Airway support is necessary in many acutely ill and injured patients. Optimal strategies assist with airway patency, oxygen delivery, and carbon dioxide excretion. Many classify airway management techniques into two categories: noninvasive (passive oxygenation, bag-valve-mask ventilation, and noninvasive positive-pressure ventilation) and invasive (supraglottic airways, endotracheal intubation, cricothyroidotomy, transcutaneous needle jet ventilation, and tracheostomy). This chapter discusses noninvasive airway management strategies and supraglottic airways. Detailed discussion of invasive airway management strategies is found in Chapter 29A (“Tracheal Intubation”), Chapter 30 (“Surgical Airways”), and Chapter 113 (“Intubation and Ventilation in Infants and Children”).
Patients may require airway management for a variety of conditions relating to hypoventilation (inadequate carbon dioxide excretion) and hypoxia (inadequate alveolar oxygen content). Management of these conditions can incorporate multiple airway strategies ranging from passive oxygenation to endotracheal intubation, and the interventions best used may vary over time in the same patient and between patients.
Patients with hypoventilation and hypoxia may have varying symptoms including weakness, fatigue, chest pain, or shortness of breath. Inadequate oxygenation and ventilation can lead to altered mentation, including anxiety, confusion, obtundation, or coma. Patients with respiratory distress may have wheezing, stridor, or a silent chest. A subjective gauge of respiratory distress is the patient’s respiratory effort or “work of breathing.”1 Dyspnea, tachypnea, hyperpnea, or hypopnea; accessory muscle use; and cyanosis are signs of increased work of breathing.
There are two types of respiratory failure. Type 1 respiratory failure has hypoxia without hypercapnia. Type 1 respiratory failure may be the result of conditions that affect oxygenation but not necessarily ventilation (e.g., pneumonia, pulmonary embolism). Patients with type 1 respiratory failure require actions that optimize oxygenation. Type 2 respiratory failure has hypoxia with hypercapnia. Type 2 respiratory failure is often the result of conditions that affect ventilation (e.g., chronic obstructive pulmonary disease). Treatment of type 2 failure requires not only optimizing oxygenation but also supporting ventilation.
ASSESSMENT OF THE AIRWAY AND VENTILATORY EFFORT
The decision to initiate airway support is often based on the patient’s clinical condition. Do not delay management efforts for laboratory testing or other studies, although these can help guide treatment.
First, assess every patient for airway obstruction, which can be functional (e.g., unconscious patient) or mechanical (e.g., foreign body). The ability to spontaneously swallow and speak provides a basic indication of airway patency, and the absence of this ability is a potential sign of obstruction. Other potential signs of airway obstruction include anxiety, wheezing or stridor, and coughing. Many conditions can cause airway obstruction (Table 28-1).
TABLE 28-1Causes of Upper Airway Obstruction |Favorite Table|Download (.pdf) TABLE 28-1 Causes of Upper Airway Obstruction
|Congenital/Genetic ||Infectious ||Medical ||Trauma/Tumor |
|Large tonsils ||Tonsillitis ||Cystic fibrosis ||Laryngeal trauma |
|Macroglossia ||Peritonsillar abscess ||Angioedema ||Hematoma/masses |
|Micrognathia ||Pretracheal abscess ||Laryngospasm ||Smoke inhalation |
|Neck masses ||Epiglottitis ||Inflammatory ||Thermal injuries...|