Fun Friday Quiz

SS_OB 1.10, BT_RA 1.2

I don’t have time to post regularly at the moment, but I couldn’t overlook such a beautiful illustration of physiology & pharmacology.

Screenshot 2021-05-21 at 14.25.51

This is part of the anaesthetic chart from a patient having caesarian section under SA. The black line is heart rate, the red bars NIBP and the green line is plethysmograph amplitude.

Why is the pleth amp so low on the left side of the graph?

Delivery was the time marked by the orange arrow. Which of the following drugs could have caused the observed changes? Bonus marks if you can explain why.





Acute Pain Scientific Evidence 5th ed is out

BT_PM 1.22

This is a weighty tome and no-one would expect you to read it cover to cover. It does, however, have really good sections describing the individual drugs, pharmacogenetics and drugs in pregnancy and lactation. The range of opiates described should also give you an idea of the spread of drugs used across different hospitals.

T/F tramadol is an effective against neuropathic pain

T/F thirty percent of the effect of tapentadol is from seretonin re-uptake inhibition

T/F buprenorphine has a ceiling effect for analgaesia, but not respiratory depression

T/F respiratory depression from buprenorphine cannot be completely reversed with naloxone

T/F sufentanil has an active metabolite, nor-sufentanil which causes antanalgaesia

Answers in APSE 5th ed section 4.3

Sending you best wishes

I recall that ladybirds are a symbol of good luck. I love them because they eat the aphids on my roses. May many ladybirds be shining on you during the vivas….

Sorry that this is a super last minute post, but I wanted to send a big dose of best wishes to the New Zealand and NSW candidates who will be sitting the vivas over the next few days.

For many of you it has been an unexpectedly long and drawn out process. You are almost at the end now. Time to wow the examiners and then you are done!

I will be thinking of you all and will raise a virtual toast to you for making it to this point in what has been an extraordinary year.

Very best wishes to you all!

Best wishes for the exam

Perhaps in the next couple of days you could take a walk on a quiet beach, like the kangaroo who left these prints on aptly named Kangaroo Island

For those of you who have chosen to sit the ANZCA primary exam this month, my very best wishes for you with the written component on Tuesday.

I hope those of you sitting have been able to maintain the focus on your studies amid the very unsettled world we find ourselves living in.

Perhaps today and tomorrow are a time to do something solely for you. What is possible will obviously differ depending on where in Australasia you live, but something enjoyable and relaxing doesn’t need to be done far from home.

I have previously written a post on the benefits of taking a short break before the exam It seems as though that post was written in a different world, but the message still holds true.

I will be thinking of you all on Tuesday – best wishes.

You are in my thoughts

KAWS exhibition at the NGV last year

We are living in a very topsy turvey world at the moment and I really feel for those of you preparing for the exam. We as human beings are poorly equipped to deal with uncertainty and yet that is what we a faced with constantly at the moment.

Today I thought I would give you links to some study tips I have posted in the past. Many of them relate to our own behaviours and habits, which are things which we still have control over.

Please remember that if you need extra help at this time, ANZCA provides access to free psychological support. Do not hesitate to access this service if you think it will benefit you in the run up to the exam.

Aim to pass the exam rather than avoid failing it – in this post I discuss the influence of a positive emotion on success and there are some tips on how to cultivate these emotions..

Study tip – avoid getting too much of a good thing… – this post talks about the double edged sword of stress. In the current climate, I think that we all need to be consciously addressing our stress levels in order to maintain ourselves in a constructive zone.

Study Tip: Gain knowledge and understanding, not familiarity  – in addition to those who are sitting the exam for a second or subsequent time, this post may be worthwhile for those of you coming back to your studies, by preparing for the vivas, having sat the written in exam in March.

The Primary Exam in just one step on a lifelong path  The words of this post, although initially intended for those who had been unsuccessful in the exam, may provide solace for those of you who feel stuck in limbo this year and had your exams and/or training plans disrupted.

I hope that all of you are able to find some moments of joy in your lives this weekend. Please know that you are all in my thoughts…

2020.1 SAQ 15 Ageing and the respiratory system

I recently visited Kangaroo Island which was ravaged by bushfires earlier this year. One thing that has flourished amidst the devastation is the grass tree. They are very slow growing, so these beautiful specimens are old but doing all they can to ensure the species survives.

Discuss the effects of ageing on the respiratory system.

Increasingly, we are having to anaesthetise older and extremely old patients. It is important to know how their physiology differs from younger patients in order to deliver the best possible care.

BT_PO 1.37 Discuss the effect of ageing on ventilation

There is another post on this topic here and as I mentioned in that post, I think that Nunn’s Applied Respiratory Physiology is the best for this subject (unfortunately the references are dotted throughout the book)

PaCO2 levels rise as a part of normal ageing due to a reduced capacity for diffusion T/F

PaO2 levels fall gradually as part of the normal ageing process T/F

The ventilatory response to hyercapnoea is blunted with ageing T/F

Compliance of the chest wall decreases with ageing due to decreased mobility of the costochondral joints T/F

FRC decreases as part of the normal process of ageing T/F

Static compliance of the lungs falls with advancing age T/F

2020.1 SAQ 14 Adverse effects of neostigmine

This photo was not taken by me. I found it at The Toxicologist Today. It is a photo of the beautiful Amanita muscaria which will produce many, but not all, of the same side effects as neostigmine.

Describe the adverse effects of neostigmine.

Another drug we use on a daily basis (at least where I work as sugammadex is deemed too expensive for routine reversal).

Over 15 yrs ago, (but still seared on my brain) I made one of the 3 drug errors I know of. I gave a baby a 5x excess dose of neostigmine having mistakenly drawn up my calculated volume from the adult rather than baby sized ampoule. One side effect was prominent. What do you think it would have been? It responded very quickly to atropine, which I assumed I had forgotten to give. It was only on inspection of my ampoules once the situation had resolved that I discovered my mistake…

You will find decent information on this topic in any pharmacology text.

BT_GS 1.40 Describe the adverse effects of anticholinesterase agents 

Neostigmine will slow the breakdown of ACh throughout the body T/F

Neostigmine will produce weakness via actions at the NMJ regardless of the dose used T/F

Bradycardia is main effect of neostigmine on the cardiovascular system T/F

Neostigmine is highly lipid soluble, so seizures are likely to occur when large doses are given T/F

Neostigmine may cause diarrhoea T/F

Patents taking neostigmine have an increased risk of acute angle glaucoma T/F

There is another post on this material here if you want some more practice.

2020.1 SAQ 13 Intravenous agent kinetics

Very much awake – my younger daughter who turns 16 today!!

Describe the time course between an intravenous injection of a general anaesthetic agent to loss of consciousness. Explain the delay using pharmacokinetic principles.

This is core business for us. You need to understand this material really well. It is also excellent material for the vivas (but bear in mind that there will not be overlap between material examined in an SAQ paper and the corresponding series of vivas)

For such a core area, the textbook coverage of this is not great. I suggest Ch 2 in Hemmings and Egan Pharmacology and Physiology for Anaesthesia.

BT_GS 1.12 Explain and describe the clinical application of concepts
related to intravenous and infusion kinetics including:
 Effect-site and effect-site equilibration time
 Concept of context sensitive half time
 Calculation of loading and maintenance dosage

BT_GS 1.30 Describe and compare the pharmacokinetics of intravenous
induction and sedative agents

Loss of consciousness (LOC) requires the effect site concentration of the agent to reach certain ‘threshold’ concentration T/F

Drug must transfer from the central compartment to the effect site in order for LOC to occur T/F

In general the longer the t1/2keo the faster the onset of LOC T/F

The time taken for loss of consciousness is equal to the time to peak effect T/F

Giving a larger dose of the drug will speed LOC by shortening the time to peak effect T/F

A low cardiac output state will slow time to loss of consciousness as delivery of drug to the effect site is slowed T/F

If you want to have a play around with some PK parameters and see how they alter plasma and effect site concentration then have a look at this site developed by PrimaryLOs

2020.1 SAQ 12 BMV resuscitation device

Here is a diagram of a typical one of these devices

Using a labelled diagram, describe how a self inflating bag-valve-mask resuscitation device works.

Found on the back on every anaesthetic machine and available on every ward. This is an essential piece of equipment which you should be able to troubleshoot.

Although not on the recommended reading list, this article provides a nice description of the two most common modern devices

BT_SQ 1.14 Describe different systems to deliver supplemental oxygen and the advantages and disadvantages of these systems

The self inflating bag is dependent on an external oxygen source to enable reinflation of the reservoir bag T/F

There is only a single one way valve present in the modern bag- valve-mask resuscitator T/F

Most devices include a pressure limiting valve which prevents delivery of very high inspiratory pressures T/F

Very minimal rebreathing occurs with normal function of these devices T/F

Oxygen flows directly into the self inflating bag T/F

These devices are foolproof and cannot be assembled incorrectly T/F

If you are interested in reading more about the development of these devices I suggest that you read this post written by Vallecula last year.

2020.1 SAQ 11 Metabolic fate of dextrose

Many years ago now I made this cake on special request by one of my daughters for her 3rd birthday. A bit more than 25g of dextrose in this one I think!

An infusion of 50 mL of 50% dextrose is given to a healthy 70kg adult. Describe the possible metabolic pathways for the dextrose.

We give people dextrose quite commonly. What happens to the sugar? This is the same amount of dextrose as is in 500mls of 5% dextrose it that is conceptually easier for you.

BT_PO 1.85 Explain the control of blood glucose 

Glucose is taken into the liver by glucose transporters that are present regardless of insulin levels T/F

The fate of the glucose is independent of the fasting status of the patient T/F

Conversion of glucose to pyruvate through glycolysis provides 2 molecules of ATP without the requirement for oxygen T/F

In the presence of insulin, glucose will be taken into muscle cells and be converted to glycogen T/F

The capacity to store glycogen is unlimited T/F

Excess glucose may be converted to fatty acids in the liver T/F

There has been a previous post on similar material here if you are after a few more statements to test yourself