The management of the airway is one of the most important tasks of the anesthesia provider (see Chapter 18). Because of the complexity of airway management, manufacturers continue to produce an endless array of tools and equipment to aid in the management of the airway. This chapter introduces the most common types of airway equipment currently available as well as describes any special setup that might be required, how the equipment is generally used, and tips on maintenance and troubleshooting.

In anesthetized or unconscious patients, the soft tissues of the oropharynx, especially the tongue, can obstruct the passageway between the mouth and the glottis. Oropharyngeal airways (OPAs) are used to stent open the oropharynx to allow passage of air/oxygen through the oropharynx. The majority of OPAs are made of curved hard plastic to conform to the oropharynx. They usually have an interior channel that allows the passage of gas or suction devices from the mouth opening through the channel into the posterior pharynx (Fig. 35.1).

OPAs are used in anesthetized or unconscious patients who cannot be easily ventilated by bag/mask ventilation or who are spontaneously breathing but have airway obstruction. They are usually not tolerated by awake patients and can cause gagging and even vomiting when used in a conscious or semiconscious patient. When inserting an oral airway, the anesthesia provider may use a tongue depressor to keep the oral airway from pushing the tongue back into the pharynx. Oral airways should be kept immediately available (easy to grab) in all settings in which airways are managed (e.g., operating room, recovery area, emergency room, rapid response, or code carts).

OPAs come in a variety of sizes from newborns to extra large adults and are often color coded to indicate the size of the airway. They are usually marked with the actual size in millimeters (50-100 mm) or with a number (5-10) that corresponds to the size in centimeters, with 8-10 the typical size range used in adults. OPAs generally cost between $0.30 and $3.00 each. The vast majority are disposable and latex free. Many institutions have single-use prepackaged disposable oral airways (Fig. 35.2). When removing the airway from the package, care must be taken to ensure that none of the packaging material remains attached to the airway prior to insertion in a patient. Plastic remnants from the packaging can be swallowed or aspirated into the patient’s lungs.

Types of OPAs

Although many of these airways can be boiled or gas/cold sterilized, the majority OPAs are meant for single use only.

Much like OPAs, nasopharyngeal airways (NPAs) are designed to be used in patients with airway obstruction. These airways are inserted through the nose and into the posterior pharynx where they can prevent the tongue from collapsing against the posterior wall of the oropharynx. NPAs are usually better tolerated than OPAs in awake or semiconscious patients with an intact gag reflex. NPAs are soft and flexible and have
an interior channel to permit the flow of gas, a beveled edge to ease passage through the nose, and a flared end to prevent the NPA from passing completely into the nose. Because of the flared end, many refer to them as a “nasal trumpet” (Fig. 35.5). Because NPAs can cause trauma to the nasal passages, a decongestant (e.g., phenylephrine nose drops) to shrink the nasal mucosa and lubricating jelly (e.g., “Surgilube” or 2% xylocaine jelly) can be used to facilitate passage of the NPA through the nose.

NPAs come in a variety of sizes. They are often sized using the “French” scale, with sizes ranging from 12 to 36 French. Dividing the French number by 3 gives the diameter of the NPA in millimeters. The majority of modern NPAs are latex free and single use only. Older NPAs were made of rubber. Do not assume an NPA is latex free unless the packaging clearly states that it is. NPAs come individually packaged or can be purchased in bulk. Prices range from $3.00 to $7.00 each. Some packages include a lubricant. As with many other medical products, the vast majority of NPAs are designed for single use and should not be cleaned and used in another patient.

Face masks and nasal cannula are used to deliver supplemental oxygen to the patient. One concept that is universal to all types of oxygen delivery systems is to make sure oxygen is flowing from the source. If a portable oxygen delivery source is to be used (oxygen tank), make sure it has sufficient oxygen for the trip. A full e-cylinder of oxygen at 1,900 psi contains about 660 L of oxygen. The amount of oxygen left in the tank is directly proportional to the amount of pressure left in the tank. If the tank reads about 950 psi, it is half full and contains about 330 L of oxygen. At 10 L/min flow through a simple face mask, this tank would have 33 minutes of oxygen left. If using wall-mounted oxygen, make sure the flowmeter is on and oxygen is flowing.

Nasal cannulas are designed to supplement the flow of oxygen to the patient. In general, one end of the tubing is connected to a metered oxygen source and the nasal portion is secured to the patient’s head with the tips (“prongs”) of the nasal cannula resting a short way inside the patient’s nostrils (Fig. 35.6). The oxygen flow is adjusted between 2 and 6 L of oxygen per minute and delivers approximately 24%-44% oxygen to the patient. If the patient requires a higher concentration of oxygen, an oxygen face mask must be used. Delivering higher than 6 L of oxygen per minute through nasal cannula is irritating to the patient and can dry out the nasal mucosa, resulting in nosebleeds. This can happen even if the cannula is attached to a humidification system.

Nasal cannulas are generally very similar in design and are usually made of a soft plastic material. They are intended for single patient use and prices range from $0.50 to $2.00 each. One of the major features of the cannula to consider is the length of the oxygen tubing, which can range from 7 to 100 ft. During patient transport, if the oxygen source is at the foot of the bed, the 7-ft length of oxygen tubing may be insufficient for the cannula to reach the patient’s head. Some anesthesia providers stretch the tubing to slightly increase its length.

Other features to consider when using a nasal cannula include attaching the tubing to a breathing circuit or sampling exhaled carbon dioxide through the nasal cannula while it is delivering oxygen. Some nasal cannulas come with an adaptor to attach the oxygen source end of the tubing to the breathing circuit (Fig. 35.7). This will allow the anesthesia provider to control the upper limit of the percentage of oxygen delivered through the cannula. For example, the anesthesia provider may wish to control the percentage of oxygen to reduce the risk of fire during a head and neck procedure performed on an awake patient. Unfortunately, the control over the oxygen concentration is not very precise. During inhalation the entrainment of room air affects the delivered oxygen concentration. If the cannula does not come with an adaptor, tape can be wound around the oxygen source end of the tubing to increase its diameter to the point where it can be snuggly fit into the breathing circuit.

Some nasal cannulas come with a gas sampling line built into the tubing. The sampling port is near the nostrils, and a separate connection port is near the oxygen source end of the cannula, which can be attached to a CO₂ gas analyzer (Fig. 35.8). The sampling tubing can often be separated from the oxygen delivery tubing to facilitate attachment to the gas analyzer. These cannulas are extremely useful during procedures performed under sedation. The sampling line is connected to a CO₂ gas analyzer and the anesthesia provider can monitor the respiratory rate,
a reasonable estimate of end-tidal CO₂, and can detect airway obstruction.

Face masks come in two general types: those used for the passive delivery of oxygen and those used for assisted ventilation. Face masks designed for the passive delivery of oxygen consist of plastic tubing for attachment to an oxygen source (or humidified oxygen source) and the delivery end, which may cover the patient’s entire face, the nose and mouth, a tracheal stoma, or just the nose.

Features to consider when selecting or purchasing face masks include the length of oxygen tubing, the type of mask, and the concentration of oxygen that needs to be delivered. The majority of the face masks on the market are for single patient use only and should not be used on other patients.

In order to deliver positive pressure ventilation via a mask, the mask must be able to form a tight seal around the patient’s mouth and nose. These masks tend to be of a more durable design than passive oxygen masks and also have an inflatable cuff around the edge of the mask to help form a seal with the patient’s skin (Fig. 35.14). The mask also has a port that accommodates a standard 15-mm inside/22-mm outside connector that fits into standard breathing circuits. Finally, many masks have four “prongs” around the connector opening. These prongs are used to attach a head strap to secure the mask to the patient’s face.

Older mask designs were made of black rubber and were sterilized after use, so they could be used on another patient. The disadvantage of these types of masks include the cost of sterilization, the risk of disease transmission, the masks are not latex free, the inflatable cuffs would decay and lose their ability to stay inflated, and the masks may prevent the anesthesia practitioner from seeing vomit come out of the patient’s mouth and into the mask. Despite these drawbacks, many are still in use today. These masks cost in the range of $20-$40. When using one of these masks, take care to ensure that the cuff is inflated properly and can hold pressure. Follow the manufacturer’s recommendations for sterilization.

Newer mask designs are made of plastic and are intended for single use only. They are typically used in the operating room with anesthesia breathing circuits or with bag-valve-mask ventilation systems. Before purchasing a new mask type, consult your anesthesia providers. Some of the masks are more difficult to hold with one hand because of the dome shape on the mask. When using a disposable mask, always check the cuff as it can lose cuff pressure when stored. The cuff can be easily inflated by attaching a syringe to the cuff port. If the cuff will still not hold pressure, the cuff may have a leak. Commonly, the valve used to inflate the mask has become incompetent and is allowing gas to escape from the cuff through the valve. These masks generally cost between $2.00 and $4.00 each. Some breathing circuits come packaged with a disposable anesthesia mask. When removing a mask from individual plastic packaging, it is critical to
make sure that plastic remnants are not present on the mask. If not completely removed, these remnants could be aspirated into the patient’s lungs when the mask is used.

Some specialized anesthesia masks (e.g., the endoscopy mask) have a port with a membrane for entry of a fiberoptic bronchoscope and a port to ventilate the patient without removing the mask from the patient’s face and without losing the ability to provide positive pressure ventilation (Figs. 35.15 and 35.16). Other face masks are designed to deliver continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BIPAP). BIPAP and CPAP are used to treat obstructive sleep apnea as well as respiratory failure in the intensive care unit (ICU). Both require a tight-fitting mask with a head strap to create a good seal to deliver positive pressure. These masks can cover just the nose or mouth. (Fig. 35.17).

Intubating the trachea is considered the gold standard for securing the airway and minimizing the risk of aspiration once the airway is established. Many consider intubating the trachea to be “invasive” and not without risk. Glottic structures like the vocal cords or arytenoid cartilages can be damaged while attempting to pass a tube through the trachea. In addition, tracheal intubation is quite stimulating to the patient and can lead to catecholamine release and large swings in heart rate and blood pressure, which can be detrimental to many patients. Since the 1960s, inventors have been experimenting with a variety of methods to establish an airway that minimizes obstruction caused by oropharyngeal structures without inserting a tube through the vocal cords into the trachea. Because these devices are positioned above the vocal cords (glottic region), they are termed laryngeal or supraglottic airways. The term laryngeal airways would only include those devices that are positioned in the pharynx just outside the larynx and does not include devices like OPAs.

There are many types of laryngeal airways. The basic design features that are present in many of these airways include the following:

This device was introduced in the late 1980s and has become one of the most popular laryngeal airways worldwide, almost eliminating the use of prolonged mask ventilation. The laryngeal mask (LM) consists of a plastic, silicone, or rubber tube connected to an inflatable silicon “mask” that forms a seal around the laryngeal inlet (Fig. 35.18). A pilot tube with an inflation valve is connected to the cuff. The device is easy to insert and highly effective. Single-use disposable models are generally made of polyvinylchloride (PVC) and range in price from $5.00 to $10.00. Multiuse models generally have a silicone cuff and range in price from $100 to $250.

Numerous manufacturers produce LMs. Several examples are provided below:

Several modifications have been made to the original design of LMs including the following:

An additional modification has been made to the design of the LM to facilitate intubation (LMA^TM Fastrach) (Fig. 35.19). Although blind or fiberoptic intubation can be accomplished with several current LM models, the “intubating” LM is specifically designed for this purpose. The intubating LM illustrated in Figure 35.19 has three components: the LM