If difficulty is encountered, retreat, regroup, and resume manual mask ventilation and oxygenation. Call for help and allow the patient to recover from any sedative – relaxant medications that have been given. No more than three intubation attempts should be made. Discuss with your staff anesthesiologist the options available to manage the anticipated difficult tracheal intubation and for patients where traditional intubation attempts have failed.
Fig. 6.15 Left image: Upper airway obstruction caused by the tongue falling backward in the supine unconscious patient. Right image: Insertion of an oropharyngeal airway restores airway patency.
Upper Airway Obstruction:
The most common cause of an upper airway obstruction in an unconscious supine patient is the tongue falling back into the hypopharynx (Fig. 6.15). In the unconscious state, there is a decrease in the tone of muscles attaching the tongue to the mandible, hyoid bone, and epiglottis. The respiratory efforts of the unconscious patient tend to pull the tongue backward causing further airway obstruction, and ultimately, the epiglottis tends to fall downward, also increasing upper airway obstruction. Apart from intubation, simple maneuvers to overcome upper airway obstruction in the unconscious supine patient include:
1 Clear the airway of any foreign material
2 Use a chin lift maneuver
3 Use a jaw thrust maneuver
4 Insert an oral and/or nasal airway
5 Position the patient on the side in the semi-prone recovery position.
Fig. 6.16 Insertion of a nasopharyngeal airway relieves airway obstruction caused by the tongue falling backward in an unconscious supine patient.
Complications of Laryngoscopy and Intubation:
Laryngoscopy and intubation result in physiologic stimulation that can lead to hypercarbia and/or hypoxia. Dental damage is always a risk during direct laryngoscopy, and patients should be made aware of this possibility during the preoperative assessment. Other potential complications include airway trauma, recurrent laryngeal nerve damage, vocal cord injury, arytenoid dislocation, or edema of the hypo pharyngeal and glottic tissues. ETT malfunction (obstruction, cuff rupture) or malposition can result in adverse events, such as inadequate ventilation, barotrauma, hypoxia, and hypercarbia.
Laryngospasm:
Laryngospasm results from stimulation of the superior laryngeal nerve and causes involuntary muscle spasm resulting in closure of the vocal cords. This can be caused by secretions or by direct stimulation of the cords. Management of laryngospasm includes gentle positive pressure and suction of secretions if the patient is not hypoxemic. Other maneuvers to assist in relieving laryngospasm include a forceful jaw thrust or pressure on the mandible just anterior to the mastoid. Pharmaceutical options include deepening anesthesia with propofol or paralysis with succinylcholine.
Negative pressure pulmonary edema is an uncommon complication that can have serious consequences and result in an otherwise healthy patient becoming critically ill. This topic is discussed in more detail in Chapter 25.
Additional Video Resources:
Examination of a patient’s airway for ease of intubation and ventilation: 5’05”
Tracheal intubation technique using direct laryngoscopy: 10’28”
Chapter 7
Intubation Decisions and Challenges
Tim O’Connor MD and Ilia Charapov MD
Learning Objectives
1 To review the subjective and objective criteria for tracheal intubation and extubation.
2 To review a goal-directed and patient-oriented approach to the pharmacology of medications used for tracheal intubation.
3 To acquire an appreciation of the specific considerations for tracheal intubation with an emphasis on: the patient’s presenting medical condition, the identification, anticipation, and management of a difficult airway, and the rational use of various airway devices in specific patient scenarios.
4 To review complications of tracheal intubation and positive pressure ventilation.
Key Points
1 Identifying the goals and conflicts for intubation provides the framework to develop a patient-specific goal-oriented plan for tracheal intubation.
2 When tracheal intubation fails, bag-mask ventilation or placement of a laryngeal mask airway device (LMAD) may be used as a rescue plan. All efforts should focus on ensuring adequate oxygenation.
3 “Awake” fiberoptic bronchoscopy (FOB) remains the gold standard for elective intubation in patients with a difficult airway.
4 A wide array of new airway devices provides clinicians with many equally valid ways to manage a difficult airway apart from FOB.
5 Insertion of an extraglottic airway, such as a laryngeal mask airway device (e.g., LMA™) may be life saving in the “cannot intubate, cannot ventilate” scenario.
6 There are two immediate clinical tools to confirm tracheal intubation: end-tidal carbon dioxide (ETCO2) measurement and visualization of the endotracheal tube (ETT) passing through the glottis.
7 Clinical experience is correlated directly with successful intubation at first attempt. Enlist expert assistance for anticipated difficult intubations.
8 Always have a backup airway plan.
Background:
Chapter 6 presented an overview of the technical skills required to perform tracheal intubation in adults. This chapter uses clinical cases to illustrate the decision process used to:
Assess a patient’s need for tracheal intubation
Identify pharmacologic goals for intubation Choose an appropriate intubation technique
Develop a plan to manage an identified difficult airway
Anticipate and manage problems related to positive pressure ventilation.
Indications for tracheal intubation:
The need to intubate a patient’s trachea may be obvious, but it can also be challenging and controversial. Tables 7.1 and 7.2 list common criteria anesthesiologists use to evaluate a patient’s need for tracheal intubation. An individual criterion is not an absolute indication. The criteria are to be used together in the context of the patient’s clinical presentation to formulate a decision concerning the patient’s need for tracheal intubation.
Goals for Intubation:
A goal-directed patient-oriented approach to the rational use of medications.
Tracheal intubation is frequently performed using a variety of medications. For the student, the rationale behind the choice, dosage, and timing of medications used for tracheal intubation is often obscure. This can be both confusing and daunting for physicians who have limited experience