Tag Archives: Anaesthesia

Are Anaesthetists Propellor Heads?

I was just reading pearls of wisdom from those Norse Gods of retrieval medicine over at Scancrit.com…a nicely laid out blog with snippets and updates of interest to not just the prehospital doctor but anyone who is involved in anaesthesia and EM, whether in the tertiary centre or out in rural Australia.

In fact, this crisp blog is perhaps what this blog should be – a useful repository of medical information for use in an emergency at 3am. I reckon I’m quite a long way off target, but time will tell.
Anyway, this week’s snippet concerned the ‘Kepler’ robotic intubation system. Now I do think that robots are kind of cool…and it seems I am not alone in this, with the urology surgeons taking up the idea of robotic surgery with enthusiasm.

I am still not convinced that a robot is needed to intubate the trachea…but the ScanCrit docs tell me that they will soon be taking over my work on Kangaroo Island and ‘tele-tubing’ my patients for me from the remoteness of Norway.

More like teletubbies I reckon, but that’s another story…

But it is fair to say that anaesthetists, as a bunch, are ‘propellor heads’. They are the most likely to have an interest in gadgets. Maybe it comes from a training programme that seems to delve uncomfortably deep into concepts such as vaporiser design, laminar flow, Hufners constant and whether or not you can give halothane intravenously (turns out you can, perhaps)
Whatever, walk into any theatre and it will be the anaesthetist who has established a personal wi-fi hotspot so that his/her MacBook, iPhone and iPad can integrate seamlessly. As a rule anaesthetists worship at the altar of all things Apple and are as au fait with the ins-and-outs of Siri as they are with describing multicompartmental pharmacokinetic models of anaesthesia.

I managed to wind up one of the FANZCAs in NSW last year by convincing him that Steve Job’s last bequest to the world before he died was the imminently due iGas workstation, allowing anaesthetists to not only monitor their patient from the tea room using an iPad and wi-fi connection to the iGas anaesthetic machine, but also to have optional remifentanil module. I swear he came in his pants at the thought. Good thing I didn’t mention the ultrasound connectivity…
In the spirit of keeping the anaesthetists happy, I have just stumbled across the following range of theatre caps – ideal for the tech-savvy anaesthetist who doesn’t mind flaunting his or her knowledge. I wonder if they will catch on?

Of course, we all know it’s the orthopods who are really the smart ones.  The paper in the Christmas BMJ last year (‘As strong as an ox and amost twice as clever?’) caused some howls of anguish from the gas board who feared loss of the intellectual high ground. It’s not for nothing we refer to the blood-brain barrier.

Not me. Now whenever the orthopod growls about ‘too much/little blood pressure’ I have carte blanche to say “Well, you’re the clever one – you fix it” and go back to racking up high-scores on Angry Birds.

“ICU is full and this patient is in asystole. And you want to fix their fracture?”

Affordable Difficult Airway Kit

Well, this week I’ve been playing with some AirQ II blocker intubating LMAs (iLMAs) sent to me from a rep.
For those of you not familiar with an iLMA, the device is designed to allow ‘blind’ intubation of the airway, using the laryngeal mask airway (LMA) as a conduit.
The progenitor, with which most rural doctors and anaesthetists will be aware of, is the FastTrach LMA. It’s reported to allow up to 73% ‘first pass’ successful intubation rates, increasing to 90% overall success with repeated attempts and the ‘Chandy manoeuvre’. It’s not a bad piece of kit and we’ve got one on our airway trolley.
However, the FastTrach requires some practice to get used to. I made a point of using it at least once a month during my anaesthetic year, just to get used to the kit. Using equipment in training is quite different to using ‘in anger’, especially when there’s an evolving airway crisis. Problems that I found were
  • not always easy to pass the endotracheal tube into trachea
  • removing the LMA whilst leaving the ETT in situ is fiddly and risks losing both
  • overall success rate is 90% – so 1:10 will fail.
The C-Trach is an advancement on the FastTrach, improving rates for first pass and overall sucess to 96% and 98% respectively – basically this device is just a FastTrach with a video screen attached. Clearly then, addition of video allows visualisation of the cords and improves success rates.
However, neither FastTrach or CTrach allow you to place a nasogastric tube..unless you obturate the ETT and remove the LMA over the top, which is potentially fraght with difficulty.
Cue the AirQ iLMA.
This ‘new improved’ iLMA gets around the problems of FastTrach and CTrach – it’s similar in appearance to the FastTrach iLMA, albeit with a less acute angle. It also has a nifty side-port to allow passage of a nasogastric tube without having to remove the iLMA
Moreover, the device comes with dedicated nasogastric ‘blockers’ – an NG tube with an oesophageal balloon which can be inflated in the oesophagus to minimise aspiration risk and yet allow decompression of the stomach.
I tried it the other day in theatre and found it easy to use. As an LMA it functioned perfectly well, although I have heard some anecdotal evidence of increased supraglottic trauma with this device.
How then to improve success rates for passage of an ETT? Minh le Cong has described this elsewhere – use of a malleable intubating stylet such as the Levitan FPS allows visually-aided intubation through the iLMA conduit.
So we now have a staged procedure for the nightmare difficult airway where intubation has failed or priority is to oxygenate
  • drop in an AirQ II and ventilate
  • pass the oesophageal blocker to decompress the tummy
  • use a fibreoptic device to intubate through the iLMA, improving intubation rate
This strategy (fibreoptic intubation through an iLMA) is Plan B of the UK’s Difficult Airway Society algorithm. Yet how many of us are really prepared to do this and have practiced on kit? Most rural docs have access to a FastTrach…so ventilation and blind intubation are possible – yet the addition of an NG tube port and allowance of fibreoptic intubation seems to offer a higher standard of care. Of course, for many small hospitals fibreoptic devices have traditionally been out of range – high cost and difficulty acquiring and maintaining skills.
But for under $3K you can pick up a Levitan scope (malleable fibreoptic intubating stylet) or the Ambu Ascope II (five disposable flexible fibreoptic scopes). They may not be as good as the fibreoptic towers that people use for an awake fibreoptic intubation…but they are bloody good gadgets to use with the above technique.
So, what would be my preferred kit for a ‘difficult airway’? Well, I’d use the Difficult Airway Society (UK) and ANZCA T04 guidelines as a starting point…and in addition to the AirQ and some sort of fibreoptic device, I’d add in a videolaryngoscope. Sounds expensive? Well my suggestions for purchase are in square brackets below – for under $4K should be affordable for small rural hospitals…
Plan A – Initial Intubation Strategy
Standard laryngoscopy – if fail, change position, blade, operator. Consider use of a videolaryngoscope in case of difficult airway. If fail, move to…
[KingVision Videolaryngoscope ~ A$1000 inc. blades]
Plan B – Alternative Intubation Strategy
iLMA to maintain oxygenation and ventilation, then secure airway using fibreoptic intubation through iLMA. If fail, move to…
[AirQ II iLMAs A$30 each]
[either Levitan FPS or AmbuAscope II fibreoptic devices to intubate through iLMA]
Plan C – Maintain Oxygenation & Ventilation, Abandon Procedure and Wake Up
Bag-mask ventilation and reverse non-depolarising neuromuscular blocker (suggamadex for rocuronium) or wait for suxamethonium to wear off. If fail, move to…
[Rocuronium for RSI – prolong time to desat]
[Suggamadex to reverse rocuronium]
Plan D – Rescue Techniques for Failed Oxygenation & Ventilation
Bag 1 – Paediatric or Easy Anatomy
Needle Cricothyroidotomy technique

Bag 2 – Adult or Easy Anatomy
Scalpel-Bougie-ETT technique

Bag 3 – Impossible Anatomy
Scalpel-Finger-Needle technique
[Melker Kit]
I wouldn’t bother with the pre-packaged kits like QuickTrach or Seldinger kits as first line for CICV – in the heat of the moment, faffing around with wires etc can be a disaster. Better to have three equipment bags set up as above using standard equipment – oxygenate first – then move on to seldinger or formal tracheostomy. Some have commented that doing the above is sufficient to ‘save the day’ then either wake up the patient or proceed to successful laryngoscopy.

Tracheal Trauma

When I was a young lad, one of the things that would excite me was stories of pirates and murderous ‘cut-throats’. At the age of ten, the idea of a ‘cut throat’ was somehow synonymous with a quick death. Fast wind forward a decade or so (ahem, well maybe more) and I’m reflecting on some of the more interesting cases of 2011.

One was a young man involved in a ‘glassing’ in the local pub. He presented to the ED via ambulance, maintaining his own airway but with an obvious zone 1 neck injury. Now, I teach in the animal lab on EMST courses and it amazes me how difficult it can be to identify the appropriate place to perform a tracheostomy. We aim for the cricothyroid membrane, but I’ve seen FACEMs bugger it up completely and transect the trachea (even once the oesophagus and damn near severe the vertebral column!)

Anyhow, this chap’s assailant had obviously either been on an EMST course or had performed percutaneous tracheostomies in the ICU – because with just a broken beer glass, he’d managed to make a perfect incision in the victim’s trachea, between 2nd and third tracheal rings. OK, not the cricothyroid membrane, but otherwise a damn near perfect tracheostomy!

So we took him upstairs and performed an awake fibreoptic intubation with a surgeon scrubbed and ready to perform a tracheostomy. And the patient did OK (had an injury to posterior tracheal wall with oesophageal perforation confirmed on oesophagoscopy, but no mediastinitis and injury healed over time in ICU).

So I’ve been thinking about these sort of injuries and how best to manage them with my (limited) kit back in the bush. Although reasonably rare, both blunt and penetrating laryngotracheal injuries present difficulties for the rural GP-anaesthetist…as the airway needs to be secured ASAP.

And this is not a hypothetical – such injuries are not uncommon in the bush – the classic is ‘clothes-line’ injury where a quad or trail-bike rider impacts a fencing wire at speed, sustaining tracheal injury. Add to that ‘robust’ sports, the usual gamut of farming and motor vehicle injuries..so the rural docs needs to have some form of game plan on how to manage these. And the ‘exam answer’ for ANZCA may not be applicable for the rural doctor, with limited equipment/backup.

The danger of course is that attempts at direct laryngoscopy may cause complete tracheal disruption, with subsequent passing of the ETT tube down a false passage, development of subcutaneous emphysema, failed ventilation and a spiral down into demise.

Every now and then, one hears of paramedics just popping a suitably sized ETT tube through the hole made in a traumatic tracheostomy – a fine strategy for the penetrating injury, but not available for blunt injury or small penetrating wounds.

How then to approach this? There isn’t a great deal in the literature and my FANZCA colleagues fall back on the ‘awake fibreoptic intubation’ answer…which is fine in the tertiary centre, but impractical in a small rural hospital.

So, what to do when faced with a patient with tracheal injury and needing emergent intubation (let’s assume they are becoming obtunded or failing to keep SpO2 up). My thoughts?

– direct laryngoscopy. May seem controversial, but this is what I am best at and the equipment is readily to hand (ETT/bougie). However DL risks disruption of the larynx/trachea and a false passage, making further attempts at intubation impossible.

– do a formal tracheostomy under local. Sounds fine, especially if can delegate to a surgeon. If I am in luck there may be an ENT surgeon visiting for a fishing trip, otherwise it’s going to be a messy scrabble with a patient who may refuse to lay flat/be combative. Nasty, but potentially do-able with equipment to hand (betadine-gloves-drape-local anaesthetic-scalpel-lots of gauze-retractors-ETT-lots of light-assistant)

– indirect laryngosocopy using videolaryngoscope. I like this idea, as intuitively seems to involve less mechanical distraction of the larynx…and the KingVision allows easy passage of a bougie, then railroad ETT over the top. Parker-tipped ETT to try and avoid any ‘hang up’ at the arytenoids…

– use an iLMA to maintain oxygenation – then intubate with ETT through this using either AmbuAscope or a malleable intubating stylet such as Bonfils or Levitan. To my mind the Ascope seems to offer an advantage here as could use iLMA as a conduit then follow down to carina…ensuring no false passage – then railroad ETT over the top. The shaped intubating-stylets allow one to visualise the laryngeal inlet..but not to insert down to carina, so potentially will intubate through the cords, but suffer false passage further down.

– topicalise the airway and perform an awake fibreoptic intubation. Preferred technique of my FANZCA colleagues, but it’s hard to do enough AFOIs to keep ‘current’. Now is not the best time for a relative novice to be trying!

What do other’s think?

– any thoughts on above?

– gas induction or classic RSI?

– what kit do you have available to assist you, either now..or planned.

Bring it on…