Abstract
Awake intubation is underused and relevant whenever difficult airway is predicted. Evidence suggests that awake videolaryngoscope-guided intubation is faster with equivalent success rate, safety profile and patient acceptance compared with flexible optical bronchoscope (FOB)-guided intubation. For successful awake intubation four elements are essential: continuous oxygenation, topicalisation, equipment handling skills and sedation. Thorough preparation is vital for the success of the procedure. This includes availability of relevant personnel, appropriate equipment, chosen method of oxygen delivery, and local anaesthetic and sedative drugs. The authors’ preferred position for awake FOB-guided intubation is face-to-face, and for awake videolaryngoscope-guided intubation the deckchair head-end position. Lidocaine is the most used local anaesthetic, applied using a variety of techniques. Meticulous and dose-appropriate application of local anaesthetic is crucial for success. Procedural sedation may be used to enhance your technique following a very careful patient evaluation for the suitability of sedation. Evidence supports using dexmedetomidine or remifentanil in order to create a situation where the patient is cooperative, oriented and tranquil. If possible, one anaesthetist with the sole responsibility of administering sedation and patient monitoring should be present during the procedure. Tracheal extubation of a patient who has been intubated awake should be planned after careful overall risk assessment of the safety of the procedure.
Introduction
Awake tracheal intubation implies securing the airway in an awake spontaneously breathing patient with or without the use of sedation. Awake intubation is regarded as a gold-standard technique for difficult airway management. It will keep many options for airway management open when compared with those available after general anaesthesia and should be considered in any patient whose airway is predicted to be difficult to manage.
The ability of anaesthetists to predict airway management difficulty is uncertain due to a lack of reliable predictive tests. The decision-making process is further impeded by anaesthetists’ apparent reluctance to perform awake intubation, even when clearly indicated, occasionally resulting in major airway complications or death. The potential for difficult airway management to cause harm cannot be emphasised enough and is supported by considerable evidence.
Awake intubation requires four vital elements for the anaesthetist to master: (i) continuous oxygenation, (ii) topicalisation, (iii) equipment handling skills and (iv) sedation. Laboratory and clinical training should provide opportunities for anaesthesiologists to practise equipment handling skills and awake intubation. In this chapter, we focus on the awake aspect of intubation. The details of intubation techniques are described in other chapters (see Chapters 16 and 17). Awake tracheostomy or cricothyroidotomy are discussed in Chapter 20.
Decision making
The decision to perform awake tracheal intubation should be guided by the most senior anaesthetist’s skill and equipment availability and on thorough assessment of the patient’s airway.
The authors use the following as broad guidance to decision making on whether to perform awake tracheal intubation or not. Predicted difficulty to oxygenate using a face mask or supraglottic airway (SGA) are clear indications for awake intubation. All patients with predicted difficult tracheal intubation should be considered for awake intubation: further information from imaging and nasendoscopy may be valuable. The need for awake tracheal intubation becomes clearer in patients with predicted difficult intubation when there is added aspiration risk, reduced apnoea tolerance (e.g. obesity) or a predicted difficult front of neck airway (FONA). Patients who have a previously documented difficult airway should also be considered for awake intubation.
Tip. Consider awake tracheal intubation if you think there is even a small chance that your patient may not be easy to oxygenate. This may include patients with obstructive sleep apnoea, morbid obesity, limited mouth opening or impending airway obstruction in patients with head and neck pathology.
Preparation for Awake Tracheal Intubation
Consent
The process of consent forms an important part of the awake tracheal intubation procedure. When the clinician judges it is desirable to perform awake tracheal intubation, the procedure should be clearly explained to the patient, to ensure informed consent. Before the procedure, it is good practice to document the patient’s agreement to awake tracheal intubation and a summary of the discussion.
Complication. Consent refusal.
Solution. Patient refusal is a contraindication. However, by preparing your rationale for awake tracheal intubation prior to discussing with the patient and explaining the reasons it is a safer option, very few will disregard your claim. Explain to the patient that they will remain in control of the procedure as they can stop it at any time if they feel any discomfort and this will be dealt with before continuing.
Set-Up
Meticulous preparation before the start of the awake tracheal intubation procedure is likely to increase success. Decide the positioning of the operator, the patient, and the screen display from the device that you are using. They should be aligned so the operator, the patient and screen are in one line of sight requiring minimal head movement to refocus attention on each component (Figures 9.1 and 9.2). Two set-up positions are favoured by most anaesthetists:
Face-to-face: this is the authors’ preferred position for all awake flexible optical bronchoscope (FOB)-guided intubations (Figure 9.1). This set up enables the patient to be sitting upright (especially relevant in dyspnoeic patients) and encourages patient communication and visual monitoring of the patient’s level of sedation and comfort. It is also likely to be less intimidating for the patient.
Tip. Face-to-face may be more difficult for the operator initially but after a few procedures the benefits are realised and few change back to head-end positioning.
Head-end: some operators find it easier to stand at the head end of the patient due to the similarity of this set-up to direct laryngoscopy in an anaesthetised patient. This set-up, however, may reduce the flexibility of patient positioning (head-up position difficult to achieve) and reduces the ability to visually monitor and communicate with the patient. It may be the only option when performing awake videolaryngoscope-guided intubation. An acceptable compromise for awake videolaryngoscope-guided intubations may be a deckchair position with the patient sat up, but the trolley position adjusted so the head end is lowered to the desired level, aiming to keep both patient and operator comfortable (Figure 9.2).
Figure 9.1 Face-to-face position for awake FOB-guided intubation. Degree of sitting up is adjusted according to patient condition and operator preference.
Figure 9.2 Head-end position for awake FOB- and videolaryngoscope-guided intubation using deckchair set-up.
The safest environment for performing awake tracheal intubation is in the operating theatre as this is large enough to accommodate extra equipment and additional anaesthetic and surgical personnel if needed.
When deciding about the route of intubation (nasal vs. oral) factors such as surgical access, presenting airway pathology, post-surgery airway management plan and the operator’s preference should be considered. There is no evidence to support one route of intubation over the other.
Equipment
Laryngoscope
Awake tracheal intubation can be performed using any known method for intubation (see more options in Chapter 32) but in this chapter, we will focus on FOB- and videolaryngoscope-guided intubation. Current evidence suggests that awake videolaryngoscope-guided intubation is faster than FOB-guided intubation with equivalent success rate, safety profile and patient acceptance. Currently, there is no evidence to support the use of any individual videolaryngoscope design for awake intubation, but as there are few studies this may simply reflect a lack of evidence. A device with a blade that moves around the tissues rather than requires tissue displacement is logically preferable.
Tip. When learning to perform awake videolaryngoscope-guided intubation, prepare the patient and have both FOB and videolaryngoscope available. Try the videolaryngoscope first. If you or your patient becomes uncomfortable with the procedure, stop it and secure the airway with the FOB. Repeat this with different patients until you complete the intubation using a videolaryngoscope. Once acquired, you will find the skill of awake videolaryngoscope-guided intubation a very useful addition to your skill mix.
Related posts:
Chapter 4 – Structured Planning of Airway Management
Chapter 6 – Pre-anaesthetic Airway Endoscopy, Real and Virtual
Chapter 15 – Tracheal Tube Introducers (Bougies), Stylets and Airway Exchange Catheters
Chapter 22 – The Airway in Obstetrics
Chapter 31 – Airway Management during CPR
Chapter 26 – Ear, Nose and Throat Surgery: Airway Management
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