A primary brain injury occurs at the time of initial mechanical trauma. An additional secondary brain injury begins immediately after impact. Inflammatory and neurotoxic processes result in raised intracranial pressure, decreased cerebral perfusion and ischaemia. This secondary injury is worsened by further physiological insults such as hypotension and hypoxia.

Assessment of the patient begins with an ABCD approach and should take place alongside resuscitation. Airway management is the priority, and this must be safely secured when indicated. Cervical spine injury is often associated with a head injury. The neck should be immobilised. Hypoventilation causes hypoxia and hypercapnia. Controlled ventilation to achieve a PaCO2 of 4.5 - 5 kPa and a PaO2 of > 13 kPa is recommended to control intracranial pressure. Hypotension reduces cerebral perfusion; a mean arterial pressure of > 90 mmHg should be targeted. Neurological assessment is undertaken using the Glasgow Coma Scale (GCS). A GCS less than 8 is considered a serious head injury and is often an indication for tracheal intubation. Other indications are described. Transfer to a neurosurgical unit is often required. Safe transfer guidelines must be followed.

An anaesthetist may control the airway through the application of several methods and the use of specific equipment. Primarily, the patient’s position must be optimised to allow for an open airway. An appropriate face mask should be fitted around the patient’s mouth ensuring there are no leaks. In the case of an obstructed upper airway the use of oral or nasal devices, such as a Guedel or nasopharyngeal airway, can allow the obstruction to be bypassed and aid effective oxygenation. Supraglottic airway devices (SADs), such as the laryngeal mask or i-gel, are frequently used to provide oxygenation and ventilation in spontaneously breathing patients and form part of the difficult airway algorithm. A variety of devices and generations are now available which have additional benefits of allowing gastric content suction and the passage of flexible scopes to visualise the airway and aid intubation. The tracheal tube is discussed with all its features and benefits of allowing for a definite and secure airway.

Tracheal intubation is a fundamental skill in airway management and there are several techniques used to achieve this. Classically, the use of a laryngoscope has been used for intubation of the airway by allowing direct visualisation of the glottis. A range of laryngoscopes exist with differences in their blades and sizes with the Macintosh blade the most frequently used. Other laryngoscopes discussed include the Miller and McCoy. Videolaryngoscopes consist of a high-resolution camera at the tip of the blade to allow for indirect visualisation of the glottis. Similarly, the range of shapes and sizes is vast. The use of videolaryngoscopes has introduced the ‘shared screen’ principle allowing others to also have a view during intubation and this can aid training and teaching. Awake tracheal intubation can be performed using flexible scopes or videolaryngoscopes and is recommended for anticipated difficult airway cases. Confirmation of tracheal tube placement is critical and should be performed in every case using capnography. Clinical signs may be unreliable and additional uses of flexible scopes and ultrasound may also be used.

Perioperative cardiac arrest occurs in about 1 in 3,000 anaesthetics. The majority occur in older, frailer patients (1 in 1,200), and in high-risk or emergency surgery. The cause may be the result of underlying medical disease – usually cardiac, secondary to surgery – usually due to haemorrhage or secondary to an anaesthetic cause – usually due to hypoxia and hypercapnia, typically resulting from airway problems.

The Resuscitation Council has issued algorithms to guide management of basic and advanced life support in both adults and children. Advanced life support secures the airway and supports the circulation using drugs with the aim of the return of spontaneous circulation. Two main types of arrhythmia occur in a cardiac arrest:

• Non-shockable: pulseless electrical activity (PEA) – a QRS complex without a palpable pulse and asystole

• Shockable: ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT)

Potentially reversible causes of cardiac arrest should be actively sought and treated. There are special circumstances after 28 weeks of pregnancy which require attention and are described. A traumatic cardiac arrest resuscitation algorithm is discussed.

A difficult or failed intubation may occur in the elective or emergency setting, and it is therefore important that every anaesthetist has a plan and knows the failed intubation algorithm. The Difficult Airway Society (DAS) in the UK have published guidelines on the management of failed tracheal intubation which are discussed in this chapter, also described as the ‘Can’t intubate, can’t ventilate’ algorithm. The algorithm follows a stepwise approach starting with Plan A the goal to achieve tracheal intubation and how this may be optimised. Plan B describes the use of supraglottic airway devices to allow for oxygenation when intubation has not succeeded. Plan C advises the clinician to return to facemask ventilation in the case of failed oxygenation and consider waking up the patient if circumstances allow. Plan D describes emergency front-of-neck asses using a scalpel cricothyroidotomy approach.

The priorities of airway management during cardiopulmonary resuscitation are to minimise interruptions in chest compressions, to optimise blood flow and oxygen delivery to vital organs and to minimise delays in defibrillation if the initial rhythm is shockable. Thus, during the initial treatment of cardiac arrest, unusually, the circulation takes priority over the airway. Maintaining a patent airway will enable ventilation and oxygenation of the lungs, which becomes increasingly important after the first 3–4 minutes of sudden primary cardiac arrest (i.e. of cardiac cause). The optimal airway management strategy during cardiac arrest is uncertain. Many cardiac arrest patients are treated with multiple airway devices and this stepwise approach to airway management is difficult to study in controlled trials. The results of three recent randomised clinical trials suggest tracheal intubation should only be used in those settings with a high intubation success rate. While early oxygenation and ventilation are logically more important after asphyxial cardiac arrest existing resuscitation guidelines recommend the same sequence of actions regardless.

The flexible optical bronchoscope has unparalleled utility for difficult airway management and is part of every difficult airway management algorithm. The device can facilitate intubation for patients with airway tumours and bony or soft tissue abnormalities. It provides continuous visualisation of the airway during management, can be used to deliver local anaesthetics to the airway and is relatively less traumatic compared to other devices. Mastery of the device requires significant practice and the practitioner must use the device regularly to maintain skills. Several tips for success and pitfalls to be avoided are discussed.

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.

Lung ultrasound is a point-of-care test particularly well suited to diagnose pneumothorax, pleural effusion, pulmonary edema, and consolidation. In the operating room setting imaging can establish a baseline for comparison to maximize confidence in later examinations displaying new pathology. In conjunction with cardiac and IVC ultrasound, the etiology of hypotension can be ascertained as hypovolemic, distributive, and cardiac. In addition, even more basic assessment regarding volume status and fluid responsiveness is improved. Ultrasound can be used to guide, confirm, and localize tracheal tube placement. In the postoperative setting pulmonary ultrasound can facilitate clinical decisions regarding weaning patients from mechanical ventilation and the need for ICU admission.