Anaesthesia has expanded outside of the operating theatre to encompass both intensive care medicine and pain medicine, but in addition over the last 10 years or so, the anaesthetist’s role has been redefined as a perioperative physician.

As a result, anaesthetists now have major input into preoperative assessment and preparation of patients for major surgery, optimizing medical conditions such as diabetes l and anaemia (including in iron therapy for the latter). Patients may also require referral to a high risk anaesthetic clinic (HRAC). Here they may also undergo risk stratification, so that the most appropriate surgery and care is provided including postoperative care. This may include preoperative cardiopulmonary exercise testing (CPET).

A major area of current interest is prehabilitation for some surgeries, and following chemotherapy. This involves improving preoperative aerobic fitness, nutrition and psychology to improve outcome.

Postoperatively, there is a focus not only the provision of oxygen therapy and fluids analgesia (with PONV prophylaxis), but also on thromboprophylaxis and appropriate antibiotics. In particular patients should be able to partake in early drinking, eating and mobilization, which itself requires avoidance of prolonged iv fluids, urinary catheters, NG tubes and surgical drains.

Finally early recognition and appropriate management of both surgical and medical complications is paramount.

There are various concepts that help explain the diagnosis and management of ICU patients, who often have a degree of similar physiology – including shock and systemic Inflammatory response syndrome. This very often results in organ system dysfunction/failure, often starting with one organ and sometimes progressing to multi-organ failure.

ICU patients are a varied group including trauma, various medical conditions (heart failure, pneumonia, stroke, epilepsy, diabetic coma, sepsis from any cause, thromboembolism) surgical conditions including postoperative complications, and chemotherapy related problems.

Oxygen delivery (DO2 ) is a key concept here, described by a simplified delivery equation,

DO2 = cardiac output × SaO2 × [Hb].

Cardiac output (CO) is the product of stroke volume (SV) and heart rate (HR), so the equation can be rewritten:

DO2 = SV× HR × SaO2 × [Hb]

Which gives four areas to target optimization.

Sepsis is a common cause of clinical problems. It requires rapid management of ‘the sepsis six’: blood lactate measurement, blood cultures, intravenous antibiotics, administration of oxygen, intravenous fluids and urinary output measurement.

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.

Postoperative problems may be similar to those described in Chapter 19 including respiratory and cardiovascular problems (eg airway obstruction, cyanosis). In addition, there may be problems such as failure to breathe, delayed awakening, postoperative nausea and vomiting, inadequate neuromuscular function (following the use of NMBDs), shivering and temperature disturbances.

Meticulous intraoperative care can substantially reduce these problems such as meticulous airway management, confirmation of adequate return of neuromuscular function, postoperative nausea and vomiting prophylaxis and prevention of intraoperative hypothermia.

Patients presenting for emergency surgery will often have limited time for improvement of their medical status; however every effort should be made in the relatively short time to address and treat dehydration, electrolyte abnormalities, haemorrhage, pain, sepsis and if possible other physiological systems impairment (e.g. kidney, liver, coagulation, CNS).

Patients who require general anaesthesia often require rapid sequence induction, with preoxygenation, cricoid pressure and tracheal intubation to prevent aspiration of gastric contents. A plan for a failed tracheal intubation is essential. In addition, planning postoperative care is essential, which may involve intensive care.

Whilst modern anaesthesia is considered safe, complications are nevertheless not uncommon and continuing efforts are directed to improve patients’ safety. Very serious avoidable events are called ‘never’ events, but sadly do occur, not infrequently. There are often may factors leading to patient risk including both human factors (fatigue and working under pressure) and organisational factors (poor working environment, faulty equipment, monitoring, and IT systems)

Risk should be assessed preoperatively for major surgery and/or patients with comorbidities. There are a number of scoring and prediction models to assist in this process.

Moreover, there are various check lists and care bundles designed to reduce risk further (e.g. WHO checklist, sepsis bundle etc).

In the preoperative period patient optimization is key, treating intercurrent diseases (including anaemia) and assisting in reducing smoking and alcohol intake, and optimizing nutrition. Intraoperatively there is great focus is on safety, including the recognition of an oesophageal intubation. Other areas are the prevention of end organ injury from hypotension, lung protection, and the prevention of postoperative confusion and delirium. In the postoperative period, the focus is on promoting return to normal function, with appropriate analgesia, thromboprophylaxis, oxygen therapy, fluid therapy as required.

In the very high risk setting, lesser surgery or indeed no surgery at all may be the best option for a patient.

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.

Vascular access is a fundamental skill in anaesthesia and intensive care, not only for drug administration but also for delivery of fluids and blood products, and for sampling for blood tests. Peripheral venous access is used for all patients undergoing surgery, but for major surgery and/or very unwell patients, central venous access and arterial access may also be required.

Flow rates through cannulae are key in determining the size of cannula chosen, and are proportional to the fourth power of their internal radius. All vascular access must be inserted aseptically, and removed if signs of infection develop. Serious complications, particularly after central venous access are well described including pneumothorax, haemothorax and cardiac tamponade. The use of ultrasound for facilitating access is mandated for central access, but is also increasing for both more difficult arterial and peripheral venous access.

Obstetric anaesthesia is one of the high-risk areas of anaesthetic practice and is feared by many novices. Physiological differences of the pregnant patient are discussed.

The anaesthetist may have three main functions in the labour ward: provision of support and analgesia for the parturient, care of the patient in the obstetric theatre and care of the patients in the maternity high-dependency unit. Effective labour analgesia requiring the support of an anaesthetist may include the use of Entonox, IV/IM medications, and placement of an epidural or spinal. Remifentanil PCAs may be preferred in patients with contraindications to regional intervention and set-up may follow strict protocols and meticulous monitoring. A caesarean section may be an emergency depending on the threat to the health of the mother or fetus and may require urgent timely intervention. Regional anaesthesia is frequently the first choice, but some cases may require a general anaesthetic. Both types of interventions may carry risks and complications. Failed tracheal intubation in the obstetric patient should follow the OAA and DAS management guidelines.

Understanding the different types of intravenous fluids is a key area of perioperative practice. Whilst there is a choice of crystalloid and colloid solution, the majority of anaesthetists will administer balanced crystalloid solutions which contains electrolytes and pH close to that of plasma, such as Hartmann’s solution or Plasma-Lyte 148, avoiding the routine administration of 0.9% Sodium chloride 5% Glucose, and colloids such as starches an gelatins.

Fluids are given intraoperatively for three reasons: firstly, to replace existing deficits (which can be substantial in emergencies, bowel obstruction, prolonged starvation etc), secondly to maintain fluid balance and finally to replace surgical losses (both blood/fluid loss and insensible losses from evaporation).

In practice, most anaesthetists start with 1–2 l of crystalloid, although the volume of fluid administered can be guided by clinical assessment (arterial blood pressure and heart rate). In major cases a fluid challenge (e.g. 250 mls of crystalloid) is administered and the response of central venous pressure or stroke volume are assessed. This will help to minimise the risk of both hypervolaemia and hypovolaemia, both of which will impair tissue oxygenation.

These procedures include diagnostic cystoscopies, the treatment of tumours in the urogenital tract (kidney, ureters, bladder and prostate) and treatment of urinary calculi. The majority of major urological surgery is performed with minimally invasive surgery, either from cystoscopes/resectoscopes (bladder and benign prostatic surgery) or via laparoscopic /robotic route (such as for malignancies of the kidney, bladder and prostate).

A common operation is for benign prostatic hyperplasia and often involves transurethral resection of the prostate (TURP). This can be performed under regional (spinal) anaesthesia or general anaesthesia. Major problems can occur from blood loss and absorption of irrigating fluids (the latter referred to as TURP syndrome). This may require intensive care treatment with diuresis, correction of electrolyte abnormalities, circulatory support and even postoperative ventilation.

Many patients are elderly and have significant comorbidities. In addition, patients are at risk of bleeding, urosepsis and impairment of renal function perioperatively.

Monitoring is essential to safe anaesthesia and should be applied to any case wherever an anaesthetic is conducted. Safe monitoring of an anaesthetised patient includes the presence of a trained anaesthetist together with clinical and technical monitoring. Regular checking and maintenance of equipment should be undertaken. Safe monitoring aspects of the anaesthetic machine are emphasised in this chapter. Vital technical monitoring includes the use of electrocardiogram trace, pulse oximetry, respiratory rate, blood pressure and capnography. Depth of anaesthesia monitoring is discussed during the use of total intravenous anaesthesia (TIVA). Similarly, the use of neuromuscular monitoring is described as essential for patients who have received neuromuscular blocking drugs.

Specialised patient monitoring devices may be used in some cases, such as the use of invasive cardiac output monitoring, arterial or central venous pressures, neurological evoked potentials, or cerebral oximetry.

Errors made by anaesthetists may result in morbidity and even mortality.

These errors can result from the placing and subsequent care of cannulae. It is vital to ensure that they are correctly sited, flushed after use and the needle is disposed of appropriately. For arterial cannulae it is vital that they are also correctly flushed and adequate dead space is removed prior to analysing samples, with the transducer at the correct height.

The airway is fundamental in anaesthesia and ensuring correct tracheal tube placement is paramount. In addition, mishaps can occur with disconnections, failure to deliver the correct gases and volatiles, as well as faulty equipment including laryngoscopes and suction equipment. Monitoring equipment is a key area and ensures the is patient is breathing correct quantities of oxygen and is properly anaesthetised. Do not disable the alarms on monitors.

Always ensure the correct drug is given in the correct dose by the correct route. Labelling of drug syringes will assist. Ensure that no drugs intended for regional blockade (eg epidurals) are injected intravenously and vice versa.

Finally transfer of patients into and out of theatre should only take place when the patient is stable.

The safe administration of drugs is a key area in anaesthesia and intensive care. Ensuring patients receive the correct dose of the correct drug requires great care during the drawing up process (with any dilution required) and appropriate drug labelling. The anaesthetist must always remain vigilant for adverse drug reactions including anaphylaxis. Some of the drugs classes encountered maybe familiar to novices (such as opioids and some sedatives, antibiotics) but others will be less familiar (especially intravenous and volatile anaesthetic agents, both depolarising and non-depolarising neuromuscular blocking drugs, and nitrous oxide). Anaesthetists are often required to administer other drugs such as antibiotics, drugs affecting coagulation and drugs to assist imaging.

New areas are discussed, such as the transition away from nitrous oxide, desflurane and suxamethonium and the widespread use of sugammadex to reverse rocuronium, as well as the choice of total intravenous anaesthesia (TIVA) or volatile-based anaesthesia.

Both anaesthesia for maxillofacial and ENT surgery may require ‘sharing’ the airway with the surgeon, or at least having limited access to the airway and a number of airway devices are available to ensure the patient has a patent and secure airway at all times.

A number of areas need to be considered. Many patients are children, there is a risk of airway contamination with blood, bone teeth etc. In particular, perioperatively, it is easy to underestimate blood loss blood can be swallowed. Another area is patients with head and neck cancers. These patients may not only have a number of comorbidities (heavy alcohol and/or nicotine use, cachexia and weight loss) but have very difficult airways to manage because of tumour involvement or radiotherapy.

Patients with significant airway problems (from infection, tumour, radiotherapy) may need awake fibreoptic tracheal intubation)

Middle ear surgery may also require induced hypotension and prophylaxis of postoperative nausea and vomiting.

Sometimes you will be asked to provide anaesthesia for patients outside of operating theatre environment. This includes the psychiatric unit for electroconvulsive therapy (ECT),

the accident and emergency department, the coronary care unit and the radiology department. In addition, you may be asked to maintain anaesthesia for the interhospital transfer of patients.

The same standards of safe delivery of anaesthesia still apply. These include qualified, experienced assistance, a fully functioning anaesthetic machine, suction and a tilting trolley/table and the usual array of laryngoscopes, face masks, airways and tracheal tubes. In addition, there must be the standard monitoring equipment, the usual drugs including emergency drugs and facilities for resuscitation including drugs and a defibrillator.

In some circumstances it may be possible (although inconvenient) to transfer the patient to main theatres, but in some cases, this is not possible. This includes diagnostic and interventional radiological procedures, which for the latter may be complex and lengthy. In addition, MRI requires specific MRI “safe equipment”. Finally, the transfer of patients via ambulance requires the patient to be physiologically stable prior to departure and this may require tracheal intubation, as well as appropriate monitoring (e.g. arterial line) and drugs (e.g. inotropes).

Blood transfusion may be required in the perioperative period for patients who have lost or actively losing blood. In order to manage this scenario, it is essential you know the patient’s circulating blood volume (based on their weight and age) and be able to estimate how much blood has been lost, which is not always straightforward, as some blood loss may be concealed. A blood loss of less than 10% of total blood volume does not usually require a transfusion; blood loss of greater 30% of total blood volume invariably requires transfusion.

Laboratory and/or point of care testing can be invaluable to guide to both blood transfusion and other blood components such as FFP platelets. Every hospital will have a major haemorrhage protocol.

There are many complications associated with blood transfusion including fever, hypothermia, circulatory overload and lung injury, immunological reactions, acid–base disturbances, hyperkalaemia and hypocalcaemia. In addition, infections may be transmitted such as HIV and hepatitis. Finally a serious error is to transfuse the wrong blood to a patient caused by errors including blood bottle mislabelling, or not checking the blood against the patient’s wristband.