The first goal of airway management, regardless of a patient's ability to breathe spontaneously, is the establishment of a patent airway. This may be all that is required in a patient who has an upper airway foreign body or a patient who has suffered a loss of consciousness with loss of pharyngeal tone. The importance of proper positioning cannot be overemphasized. The success of airway management is predicated on this very basic but often overlooked issue. Placing the patient in the “sniffing” position, or lateral decubitus position, may correct many upper airway obstructions due to soft tissue impingement.11 The “sniffing” position is achieved by flexing the cervical spine approximately 15° and extending the atlantooccipital joint maximally (Figure 7-1). This is the position one subconsciously adopts in order to sniff and smell. Head extension in this manner must be omitted in the patient for whom cervical spine precautions are in effect. This position can also be achieved with the chin-lift and/or jaw-thrust maneuvers.
The “sniffing” position for successful airway management.
If the patient is obese or has large breasts, they often cannot be effectively managed in a supine position. The normal sniffing position in an obese person is often not sufficient to relieve an airway obstruction (Figure 7-2A). Place a ramp or shoulder roll under the patient's upper back to achieve the sniffing position (Figure 7-2B).
Airway management in the obese patient. A. The normal “sniffing” position is inadequate to open the airway. The red line represents the axis of the airway. B. A ramp placed under the head and shoulders will achieve the “sniffing” position.
The jaw thrust is one of the most basic maneuvers and an initial method of establishing a patent airway.12 The tongue is attached to the mandible and falls into the pharynx in the supine patient. The goal of the jaw-thrust maneuver is to move the tongue away from the palate and posterior pharyngeal wall. The jaw-thrust maneuver is a two-handed technique that can also be used with the face mask and a second person to provide positive-pressure ventilation. The operator is positioned at the head of the patient and places their fingers on the angles of the patient's mandible bilaterally, then displaces the mandible anteriorly (Figure 7-3). This maneuver elevates the tongue from the pharynx and allows air to flow unobstructed and posterior to the tongue.
The chin lift is also one of the most basic maneuvers and an initial method of establishing a patent airway.12 The chin lift is performed by the operator placing their fingers on the inferior surface of the patient's mandible (Figure 7-4). Do not place any of the fingers on the soft tissues of the submandibular space, as this will elevate the tongue and cause further obstruction. Lift the chin in an anterior and cephalic direction. The head may also be tilted slightly posterior to aid in opening the airway.
The majority of airway obstructions occurs in the region of the pharynx.13 In addition to proper positioning, one can use various aids to overcome this site of obstruction and facilitate effective ventilation. The most commonly used devices are oropharyngeal (oral) and nasopharyngeal (nasal) airways. Regardless which device is chosen, it is important to place a large enough airway to bridge the area of soft tissue impingement on the pharynx.
Nasal airways are soft rubber or plastic tubes that are inserted through the nostril and into the oropharynx, just above the epiglottis. Nasal airways are available in numerous sizes (Figure 7-5). The proximal end has an enlarged flange that rests against the patient's nares and prevents the nasal airway from slipping backward into the nose and becoming a foreign body in the patient's airway. The larger the inner diameter, the longer the tube. Once positioned, the nasal airway is more comfortable for the patient than an oral airway, but nasal airways carry the significant risk that their placement may result in epistaxis.3,10 A size 30 or 32 French nasal airway is appropriate for most adults. It can be safely placed in the conscious, semiconscious, or unconscious patient, and can also be used when an oral airway cannot be placed (e.g., oral trauma, braces, seizures, trismus, etc.). It is imperative to also perform the jaw thrust and/or chin lift to prevent the tongue from obstructing the patient's airway when using a nasal airway.
Insertion of a nasal airway is a rapid procedure. Choose the proper size nasal airway by placing the flared end of the airway near the tip of the patient's nose. The distal end of the nasal airway should be at the external auditory canal. Liberally apply a water-soluble lubricant or an anesthetic jelly to the nasal airway. If not contraindicated, apply a vasoconstrictor to the patient's nasal mucosa. Gently insert and advance the nasal airway with the beveled tip against the nasal septum (Figure 7-6). This will prevent any epistaxis from the tip of the nasal airway getting caught on the inferior or middle turbinate. Also insert it along the floor of the nasal cavity adjacent to the septum. Continue to advance the nasal airway completely until the flared end is against the patient's nostril. Rotate the nasal airway 90° so it is concave upward. If resistance is encountered during insertion, slight rotation will often facilitate the passage of the nasal airway. If resistance is still encountered, insert the nasal airway into the other nostril or use a smaller nasal airway. Supplementary oxygen or positive-pressure ventilation with a bag-valve-mask device can be started after insertion of the nasal airway.
Insertion of the nasopharyngeal airway.
Insertion of a nasal airway may be associated with complications. If the device is too long, it may cause laryngospasm and vomiting. It may also be placed with its tip in the esophagus, resulting in gastric distention and subsequent aspiration. Nasal mucosal injury upon insertion can result in epistaxis and aspiration of blood.
The oropharyngeal (oral) airway is a semicircular plastic device that holds the tongue up and away from the posterior pharyngeal wall (Figure 7-7). Oral airways cause less trauma and are more easily placed than nasal airways. Oral airways must be used only in unconscious patients. They may result in laryngospasm and vomiting if placed in a conscious or semiconscious patient.14 An 8.0, 9.0, or 10.0 cm oral airway is appropriate for most adults.
Oral airways have many uses. The primary indication is to maintain a patent airway. It will prevent the patient from biting, occluding, and lacerating an endotracheal tube. It facilitates oropharyngeal suctioning by removing the tongue from the airway, and will also protect the tongue from bites during seizure activity.
Insertion of the oral airway is a quick and simple procedure. Choose the proper size oral airway. The correct size is estimated by placing the proximal flange of the oral airway next to the patient's mouth. The distal tip should lie just above the angle of the mandible. Clear the mouth and oropharynx of any blood, secretions, or vomit with a Yankauer suction catheter. Open the patient's jaw with the nondominant hand. Separate the patient's jaws with a “scissors-like” action of the thumb on the lower teeth and the index or middle finger on the upper teeth. Insert the oral airway curved side down (Figure 7-8A). The tip will slide along the hard palate. Insert it until the plastic flange on the proximal end is at the patient's lips. Rotate it 180° so that the curve of the oral airway follows the curvature of the tongue.
Insertion of the oropharyngeal airway. A. It is inserted with the curve toward the tongue. After insertion, it is rotated 180°. B. It is inserted with the curve toward the palate. A tongue blade is used to depress the tongue and facilitate insertion.
An alternative method is to use a tongue blade to depress the tongue and then insert the oral airway as described above. If the tongue blade is used, the oral airway may also be inserted with the curve side upward (Figure 7-8B). Supplementary oxygen or positive-pressure ventilation with a bag-valve-mask device can be started after the insertion of the oral airway.
Insertion of an oral airway is not a benign procedure. If the oral airway is not inserted properly, it can push the tongue posteriorly and further obstruct the oropharynx. Significant lacerations can occur if the lips or tongue are caught between the teeth and the oral airway. If the oral airway is too long, it can force the epiglottis closed against the vocal cords and produce a complete airway obstruction. Too small of an oral airway will force the tongue against the pharynx and produce an obstruction.
The likelihood of success in airway management is often predictable, given enough time to fully assess a patient's history and anatomy (please refer to Chapter 6).15 The ease of mask ventilation and intubation is directly related to anatomy. Anesthesiologists rely on a series of evaluations and classification criteria to help predict the success of airway management. The most widely used classification is the Mallampati classification (Figure 6-6).16 This evaluation—coupled with an examination of the patient's body habitus, thickness of the patient's neck, temporomandibular joint function, ability to fully open the mouth, dental structures, cervical range of motion, and thyromental distance—can help predict the ease or difficulty of airway management.15–21
A distinction must be made between ease of mask ventilation and ease of oral endotracheal intubation. The two are often correlated but can, at times, be completely unrelated. For example, a patient with a normal body habitus who is in a cervical halo may be very easy to ventilate by mask but impossible to intubate orally via direct laryngoscopy. Conversely, the patient who is obese, suffers from sleep apnea, but has a Mallampati class 1 airway may be very easy to intubate but virtually impossible to ventilate by mask.
After achieving the proper positioning, the presence of spontaneous respirations must be evaluated. If the patient is not breathing and there is no evidence of a foreign body, positive-pressure ventilation must be initiated. In the awake patient with complete airway obstruction due to a foreign body, the Heimlich maneuver is the method of choice.2 If the patient has become unconscious and the foreign body is clearly visible, remove it. However, caution must be used to prevent forcing the object further into the airway. Instrument removal of airway foreign bodies with a McGill forceps is possible if the foreign body is visible and within reach of the forceps.
Once the airway is patent, the options for positive-pressure ventilation include mouth-to-mouth, mouth-to-mask, and bag-valve devices (mask ventilation). The remainder of this section will review the latter, as the other two options are not used in Emergency Departments or hospitals. The key to effective mask ventilation is ensuring a continually patent airway. This is initially achieved by placing the patient in the sniffing position, coupled with a combination of chin lift and jaw thrust. Neglect of this key maneuver leads to an excessive use of positive-pressure ventilation in an attempt to compensate for an obstructed upper airway. Improper patient positioning associated with positive-pressure ventilation will force gas into the stomach, increasing intraabdominal pressure and resulting in the need for ever-increasing positive pressure on the airway. Rising intraabdominal pressure will eventually make ventilation difficult or impossible, and significantly increase the risk of gastric aspiration. When called upon to mask ventilate a patient, always keep in mind the importance of proper positioning and the use of an appropriately sized oral or nasal airway as an adjunct.
Face masks should be made of clear plastic and/or silicone, have a soft seal, and have an anatomic shape that conforms to the contours of the patient's face. Typical adult sizes are 3, 4, and 5. The mask must be large enough to completely cover the nose, mouth, and chin but not so large as to allow a leak. It should not cover any part of the patient's eyes. There are two ways to properly hold a face mask. The one-handed technique is performed with the nondominant hand (Figure 7-9). The operator should be positioned at the top of the bed looking down at the patient's head. Place the little, ring, and middle fingers under the patient's mandible. Place the index finger and thumb on the bottom and top portions of the mask. This technique allows the operator to simultaneously lift the mandible and extend the atlantooccipital joint while applying enough downward pressure on the face mask to create an airtight seal. An elastic head strap is a very helpful device to aid in sealing the mask tightly. The dominant hand is used to ventilate the patient through the bag-valve device.
The one-handed, one-person mask ventilation technique.
A two-handed technique may be necessary in patients with facial hair and those who are obese, elderly, or edentulous. Two people are required to perform this technique, in which both of the operator's hands are applied to the face mask to aid in the creation of a tight seal and align the airway properly (Figure 7-10). Place the face mask on the patient's face. Place the index, middle, ring, and small fingers of the left hand on the body of the left side of the patient's mandible. Position the right hand similarly on the right side of the patient's mandible. Apply both thumbs to the mask and apply pressure to create a seal. Anteriorly elevate the mandible to perform the jaw-thrust maneuver. This is the two-person technique and makes it necessary to have an assistant apply positive pressure through the bag-valve device attached to the face mask. It is preferable, whenever possible, to use the two-person technique which allows for improved bag-valve-mask ventilation.25
The two-handed, two-person mask ventilation technique.
A relatively new device can be used to assist in ventilation instead of a traditional face mask. The NuMask™ (NuMask Inc., Woodland Hills, CA) solves the problem of having to create an airtight face mask seal in patients. This device is an intraoral mask for teenagers and adults that connects to a bag-valve device and eliminates the need for a face mask (Figure 7-11A). It is especially useful in patients whom it is difficult to get a good face mask seal (e.g., obese, facial hair, and facial trauma) or for the one-person bagging technique. The company makes a retention shield that wraps around the patient's head to secure the device and seal the patient's nostrils. This allows for easy one-person bagging.
The NUMASK™ intraoral mask. A. The device. B. The device is inserted between the patient's teeth/gums and their lips/cheeks. C. Proper hand positioning to seal the patient's nostrils and lips. D. An alternative hand positioning.
The NuMask™ is simple to insert into the patient's mouth. Place the device into the patient's mouth. It should sit between the patient's teeth/gums and the cheeks/lips (Figure 7-11B). Use the thumb and index finger of the nondominant hand to pinch the patient's nostrils closed (Figures 7-11C & D). Use the hand and remaining fingers to wrap around the external tube portion and to seal the patient's lips over the intraoral portion of the device (Figures 7-11C & D). The moisture in the patient's oral cavity maintains the airtight seal. Attach the bag-valve device and begin ventilations. If ventilation is difficult, remove the NuMask™, insert an oral airway, replace the NuMask™, and begin ventilations.
There are numerous advantages of using the NuMask™ over the traditional face mask. It is ideal for operators with small hands who have difficulty grasping and maintaining a seal with a face mask. While initially cumbersome to use, it is easier to maintain a seal than a face mask. Ventilation is easier when only one person is available to bag and ventilate the patient. It can be used in patients in whom a good face mask seal is difficult. The device can be used in both conscious and unconscious patients as it should not cause a gag reflex. Finally, the one size available will fit most teenagers and adults. A pediatric version is not available.
A bag-valve device is used to provide positive-pressure ventilation. It consists of a self-inflating bag connected to oxygen on one end and a one-way (nonrebreathing) valve on the other. They are available in several sizes depending on the age of the patient (Figure 7-12). The valve end is connected to the face mask, or other airway device, to allow one-way flow of oxygen. The other end has tubing to attach the bag to an oxygen source. This device can also force air into the esophagus and stomach and place the patient at risk for aspiration if not used properly.
The bag-valve-mask device. From left to right: adult size, child size, and infant size.
It may be difficult to provide adequate ventilatory volumes through the bag-valve device attached to a face mask. This is often due to an inadequate seal of the face mask on the patient while maintaining an open airway. It can also result from inadequate squeezing of the bag to generate an appropriate volume of air flow. Consider using the two-person technique to resolve these issues. If ventilation is difficult in a child, change the face mask from the standard tear-drop shaped mask to a circular-shaped face mask.
Stand above the patient's head. Place the patient in the sniffing position. Apply a face mask. Attach the bag-valve device to the face mask and begin positive-pressure ventilation. Begin ventilations at a rate of 10 to 12 per minute, or squeeze the bag every 5 to 6 seconds. If ventilation is difficult, apply the jaw-thrust and/or chin-lift maneuvers. If ventilation is still difficult, insert an oral or nasal airway. If ventilation is still difficult, the patient requires an invasive airway device immediately.
The American Society of Anesthesiologists has published an algorithm to facilitate decision making in the face of airway management problems. A detailed discussion of the various intubation options is presented in following chapters.