Securing the airway and assuring adequate ventilation are the first priorities in the resuscitation of any acutely ill or injured patient. Without a patent airway and adequate gas exchange, other resuscitative measures will usually be futile. Thus, attention to the airway must precede or occur simultaneously with any other type of management. The exception is the initial defibrillation in cardiac arrest due to ventricular fibrillation, if it can be performed immediately. (See Figure 10–1.)
First, determine the patient's level of consciousness and note the presence of respirations and grade respiratory effort. In patients with known or suspected cervical spine (C-spine) injury, all assessments and maneuvers should be undertaken with the C-spine immobilized in a neutral position to prevent cord injury.
Apneic, Unconscious Patients
If the C-spine is not injured, place the head in the sniffing position with the chin lift maneuver to open the airway (Figure 10–2). For patients with potential C-spine injuries, a jaw-thrust maneuver should be used. Clear the airway of obstructions, using a rigid suction catheter to remove any blood, vomitus, or secretions from the oropharynx. Remove any large obstructing foreign bodies from the oropharynx manually or with Magill forceps (see Chapter 9).
In the sniffing position, the head is slightly extended and the neck is flexed on the shoulders. This aligns the axis of the airway with the mouth and pharynx, facilitating direct visualization of the cords during intubation. It is particularly important in young children and infants, in whom the larynx is considerably more anterior. A pad beneath the occiput improves flexion of the neck. This position cannot be used when there is cervical spine injury.
If the patient remains apneic, assist ventilation using a bag–valve–mask device (eg, Ambu bag) or mouth-to-mouth breathing (see Chapter 9). If adequate personnel and equipment are available, immediately perform endotracheal intubation.
Patients with Respiratory Effort
Administer high-flow oxygen. Clear and position the airway as described above. Identify evidence of upper airway obstruction. Prolapse of the tongue and accumulation of secretions, blood, or vomitus are common causes of obstruction. Signs may include wheezing, sonorous respirations, stridor, cough, and dysphonia. Upper airway obstruction should be removed if present. Back blows or the Heimlich maneuver may clear the obstruction. If not, use suction or direct visualization and a Magill forceps or finger. Blind finger sweep is contraindicated. Obstructions that recur or persist require endotracheal intubation, either orotracheally or via cricothyroidotomy, tracheostomy, or percutaneous transtracheal jet ventilation (PTTJV) (see also Chapters 7, 9, and 50).
Evaluate the effectiveness of the patient's respiratory effort. Helpful signs include respiratory rate, tidal volume, accessory muscle use, level of consciousness, skin color, upper airway sounds, and auscultated lung sounds. Further assessment may include pulse oximetry, arterial blood gas measurement, end-tidal CO2 capnography, and chest radiography. If intubation is indicated (Table 10–1), continue high-flow oxygen and assist ventilation as needed. Assemble all items necessary for the appropriate method of intubation (Table 10–2). Check for equipment malfunction. If the patient is alert, inform him or her of your plan.
Table 10–1. Indications for Intubation. |Favorite Table|Download (.pdf)
Table 10–1. Indications for Intubation.
- Respiratory insufficiency
- Airway obstruction
- Foreign body
- Fixed mass
- Traumatic deformity
- Continued bleeding, secretions, or emesis
- Inability to protect airway
- Altered mental status
- Loss of normal airway reflexes
- Need for hyperventilation
- Head injury
- Metabolic acidosis in critically ill or injured patient
- Anticipated or impending airway compromise
- Multiple trauma
- Need for sedation or paralysis
Table 10–2. Essential Airway Management Equipment. |Favorite Table|Download (.pdf)
Table 10–2. Essential Airway Management Equipment.
- Nasal cannula
- Non-rebreathing masks of various sizes
- Suction—rigid pharyngeal, flexible
- Oral and nasal airways—range of sizes
- Bag–valve–mask units—adult and pediatric sizes
- Water-soluble lubricant
- Vasoconstrictive topicals
- Anesthetic topicals (jelly and spray)
- Laryngoscope handles
- Laryngoscope blades—range of sizes (curved or straight based on operator preference)
- Low-pressure cuff endotracheal tubes of varying sizes
- Intravenous access (advised)
- End-tidal CO2 detector or esophageal tube detector
- Wire cutters
All patients with airway or ventilatory compromise require high-flow oxygen. Oxygen through a nasal cannula at flow rates up to 6 L/min provides a patient with 20–40% inspired oxygen concentration. A variety of masks are available that can accept oxygen flow rates of 5–15 L/min. Masks equipped with reservoirs and non-rebreathing valves can deliver oxygen concentrations close to 100% at flow rates of 10 L/min if an adequate seal can be maintained between the mask and face.
Before attempting intubation, preoxygenate the patient with 100% oxygen for 5 minutes or have the patient perform eight vital capacity breaths. In a ventilating patient, this should provide 6–7 minutes of protection against hypoxia if the patient becomes apneic. Caution should be exercised because this time interval can be significantly shortened in an ill patient. In an apneic patient, preoxygenation with a bag–valve–mask unit provides 2–3 minutes of protection against hypoxia.
A rigid-tipped suction catheter should be available at all times to keep the airway clear of blood and secretions. The suction device should be set at 120 mm Hg. After intubation, suction the tracheobronchial tree with a sterile, flexible catheter as necessary.
When the jaw thrust or chin lift is ineffective in airway opening, a nasal or oral airway may support collapsed oropharyngeal tissues and permit adequate ventilation. A range of sizes should be readily available in all areas of the emergency department (Figure 10–3).
Important basic airway devices to relieve upper airway obstruction from collapsed pharyngeal tissues. A: Oral airway. B: Nasal airway.
The oral airway should only be used in an obtunded patient. It may be inserted over a tongue blade or positioned upside down as it enters the mouth and rotated after the tongue is cleared. The former is preferred in pediatric patients as to prevent trauma to the soft palate. Positioned correctly, it retracts the tongue upward and anteriorly. Care must be taken not to push the tongue backward into the pharynx, worsening the obstruction. An oral airway that is too long could potentially displace the epiglottis over the larynx, resulting in complete obstruction.
The soft, rubber, noncuffed nasopharyngeal tube tends to be better tolerated in a semiobtunded patient. Lubricate the tube with anesthetic jelly before insertion. Insert it through the least obstructed nostril, advancing it posteriorly along the floor of the nostril until it bypasses the tongue. If it is too long, it may enter the esophagus, resulting in ineffective positive pressure ventilation and gastric distention. Epistaxis may occur during insertion, and suction should be available.
In patients with intact airway reflexes, placement of either device may cause emesis, gagging, or laryngospasm. During and after placement, head position should be maintained to optimize airway patency. Where indicated, spinal precautions must be maintained. Evaluate breath sounds after placement of either device to ensure that obstruction has not occurred. Care must be taken to avoid trauma during placement.
Positive Pressure Ventilation
Following airway opening, positive pressure ventilation may be used to preoxygenate a patient before intubation. Occasionally it may be the only form of ventilation available in an apneic patient when an airway cannot be secured. In general, however, it is not recommended for prolonged ventilation owing to gastric dilatation and technical difficulty.
The bag–valve–mask unit is the device most commonly used to provide positive pressure ventilation in the emergency department. The bag–valve–mask unit has a self-inflating reservoir that accepts 15-L/min oxygen flows. A non-rebreathing valve permits this reservoir air to enter through a separate port from air that is being expired. At these flow rates, inspired air will approach 100% oxygen, provided adequate seal is established. The self-filling bag permits use with spontaneously breathing patients. The unit can usually be attached to an endotracheal tube (ET) after intubation for manual bag-assisted tracheal ventilation.
The procedure for using the bag–valve–mask unit is described in Chapter 7. Use of this device is difficult in the hands of a single operator because effective bag–valve–mask ventilation depends on a tight seal between the mask and face. Often this requires two hands and a second operator to compress the bag. Many circumstances of anatomic variation, facial hair, or maxillofacial trauma make a tight seal impossible. During bag–valve–mask ventilation, proper head position must be maintained to preserve airway patency. Monitor the effectiveness of ventilation closely by frequent assessments of chest wall movement, lung sounds, and gastric dilatation.
The positive pressure generated by bag–valve–mask ventilation leads to gastric dilatation and abdominal distention. This results in decreased lung compliance and significant risk of emesis and aspiration. A clear mask is recommended to identify emesis. Suction equipment must be available. In patients with unprotected airways, cricoid pressure (the Sellick maneuver) is recommended (Figure 10–4). To perform the Sellick maneuver, apply firm, direct pressure on the circumferential cricoid cartilage. This will compress the esophagus posteriorly, decreasing gastric dilatation and reflux. If emesis occurs, release pressure on the cricoid to prevent esophageal rupture and aggressively suction the hypopharynx. If bag–valve–mask ventilation must be prolonged for any reason, place a nasogastric tube to reduce gastric dilatation and its consequences. Because of operational difficulties and risks of aspiration, the bag–valve–mask is a temporizing measure under most circumstances. Patients who require bag-assisted ventilation should generally be intubated as soon as it can be accomplished safely and practically.
The Sellick maneuver. Firm pressure on the cricoid cartilage compresses the esophagus, preventing aspiration of gastric contents when airway reflexes are absent.
The mouth-to-mask technique is another method of providing positive pressure ventilation. This method may be easier for a single operator, because both hands can be used to seat the mask. Supplemental oxygen is provided via a port in the mask or via a nasal cannula worn by the operator.
Prehospital Airway Devices
Extraglottic devices can be used emergently, if no rapid sequence intubation (RSI) protocol exists or endotracheal intubation fails in the field. The esophageal tracheal Combitube (ETC) may even be potentially used as an ET if blind insertion results in tracheal placement, but this phenomenon is uncommon. Alternatively, the King LT airway is now becoming a popular device due to its ease of use and rapid deployment.
The ETC has found favor in prehospital and emergency department settings. It comprises two tubes that form a single double-lumen tube. A proximal balloon isolates the hypopharynx, whereas the distal balloon occludes the esophagus or the trachea, depending on its location. The tube is inserted blindly and is fairly stiff, so that it usually enters the esophagus. Tube 1 (larger tube) is closed distally with side holes for ventilation. Tube 2 (smaller tube) is open distally and gives a direct route to either the lungs or the stomach. Tube 1 is always ventilated first, when confirming placement of the tube. Advantages of the ETC include ease of placement, partial protection of the airway from aspiration, and lack of manipulation of the C-spine in the trauma patient.
The King LT airway is a single-lumen tube with two cuffs, but both are inflated simultaneously at a solitary site instead of the two required on an ETC. A ventilation port exists between the oropharyngeal and esophageal cuffs that provides ventilation toward the larynx. Insertion of King LT airway utilizes a similar technique as the ETC.
Esophageal tubes are contraindicated in semiobtunded patients, children, and patients less than 120 cm in height. Do not use them when there is known esophageal injury or ingestion of caustic substances. Complications are listed in Table 10–3. Because of reports of esophageal trauma, some authors recommend Gastrografin swallow or endoscopy after use of an esophageal obturator airway (EOA)-like device. Due to the established complication profile and the evolution of superior alternative devices, the use of esophageal tubes should be discouraged.
Table 10–3. Complications of Esophageal Airways. |Favorite Table|Download (.pdf)
Table 10–3. Complications of Esophageal Airways.
- Unrecognized endotracheal intubation
- Incorrect positioning in pharynx
- Inadequate mask or balloon seal
- Esophageal or pharyngeal trauma due to placement, cardiopulmonary resuscitation, or retching
- Tracheal compression due to incorrect balloon position
- Balloon rupture or leakage
- Anterior displacement of larynx
- Emesis on removal
- Gastric rupture
Patients intubated with an EOA in the field will need endotracheal intubation on arrival in the emergency department. If an ETC or King LT airway is in place, it may be used temporarily for continued resuscitation, but a premium should be placed in establishing a cuffed, endotracheal intubation.
Cuffed Oropharyngeal Airway
The cuffed oropharyngeal airway is a modified oropharyngeal airway with a large distal inflatable cuff. It is inserted like a traditional oral airway, and the cuff is then inflated in the supraglottic space. This device is useful in resuscitation because of its ease of insertion and the low level of skill required to place it. The disadvantage of the device is that it has no distal balloon and gastric contents may be more easily aspirated as compared to the ETC.
Agro F et al: Associated techniques for tracheal intubation. Resuscitation 2000;47:343
(review of different techniques for establishing a patent airway).
Foley LJ et al: Managing the airway in the critically ill patient—Bridges to establish an emergency airway and alternate intubating techniques. Crit Care Clin 2000;16:429
(review of alternative airway management techniques).
Levitan RM et al: Airway management and direct laryngoscopy—A review and update. Crit Care Clin 2000;16:373
(review of airway management techniques).
Orebraugh SL: Difficult airway management in the emergency department. Emerg Med 2002;22:31
(review of techniques for managing the difficult airway).
Shuster M et al: Airway and ventilation management. Cardiol Clin 2002;20:23
(review of airway management techniques).
1This chapter is a revision of the chapter by Julia Nathan, MD, from the 4th edition.