary equipment and medications to ensure timely and smooth transitions and provide the highest level of patient safety. The setup for routine intubations likely varies between institutions and anesthesia practitioners; thus, it is important to consult with the administration for specifics. Most commonly, setup for a routine intubation includes the following:

• Equipment
  • Anesthesia machine (on and checked), circuit, and mask
  • Bag/valve/mask (such as AMBU bag)
  • Oxygen (from cylinder or wall source)
  • Suction with Yankauer tip attached
  • Stethoscope
  • LMAs
  • Oral endotracheal tubes and stylets
  • If stocking a specialized OR, then specialty endotracheal tubes such as nasal or oral RAEs, laser resistant, bronchial blockers, an assortment of double lumens, or wire reinforced, etc.
  • Syringe for inflating cuff(s) and tape to secure endotracheal tubes
  • Laryngoscopes (handles short and regular, and curved and straight blades of varying sizes)
  • Blankets and pillows to help with head/neck positioning
  • CO₂ monitor (capnograph or colorimetric)
• Medications (the stocking of which is most often managed by the OR pharmacy but may be managed by technologists)
  • Functioning IV (for medication delivery)
  • Nose spray and local anesthetic for nasal or awake intubations (see section on “Flexible fiberoptic bronchoscopes”)
  • Intubation or sedation medications

Difficult Intubations

Difficult endotracheal intubations may be expected or come as a surprise. In some ways, therefore, preparation for a routine airway is always preparation for a difficult airway, and preparation for a known difficult airway involves few extra steps. At any time during airway management, difficult can be encountered, and clinicians need rapid help with patient positioning, medication administration, and equipment and device management. Technologists are a critical part of the care team.

Difficult Airway Algorithm

The American Society of Anesthesiologists’ (ASA) Difficult Airway Algorithm provides clinicians with valuable structure regarding challenging airway management (see Chapter 18, Principles of Airway Management). It is worthwhile to emphasize that airway management strategies are complex and often change rapidly. Within the structure of the algorithm, the technologists’ role is clear: be part of the patient care team by helping clinicians do their job safely and rapidly. Airway management proceeds more smoothly when the technologist is present and has at the ready any requested device. An experienced anesthesia technologist is invaluable in the management of difficult airways.

Difficult Airway Cart

Dedicated difficult airway carts are a critical part of the anesthesia department. Typically, they contain routine and lesser-used airway supplies and equipment (e.g., specialized stylets and endotracheal tube exchangers, tracheostomy kits, etc.) within a highly portable trolley. Ensuring proper functioning and maintenance of the equipment in the difficult airway cart is an important responsibility of the anesthesia technician. The carts must be clearly labeled and well organized. Most medical centers have such carts with both adult and pediatric variations, but their content may vary widely. Chapter 57 gives an example of what to stock. Figure 40.3 shows another common difficult airway cart configuration.

The following items are usually set up in preparation of the expected difficult airway:

• Equipment and medications
  • Include all items listed under “Preparing for Endotracheal Intubations—Routine”. Additionally, include an array of smaller than usually used cuffed endotracheal tubes
  • Indirect/specialized intubation scopes (fiberoptic and video) assembled, all components present, turned on, checked at the point of potential use with suction attached (separate from the assembled Yankauer suction)
  • Intubating stylets (bougie, lighted)

Preparing for Surgical Airway Techniques

Emergency surgical access of the airway through the neck may be a lifesaving procedure in the dreaded “can’t intubate/can’t ventilate” situation. Without establishing a secure airway within only a few minutes, the patient is likely to suffer permanent brain injury or death, and therefore, this is a dire emergency. Success rests on the clinician’s ability to correctly identify a small thin membrane (cricothyroid) located on the neck just below the thyroid cartilage or “Adam’s apple.” It is through this precise location that the airway may be accessed in an emergency. A few variations of emergency airway access are as follows:

1. Cricothyrotomy

• Emergency preassembled kits consist of an angiocatheter-like catheter over a needle, guidewire, scalpel, dilator, tracheal hook, cricothyrotomy tube that can connect directly to bag/valve/mask or circuit, syringe, and neck strap. Briefly:
  • After the angiocatheter has been placed through the cricothyroid membrane and into the trachea, the needle is aimed toward the patient’s feet, and the guidewire is advanced.
  • After needle removal, the opening is dilated, and the cricothyrotomy tube is placed into the airway over the wire.
  • After the wire is removed, the tube is connected to a ventilation device. If possible, fiberoptic bronchoscope confirmation of tube position (in the airway) prior to ventilation is ideal.

2. Retrograde intubation

• Another approach is the retrograde intubation. Here, the wire that has been entered into the trachea is directed toward the head. The goal then is to capture the wire at the mouth and use it as a guide for the endotracheal tube into the trachea. Alternatively, the wire can be captured and threaded through the working port of a fiberoptic scope, on which there is a preloaded endotracheal tube. The wire is used to guide the scope into the airway. The wire is removed, and the endotracheal tube is advanced off the scope into the trachea.
• Similar to the cricothyrotomy, prepackaged retrograde wire kits are on the market. These include an angiocatheter-like catheter over a needle, syringe, straight and J-tip wire guide with position markings, hemostat, Magill forceps, adapters (15-mm and female Luer-Lock connectors).

3. Percutaneous transtracheal jet ventilation

• A faster but less secure approach is percutaneous transtracheal jet ventilation. For this, a 14-gauge angiocatheter is passed through the cricothyroid membrane and into the airway. A jet ventilator is then attached to the remaining angiocatheter after the needle has been removed. See below “Jet Ventilation.” This requires a male Luer-Lock connector on the jet ventilation tubing to attach to the female angiocatheter connector.

Ventilation Through Small-bore Tubing

Management of the emergency airway may result in placement of a very small-bore catheter. In that setting, a means to deliver a high-pressure jet of oxygen will be needed to overcome the high resistance to gas flow seen in very small diameter tubes. The gas source can be centrally plumbed and accessed at the wall or from an E or H oxygen cylinder. The most common delivery systems are as follows:

1. Jet ventilation

• These systems are useful in some routine surgeries in which conventional ventilation is nonideal and in the emergency setting. Various commercially produced systems are available as seen in Figure 40.10. Minimally, all contain a pressure regulator and gauge; a means to control the pressure, duration, and percent oxygen delivered; and should have small-bore tubing with a male Luer-Lock connector. Jet ventilators can be used with angiocatheters as described above, intubating bougies (i.e., Aintree Intubation Catheter), or airway exchange catheters (i.e., Arndt Airway Exchange Catheter).

2. Oxygen flush valve

• Here, the anesthesia machine’s oxygen flush valve is used as part of a system to deliver a high-flow jet of oxygen. For this, a 3-cc Luer-Lock syringe and a size 7 endotracheal tube are needed. A new connector is made by taking the endotracheal tube connector and press fitting it snuggly into the open end of the 3-cc syringe barrel as seen in Figure 40.11. This homemade piece now connects the standard anesthesia circuit to the female end of the airway device (angiocatheter, bougie, Aintree, etc.). The flush valve may be used to judiciously deliver short bursts of high-pressure oxygen.

FIGURE 40.10. Jet ventilator.

FIGURE 40.11. Endotracheal tube connector and 3-cc syringe.

Ventilation through either of these jet ventilation methods in the emergency setting is extremely dangerous because gas is being delivered under high pressure to a potentially obstructed airway. Establishing a route for oxygen to get into the patient is potentially lifesaving. However, unless the gas has a way to get out again, the patient can develop high pressure in the lungs, pressure injury to the lungs, or excess pressure in the chest preventing blood return to the heart from receiving gas under the high pressure coming from the wall (55 PSI). Thus, the anesthesia providers will be watching carefully for exhalation and continuing to work hard to establish better ventilation.

Summary

This chapter has characterized the wide range of equipment commonly utilized to access the airway for tracheal intubation. Preparation for routine and difficult intubations has been outlined. Checklists for setup, maintenance, operation, and troubleshooting of airway management equipment have also been included. Also covered are a few emergency techniques important to mention because of the unique nature of the procedures, equipment, and the need for help from all people on the care team. This chapter presents a broad overview of these tools and techniques so that anesthesia technologists may better understand the field, how best to handle and care for this equipment, and be valued active care team participants.

Review Questions

1.  A patient needs to be intubated after a car accident. She has a suspected cervical (neck) spine injury. Which is the LEAST ideal device to use?

A)  Fiberoptic bronchoscope

B)  Rigid video laryngoscope

C)  Laryngoscope with MAC 3 blade

D)  Intubating LMA

E)  None of the above

Answer: C

This approach requires visual alignment of the mouth with the vocal cords to obtain a direct view of the glottic opening. The head and neck will need to be manipulated, an unwise move after an injury to the neck. All the other choices do not require extensive neck manipulation and are therefore safer.

2.  When setting up a channeled rigid video laryngoscope, which adjunct/device should always be readily available?

A)  Miller blade

B)  Stylet

C)  Bougie

D)  LMA

E)  All of the above

Answer: C

A gum elastic bougie may be requested by the anesthesia practitioner to assist with placement of the endotracheal tube if the blade is too short to reach and direct the tube into the trachea. The bougie can be placed through the endotracheal tube and be manipulated to access the trachea.

3.  Nonchanneled rigid video laryngoscopes require the endotracheal tube be passed into the airway separately from the rigid video laryngoscope. Which device must always accompany the rigid video laryngoscope?

A)  Miller blade

B)  Stylet

C)  Bougie

D)  LMA

E)  All the above

Answer: B

Nonchanneled scopes require the endotracheal tube be loaded onto a reusable proprietary stylet and advanced independently into the mouth and airway. A standard disposable stylet may suffice if the device-specific stylet is unavailable.

4.  A persistent nosebleed requires an intervention that requires intubation. Which of the following methods is likely the clinicians’ first choice for placing an endotracheal tube in a patient with blood in the oropharynx?

A)  Pediatric fiberoptic bronchoscope

B)  Rigid video laryngoscope

C)  Laryngoscope and a Yankauer-tipped suction

D)  Bougie

E)  None of the above

Answer: C

The laryngoscope and a Yankauer-tipped suction will provide the largest view and best suction. The fiberoptic scope’s small lens is likely to become occluded by excessive blood in the oropharynx. Also, most fiberoptic scopes have limited suctioning ability, and depending on the rate of bleeding, they may prove usable due to inadequate blood clearance. A rigid video laryngoscope’s lens may also occlude. A bougie is an option but is a “blind” technique and may be chosen as a backup plan after attempted visualization.

5.  A nasal RAE endotracheal tube may be requested for head and neck surgery. To aid placement, which of the following might be useful?

A)  Magill forceps

B)  Laryngoscope

C)  Fiberoptic bronchoscope

D)  Yankauer-tipped suction

E)  All of the above

Answer: E

Because the endotracheal tube needs to travel through the nostril into the back of the throat, a stylet cannot be used to direct the tube through the glottic opening. The tip of the tube may need to be directed into the trachea by use of Magill forceps. Standard intubation equipment (suction, laryngoscope with different blades) is also needed. If the mouth opening is limited, the tube will need to be directed by use of a fiberoptic flexible scope.

6.  During a difficult intubation, which of the following will be useful?

A)  Multiple laryngoscopic blades

B)  Intubating LMAs

C)  Rigid video laryngoscope

D)  Fiberoptic bronchoscope

E)  All the above

Answer: E

If presented in an organized manner, the more options the better.

SUGGESTED READINGS

American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Practice guidelines for management of the difficult airway. Anesthesiology. 2003;98:1269-1277.

Benumof J, Hagberg CA. Benumof’s Airway Management: Principles and Practice. Philadelphia, PA: Mosby; 2007.

Klinger K, Infosino A. Chapter 16: Airway management. In: Miller RD, Pardo MC Jr, eds. Basics of Anesthesia. 7th ed. Philadelphia, PA: Elsevier; 2018.

Klock PA Jr, Anderson J, Hernandez M. Chapter 32: Airway management. In: Longnecker DE, Mackey SC, Newman MF, et al, eds. Anesthesiology. 3rd ed. New York: McGraw-Hill; 2018.