An anaesthetic walkthrough
One of the things I would have appreciated when I started as a novice anaesthetist is a little bit of a heads up as to exactly what to expect for your run of the mill 'standard' anaesthetic, just so every single step didn't come as a complete surprise.
So I thought I'd write one.
We've written a similar post here, which is a bit more of an overview of what general anaesthesia involves. Today's post is more specific as to the exact steps you as the anaesthetist will take.
Now I'll preface as always by saying this is anaesthetics, so there are always going to be many ways of achieving a great outcome and everyone does it their own way. But if you're just starting out, the following is a good reference point.
I hope you find it useful!
A fit and well 34 year old with acute appendicitis is scheduled for a laparoscopic appendicectomy.
- No allergies
- No previous medical history or regular medications
- Previous anaesthetics without any problem
- Well fasted since yesterday, not vomiting or nauseated
- Good mouth opening and Mallampati 1
- Consented for a general anaesthetic, with local anaesthetic infiltration of port sites
Ingredients to prepare:
- A hypnotic agent - propofol 1% 20ml
- A fast-acting opioid for intubation* - fentanyl 100mcg
- A muscle relaxant - rocuronium 1mg/kg
- An antiemetic - ondansetron 4-8mg
- Another antiemetic for good measure - dexamethasone 3.3-6.6mg
- Some antibiotics - co-amoxiclav 1.2g
- A longer acting opioid for pain relief after - morphine 10mg in 10ml
*Why do you need an opioid for intubation?
The aim of intubation is to safely pass a tube between the exquisitely sensitive vocal cords.
We give a muscle relaxant to paralyse the muscles and relax the vocal cords, allowing the tube to pass between them, but the act of laryngoscopy is so stimulating that it causes a surge in blood pressure and heart rate, even though the patient is asleep.
While giving someone a sedating agent such as propofol is helpful for reducing this response, it is far more effective to give a strong, rapid-acting opioid such as fentanyl, alfentanil or remifentanil as well.
- Ephedrine - 10ml syringe (30mg in 1ml diluted into 9ml 0.9% saline)
- Metaraminol - 5ml syringe (0.5mg/ml neat solution)
- Atropine - 600mcg in 1ml
- Glycopyrrolate - 200mcg in 1ml
- More propofol!
I won't go into all the ins and outs of what equipment to use when, as we've got other posts for that.
For a laparoscopic appendicectomy as a junior trainee anaesthetist in the UK, the expectation is that you will be intubating with a cuffed oral endotracheal tube.
- Woman or small man - size 7.5mm
- Man or large woman - size 8mm
How you choose to insert this tube is personal, but your options are threefold:
- Direct laryngoscopy - Macintosh 3 for women, 4 for men
- Video laryngoscopy with Mac blade - sizing depends on brand
- Video laryngoscopy with hyperangulated blade and stylet
There's a vast amount of back and forth as to what should be your first choice for intubation - just go with what your consultant is advising to begin with, until you develop a preference.
The key is not to hyper-focus on your plan A, and have lots of other options available.
As the patient gets wheeled into the anaesthetic room, try to look less terrified than they are and welcome them with reassuring chit chat as you feel appropriate.
ODPs are exceptionally good at this.
Then the anaesthetic team check the patient's identity, wrist bands, allergy status, consent form etc to ensure the right patient has arrived expecting the correct operation, (on the right limb if applicable).
At this point I explain the following to the patient just to set their expectations for the next few minutes:
- We're going to put on some standard monitoring (ECG, sats probe and BP cuff)
- I'll put in a cannula
- Then I'll give them some oxygen to breathe and we'll go off to sleep after that
Personally I like at least a green 18G cannula for anything involving the abdomen. Some are happy with a pink, some insist on grey, I've not yet seen anyone chance it with a blue.
Attaching your IV fluids at this point does two things:
- Reassures you that the cannula is working (steady drip rate)
- Flushes in your induction drugs
Usually while you're faffing around trying to find a vein the ODP has already managed to get the monitoring on and may or may not begin distracting the patient to help your efforts.
There's going to be a period of time immediately after you have given the induction drugs, and before you've intubated, where the patient is not going to breathe.
If you did this with a patient on room air, they'll start to desaturate in 30-45 seconds.
If you fill their lungs up with pure oxygen before hand, you can buy yourself up to 10 minutes of faffing time to get the tube in.
Take time to preoxygenate properly.
Hold the mask gently onto the patient's face and take the time to get a proper seal, such that the mask is misting with each breath and there is a nice CO2 waveform on the monitor.
While you're preoxygenating, grab the suction and tuck it under the patient's pillow on your dominant hand side.
Then in order:
- Fentanyl (then pause for a minute as it takes about 2 mins to work)
- Propofol (smooth steady injection of 20ml over about 20-30 seconds)
Tell them to keep their eyes open as long as possible. Once eyes close and they have no response to a jaw thrust (many people just check eyelash reflex) then it's safe to inject muscle relaxant.
For a proper rapid sequence induction you need to do this all rather quickly, and current guidelines suggest cricoid pressure as well, but for this fasted, low risk case, we're doing a 'modified' RSI.
Now wait, and try to relax as you wait 45 seconds for the rocuronium to work.
Don't rush. You've preoxygenated the patient, and have the following to help you:
- Plenty of time
- Other airway options
- An ODP
- A senior supervisor
When you start out, the understanding is that you'll probably have a go at laryngoscopy with a moderately low threshold for handing over to your senior if you're having any difficulty.
In general, seniors will try and facilitate you achieving a successful intubation, so if they're encouraging you to keep trying then it usually means that they're happy the patient is stable enough for you to keep looking.
If you feel uncomfortable or unsafe at any point, just say so, and a clear 'I'm not happy, I'd like you to take over' will get them involved pretty sharpish.
I heard the most wonderful description of how to perform direct laryngoscopy recently:
"You're putting the patient into first gear"
This is in reference to the arm movement with which you manipulate the laryngoscope. After carefully inserting the blade into the mouth and the tip reaching the base of the epiglottis, your arm motion is to the left and forward, with a little up as well.
I usually say to push your arm upwards and forwards towards where the wall in front of you meets the ceiling.
The key is not to 'cock' your wrist back like a can opener - this is a surefire way to break teeth - the motion is a 'push' forwards and up with minimal twisting or angulation.
There are hundreds of useful videos on YouTube like this absolutely fabulous one from ABC's of Anaesthesia.
Keeping them asleep
Congratulations, the tube is between the cords and there is a reassuring end tidal CO2 trace on the monitor.
Take a deep breath, chill out, and put the patient onto the ventilator. Tie your tube into place and then think about how you keep them asleep, because your propofol is going to wear off in a minute or two.
There are two options:
- Inhalational anaesthesia - in which case you need to turn some vapour on at this point
- TIVA - in which case check your pump is working, your cannula is still where it should be, and the infusion rate is appropriate
For the purposes of this case we'll use inhalational anaesthesia.
There's a danger zone of awareness
All good things take time, and the same applies to anaesthesia. When you switch the sevoflurane on, it's not going to work instantly, as the levels of vapour need to build up in the lungs, blood and brain for it to have its effect.
This means there is a potential point where the propofol bolus is wearing off and the sevoflurane is not yet fully effective (clearly this doesn't apply to TIVA).
You just want to make sure you're starting the vapour reasonably quickly (within a few minutes) after giving your induction drugs.
I promise we have all been so thrilled at getting the tube in successfully that we've completely forgotted about switching the vaporiser on. Your senior (and hopefully your ODP) will be watching out for this, so don't stress!
During the operation
Once the patient is settled on the table, you're in autopilot mode. Your job is to monitor and anticipate any issues.
When you're happy the patient is stable and the operation is underway, it's paperwork time, of which there are two components:
- Anaesthetic Chart
- Drug Chart
The anaesthetic chart is the legal record of what you did.
This is important to appreciate because it's the first thing that gets looked at if there are any issues, and that can be up to years later.
Memories fade, recollections get corrupted, but the anaesthetic chart remains, so a well-presented, thorough and accurate chart documenting what you did for the patient is extremely important.
What information is on the chart?
- When you started, and who was in charge
- What IV access and monitoring you used
- What drugs and fluids you gave
- How you managed the airway and how easy it was
- The observations during the case, and what settings you changed
- Instructions for afterwards in recovery
Depending on where you work the observations may be automatically recorded by the anaesthetic monitoring machine or you may have to document them manually.
Assume that nobody else is going to look at the drug chart for the next 24 hours, and take responsibility for ensuring the patient gets all the regular medications they need (especially parkinson's meds and insulin) as well as appropriate rescue pain relief and anti-sickness.
On the regular side
- Paracetamol 1g QDS (adjusted for weight as required)
- Ibuprofen 400mg TDS (if no contraindications)
- Patient's regular meds (if no contraindications and as BP allows)
If they're on an important medication regularly but you don't want them to have it immediately post operatively for whatever reason, it's reasonable to write it in and then put 'review' prior to the next dose, so that it doesn't get forgotten.
On the PRN side
- IV morphine up to 10mg in 1-2mg aliquots in recovery only
- Oramorph 10-20mg 2-4 hourly
- Ondansetron 4-8mg up to TDS
- Cyclizine 50mg up to TDS
- Naloxone 100-400 mcg PRN if respiratory rate less than eight
- IV fluids if likely to be nil by mouth for a prolonged period of time
- Lactulose or similar if high opioid requirement
Usually at some point after this you'll be sent for coffee.
Waking the patient up
It's far better to wake the patient up a bit late than a bit early, so don't rush.
Once the surgeon is close to finishing suturing the skin, or once they've finished, switch off the sevoflurane and increase the fresh gas flows to 15 litres per minute to wash out the vapour from the lungs.
Depending on the patient, what other sedatives you've given and the length of the operation, you'll have about 5-10 minutes before the patient wakes up.
Suction out the mouth and pharynx to ensure the patient doesn't aspirate on a pool of secretions once the tube comes out, and insert a bite block or oropharyngeal airway next to the tube, so that the patient doesn't bite the tube as you try and take it out.
Make sure the muscle relaxation has been adequately reversed, by checking their neuromuscular activity with a nerve stimulator, and reverse any remaining paralysis with either:
- Neostigmine and glycopyrrolate
When to take the tube out
Be patient, and refuse to be rushed by hasty surgeons and theatre coordinators.
You need two things before you can extubate safely:
- The patient needs to be breathing by themselves
- You need to be happy they will protect their own airway
This is like landing a plane - you want to make sure you touch down and take the tube out at the right time. It's just as risky as intubation - if not more so because you're in less control of the patient's depth of anaesthesia - so be sure to preoxygenate as if you're about to intubate again.
- Too early and the patient can go into laryngospasm and stop breathing, or aspirate on an unprotected airway
- Too late and they'll be unnecessarily uncomfortable
In reality in a healthy young person for a laparoscopic appendix, it's far better to err on the side of too late, because it won't do them any harm, they just might be a little displeased about having a tube in their mouth.
Once the patient is extubated and you're happy their breathing well and protecting their airway (decent cough) then you can wheel them round to recovery and hand over to the recovery team.
Well done you.
Share the Stress
It's very easy to feel that the entire anaesthetic responsibility is on your shoulders, especially when you go on call for the first time.
While it is true that you are rather responsible for the wellbeing of the stranger that you've just rendered unconscious and paralysed, remember that you have a team to help you.
- Your ODP probably qualified before you were born
- The scrub nurse has done more anaesthesia than you by a factor of twelve
- The theatre support worker knows instinctively when something doesn't look right
If you're worried, or think you might be missing something, just ask and you will receive help immediately. You are never really on your own, and everyone in the room wants to help you do your best for the patient.
After I've intubated, I frequently ask my ODP "Do you think I'm missing anything?" just to sense check my work and ensure they're happy with what I'm doing. It opens up the dialogue, and on more than one occasion I have received a very sensible and helpful reply such as,
"Maybe some sevoflurane?"