Key Learning Points

1. 1. Poor airway assessment and planning and failure to follow guidelines were highlighted as major issues in the Royal College of Anaesthetists 4th National Audit Project (NAP4). A lack of equipment was identified as an issue particularly prevalent in the intensive care environment.

2. 2. Factors which enable prediction of a difficult airway should be assessed for early to allow appropriate forward planning.

3. 3. It is important to have a well-organised, appropriately stocked and signposted difficult airway trolley, with regular teaching and updates to ensure all staff groups are familiar with the equipment.

4. 4. Thorough knowledge of the Difficult Airway Society’s guidelines on how to manage an unpredicted difficult airway in adults is essential. As of 2018, these include one specific to the intensive care unit – ‘Guidelines for the management of tracheal intubation in critically ill adults’.

5. 5. One must be able to appreciate the differences in emergency management of a tracheostomy (with a patent upper airway) and a laryngectomy (without a patent upper airway).

The mucopolysaccharidoses are a diverse group of lysosomal storage diseases that present multiple challenges to the anesthesiologist. Key features include difficult mask ventilation, difficult intubation, cardiac disease, coronary ischemia, obstructive sleep apnea, and skeletal abnormalities. Careful and thorough preoperative evaluation is crucial for anesthetic planning and safe management. It should emphasize airway management along with the cardiovascular, pulmonary, and neurologic systems. Cardiac valvulopathies and ventricular dysfunction are common and must be managed appropriately. Postoperative consideration should be given to caring for these patients in a high-acuity environment depending on the type of surgery and the severity of the underlying disease.

Airway management and failed intubation in the pregnant woman present unique challenges which differ from the non-pregnant patient. The provision of general anaesthesia in the obstetric population requires additional considerations of the physiological changes in pregnancy, environmental factors and the safe outcome of mother and baby. Appropriate team planning, preparation and performance of rapid sequence induction should be carried out in order to help to reduce adverse airway events. The OAA/DAS guidelines are designed to help to standardise teaching, reduce the incidence of failed intubation and give guidance on further management should failed intubation occur.

Supraglottic airways (SGAs) have been part of core anaesthetic practice for approximately 30 years, since the introduction of the classic laryngeal mask which is described in some detail. In many countries an SGA is now used for airway management for the majority of anaesthetics. Optimal use and insertion technique are described. The range of SGAs available and their roles have expanded dramatically in this time. Second generation SGAs are those designed to reduce the risk of aspiration and are emphasised in this chapter. With the wide range of SGAs available it can be problematic to decide which device to use and this is especially so as the boundaries of acceptable use are ever widened. This chapter describes those devices with the greatest versatility and utility – arguably also with the greatest safety profile too – and some newer devices. SGAs have a major role to play in advanced and difficult airway management. The use of an SGA as a rescue device and as a conduit for intubation during management of the difficult airway is described in detail.

Transoral robotic surgery (TORS) allows resection of otherwise inaccessible pathology. It generates unique challenges to the airway management of the patient due to the shared location of the anaesthetist and the surgeon’s equipment. A close cooperation between the anaesthetic and surgical team is required, for the safe handling of the airway. The anaesthetist needs to be able to employ a variety of airway manoeuvres in order to ensure the airway patency throughout the perioperative and post-operative period. The airway of the TORS patient is characterised by its dynamic nature, as it changes due to the surgery, swelling and bleeding.

When airway management is indicated, to avoid a bad outcome, patient safety will be maximised by careful decision making about and careful implementation of the chosen approach. This chapter addresses planning for the safest approach to securing the airway by assessing the patient for anatomical and physiological predictors of difficulty with airway management. When such difficulty is predicted, awake tracheal intubation will often provide the best margin of safety; indications for the procedure are discussed. Equally, when technical difficulty is predicted, the pre-conditions required to safely proceed with airway management after the induction of general anaesthesia are addressed. Predicted or not, difficulty encountered with tracheal intubation or supraglottic airway use in the unconscious patient must be met with a methodical and stepwise approach. This includes calling for help, maintaining patient oxygenation and methodically proceeding from one device type or technique to another, thus avoiding multiple futile attempts with the same device. Failure of a maximum of three attempts at the intended technique (most often tracheal intubation or use of a supraglottic airway) should be taken as an indication to refrain from further attempts, call for help, maintain patient oxygenation and reassess the plan for next steps. Finally, a ‘cannot intubate, cannot oxygenate’ situation is defined by the failure to successfully oxygenate the patient with all of tracheal intubation, face mask ventilation or a supraglottic airway and requires prompt front of neck airway access (‘surgical airway’).

Patients undergoing ear nose and throat (ENT, otorhinolaryngeal) surgery probably present more airway management challenges than any other branch of surgery. ENT procedures encompass a range of operations varying in duration, severity and complexity from simple short cases such as myringotomy, through to complex resection and reconstructive surgeries for head and neck cancer. In all cases the surgical team operates close to the airway and in many within the airway, which is therefore shared with the anaesthetist. In this chapter, the authors discuss in some depth these challenges and how to address them, airway management and ventilation options and strategies including but not limited to awake intubation, different subtypes of jet ventilation, and high flow nasal oxygenation as well recent advances in the field. They further discuss extubation strategies and controversies as well as a plan to manage commonly encountered complications such as bleeding in the airway. For a successful outcome, these ‘shared airway’ procedures require close communication and cooperation between anaesthetist and surgeon, an understanding of each other’s challenges, knowledge of specialist equipment, and a thorough preoperative evaluation to identify potential risk factors for poor perioperative outcomes.

Conventional airway management, including intubation and the various modes of lung ventilation, is usually successful. When it fails (cannot intubate, cannot ventilate/oxygenate) it is a life-threatening emergency and will lead to hypoxic brain damage in a few minutes, followed by death, if not resolved. The common final pathway for securing the airway and oxygenation is an emergency front of neck airway (eFONA). Immediate action with a clear plan, appropriate equipment and skills is essential. The ability to efficiently perform an eFONA is a fundamental requirement for any practitioner engaged in advanced airway management. Many techniques are described and it is a difficult area to study, so the evidence of superiority of one technique over others is hard to establish. Preparation, in terms of equipment availability, procedural practice, team familiarity and prompt transitioning through the algorithm when other techniques fail, is important for patient safety. These human factors aspects of eFONA management are at least as important as the procedural technique chosen. This chapter considers the risk factors for airway failure and management of the cannot intubate, cannot oxygenate situation and eFONA procedure in adults and children.

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.

A major challenge of airway management is safe care of the patient with a narrowed airway. Small tracheal tubes offer one solution but pose a problem with ventilation. While inspiration may be achieved by use of a high-pressure source to overcome airway resistance, two problems exist: first, the high-pressure source demands technical excellence and exposes the patient to a high risk of barotrauma; second, conventional (passive) exhalation through a narrow tube is slow and cannot achieve a normal minute ventilation with a tracheal tube of less than 4.5 mm diameter. Recently technical developments have led to the ability to assist expiration and make it, like inspiration, an active process. This technology is used in the Ventrain manual ventilator, the 2.4 mm wide Tritube tracheal tube and the Evone automatic ventilator. These new devices and the applied technology enable solutions for safe management of the narrowed upper airway.

Direct laryngoscopy should be preceded by airway assessment and discussing rescue strategies with assisting staff. The initial plan and rescue techniques should be based on an understanding of normal airway anatomy and its variants. This chapter uses the two curve theory and the three column model to describe and functionally classify both the normal and difficult airways. This classification then provides the operator with an understanding of the various causes of difficult airways and how they are related to each other and airway morphology (two curve theory). These two concepts form the basis for the decision process to performing direct laryngoscopy and choosing the right laryngoscope blade for the job. Endobronchial intubation is discussed in detail.

Maxillofacial and otolaryngology/head and neck surgery health-care professionals play a vital role in field hospitals due to their expertise in caring for acute trauma care patients and treating emergent life-threatening conditions; that is, airway injuries and head and neck infections. In this chapter, we review common conditions and injuries treated by this team. The large volume of the expected patients presenting with various related conditions make the presence of the otolaryngologist/head and neck surgeon extremely valuable.