Topics included on this page:
This is a mammoth topic, but for the purposes of this article, we’ll stick to the information we need from the patients on the day of surgery.
For novice anaesthetists planning to take the primary FRCA, this is an entire station (sometimes 2) in the OSCE and it is worth building good habits from the start. My advice is to memorise the chart you use in your hospital and the information you need from there, and you can then always use a systematic method of doing an assessment even if you don’t have the chart in front of you.
This is the way I do it, but please feel free to adapt:
Other things to look at:
- Some patients may already have been seen by a consultant anaesthetist in a pre-operative assessment clinic and it is useful to look at the letter to see what was discussed. This is common for high risk patients or patients having high risk operations, or patients with special requirements including patients with needle phobia/significant problems with previous anaesthetics. It is a good way to discuss a lot of the issues that are important to the patient and make a plan beforehand without the pressure of making these decisions and having these conversations for the first time the morning before surgery.
- Previous anaesthetic charts are super useful especially for patients with difficult airways or kids. I normally note down particular things in charts that are helpful for the next anaesthetist, for example for children with special needs I might note that they were very calm with music or that they responded well to having both parents in the room.
- Surgical clinic letters can sometimes be useful to see what the reason for the operation was and what was discussed with the patients by the surgical team and we can be more emphatic to what they require and what has led to them having the operation.
Induction of anaesthesia is the process of putting a patient to sleep for a general anaesthetic, or the process of delivering an anaesthetic for the patient, for example using a regional anaesthetic.
In the UK, we do this in anaesthetic rooms such as the one shown below, which are just through the doors from the operating theatre. This is our comfort zone (hence the name of this website!) where we can concentrate on what we are doing without the distraction of the theatre teams preparing their equipment inside the operating theatre, and it is a more comforting environment for the patient than the theatre full of equipment and scary looking tools. This is particularly useful for paediatric patients.
For general anaesthesia, the induction process involves the following:
- Checking the patient in
- Establishing appropriate monitoring
- Establishing IV access
- Pre-oxygenating the patient (giving the patient oxygen to fill their lungs with fresh air)
- Delivering medication to put a patient to sleep. Common agents used include an opioid analgesic (usually Fentanyl), and a sedative agent such as propofol. In children we commonly induce anaesthesia using inhalational methods with a mixture of inhaled gases such as sevoflurane and nitrous oxide and oxygen. A muscle relaxant is sometimes used.
- Once the patient is asleep, they will require an airway device to be inserted to maintain their airway patency through the operation. This can be anything from a supraglottic airway device to any number of advanced endotracheal tubes. Once in place, we perform a few checks to make sure this is in the correct place and then secure the device in place with tape or a tie.
- The eyes are protected and the patient is prepped for any special surgical requirements including tourniquet application, or urinary catheter insertion.
- Some patients require additional invasive monitoring to be inserted once asleep including arterial lines, central lines, and additional IV cannulas. This is done at this stage.
- Some patients are undergoing general and regional anaesthetic techniques, and some of the regional techniques are done under anaesthesia at this stage. Other patients have regional anaesthesia (see below) before a general anaesthetic.
For pure regional anaesthesia techniques, the induction process involves the following:
- Checking the patient in
- Establishing appropriate monitoring
- Establishing IV access
- Positioning the patient to have their block – may involve sitting up at the side of the bed/lying on their side etc
- Cleaning of the area that we are going to block
- ‘Scrubbing in’ – wearing a cap, mask, sterile gown and sterile gloves and using sterile equipment on the clean area to minimise infection
- ‘Stop before you block ‘ – a verbal or written check to ensure we have the correct patient having the correct block on the correct side if applicable
- Delivery of the regional anaesthetic
- Checking that the regional anaesthetic is working appropriately for the procedure (this involves a variety of techniques depending on the specific block used, but usually involves testing the sensory, motor and autonomic nervous system)
Once we are happy with all the above, we will take the patient into the operating theatre. At this point this can be dangerous. This is a period where the patient is (in most centres) not connected to a breathing machine or any monitoring (portable monitoring is coming in for some centres to help reduce the risks from this) and is being moved from one room to another. Any number of things may happen including dislodgement of cannulas or airway devices, a drop in blood pressure or oxygenation, the patient being injured in the process of moving through and being moved from the trolley onto the operating table, or other equipment malfunction.
For patients who have been given an IV agent to go to sleep, then kept asleep with inhalational/volatile anaesthetic agents, the period upon disconnecting from the anaesthetic machine in the anaesthetic room (which has the inhalational agent in it being delivered to the patient), and being reconnected to the machine in the operating theatre is particularly concerning for accidental awareness under general anaesthesia (AAGA).
This is a condition where the concentration of anaesthesia in the patient reduces (because none is being delivered) and the patient begins to emerge from anaesthesia (see graph below). It can be very distressing to ‘wake up’ in the middle of the move between rooms or whilst one is being transferred across onto the operating table. It takes some time to then reintroduce enough concentration of anaesthetic after reconnecting the patient to the new machine to avoid AAGA. To avoid this, most anaesthetists will get the patient to a higher concentration of anaesthetic in the anaesthetic room, then aim for a higher concentration initially in theatre, or give more IV agent just before moving across. There are a number of methods of doing this safely but it is important to understand the reasoning behind it.
Hence it is important to ‘Mind the Gap’ (the original paper about this in 2011 is available here). This is not the time for small talk and distractions and the anaesthetist has to concentrate on making sure the time between reestablishing monitoring and medications and ventilation is minimised and that the patient is kept safe throughout. Lapses in concentration here can be fatal, so give us some time to set up before asking questions!
Once induction of anaesthesia is complete and the patient has an airway device in place, we have to keep the patient asleep and stable through the operation. This phase is termed ‘maintenance’ of anaesthesia.
You can divide up maintenance into an ABCDE format familiar to most doctors:
Airway – which device are we using? How have we secured it? How do we know it is in the correct place?
Breathing – have we set the ventilator appropriately? Are we oxygenating well and removing carbon dioxide appropriately? How are we monitoring the patient’s breathing?
Circulation – do we have appropriate monitoring and have we responded to changes in blood pressure? Are IV fluids indicated, or blood products? What about medication to keep the patient’s blood pressure in a normal range, or to avoid arrhythmias? If the patient begins to bleed, do we have a way of giving the patient warmed blood products?
Disability can be divided into:
Sedation – how is the patient being kept asleep? With intravenous agents? Or inhalational agents?
Analgesia – how is the patient being kept comfortable? Sedation does not equate analgesia. Postoperative pain is a significant problem and hard to manage. Untreated pain leads to a stress response with an effect on the patient’s cardiovascular system.
Paralysis – how is the patient being kept immobile? How can we tell if the medication is wearing off? Is it important to be immobile in this operation?
Temperature control – anaesthesia and the theatre environment leads to significant heat loss by radiation, convection, conduction and evaporation. How are we keeping the patient warm and how are we measuring their temperature?
Glucose control – starvation ketosis can occur after a long time of fasting, particularly in children. Diabetics require frequent blood sugar monitoring. An undetected low or high blood sugar level in a patient having an anaesthetic is dangerous to the patient and is detrimental to wound healing and can lead to post operative infections.
Everything else can be divided into:
VTE prophylaxis – is the patient at risk of VTE? If so, how are we keeping them safe?
Positioning – is the patient appropriately positioned to avoid pressure sores or injuries? The patient cannot move to reposition themselves during anaesthesia. Are they strapped to the table appropriately to avoid them falling off if the table has to positioned in a special way during the operation?
Anaesthetic ‘feng shui’ – is the arrangement of the patient, the anaesthetic machine, the surgical machines and equipment, and the team members appropriate so that we can reach the patient easily to help support them in an emergency and we are not in each other’s way?
Once we have done all the checks above, we can relax and complete our documentation on our anaesthetic charts, prescribe postoperative medication, and do an abbreviated form of the checks again every 5 minutes or sooner.
At the end of the operation, the patient now needs to be woken up and transferred safely to the recovery room.
The anaesthetic that was being used for maintenance is stopped, and depending on the agent used, a variable amount of time will have to elapse for the concentration of the drug to reduce enough that the patient is able to breathe for themselves and wake up. This is a period of the anaesthetic that is just as risky as the initial ‘going off to sleep’ period.
The aim of the game is to make sure the patient wakes up warm, comfortable (ie not in pain), able to breathe and move appropriately (adequate steps have been taken to reverse muscle relaxation, if applicable), and safely monitored by trained staff in a safe place, be it theatre or recovery.
To achieve this, analgesia and reversal for muscle relaxation is given pre-emptively before the patient wakes up, the patient is kept on continuous monitoring, and the airway device is only removed when the patient is ‘awake’ enough that they have regained their airway reflexes and can cough/spit it out. This can be done in recovery or in the operating theatre depending on what type of anaesthetic and device was used.
Once safe in recovery, we will handover the patient to the recovery staff who will look after the patient until they are fully awake, comfortable, have stable observations and have no further concerns.
The surgical team will also handover to the recovery staff about what operation has been done, what drains/dressings/slings have been applied to the patient and what to watch out for in the initial recovery period. They often also give the recovery staff information that should be then handed over to the ward teams when the patient leaves recovery also.
Recovery staff are specially trained to recognise when patients are experiencing symptoms that may be due to a sinister cause such as bleeding or hypoglycaemia. This is a special skill given that most patients wake up slightly disorientated after a general anaesthetic and may not be awake enough to communicate the problem to us. Additional analgesia or anti sickness medication may be required. Some patients may have to stay in recovery overnight with special monitoring after particular operations, or if they have particular risks such as obstructive sleep apnoea.
Other useful links:
The Royal College of Anaesthetists have designed some specific preoperative care modules on e-learning for health:
01_09_02 The Purpose of Preoperative Visiting
01_09_03 History and Examination
01_09_05 ASA Grading and Preoperative Investigations
01_09_06 Risk and Consent
Pre-operative assessment and patient preparation – AAGBI 2010
Consent for anaesthesia – AAGBI 2017
RCoA curriculum for pre-operative anaesthesia
Our page on peri-operative medicine with links to BJA education articles and webinars
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