Most anaesthetists probably remember the first time they heard the ‘death spiral’. This is a colloquial term used for the lowering pitch of the pulse oximeter tone as the oxygen levels fall. Once learnt, it becomes an unforgettable and daily part of your anaesthesia practice.

I was thinking about all the non visual cues that I’ve learnt over the years and realised that many of these are not obvious and often take time to learn.

If you only rely on what you see, you may miss a great deal of what is happening and react slowly to an unfolding crisis. After all, your eyes can only focus on a small area at any one time, whereas your ears are able to take in all the sounds in your vicinity. With time, you’ll find that you can rapidly react to an unfolding issue even before you see it.

Here are a few of the non visual cues that are of critical importance.

The surgeon

Each surgeon has a certain style, whether it’s surgical technique, manner, speech etc. One thing that becomes very obvious is the change in voice when something is not going well.

They may talk louder, faster, more abruptly, with more profanity or even become deathly quiet. These are cues that you need to pay closer attention to the patient, surgeon and your monitor and perhaps ask directly if everything is okay.

The suction

This little device sounds like a constant hum in the background during surgery. As it is used for suction of fluids (i.e. blood) it is critically important that you pay close attention to this sound. It signal the start of catastrophic blood loss and the need for rapid replacement of blood products and cardiovascular support.

During caesarean section, the loud suctioning of amniotic fluid signals surgical entry into the uterus and is an indicator that the baby is being delivered. At this point you need to consider uterotonic administration (oxytocin).

The pulse oximeter or ‘sats probe’

This amazing device conveys much valuable information. Each sensed pulse produces an audible tone. This tone changes in pitch if the oxygen saturation changes. For example, if the oxygen levels fall from 99% to 90%, the tone will drop in pitch as the saturations fall. This is an incredibly useful signal to notify the anaesthetist that the oxygen levels are falling even when they are performing another task.

The pulse oximeter tone also gives an indication of heart rate (as does the ECG and arterial line).

Your ability to rapidly detect a sudden bradycardia could mean the difference between treating a heart rate of 20 or asystole.

Likewise imagine a sudden rise in heart rate. The patient may be too ‘light’ or require analgesia. The difference in detecting this quickly may mean preventing awareness or the patient moving suddenly.

Monitor alarms

This is the most obvious non visual cue. I won’t say too much except that there is an incredible amount of research that has gone into ensuring how alarms are programmed. They are of a certain pitch, volume and frequency to ensure they are the optimal balance of a few things. They must notify the clinician, but not contribute to excess noise pollution or lead to habituation.

It is vital that as a anaesthetist you are comfortable setting the thresholds for your alarms that are appropriate to each patient. For example, if the default blood pressure alarm activates at 80mmHg, this could be unsafe for a hypertensive patient with severe aortic stenosis who needs a higher coronary perfusion pressure. Reprogram each alarm that is crucial for your particular patient.

If there are any other nom visual cues that you find useful, please post or comment below!

It seems that regional anaesthesia is somewhat past its heyday. 

Many hospitals have adopted other techniques for pain management in operations that were once common practice grounds for regional, hospitals don’t have the systems set up to facilitate fast turnover and having sufficient time for regional anaesthesia onset and there are no studies to prove convincingly any long term morbidity or mortality benefit. 

However in my experience this is one of the most incredibly useful skills in your anaesthesia quiver!

There will be many times in your career that you will be required to anaesthetise an incredibly sick patient for a peripheral/limb procedure. 

Imagine a patient from ICU requiring an urgent open reduction and fixation of his fractured ankle. He is 150kg, on BIPAP for pneumonia, heart failure with EF30% and saturating at 90% due to his severe COPD. Performing a general anaesthetic for this operation is definitely an option and will require a lot of prep time and may result in airway management difficulty, CVS instability and oxygenation risks. And this situation isn’t that uncommon! It will arise time and time again whether it’s an upper limb procedure, lower limb procedure or the elective arterio-venous fistula in a sick renal patient. 

I would argue your ability to perform effective regional anaesthesia improves welfare for the patient and ease of providing effective anaesthesia for you and your team!

So with fewer opportunities to provide regional anaesthesia how do you gain enough experience? If practice makes perfect how do you get enough practice?

It is vital to manufacture practice and create opportunities!

What do I mean? Well there are a few select skills with ultrasound (US) guided regional anaesthesia that you can master even with minimal practice at actual regional anaesthesia. ‘Chunking’ these skills and practising them separately is one of the best ways to learn difficult and uncommon techniques

These skills are:

1. US scanner competence
2. Sono-anatomy mastery
3. US-Needle coordination

US scanner competence

• Bring out the US scanner at every opportunity to scan nerves, veins, arteries and hearts
• Learn a systematic way of improving your image. 
  • Select the correct probe
  • Select the depth
  • Optimise the gain (how much signal or ‘whiteness’ comes back)
  • Select the focal point
  • Probe manipulation: practice sliding, tilting, rotating and translating

Sono-anatomy mastery

Sono-anatomy is like exploring a new neighbourhood. The first few times everything is unfamiliar and you won’t recognise much. You then decide to buy a map and explore your new neighbourhood every day and suddenly you will start to recognise signs, roads, laneways and your favourite cafes and shops. 

The way I increased my familiarity with the sonoanatomy neighbourhood was to scan a patient every day. My map was Ultrasound Imaging for Regional Anaesthesia from www.usra.ca/education/booklet.php (electronic copy available on iTunes). This is an exceptional resource, which shows the labelled cadaveric and sono-anatomy so you can trace the nerves from proximal to distal in the upper and lower limb. 

Put a probe on the consented patient and try the following. For your lower body cases try tracing the brachial plexus from the interscalene, to supraclavicular, infraclavicular and axillary views and then trace the terminal nerves (ulnar, median and radial) from axilla to the wrist. Likewise during your upper body cases you can ‘walk’ around the lower limb sono-anatomy neighbourhood tracing the femoral nerve and sciatic nerves. Use Ultrasound Imaging for Regional Anaesthesia to show you the relevant structures.  

After doing this a few times you will gain familiarity of the  

• nerve plexuses
• nearby structures, 
• the way nerves often follow vascular structures and
• the way they differ from tendons and muscles.
• With even more experience you will notice the inter-patient variability and abnormal anatomy. This becomes increasingly relevant when you notice that some patients are difficult to block because they have aberrant nerves, tissue/septae that divide plexuses or vascular structures running nearby.

Another great way to have guided practice is to sign up to one of the many US regional anesthesia short courses. 

Other useful resources include:

• www.nysora.com
• www.asra.com
• AnSo app

US needle coordination

There are many techniques that are common in anaesthesia and enable us to practice US needle coordination. After you have mastered cannulation try performing cannulation with US guidance. This is a great way to improve your success with difficult cannulation but also a great way to learn how to coordinate your needle manipulation in one hand and the US probe in the other. 

Other slightly advanced techniques to improve US coordination are US guided arterial line insertion and central line insertion.

In my experience there were some relatively common opportunities for US guided regional anaesthesia. The fascia iliaca blockand femoral nerve blockare considered relatively safe and easy techniques and where I developed most of my skills in US coordination. They are superficial, the landmarks are easy to find, have few critical structues and inadvertent vascular puncture can be compressed to stop a haematoma. When clinically indicated, do these regional blocks with US guidance.

So there is it! My method for trying to increase your learning curve, when your learning opportunities might be few and far between.

Any questions or comments please email me 

Anaesthesiacollective@gmail.com

https://riskcalculator.facs.org is an exceptional resource to provide reasonably accurate and patient specific risk information to help guide your perioperative decision making.

This calculator uses a series of 20 questions and the surgical procedure to provide 18 different outcomes within 30 days of the procedure. These include risk of death, serious complications and even the chance of whether the patient will need postoperative rehab.

Before this calculator existed I felt that I had a lack of insight into the risks outside of the intra-operative anaesthesia risk. As anaesthetists, we rarely follow up our patients and may not be aware of the patient’s risk a month after the operation. Even our surgical colleagues may not have great data on their patient’s risk profile on such a large scale.

This calculator was built using data from over ‘4.3 million operations in over 730 participating hospitals from 2013-2017‘

I find the calculator most useful when I have a particularly unwell patient. I am able to quickly plug in the requested data points and then assess the risk. Have a look at the risk profile below for this imaginary elderly male undergoing a laparoscopic cholecystectomy.

I find this incredibly useful information to guide my perioperative management and providing informed consent to the patient.

For example I may

• refer to HDU/ICU preop
• discuss risk factor modification and use it as a ‘teachable moment’
• use the data to highlight how high risk (or low risk) something might be to a patient or colleague who has a different opinion on the risk level
• plan post op nursing or rehab requirements
• choose to recommend a particular operation in a centre with ICU/cardiology support
• discuss the risks and benefits with more evidence than limited by my own experience

any questions please comment below!