Patient of the week – 2

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Another piece for the V&A, this made entirely from cutlery (I am drawing a long bow for today’s post)

Here is another case in this sporadic series

Some months ago I looked after a young patient who had been retrieved following a machete injury near the shoulder, resulting in almost total amputation of the arm. The injury had occurred some hours previously, with the patient left at the side of the road.

He had been intubated by the retrieval team at the scene.

On arrival to the Emergency Department his potassium level was 6.5 mmol/L

BT_GS 1.38

Normal serum potassium rise following an intubating dose of suxamethonium is 1.5mmol/L TRUE/FALSE

BT_PO 1.72

ECG changes associated with hyperkalaemia include tall peaked T waves and a shortened PR interval. TRUE/FALSE

He was taken to theatre to reattach the arm. He was hypovolaemic and anuric.

I set about trying to lower his serum potassium and restore his blood volume.

BT_PO 1.40

Salbutamol may be detected as halothane when nebulised within the circle circuit TRUE/FALSE

BT_PO 1.72

Calcium gluconate is used in the  management of hyperkalaemia as it lowers serum potassium TRUE/FALSE

BT_RT 1.9

Hyperkalaemia and hypercalcaemia are potential metabolic consequences of massive transfusion    TRUE/FALSE

To be honest, nothing I tired (and I tried a lot of everything I could think of, short of starting dialysis) lowered his potassium at all. But at least it didn’t increase any further. He survived the reimplantation  and was transferred to ICU for further management, including some much needed haemodialysis.

BT_RT 1.17 and 1.18 Adrenaline in shock and resuscitation

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Not sure that these fit the topic, but they were beautiful and I am a sucker for a rainbow (viewed at the V&A). I think these would give you a surge of dopamine rather that adrenaline, but we will save that for another day…

The current ARC guidelines (see 11.5) provide a very minimalist approach to drug therapy in cardiopulmonary resuscitation, emphasising the importance of high quality and minimally interrupted CPR. However of the couple of drugs left, adrenaline in front and centre.

BT_RT 1.17 With reference to the management of shock, describe the pharmacology of vasopressors and inotropes, including:

adrenaline,

and lots of other drugs (click on the link to view them)

BT_RT 1.18 With reference to cardiopulmonary resuscitation, describe the pharmacology of

adrenaline,

vasopressin,

amiodarone and

lignocaine

 

During cardiac arrest, adrenaline has a role in the treatment of both shockable and non shockable rhythms     TRUE/FALSE

Adrenaline has been shown to improve the chances of return of spontaneous circulation in arrest situations   TRUE/FALSE

Adrenaline is useful in the treatment of anaphylactic shock, in part, because it prevents further mast cell degranulation  via a beta mediated response TRUE/FALSE

Adrenaline may improve myocardial blood flow in low flow states as it causes aortic diastolic pressure to rise   TRUE/FALSE

If giving adrenaline via the endotracheal tube, the dose should be increased by 10 fold TRUE/FALSE

 

BT_RT 1.2 Integrate knowledge of factors determining cardiac output to classify causes of shock

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To fit with today’s theme is this photo of Tippoo’s Tiger, on display at the V&A Museum, London. This wind-up piece has an organ inside and when the handle was turned it supposedly “imitated the European victim’s dying wails of agony” – delightful! It was found in the music room of Tipu Sultan after his death in 1799

Let’s knock off another LO before we get started on the core business of today –

BT_RT 1.1  Define shock

Shock is defined as a state where tissue perfusion is inadequate to meet the metabolic requirements of that tissue     TRUE/FALSE

Ok, now for the main event. This topic is covered quite well in Oh’s Intensive Care Manual  and Guyton and Hall Textbook of Medical Physiology – details here. I suspect it is well covered in lots of places actually 😉

BT_RT 1.2 Integrate knowledge of factors determining cardiac output to classify causes of shock

All causes of shock are associated with an absolute reduction in cardiac output    TRUE/FALSE

Cardiogenic shock occurs when the heart is unable to pump blood sufficiently to maintain perfusion      TRUE/FALSE

Neurogenic shock and anaphylaxis are both examples of distributive shock  TRUE/FALSE

Anaesthesia may cause neurogenic shock     TRUE/FALSE

Hypovolaemic shock can be used to describe any form of shock where there is inadequate venous return   TRUE/FALSE

 

And finally one last photo of the tiger and its hapless victim…

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BT_SQ 1.13 Describe and classify breathing systems used in anaesthesia (episode 2).

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I photographed this little guy in Hong Kong – he’s (or perhaps she’s??) looking bit ragged. Following yesterday’s post I did a bit of research. It tuns out that sea jellies have no breathing system at all. They meet their oxygen requirements through diffusion across their bodies….

Today we will turn our focus to the circle system. This is something most of us use every day. I asked a viva on it in the last exam and was surprised by many of the answers I was given.

The circuit is circular with unidirectional valves – does that mean that gas flows in only one direction throughout the entire system?

BT_SQ 1.13  Describe and classify breathing systems used in anaesthesia. Evaluate their clinical utility and hazards associated with their use

The circle circuit, as commonly used in current anaesthetic practice, is a closed system  TRUE/FALSE

With the standard circle arrangement, fresh gas commonly flows through the CO2 absorber   TRUE/FALSE

Placing the APL valve before the CO2 absorber (on the expiratory limb) helps to conserve the CO2 absorbent  TRUE/FALSE

When running the circle as a closed circuit, minimal gas monitoring is required, as it is a stable system        TRUE/FALSE

A safe circle system requires the fresh gas flow to be placed between the patient and the expiratory valve  TRUE/FALSE

BT_SQ 1.13 Describe and classify breathing systems used in anaesthesia.

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What sort of  breathing system do those guys have? Certainly none of the ones we will be discussing today…

Today I will focus on the Mapleson classification of breathing systems. Here is an article written about them by Mapleson himself. He is still alive and in his 90s. You can read a little more about him here. Textbooks on the ANZCA primary exam reading list generally cover this topic adequately too.

BT_SQ 1.13 Describe and classify breathing systems used in anaesthesia. Evaluate their clinical utility and hazards associated with their use

The Mapleson A circuit is more efficient for a spontaneously ventilating patient compared with Mapleson D    TRUE/FALSE

A Mapleson E circuit is also referred to as classic T-piece     TRUE/FALSE

In the Mapleson D circuit the reservoir bag is located off the expiratory limb    TRUE/FALSE

The Mapleson D circuit is more efficient for controlled ventilation (CV) compared with spontaneous ventilation, due to the longer expiratory phase with CV    TRUE/FALSE

The Mapleson C circuit is the most efficient of these systems for spontaneous ventilation TRUE/FALSE

 

Study tip: sit the exam when you’re ready

That may seem like a ridiculously obvious statement.

However, speaking with registrars who have failed the exam, sometimes multiple times, they often say they should not have attempted the exam when they initially did.

I realise that there is an imperative, real or implied, to sit the exam as soon as possible in your training. For the majority of people it is completely feasible to prepare for, and sit the exam within the first two years of Basic Training. However as far as I can see in Regulation 37, which details the requirements for training,  you actually have at least 4 yrs to attempt it.

If you end up at a point where you really don’t think that you are ready to sit the exam, please think twice (or three or four times) before “just giving it a go”.

Now I am not talking about the feeling we all get, where you don’t feel 100% ready to sit the exam. However, you have: put in a very concerted effort with your studies; covered the syllabus; done lots of exam practice; had people review your questions and all the signs are looking good. It is normal to have the heebie jeebies.

I am talking about the situation where, for one reason or another, your exam preparation has been significantly compromised. Perhaps there was more work to do that you realised and you just didn’t leave yourself enough time. There are a myriad of other social and work related issues which can derail an attempt. You may have been avoiding giving people practice questions to look because you don’t want to look silly ( that to me is a sign you are not quite ready – much, much better to get the feedback which helps you improve before you sit the exam, not after you fail)

I would counsel you to NOT just give it a go for the experience. Wait until you are properly prepared.

We are all highly achieving individuals. It is not in our nature to fail and a lot of you will never have failed anything up until this point of your lives. Do not underestimate how psychologically devastating it is to fail something, even when you have convinced yourself you were not going to pass in the first place. I do not know one person who has felt ok with it….

Statistically, your first attempt at the exam is the one where you have by far the greatest likelihood of passing. Make it you best posssible shot – sit the exam when you are ready.

( A little birdie told me that the applications for the next exam open on Monday ……)

And finally, today’s photo is from my garden. Hope you have a lovely weekend….

BT_PO 1.122 Classify and describe the pharmacology of anti-platelet drugs

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Vallecula suggested that the photo from the other day (quite similar to this one) could have been the wall of the operating theatre due to platelet dysfunction. I liked that description and thought it apt for today’s topic….

Here is a link to the BJA education article on antiplatelet agents. The link above will take you to the post with an article on the physiology. Again these agents will be widely covered in the textbooks…

BT_PO 1.122 Classify and describe the pharmacology of anti-platelet drugs

Both clopidogrel and prasugrel are prodrugs and subject to inter-individual differences in activity due to genetic polymorphism of their metabolic pathways       TRUE/FALSE

Both clopidogrel and prasugrel block the ADP receptor and are hence associated with the same risk of bleeding as each other       TRUE/FALSE

Platelet function returns to normal approximately 7 days after ceasing abciximab  TRUE/FALSE

All GP IIb-IIIa receptor antagonists can produce thrombocytopenia TRUE/FALSE

Low dose aspirin (75 100mg/day) is the only drug which selectively inhibits the COX-1 isoenzyme    TRUE/FALSE

 

Happy Birthday to us!

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(cake via pinterest – yum!!)

It is a year ago today that Dr Primarylos authored the first ever post on this blog.

Since that time: there have been 10 contributors to the blog; we have posted 280 posts; the blog has been viewed almost 33,000 times in 69 countries, across all continents except Antarctica.

Thank you so much for your continued support of our blog. Our aim is to provide a useful resource and I hope that we are doing, and continue to do, that.

As a little bit of a one year retrospective, I have included links to the most popular posts by each of our authors (reverse alphabetical order as those guys never get to be at the top)

woundedwildebeest  Examiner musings on candidacy Pt I

vallecula Study Tip – doing effective revision

transpedanticacid Preparing for the Primary

SpeakNoEvil 8 minutes….

slowwaves BT_GS 1.52 Explain the principles involved in the electronic monitoring of depth of sedation, including EEG analysis.

primarylos Induction Agents BT_GS 1.57  (this is co-incidentally also the first post – that’s cool)

lantanapurpura BT_PM1.18 : neuraxial opioids

devilsadvocate Study Tips: “I keep six honest serving men (they taught me all I knew); Their names are What and Why and When And How And Where and Who.” – Rudyard Kipling, The Elephant’s Child

cynicalanaesthetist Cool books that should be on the ‘Recommended texts for the Primary’ list #2

aGasgal The primary exam does not define you

I found it interesting that many these posts were not actually related to the learning outcomes, but rather study tips or encouraging words. Please do be encouraged – the ANZCA Primary Exam is an exacting one, but is is achievable and your presence here is a positive sign.

Cue the music – let’s celebrate!!

BT_PO 1.112 Describe the physiology of haemostasis, including the role of platelets


This photo is from the Yayoi Kusama exhibition I went to in Washington earlier this year. Each visitor was given a sheet of stickers to place in the room. Aggregated platelets???

This topic will be covered in any physiology textbook, but also a nice overview in BJA Education here.

It seems to be quite a popular in the vivas as it lends itself to integtation of physiology and pharmacology (which I will cover on Thursday)

BT_PO 1.112 Describe the physiology of haemostasis, including:

• Coagulation

• The role of platelets

• Fibrinolysis

von Willebrand’s factor is essential for platelet activation  TRUE/FALSE

Fibrinogen and collagen are both ligands for platelet glycoprotein receptors  TRUE/FALSE

Thrombopoeitin is produced by the liver and kidneys in response to thrombocytopenia  TRUE/FALSE

Glycoprotein IIb -IIIa is important for platelet aggregation. TRUE/FALSE

Platelet activation results in release of light and dense granule contents TRUE/FALSE
I noticed that the link in yesterday’s post was broken – it’s fixed now

BT_GS 1.66 Describe the physiological effects of hypo/hyperthermia

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Kyoto.

We are generally concerned about our patients’ temperature intraoperatively and I have seen the curve that shows how temperature changes during the course of a GA drawn more times than I care to remember, but does it actually matter?

Miller’s Anaesthesia has a whole chapter on thermoregulation and anaesthesia and this old article from BJA education contains a reasonable brief overview of the topic.

BT_GS 1.66 Describe the physiological effects of hypo/hyperthermia

Hypothermia produces a linear reduction in cerebral metabolic rate of approximately 8% per degree Celsius temperature reduction    TRUE/FALSE

Hypothermia results in a reduction in platelet function TRUE/FALSE

Hypothermia directly inhibits the coagulation cascade, but this is often not detected as coagulation is assessed at 37°C     TRUE/FALSE

The duration of action of vecuronium is at least doubled by a 2°C fall in core temperature   TRUE/FALSE

Mild hypothermia has been shown to activate the sympathetic nervous system, which has a protective effect against surgical site infections TRUE/FALSE